The most common microdeletion syndrome caused by deletion of 22q11.2. Characterized by congenital heart defects, thymic hypoplasia, immunodeficiency, hypocalcemia, and characteristic facial features. Variable expressivity.

A chronic inflammatory skin condition of the pilosebaceous unit characterized by comedones, papules, pustules, nodules, and cysts. Affects 85% of adolescents but can persist into adulthood. Severe forms include nodulocystic acne and acne conglobata with risk of permanent scarring.

A neurodevelopmental disorder characterized by inattention, hyperactivity, and impulsivity. Begins in childhood and often persists into adulthood. Affects approximately 5-7% of children and 2.5-4% of adults globally. Three subtypes: predominantly inattentive, predominantly hyperactive-impulsive, and combined.

Progressive degenerative disease of the macula causing central vision loss. Leading cause of irreversible blindness in adults over 50 in developed countries. Dry (atrophic) and wet (neovascular) forms.

An inherited disorder causing low levels of alpha-1 antitrypsin (AAT), a protein protecting lungs from neutrophil elastase. Leads to early-onset emphysema (especially in smokers) and liver disease. Most common in European populations.

A chronic inflammatory arthritis primarily affecting the axial skeleton (spine and sacroiliac joints), causing pain, stiffness, and potential fusion. A form of spondyloarthritis. Strong association with HLA-B27. Onset typically in young adulthood.

A group of mental health conditions characterized by excessive fear, worry, and related behavioral disturbances. Generalized Anxiety Disorder (GAD) involves persistent, uncontrollable worry about everyday things. Most common mental health disorder.

Chronic inflammatory airway disease causing reversible bronchospasm, wheezing, dyspnea. Affects 262 million globally. Can be life-threatening during severe attacks.

The most common sustained cardiac arrhythmia, characterized by chaotic electrical activity in the atria leading to irregular ventricular response. Increases risk of stroke five-fold and heart failure. Prevalence increases with age, affecting ~10% of people over 80.

A complex neurodevelopmental condition characterized by challenges with social communication and interaction, and restricted, repetitive patterns of behavior, interests, or activities. Spectrum disorder ranging from mild to severe. Affects approximately 1-2% of population, more common in males.

A chronic liver disease in which the immune system attacks the liver, causing inflammation and potentially leading to cirrhosis and liver failure. Can occur at any age, more common in women. Often associated with other autoimmune conditions.

A group of disorders characterized by autoimmune destruction of multiple endocrine glands. Type 1 (AIRE gene): mucocutaneous candidiasis, hypoparathyroidism, adrenal insufficiency. Type 2: adrenal insufficiency, autoimmune thyroid disease, type 1 diabetes.

A mental health condition causing extreme mood swings including emotional highs (mania/hypomania) and lows (depression). Formerly called manic depression. Types I and II. Affects approximately 2.8% of adults globally.

A chronic lung condition characterized by permanent abnormal dilation and destruction of bronchial walls, leading to impaired mucus clearance, recurrent infections, and progressive lung damage. Often underdiagnosed. Can be post-infectious or associated with underlying conditions.

A clouding of the normally clear lens of the eye, leading to decreased vision. Most commonly age-related but can be congenital or secondary to other conditions. Leading cause of blindness globally but highly treatable.

An immune-mediated enteropathy triggered by gluten ingestion in genetically susceptible individuals (HLA-DQ2 or DQ8). Autoantibodies (tTG-IgA) cause villous atrophy in small intestine. Associated with dermatitis herpetiformis and increased lymphoma risk.

Progressive, irreversible loss of kidney function over months to years. Stage 4 (eGFR 15-29 mL/min) and Stage 5/end-stage renal disease (eGFR <15 mL/min or dialysis). Requires renal replacement therapy. Leading causes: diabetes and hypertension.

The most common adult leukemia in Western countries, characterized by clonal proliferation of mature B lymphocytes. Often indolent with watchful waiting for early stage. Median age at diagnosis 70 years. Can transform to aggressive Richter syndrome.

A progressive inflammatory disease of the pancreas causing permanent structural damage and loss of function. Characterized by chronic abdominal pain, exocrine insufficiency (malabsorption), and endocrine insufficiency (diabetes). Most commonly caused by alcohol.

A rare autoimmune disorder causing progressive weakness and sensory loss due to immune-mediated demyelination of peripheral nerves. Chronic counterpart to Guillain-Barré syndrome. Requires ongoing treatment to prevent progression.

End-stage liver disease characterized by replacement of normal hepatic architecture with fibrosis and regenerative nodules. Results from chronic liver injury. Irreversible but progression can be halted.

An extremely painful primary headache disorder characterized by severe unilateral orbital, supraorbital, or temporal pain lasting 15-180 minutes, occurring in clusters (periods of frequent attacks). Known as 'suicide headache' due to intensity. More common in men.

Chronic progressive condition where heart muscle cannot pump enough blood to meet body needs. End-stage of many cardiac diseases with poor prognosis.

Advanced chronic obstructive pulmonary disease (GOLD grades 3-4, FEV1 <50% predicted). Characterized by persistent respiratory symptoms and airflow limitation. Third leading cause of death globally. Severe disease significantly impairs quality of life and increases mortality.

Atherosclerotic narrowing of coronary arteries reducing blood flow to heart muscle. Leading cause of death globally.

Respiratory illness caused by SARS-CoV-2 virus. Global pandemic 2020-2023. Range from asymptomatic to severe pneumonia, ARDS, death. Long COVID affects millions.

Persistent symptoms following acute COVID-19 infection, lasting weeks to months after initial recovery. Affects multiple organ systems. Estimated 10-30% of COVID-19 survivors develop long COVID. Symptoms can be debilitating and fluctuating.

A rare, fatal prion disease causing rapidly progressive dementia. Sporadic CJD (85% of cases), genetic (10-15%), and acquired/variant (<1%). Caused by misfolded prion protein (PrP^Sc) leading to spongiform changes in brain. Always fatal within months.

A type of inflammatory bowel disease (IBD) causing chronic inflammation of the gastrointestinal tract from mouth to anus, most commonly affecting the ileum and colon. Transmural inflammation can cause strictures, fistulas, and abscesses.

Formation of a blood clot in a deep vein, usually in the legs. Can lead to pulmonary embolism, a life-threatening complication. Part of venous thromboembolism (VTE). Requires immediate anticoagulation.

Cognitive decline caused by impaired blood flow to the brain, typically from strokes or small vessel disease. Second most common dementia after Alzheimer's. Often coexists with Alzheimer's (mixed dementia). Stepwise progression correlating with vascular events.

An autoimmune condition where the pancreas produces little or no insulin. Previously known as juvenile diabetes, it typically appears during childhood or adolescence but can develop in adults. Requires lifelong insulin therapy.

A chronic metabolic disorder characterized by high blood sugar, insulin resistance, and relative lack of insulin. The most common form of diabetes, accounting for 90-95% of cases. Often preventable and sometimes reversible with lifestyle changes.

A diabetes complication affecting the eyes, caused by damage to blood vessels in the retina. Leading cause of blindness in working-age adults. Can progress from mild non-proliferative to proliferative retinopathy with neovascularization.

A chronic, relapsing inflammatory skin condition characterized by intense itching, dry skin, and eczematous lesions. Part of the 'atopic triad' with asthma and allergic rhinitis. Affects up to 20% of children and 10% of adults. Often begins in infancy.

Chronic neurological disorder characterized by recurrent, unprovoked seizures due to excessive neuronal activity in brain. Affects 50 million people worldwide. Many types: focal, generalized, unknown onset. Often begins in childhood or after age 65.

A condition in which excess fat builds up in the liver, not due to alcohol use. The most common chronic liver disease worldwide, affecting 25% of the global population. Ranges from simple steatosis to nonalcoholic steatohepatitis (NASH) which can progress to cirrhosis.

A chronic disorder characterized by widespread musculoskeletal pain, fatigue, sleep disturbances, and cognitive difficulties. Central sensitization syndrome where pain signals are amplified. Affects 2-4% of population, predominantly women.

Inflammation of the stomach lining. Can be acute (sudden onset) or chronic (long-term). Common causes include H. pylori infection, NSAID use, and excessive alcohol consumption. Can lead to ulcers and increased stomach cancer risk if untreated.

A chronic digestive disease where stomach acid or bile irritates the food pipe lining. Occurs when the lower esophageal sphincter relaxes abnormally or weakens. Affects approximately 20% of adults in Western countries. Can lead to serious complications if untreated.

Diabetes diagnosed for the first time during pregnancy. Affects approximately 2-10% of pregnancies worldwide. Increases risk of complications for both mother and baby but usually resolves after delivery. Women with GDM have 50% lifetime risk of developing type 2 diabetes.

An intestinal infection caused by the parasite Giardia lamblia (also called Giardia intestinalis or duodenalis). Common waterborne disease causing diarrhea, gas, and stomach cramps. Most common intestinal parasitic disease in US.

A group of eye conditions damaging the optic nerve, often due to abnormally high pressure in the eye (intraocular pressure). Leading cause of irreversible blindness worldwide. Primary open-angle glaucoma most common; angle-closure glaucoma is emergency.

A chronic inflammatory arthritis caused by hyperuricemia and deposition of monosodium urate crystals in joints and tissues. Characterized by recurrent acute flares and progressive joint damage. Associated with metabolic syndrome, cardiovascular disease, and chronic kidney disease.

An autoimmune disorder causing hyperthyroidism due to thyroid-stimulating immunoglobulins (TSI) activating the TSH receptor. Associated with Graves' ophthalmopathy (thyroid eye disease) and dermopathy.

Structural abnormalities of one or more heart valves (aortic, mitral, tricuspid, pulmonic) causing stenosis (narrowing) or regurgitation (leakage). Can be congenital or acquired. Aortic stenosis most common in elderly; rheumatic heart disease prevalent in developing countries.

An inherited disorder causing excessive iron absorption and deposition in organs, leading to organ damage. Most common form caused by HFE gene mutations (C282Y). Called 'bronze diabetes' historically due to skin pigmentation and diabetes.

Rare inherited bleeding disorders caused by deficiency in clotting factor VIII (Hemophilia A) or IX (Hemophilia B/Christmas disease). X-linked recessive inheritance affecting primarily males. Characterized by prolonged bleeding after injury, surgery, or spontaneous bleeding into joints and muscles.

Viral infection causing liver inflammation, transmitted via blood. Often chronic, leading to cirrhosis and liver cancer. Curable with direct-acting antivirals (DAAs). 58 million chronically infected.

A viral infection caused by hepatitis C virus (HCV) that causes liver inflammation, potentially leading to cirrhosis, hepatocellular carcinoma, and liver failure. Chronic infection develops in 75-85% of acute cases. Curable with direct-acting antivirals.

A condition where the thyroid gland produces too much thyroid hormone (T3 and T4). Accelerates the body's metabolism, causing unintentional weight loss, rapid heartbeat, sweating, and nervousness. Graves' disease is the most common cause.

A condition where the thyroid gland doesn't produce enough thyroid hormones. Slows down many of the body's functions. Hashimoto's thyroiditis is the most common cause in developed countries. Can occur at any age but is more common in older women.

Viral respiratory infection caused by influenza A and B viruses. Annual epidemics causing significant morbidity and mortality. Vaccine composition updated yearly.

A common functional gastrointestinal disorder affecting the large intestine, characterized by abdominal pain and altered bowel habits (diarrhea, constipation, or both). Brain-gut interaction disorder without structural abnormalities. Affects 10-15% of global population.

Recurrent formation of solid mineral deposits in the kidneys, causing severe pain and potential kidney damage. Affects 1 in 10 people; 50% recurrence rate within 5-10 years without preventive measures. Most common type: calcium oxalate.

A chromosomal disorder affecting males with an extra X chromosome (47,XXY). Characterized by hypogonadism, tall stature, infertility, and variable cognitive/behavioral features. Most common sex chromosome disorder in males.

A myeloproliferative neoplasm characterized by the Philadelphia chromosome (t(9;22)) creating the BCR-ABL fusion gene, leading to constitutively active tyrosine kinase. Chronic phase is indolent; without treatment progresses to accelerated phase and blast crisis.

The progressive form of non-alcoholic fatty liver disease (NAFLD), characterized by hepatic steatosis with inflammation and hepatocyte injury, with or without fibrosis. Can progress to cirrhosis and hepatocellular carcinoma. Now called MASH (metabolic dysfunction-associated steatohepatitis).

A heart rhythm disorder that can potentially cause fast, chaotic heartbeats (torsades de pointes), leading to fainting, seizures, or sudden death. The QT interval on ECG is prolonged, indicating delayed ventricular repolarization.

Malignant tumor arising from lung tissue. Leading cause of cancer death worldwide (1.8 million deaths/year). Two main types: non-small cell (NSCLC, 85%) and small cell (SCLC, 15%). Strongly associated with smoking but affects non-smokers too.

A tick-borne illness caused by Borrelia burgdorferi bacteria. Most common vector-borne disease in US. Transmitted by Ixodes scapularis and Ixodes pacificus ticks. Can affect joints, heart, and nervous system if untreated.

The most common hereditary colorectal cancer syndrome, caused by mutations in mismatch repair genes (MLH1, MSH2, MSH6, PMS2, EPCAM). Increased risk of colorectal, endometrial, ovarian, gastric, urinary tract, and other cancers.

A common but serious mood disorder causing persistent feelings of sadness and loss of interest. Affects approximately 280 million people worldwide, leading cause of disability globally. Can occur at any age.

A malignant tumor of melanocytes, the pigment-producing cells of the skin. The most serious form of skin cancer with high metastatic potential. Incidence rising globally, particularly in fair-skinned populations. Early detection critical for survival.

A disorder of the inner ear causing episodes of vertigo, fluctuating hearing loss, tinnitus, and aural fullness. Caused by abnormal fluid buildup in the inner ear (endolymphatic hydrops). Affects approximately 12-30 per 100,000 people.

A life-threatening infection of the meninges (membranes surrounding the brain and spinal cord) caused by bacteria. Medical emergency requiring immediate antibiotic treatment. Can cause brain damage, hearing loss, and death. Vaccines available for some types.

A primary headache disorder characterized by recurrent attacks of moderate to severe throbbing pain, usually on one side of the head, often accompanied by nausea, vomiting, and sensitivity to light and sound. Can last 4-72 hours. Second most disabling condition worldwide.

A contagious disease most commonly caused by Epstein-Barr virus (EBV). Characterized by fever, sore throat, swollen lymph nodes, and fatigue. Often called 'mono' or 'kissing disease' due to transmission via saliva. Most common in adolescents and young adults.

A chronic autoimmune disease of the central nervous system where the immune system attacks the myelin sheath covering nerve fibers. Characterized by relapsing-remitting or progressive course. More common in women (3:1 ratio) and at higher latitudes.

An autosomal dominant disorder caused by NF1 gene mutations, characterized by multiple neurofibromas, café-au-lait spots, and learning disabilities. Increased risk of malignancies including malignant peripheral nerve sheath tumors.

Complex chronic disease characterized by excessive adipose tissue accumulation (BMI >=35). Associated with metabolic dysfunction, inflammation, and increased morbidity/mortality. Now recognized as relapsing-remitting disease requiring long-term management.

A chronic mental health disorder characterized by uncontrollable, recurring thoughts (obsessions) and behaviors (compulsions) that the person feels compelled to repeat. Often time-consuming and interferes with daily life.

Inflammation of the optic nerve causing vision loss, usually in one eye. Often associated with multiple sclerosis but can occur in isolation or with other demyelinating diseases. Typically affects young adults.

A systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to increased bone fragility and fracture risk. Often called the 'silent disease' because bone loss occurs without symptoms until fracture occurs.

A rare acquired hematopoietic stem cell disorder causing hemolytic anemia, thrombosis, and bone marrow failure due to PIGA gene mutation. Red blood cells lack CD55 and CD59, making them susceptible to complement-mediated lysis.

Open sores that develop on the inside lining of the stomach (gastric ulcers) and the upper portion of the small intestine (duodenal ulcers). Most common cause is H. pylori infection or NSAID use. Affects approximately 4% of the global population.

An inherited metabolic disorder caused by deficiency of phenylalanine hydroxylase, leading to accumulation of phenylalanine. If untreated, causes severe intellectual disability, seizures, and behavioral problems. Newborn screening allows early treatment.

Infection causing inflammation of lung air sacs (alveoli). Can be bacterial, viral, or fungal. Leading cause of death in children worldwide and serious illness in elderly.

A common hormonal disorder affecting women of reproductive age, characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. Leading cause of infertility. Associated with metabolic syndrome and increased cardiovascular risk.

A chronic myeloproliferative neoplasm characterized by overproduction of red blood cells due to JAK2 V617F mutation in most cases. Increases blood viscosity and risk of thrombosis, leading to strokes, heart attacks, and clots.

A chronic cholestatic liver disease characterized by inflammation and fibrosis of bile ducts, eventually leading to cirrhosis. Strongly associated with inflammatory bowel disease (70% of patients). Increased risk of cholangiocarcinoma and colorectal cancer.

A chronic immune-mediated inflammatory skin disease characterized by well-demarcated, erythematous plaques with silvery scale. Affects 2-3% of global population. Associated with psoriatic arthritis, cardiovascular disease, and metabolic syndrome.

A mental health condition triggered by experiencing or witnessing a terrifying event. Characterized by intrusive memories, avoidance, negative changes in thinking and mood, and hyperarousal. Can develop after combat, assault, accidents, or natural disasters.

The most common chronic rheumatic disease in children, characterized by persistent joint inflammation lasting >6 weeks in children <16 years. Multiple subtypes including oligoarticular, polyarticular, and systemic (Still's disease). Can cause permanent joint damage and growth abnormalities.

A multisystem inflammatory disease characterized by formation of non-caseating granulomas, most commonly affecting the lungs and lymph nodes. Of unknown cause, thought to involve abnormal immune response to environmental triggers in genetically susceptible individuals.

Severe chronic mental disorder characterized by disruptions in thought processes, perceptions, emotional responsiveness, and social interactions. Involves positive symptoms (hallucinations, delusions), negative symptoms (apathy, withdrawal), and cognitive impairment.

A life-threatening organ dysfunction caused by a dysregulated host response to infection. Medical emergency with high mortality. Septic shock is a subset with circulatory and cellular/metabolic dysfunction. Leading cause of death in hospitals.

A systemic autoimmune disease primarily affecting exocrine glands, particularly lacrimal and salivary glands, causing dry eyes and mouth. Can affect any organ system (systemic Sjögren's). Strongly female predominance (9:1). Associated with increased lymphoma risk.

A sleep-related breathing disorder characterized by recurrent episodes of complete or partial upper airway obstruction during sleep, causing apneas or hypopneas. Leads to fragmented sleep, daytime sleepiness, and cardiovascular complications. Often undiagnosed.

A bacterial infection of the throat and tonsils caused by group A Streptococcus (GAS). Common in children but can affect all ages. If untreated, can lead to serious complications including rheumatic fever and post-streptococcal glomerulonephritis.

Acute cerebral infarction caused by interruption of blood supply to the brain, typically from thrombosis or embolism. The most common type of stroke (85% of all strokes). Time-critical emergency requiring rapid intervention. Leading cause of disability worldwide.

The most common solid tumor in young men (15-35 years). Two main types: germ cell tumors (seminoma and non-seminoma) and non-germ cell tumors. Highly curable even when metastatic. Associated with cryptorchidism and family history.

A parasitic disease caused by Toxoplasma gondii. Most people experience no symptoms, but can cause serious complications in pregnant women and immunocompromised individuals. Transmitted through undercooked meat, cat feces, and mother-to-child.

Bacterial infection caused by Mycobacterium tuberculosis, primarily affecting lungs but can involve any organ. Leading infectious cause of death worldwide. Latent infection common; active disease in 5-10% of infected.

A chromosomal disorder affecting females with complete or partial absence of one X chromosome (45,X or mosaic). Short stature, ovarian dysgenesis, cardiovascular abnormalities (coarctation, bicuspid aortic valve), and specific learning disabilities.

Autoimmune destruction of pancreatic beta cells causing absolute insulin deficiency. Requires lifelong exogenous insulin. Onset typically in childhood/adolescence but can occur at any age.

Progressive metabolic disorder characterized by insulin resistance and relative insulin deficiency. Accounts for 90-95% of diabetes cases. Strongly associated with obesity and sedentary lifestyle.

An autoimmune condition where the immune system destroys insulin-producing beta cells in the pancreas. Requires lifelong insulin replacement. Onset often in childhood or adolescence but can occur at any age. Strong genetic and environmental component.

A chronic inflammatory bowel disease causing inflammation and ulcers in the innermost lining of the colon and rectum. Limited to continuous mucosal inflammation of the colon. Risk of colorectal cancer increased after 8-10 years of disease.

An inherited disorder causing both hearing loss and progressive vision loss (retinitis pigmentosa). Most common cause of combined deafness and blindness. Three clinical types with varying severity and progression.

An autosomal dominant disorder caused by VHL gene mutations affecting tumor suppressor function. Predisposes to hemangioblastomas (brain, spinal cord, retina), clear cell renal cell carcinoma, pheochromocytoma, and pancreatic cysts.

An autoimmune disorder characterized by loss of melanocytes resulting in depigmented patches of skin and hair. Affects 0.5-2% of global population. Can be segmental (limited) or non-segmental (generalized). Associated with other autoimmune diseases.

The most common inherited bleeding disorder, caused by deficiency or dysfunction of von Willebrand factor (vWF), essential for platelet adhesion and as carrier for factor VIII. Three main types with varying severity.

A group of hereditary disorders affecting tyrosine metabolism. Type I most severe, caused by fumarylacetoacetate hydrolase deficiency. Causes liver failure, renal dysfunction, and neurologic crises. Types II and III less severe with mainly skin/eye or developmental symptoms.

The most common genetic disorder in populations of Northern European descent, causing iron overload due to increased intestinal absorption. Leads to cirrhosis, hepatocellular carcinoma, and liver failure if untreated. HFE C282Y homozygosity most common.

A rare glycogen storage disease caused by glycogen branching enzyme deficiency. Accumulation of abnormal glycogen (polyglucosan) causes progressive liver failure, cirrhosis, and death in infancy or childhood. Also affects muscle and nervous system.

A chronic inflammatory skin condition primarily affecting the face, characterized by facial redness, visible blood vessels, papules, and pustules. Often mistaken for acne or sunburn. Four subtypes: erythematotelangiectatic, papulopustular, phymatous, and ocular rosacea.

A condition in which the eyes do not properly align with each other when looking at an object. One eye may turn in, out, up, or down. Can cause amblyopia (lazy eye) in children. Affects depth perception.

Serious mental health conditions characterized by severe disturbances in eating behaviors and related thoughts and emotions. Types include anorexia nervosa, bulimia nervosa, and binge-eating disorder. Can be life-threatening.

Iron overload disorder causing liver damage. Covered in detail in hematologic section. Primary focus here on hepatic manifestations including fibrosis, cirrhosis, and hepatocellular carcinoma risk.

Cancer that forms in the cells of the breasts. Most common cancer in women worldwide. Can occur in men rarely. Subtypes include ductal carcinoma in situ, invasive ductal carcinoma, and invasive lobular carcinoma. HER2, hormone receptor status important.

Cancer that occurs in the prostate, a small walnut-shaped gland in men that produces seminal fluid. Second most common cancer in men. Most grow slowly; some are aggressive. PSA screening controversial.

The most common type of skin cancer, originating from basal cells in the epidermis. Slow-growing and rarely metastasizes but can cause local tissue destruction. Strongly associated with UV exposure.

The second most common type of skin cancer, arising from squamous cells in the epidermis. More aggressive than BCC with metastatic potential. UV exposure main risk factor.

Cancer that begins in the lining of the uterus (endometrium). Most common gynecologic cancer in developed countries. Type I (endometrioid) associated with estrogen; Type II (serous) more aggressive.

Cancer that begins in the cells of the bladder, most commonly urothelial carcinoma. Smoking is the leading risk factor. Often presents with painless hematuria.

Infrequent bowel movements or difficulty passing stools that persists for several weeks or longer. Can significantly affect quality of life. Various types: normal transit, slow transit, and outlet dysfunction.

A rare esophageal motility disorder where the lower esophageal sphincter fails to relax and the esophagus lacks normal peristalsis. Causes difficulty swallowing and regurgitation. Degeneration of nerve cells in esophagus.

A chronic immune/antigen-mediated disease characterized by eosinophil-predominant inflammation of the esophagus. Associated with food allergies and atopic conditions. Increasing in incidence.

An inherited disorder characterized by hundreds to thousands of adenomatous polyps in the colon and rectum. Without intervention, nearly 100% risk of colorectal cancer. Associated with APC gene mutation.

Rough, scaly patches on the skin caused by damage from the sun's ultraviolet (UV) rays. Considered precancerous lesions that can develop into squamous cell carcinoma. Most common on sun-exposed areas.

A common inflammatory skin condition causing flaky, scaly patches, red skin, and dandruff. Affects areas with many oil glands including scalp, face, and trunk. Associated with Malassezia yeast overgrowth.

An autoimmune condition causing patchy hair loss, typically on the scalp, but can affect any hair-bearing area. Occurs when immune system attacks hair follicles. Can progress to total hair loss (alopecia totalis) or universalis.

A skin reaction caused by contact with an irritant (irritant contact dermatitis) or allergen (allergic contact dermatitis). Causes red, itchy rash. Very common occupational skin condition.

A highly contagious bacterial skin infection most common in young children. Characterized by red sores that quickly rupture, ooze, and form honey-colored crusts. Caused by Staphylococcus or Streptococcus bacteria.

A fungal infection of the feet, particularly between the toes. Common in people with sweaty feet who wear tight-fitting shoes. Highly contagious and can spread to other parts of body.

A viral infection causing a painful rash, caused by reactivation of the varicella-zoster virus (chickenpox). Characterized by a stripe of blisters on one side of the body. Risk increases with age.

A clouding of the normally clear lens of the eye, most commonly due to aging. Leading cause of vision loss worldwide. Develops gradually and affects both eyes, usually one more than the other.

Inflammation of the conjunctiva, the thin clear tissue that lies over the white part of the eye and lines the inside of the eyelid. Can be viral, bacterial, or allergic. Highly contagious in infectious forms.

A complication of diabetic retinopathy where fluid builds up in the macula, the part of the retina responsible for sharp central vision. Leading cause of vision loss in people with diabetes.

A multifactorial disease of the tears and ocular surface resulting in discomfort, visual disturbance, and tear film instability. Can be due to decreased tear production or increased evaporation.

Inflammation of the uvea, the middle layer of the eye consisting of the iris, ciliary body, and choroid. Can be infectious or non-infectious. Serious condition that can lead to vision loss.

A blockage of the small veins that carry blood away from the retina. Can be central (CRVO) or branch (BRVO). Second most common retinal vascular disease after diabetic retinopathy.

A group of conditions affecting the temporomandibular joint, jaw muscles, and facial nerves. Causes pain and dysfunction in the jaw joint and muscles controlling jaw movement.

Inflammation of the bursae, small fluid-filled sacs that cushion bones, tendons, and muscles near joints. Common in shoulder, elbow, hip, and knee. Causes pain and limits movement.

Inflammation or irritation of a tendon, the thick fibrous cords that attach muscle to bone. Common in shoulders, elbows, wrists, knees, and heels. Often due to repetitive motion or overuse.

A tear in the meniscus, the C-shaped cartilage that acts as a cushion between the shinbone and thighbone. Common knee injury, especially in athletes. Can occur with twisting or degenerative changes.

A fatty acid oxidation disorder where the body cannot break down medium-chain fatty acids for energy. Can lead to hypoglycemia, seizures, and brain damage during fasting or illness. Most common fatty acid oxidation disorder.

A common viral illness that causes sores in the mouth and a rash on the hands and feet. Most commonly caused by coxsackievirus A16. Very contagious, especially among young children. Not related to foot-and-mouth disease in animals.

A mild viral illness caused by parvovirus B19, characterized by a distinctive 'slapped-cheek' rash on the face and a lacy rash on the body. Called fifth disease because it was fifth in a historical list of common childhood rash illnesses.

A common viral illness in young children caused by human herpesvirus 6 (HHV-6). Characterized by high fever followed by a rash as fever resolves. Also known as exanthem subitum or sixth disease.

A rare form of vasculitis affecting the large arteries, particularly the aorta and its main branches. Causes inflammation that damages arteries, leading to narrowing, blockage, or aneurysm formation. Affects mainly young women. Called 'pulseless disease'.

Inflammation of the bronchial tubes in the lungs, typically caused by viral infections. Characterized by cough, mucus production, and chest discomfort. Usually self-limiting but can be bothersome. One of the most common respiratory conditions.

A viral infection of the upper respiratory tract, primarily caused by rhinoviruses. The most frequent infectious disease in humans, with adults averaging 2-3 episodes per year. Self-limiting but highly contagious.

Inflammation of the tonsils, lymph nodes at the back of the throat. Can be viral or bacterial (primarily streptococcal). Common in children but can affect adults. May be acute or recurrent.

Inflammation of the sinuses causing facial pain, pressure, and nasal congestion. Usually follows a cold or allergies. Most cases viral; bacterial sinusitis less common. Can become chronic if lasting over 12 weeks.

Middle ear infection, most common in children due to eustachian tube anatomy. Caused by bacteria or viruses. Characterized by ear pain, fever, and possible hearing loss. Major reason for pediatric antibiotic use.

Inflammation of the stomach and intestines caused by viruses (norovirus, rotavirus, adenovirus). Commonly called 'stomach flu.' Highly contagious, causing diarrhea, vomiting, and abdominal cramps. Major cause of morbidity worldwide.

A viral infection affecting the salivary glands, particularly the parotid glands. Causes painful swelling of the cheeks and jaw. Can lead to serious complications including orchitis, meningitis, and deafness. Vaccine-preventable through MMR.

A highly contagious respiratory infection causing severe coughing fits ending in a 'whoop' sound. Most dangerous for infants who may stop breathing. Caused by Bordetella pertussis bacteria. Vaccine-preventable but immunity wanes.

Non-cancerous enlargement of the prostate gland common in aging men. Causes urinary symptoms including frequency, urgency, weak stream, and incomplete emptying. Very common, affecting about half of men over 50. Not related to prostate cancer.

Inflammation of the prostate gland, can be acute or chronic. Causes pelvic pain, urinary symptoms, and sexual dysfunction. Four types: acute bacterial, chronic bacterial, chronic pelvic pain syndrome (most common), and asymptomatic inflammatory.

A contagious skin infestation caused by the Sarcoptes scabiei mite. Causes intense itching and rash as the mites burrow into skin to lay eggs. Spreads through close skin-to-skin contact. Common in crowded conditions and healthcare settings.

Infestation of the scalp hair by head lice. Very common in school-age children. Causes itching but does not spread disease. Not a sign of poor hygiene. Spread through head-to-head contact. Easily treated.

Hard deposits of minerals and salts that form inside the kidneys. Can affect any part of the urinary tract. Cause severe pain when passing. Very common, affecting 1 in 11 people. Often recurrent. Types include calcium oxalate, uric acid, struvite, and cystine stones.

A common bacterial infection affecting any part of the urinary system including kidneys, ureters, bladder, and urethra. Most commonly affects the lower urinary tract (bladder and urethra). Women are at greater risk than men. Recurrent UTIs affect 20-30% of women.

The involuntary loss of bladder control, ranging from occasional leakage to complete inability to hold urine. Affects twice as many women as men, especially after pregnancy, childbirth, and menopause. Not a normal part of aging but becomes more common with age.

The consistent inability to achieve or maintain an erection sufficient for satisfactory sexual performance. Affects approximately 50% of men aged 40-70. Often an early indicator of cardiovascular disease. Can significantly impact quality of life and relationships.

A chronic condition causing bladder pressure, bladder pain, and sometimes pelvic pain. Part of a spectrum of painful bladder syndromes. More common in women. Symptoms often mimic UTI but urine cultures are negative. Cause is unknown but may involve bladder lining defects.

A connective tissue disorder characterized by the development of fibrous scar tissue (plaque) inside the penis, causing curved, painful erections. Affects 3-9% of men, most commonly between ages 45-60. Can significantly impact sexual function and psychological well-being.

A collection of fluid in the scrotum around the testicle, causing swelling. Common in newborns (usually resolves within first year) and older men. Typically painless but can cause discomfort due to swelling. Two types: communicating (patent processus vaginalis) and non-communicating.

Enlargement of the veins within the loose bag of skin holding the testicles (scrotum), similar to varicose veins in legs. Occurs in 15% of men, most commonly on left side due to venous anatomy. Leading cause of correctable male infertility.

A surgical emergency caused by twisting of the spermatic cord, cutting off blood supply to the testicle. Most common in adolescent males (ages 12-18) but can occur at any age. Requires immediate treatment within 6 hours to save the testicle. Affects 1 in 4,000 males under 25 annually.

Inflammation of the epididymis, the coiled tube at the back of the testicle that stores and carries sperm. Most common cause of acute scrotal pain in adults. Can be caused by bacterial infection (sexually transmitted or urinary pathogens) or non-infectious inflammation.

Inflammation of the urethra, the tube that carries urine from the bladder out of the body. Most commonly caused by sexually transmitted infections (chlamydia, gonorrhea) but can also be non-infectious. Affects both men and women, though symptoms are more prominent in men.

An anxiety disorder characterized by recurrent unexpected panic attacks—sudden periods of intense fear that reach a peak within minutes. Affects 2-3% of adults annually. Often associated with agoraphobia (fear of situations where escape might be difficult).

A chronic mental health condition characterized by intense, persistent fear of being watched and judged by others. Goes beyond ordinary shyness. Affects approximately 7% of adults. Often begins in childhood or adolescence. Can severely impact social and occupational functioning.

A highly contagious, vaccine-preventable liver infection caused by hepatitis A virus. Transmitted through fecal-oral route, typically via contaminated food/water or close contact. Usually self-limited with full recovery and no chronic infection. Common in areas with poor sanitation.

A liver disease caused by hepatitis E virus, transmitted primarily through contaminated water. Similar to hepatitis A in transmission and course. Most common in South Asia and East Asia. Genotypes 1 and 2 cause large waterborne outbreaks; genotypes 3 and 4 are zoonotic. High mortality in pregnant women (15-25%).

A bulge or ballooning in the wall of the aorta, the body's main artery. Can occur in the chest (thoracic) or abdomen (abdominal). Life-threatening if it ruptures. Often asymptomatic until complications occur. Associated with atherosclerosis, hypertension, and genetic conditions.

Narrowing of the aortic valve opening, restricting blood flow from the heart to the aorta. Most commonly caused by age-related calcification, congenital bicuspid valve, or rheumatic fever. Progressive disease; severe cases require valve replacement.

A condition where the mitral valve doesn't close tightly, causing blood to flow backward into the left atrium when the heart contracts. Can be primary (valve problem) or secondary (heart enlargement). Leads to heart enlargement and heart failure if severe.

Inflammation of the pericardium, the thin sac surrounding the heart. Causes chest pain and can lead to fluid accumulation (pericardial effusion) or heart compression (cardiac tamponade). Often idiopathic but can follow viral infections or autoimmune conditions.

Inflammation of the heart muscle (myocardium) that can weaken the heart and affect its electrical system. Often follows viral infections but can be autoimmune or drug-related. Can cause heart failure, arrhythmias, or sudden cardiac death.

A genetic condition causing abnormal thickening of the heart muscle, particularly the left ventricle. Most common cause of sudden cardiac death in young athletes. Can obstruct blood flow (obstructive HCM) or not (non-obstructive).

Narrowing of peripheral arteries, usually in the legs, due to atherosclerosis. Reduces blood flow to limbs causing pain with walking (claudication). Strong marker for cardiovascular disease elsewhere. Increases risk of heart attack and stroke.

Infection of the inner lining of the heart chambers and valves. Usually caused by bacteria entering the bloodstream. Life-threatening condition requiring prolonged antibiotic therapy and sometimes surgery. Risk increased in those with prosthetic valves or congenital heart disease.

Buildup of abnormal amyloid protein in the heart tissue causing stiffening and restrictive cardiomyopathy. Two main types: ATTR (transthyretin, age-related or hereditary) and AL (light chain, associated with multiple myeloma). Increasingly recognized cause of heart failure with preserved ejection fraction.

A blockage in one of the pulmonary arteries in the lungs, usually caused by blood clots that travel from deep veins in the legs (DVT). Life-threatening condition requiring immediate treatment. Can cause sudden death if massive.

Accumulation of excess fluid in the pleural space between the lungs and chest wall. Can be caused by heart failure, pneumonia, cancer, pulmonary embolism, or liver/kidney disease. Symptoms depend on amount and rate of fluid accumulation.

A pus-filled cavity in the lung surrounded by inflamed tissue, usually caused by bacterial infection. Often follows aspiration pneumonia. Associated with poor dental hygiene, alcoholism, or swallowing disorders. Modern antibiotics have reduced incidence significantly.

Collapsed lung due to air leaking into the space between the lung and chest wall. Can be spontaneous (no obvious cause), traumatic (injury), or tension (life-threatening). Primary spontaneous occurs in tall, thin young men. Requires prompt treatment.

A breathing disorder in obese people where poor breathing leads to too much carbon dioxide and too little oxygen in the blood. Often overlaps with obstructive sleep apnea. Can lead to pulmonary hypertension, heart failure, and early death if untreated.

Cancer of the voice box (larynx), most commonly squamous cell carcinoma. Strongly associated with tobacco and alcohol use. Hoarseness is the most common early symptom. Can affect voice, swallowing, and breathing depending on location.

Cancer arising from the nasopharynx, the area behind the nose and above the back of the throat. Strongly associated with Epstein-Barr virus (EBV), genetic factors, and certain dietary habits (salted fish). Common in Southeast Asia and North Africa.

Also known as delta hepatitis, caused by the hepatitis D virus (HDV) which requires hepatitis B virus to replicate. The most severe form of viral hepatitis with rapid progression to cirrhosis. Occurs as coinfection (with HBV) or superinfection (in chronic HBV).

Progressive form of non-alcoholic fatty liver disease (NAFLD) characterized by liver inflammation and damage in people who drink little or no alcohol. Can progress to cirrhosis, liver failure, and liver cancer. Associated with obesity, diabetes, and metabolic syndrome.

Sudden inflammation of the pancreas, usually mild and self-limiting but can be life-threatening. Most commonly caused by gallstones or alcohol. Presents with severe abdominal pain. Can lead to pancreatic necrosis, organ failure, or pseudocysts.

Inability to fully digest lactose, the sugar in milk and dairy products, due to deficiency of lactase enzyme in the small intestine. Very common worldwide, especially in certain ethnic groups. Not dangerous but can cause uncomfortable symptoms.

Narrowing of the esophagus causing difficulty swallowing (dysphagia). Most commonly caused by chronic acid reflux (GERD) leading to scar tissue formation. Other causes include radiation, eosinophilic esophagitis, cancer, and ingestion of caustic substances.

A cluster of conditions including increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol levels. Occurring together, they increase risk of heart disease, stroke, and type 2 diabetes. Very common in developed countries.

A group of genetic disorders causing brittle bones that break easily. Caused by defects in type I collagen. Range from mild (few fractures) to severe (lethal in infancy). Also known as brittle bone disease. Can affect teeth, hearing, and connective tissue.

A rare genetic disorder causing episodes of muscle weakness or paralysis triggered by low potassium levels. Episodes often occur during rest after exercise or high-carbohydrate meals. Muscles work normally between attacks. Can lead to permanent weakness over time.

A chronic neurological disorder affecting the brain's ability to control sleep-wake cycles. Characterized by excessive daytime sleepiness and cataplexy (sudden muscle weakness triggered by emotions). Often caused by loss of hypocretin-producing neurons. Onset typically in adolescence.

A neurological disorder causing uncomfortable sensations in the legs and an irresistible urge to move them. Symptoms worse at rest and in the evening/night. Significantly disrupts sleep. Associated with iron deficiency, kidney disease, pregnancy, and certain medications.

One of the most common causes of vertigo, triggered by specific changes in head position. Caused by tiny calcium crystals (canaliths) becoming dislodged in the inner ear. Brief, intense episodes of spinning sensation lasting less than a minute.

A tear in one or more of the four rotator cuff tendons in the shoulder (supraspinatus, infraspinatus, teres minor, subscapularis). Can occur from acute injury or degenerative changes with aging. Causes shoulder pain and weakness, especially with overhead activities.

Narrowing of the spaces within the spine, putting pressure on the spinal cord and nerves. Most commonly affects the lower back (lumbar) and neck (cervical). Causes pain, numbness, and muscle weakness. Usually age-related degenerative changes.

When the soft inner material of a spinal disc in the lower back pushes through the tough outer layer, irritating nearby nerves. Commonly called a slipped or ruptured disc. Most common in ages 30-50. Most improve with conservative treatment within 6 weeks.

Inflammation of the Achilles tendon, the large tendon connecting the calf muscles to the heel bone. Common in runners and athletes who have suddenly increased training intensity. Causes pain and stiffness along the back of the leg near the heel.

Inflammation of the plantar fascia, a thick band of tissue running across the bottom of the foot connecting the heel bone to the toes. Causes stabbing heel pain, especially with first steps in the morning. Most common cause of heel pain.

Persistent or recurrent infection of the kidneys causing progressive scarring and damage. Usually results from repeated acute pyelonephritis, often due to urinary tract obstruction or vesicoureteral reflux. Can lead to chronic kidney disease and end-stage renal disease.

Narrowing of one or both renal arteries reducing blood flow to the kidneys. Causes hypertension that can be difficult to control and can lead to kidney damage. Usually caused by atherosclerosis (older patients) or fibromuscular dysplasia (younger women).

A kidney disorder where the kidneys cannot concentrate urine due to resistance to antidiuretic hormone (ADH/vasopressin). Causes excessive thirst and excretion of large amounts of dilute urine. Can be inherited (genetic) or acquired (lithium, other medications).

A condition characterized by sudden, involuntary contraction of the bladder muscle causing urgency to urinate, often with frequency and nocturia. May or may not involve urge incontinence. Very common, especially with aging, but not a normal part of aging.

Cancer that starts in the kidneys, most commonly renal cell carcinoma (RCC). Often discovered incidentally on imaging. Associated with smoking, obesity, and hypertension. Can be cured if caught early but has poor prognosis if metastatic.

A congenital condition in males where the opening of the urethra is located on the underside of the penis rather than at the tip. One of the most common birth defects of the male genitalia. Varies in severity based on location of urethral opening.

A fluid-filled sac in the epididymis, the coiled tube behind each testicle that stores and carries sperm. Very common and benign. Usually painless and discovered during self-exam. Can vary in size. Different from testicular cancer.

A chronic eye condition where fluid in the eye doesn't drain properly, causing increased pressure that damages the optic nerve. The most common type of glaucoma. Called the 'silent thief of sight' because it causes gradual vision loss without early symptoms.

Clouding of the eye's natural lens that occurs with aging. The most common type of cataract and a leading cause of vision impairment worldwide. Develops gradually over years. Surgery is the only effective treatment and is highly successful.

Inflammation of the eyelids causing red, irritated, itchy eyelids and dandruff-like scales on eyelashes. Very common and chronic condition. Associated with dry eye, meibomian gland dysfunction, and sometimes skin conditions like rosacea or dandruff.

Blood pooling in the anterior chamber of the eye between the cornea and iris, usually due to trauma. Can cause increased eye pressure and vision loss. Medical emergency requiring prompt evaluation and management to prevent complications like glaucoma and corneal staining.

Misalignment of the eyes in adults, either persistent from childhood or newly acquired. Can cause double vision, eye strain, and difficulty with depth perception. New-onset in adults often indicates underlying neurological or medical condition requiring evaluation.

Overproduction of thyroid hormones causing accelerated metabolism. Most commonly caused by Graves' disease, toxic nodular goiter, or thyroiditis. Affects multiple body systems and requires treatment to prevent serious complications like heart problems and osteoporosis.

A medical emergency occurring when blood flow to the heart is severely reduced or blocked, causing heart muscle damage. Usually caused by a blood clot forming in a coronary artery already narrowed by atherosclerosis. Time-critical condition requiring immediate treatment to minimize heart damage.

A common bacterial skin infection affecting the deeper layers of skin and subcutaneous tissue. Usually caused by Streptococcus or Staphylococcus bacteria entering through breaks in the skin. Can spread rapidly and become life-threatening if not treated promptly.

A condition where small pouches (diverticula) form and bulge outward through weak spots in the colon wall. Very common in adults over 60 in developed countries. Usually asymptomatic but can lead to diverticulitis (inflammation) or bleeding. Associated with low-fiber Western diet.

A pregnancy complication characterized by high blood pressure and signs of damage to other organ systems, typically liver and kidneys. Usually begins after 20 weeks of pregnancy. Can lead to serious complications for both mother and baby including eclampsia (seizures). Leading cause of maternal and perinatal morbidity worldwide.

A potentially life-threatening condition where a fertilized egg implants and grows outside the main cavity of the uterus, most commonly in a fallopian tube. The pregnancy cannot proceed normally and can cause the fallopian tube to rupture, leading to severe internal bleeding. Requires immediate medical intervention.

A chronic inflammatory lung disease causing obstructed airflow from the lungs. Includes emphysema (destruction of lung air sacs) and chronic bronchitis (inflammation of bronchial tubes). Progressive disease that makes breathing increasingly difficult over time. Primarily caused by smoking.

A condition where bone mineral density is lower than normal but not low enough to be classified as osteoporosis. Considered a precursor to osteoporosis and increases fracture risk compared to normal bone density. Often asymptomatic until a fracture occurs.

A rare genetic disorder characterized by a specific set of birth defects: Coloboma, Heart defects, Atresia of the choanae, Growth retardation, Genital abnormalities, and Ear abnormalities. Caused by mutations in the CHD7 gene in most cases. Affects approximately 1 in 8,500-15,000 births.

A rare inflammatory disease affecting skin and muscles, causing muscle weakness and distinctive skin rash. Belongs to a group of conditions called inflammatory myopathies. Can occur at any age but most common in adults 40-60 and children 5-15. Associated with increased cancer risk in adults.

A rare inflammatory muscle disease causing progressive muscle weakness, particularly in the proximal muscles (shoulders, hips, thighs). Belongs to idiopathic inflammatory myopathies. Affects adults primarily, rare in children. Associated with interstitial lung disease in some cases.

An inflammatory disease causing granulomas (clumps of inflammatory cells) to form in various organs, most commonly the lungs and lymph nodes. Can affect any organ system. Cause unknown. Affects approximately 1-40 per 100,000 people, more common in African Americans and Scandinavians. Often remits spontaneously.

An autoimmune disorder characterized by recurrent blood clots (thrombosis), pregnancy complications, and the presence of antiphospholipid antibodies. Can occur alone (primary) or with other autoimmune diseases (secondary, usually lupus). Affects approximately 1-5 per 100,000 people.

An inflammatory disease of blood vessels, most commonly affecting the arteries in the head, particularly the temples. Most common form of vasculitis in adults over 50. Can cause sudden blindness if untreated. Associated with polymyalgia rheumatica in 50% of cases. Affects approximately 0.5-27 per 100,000 people.

A rare large vessel vasculitis affecting the aorta and its major branches, causing vessel wall inflammation, stenosis, occlusion, and aneurysm formation. Primarily affects young women of Asian descent. Called 'pulseless disease' because pulses may be absent. One of the most common vasculitides in Asia.

A condition characterized by an abnormal increase in heart rate upon standing, without a drop in blood pressure. Part of a group of disorders called dysautonomia. Affects primarily women aged 15-50. Can be debilitating. Affects approximately 1-3 million people in the US alone.

A genetic disorder causing noncancerous (benign) tumors to develop in many parts of the body, particularly the brain, skin, kidneys, heart, and lungs. Affects approximately 1 in 6,000 people. TSC1 or TSC2 gene mutations cause overactivation of mTOR pathway.

A rare congenital neurological and skin disorder characterized by a facial port-wine birthmark, neurological abnormalities including seizures, and eye problems such as glaucoma. Caused by somatic mutation in GNAQ gene. Affects approximately 1 in 20,000-50,000 people.

A rare, usually fatal neurological disorder causing destruction of white matter in the brain. Characterized by abnormal protein (GFAP) deposits called Rosenthal fibers. Most common form is infantile, but juvenile and adult forms exist. Affects approximately 1 in 2.7 million people. No cure available.

A rare, inherited disorder destroying the protective coating (myelin) of nerve cells in the brain and throughout the nervous system. Caused by deficiency of galactocerebrosidase enzyme. Most common form is infantile with rapid progression. Affects approximately 1 in 100,000 people.

A severe, often fatal hemorrhagic fever caused by Marburg virus, related to Ebola virus. Transmitted through contact with infected animals (primarily fruit bats) or person-to-person through bodily fluids. First recognized in 1967 in Germany and Yugoslavia. Case fatality rate 23-90%.

A rare zoonotic virus transmitted from horses to humans, causing severe respiratory and neurological disease. First identified in Hendra, Australia in 1994. Fruit bats (flying foxes) are natural reservoir. Case fatality rate 57%. Only reported in Australia.

The most common type of kidney cancer in adults, arising from the lining of the proximal convoluted tubule. Subtypes include clear cell (70-80%), papillary (10-15%), chromophobe (5%), and collecting duct. Often asymptomatic in early stages.

A chronic pain condition affecting the trigeminal nerve, which carries sensation from the face to the brain. Characterized by sudden, severe, shock-like facial pain lasting seconds to minutes. Often triggered by simple activities like eating, talking, or touching the face. One of the most painful conditions known.

A common condition in which the cavities around nasal passages (sinuses) become inflamed and swollen for at least 12 weeks, despite treatment attempts. Also known as chronic rhinosinusitis. Can affect both adults and children, causing difficulty breathing through the nose and facial pain.

A condition that causes sudden, temporary weakness or paralysis of facial muscles, typically affecting one side of the face. Results from dysfunction of the facial nerve (cranial nerve VII), often related to inflammation. Usually develops rapidly, reaching peak severity within 48-72 hours.

An inflammation of blood vessels that causes changes in vessel walls including thickening, weakening, narrowing, and scarring. Can affect arteries, veins, and capillaries. These changes restrict blood flow, resulting in organ and tissue damage. There are many forms affecting different vessel sizes and organs.

An inflammatory disorder causing muscle pain and stiffness, especially in the shoulders, neck, and hips. Symptoms are typically worse in the morning. Usually develops quickly, often overnight. Closely related to giant cell arteritis and can occur together. Almost exclusively affects adults over 50.

A complex, chronic disorder characterized by extreme fatigue that cannot be explained by any underlying medical condition and does not improve with rest. Associated with post-exertional malaise, cognitive impairment, and orthostatic intolerance.

An infection of the female reproductive organs, usually caused by sexually transmitted bacteria spreading from the vagina to uterus, fallopian tubes, or ovaries. Affects approximately 4.4% of women of reproductive age. Leading preventable cause of infertility and ectopic pregnancy.

Inflammation of the vagina that can result in discharge, itching and pain. The most common types are bacterial vaginosis, yeast infections, and trichomoniasis. Affects millions of women annually and is one of the most common reasons for gynecologic visits.

A chronic pain condition affecting the vulva, characterized by burning, stinging, irritation, or rawness. Affects up to 16% of women. The cause is unknown and diagnosis is often delayed. Significantly impacts quality of life and sexual function.

Abnormally heavy or prolonged menstrual bleeding affecting up to 25% of women. Can cause anemia and significantly impact quality of life. Often caused by hormonal imbalances, uterine fibroids, or bleeding disorders.

A combination of physical and emotional symptoms that occur 1-2 weeks before menstruation. Affects up to 90% of women of reproductive age. Severe form (PMDD) affects 3-8% and causes significant functional impairment.

Persistent or recurrent genital pain that occurs just before, during, or after intercourse. Affects up to 20% of women. Can have physical or psychological causes. Significantly impacts sexual health and relationships.

A neurodevelopmental disorder characterized by persistent patterns of inattention, hyperactivity, and impulsivity. Affects approximately 5-7% of children and 2.5-5% of adults globally. Often persists into adulthood and can significantly impact academic, occupational, and social functioning.

A condition characterized by low levels of vitamin B12, leading to megaloblastic anemia and potential neurological complications. Affects approximately 6% of people under 60 and up to 20% of those over 60. Can cause irreversible nerve damage if untreated.

Liver damage caused by excessive alcohol consumption, ranging from fatty liver to alcoholic hepatitis and cirrhosis. A leading cause of liver disease worldwide. Risk increases with amount and duration of alcohol use. Can be reversible in early stages.

The most common vaginal infection in women of reproductive age, caused by disruption of normal vaginal flora with overgrowth of anaerobic bacteria. Not sexually transmitted but associated with sexual activity. Increases risk of STI acquisition, pelvic inflammatory disease, and pregnancy complications.

Precancerous changes in cervical cells caused primarily by persistent infection with high-risk human papillomavirus (HPV). Classified as CIN 1 (mild), CIN 2 (moderate), or CIN 3 (severe/carcinoma in situ). Most cases of CIN 1 resolve spontaneously; CIN 2-3 require treatment to prevent progression to invasive cervical cancer.

Fluid-filled sacs that develop on the ovaries, extremely common in women of reproductive age. Most are functional cysts (follicular or corpus luteum) that resolve spontaneously within 1-3 menstrual cycles. Pathological cysts include dermoid cysts, endometriomas, and cystadenomas. Rarely, cysts may be malignant, especially in postmenopausal women.

A common fungal infection affecting up to 75% of women at least once in their lifetime. Caused by Candida overgrowth, most commonly Candida albicans. Characterized by intense itching and thick, white discharge. Recurrent infections (≥4 per year) affect 5-8% of women and significantly impact quality of life.

A chronic mental health condition characterized by persistent, excessive, and uncontrollable worry about everyday situations and events. Affects 3-6% of adults worldwide, with women affected twice as often as men. Causes significant impairment in social, occupational, and other important areas of functioning.

A severe mood disorder characterized by at least one manic episode, often alternating with major depressive episodes. Affects approximately 1% of the population equally across genders. Manic episodes cause significant impairment and may include psychotic features. Associated with high suicide risk and functional disability.

A mood disorder characterized by at least one hypomanic episode and at least one major depressive episode. Hypomania is less severe than mania and does not cause marked impairment or psychosis. Depressive episodes are typically more frequent and longer-lasting than in Bipolar I, with significant suicide risk.

A complex personality disorder characterized by pervasive instability in mood, interpersonal relationships, self-image, and behavior. Affects 1-2% of the general population and up to 20% of psychiatric inpatients. Associated with high rates of self-harm, suicide attempts, and significant functional impairment.

A psychiatric disorder that may occur in people who have experienced or witnessed a traumatic event. Affects 6-8% of the population at some point in life. Characterized by intrusive memories, avoidance, negative alterations in cognition and mood, and marked alterations in arousal and reactivity.

A serious eating disorder characterized by restriction of energy intake leading to significantly low body weight, intense fear of gaining weight, and disturbed body image. Has the highest mortality rate of any psychiatric disorder. Affects approximately 0.5-1% of women and 0.1-0.3% of men, typically beginning in adolescence.

An eating disorder characterized by recurrent episodes of binge eating followed by inappropriate compensatory behaviors to prevent weight gain, such as self-induced vomiting, laxative misuse, fasting, or excessive exercise. Affects 1-2% of women and 0.1-0.5% of men. Associated with significant medical complications.

An X-linked recessive bleeding disorder caused by deficiency of clotting factor VIII. The most common severe inherited bleeding disorder, affecting approximately 1 in 5,000-10,000 male births. Characterized by spontaneous and trauma-induced bleeding, particularly into joints (hemarthrosis) and muscles.

An X-linked recessive bleeding disorder caused by deficiency of clotting factor IX, also known as Christmas disease. Affects approximately 1 in 30,000 male births. Clinically indistinguishable from Hemophilia A but requires different treatment. Less common than Hemophilia A, representing 15-20% of hemophilia cases.

An X-linked lysosomal storage disorder caused by deficiency of iduronate-2-sulfatase, leading to accumulation of glycosaminoglycans (GAGs). Affects multiple organ systems including skeleton, heart, and brain. Only MPS disorder that is X-linked. Ranges from severe (with cognitive decline) to attenuated (without cognitive involvement).

A severe autosomal recessive disorder of amino acid metabolism caused by deficiency of fumarylacetoacetate hydrolase (FAH). Leads to accumulation of toxic metabolites causing liver failure, kidney dysfunction, and neurologic crises. Untreated, fatal in childhood. Newborn screening allows early treatment.