Medicine

Hematuria — presence of blood in the urine Hematuria Hematuria is blood in the urine. This article explains types, common and serious causes, diagnostic steps, and general approaches to treatment and follow-up.

Hemlock: Poisonous Apiaceae Plants — Identification, History, and Risks Hemlock Hemlock refers to several poisonous plants in the carrot family (Apiaceae). This article explains identification, toxic compounds, historical use, symptoms, treatment, and how to d…

Hemorrhoid (Piles): Causes, Types, Symptoms, and Treatment Hemorrhoid Hemorrhoids (piles) are normal vascular cushions in the anal canal that can become swollen or inflamed. This article explains anatomy, causes, symptoms, diagnosis, treatments, prev…

Hemorrhoidolysis (Galvanic Electrotherapy) Hemorrhoidolysis A minimally invasive office procedure that uses a galvanic electrode to treat internal hemorrhoids by producing a local electrochemical effect that reduces hemorrhoidal tissue and…

Hemostasis: the body's process for preventing and stopping bleeding Hemostasis Hemostasis is the physiological process that stops bleeding by sealing injured blood vessels, involving vasoconstriction, platelet plug formation, coagulation and later clot remova…

Hepatitis: causes, types, symptoms, diagnosis, treatment and prevention Hepatitis Comprehensive overview of hepatitis: liver inflammation from infectious and noninfectious causes, major types (A, B, C), symptoms, diagnosis, treatment, prevention and public-healt…

Hepatitis A: causes, symptoms, prevention, and public-health impact Hepatitis A Hepatitis A is an acute viral liver infection spread by the fecal–oral route. It usually resolves without long-term liver damage; prevention relies on vaccination and hygiene.

Hepatitis B: causes, transmission, diagnosis, prevention and treatment Hepatitis B Comprehensive overview of hepatitis B: the viral liver infection, how it spreads, clinical course, diagnosis, prevention including vaccination, treatment options, and public health…

Hepatitis C: causes, transmission, diagnosis, treatment and public health Hepatitis C Comprehensive overview of hepatitis C: the liver infection caused by hepatitis C virus, its transmission, symptoms, testing, modern treatment options, complications, prevention and…

Hepatoblastoma: Pediatric liver tumor overview Hepatoblastoma An encyclopedic summary of hepatoblastoma: its presentation, pathology, diagnosis, treatment options including surgery and chemotherapy, prognosis, and notable associations in chil…

Hepatocellular carcinoma (HCC): overview, causes, diagnosis and treatment Hepatocellular carcinoma Hepatocellular carcinoma is the most common primary liver cancer. This article covers causes, symptoms, diagnostic approach, staging, treatment options and prevention strategies.

Herd immunity: concept, mechanisms, and public health implications Herd immunity Herd immunity is population-level protection from infectious disease achieved when enough people are immune, reducing spread and protecting those who cannot be immune themselves.

Hereditary haemochromatosis A genetic iron‑overload condition in which excess iron builds up in organs; causes, symptoms, diagnosis, treatment and inheritance are explained.

Hernia: causes, types, diagnosis and treatment Hernia A hernia occurs when an organ or tissue protrudes through a weakened area; this article explains types, causes, symptoms, diagnosis, management and historical developments in repai…

Heroin (diacetylmorphine): overview, effects, history, and risks Heroin Comprehensive overview of heroin (diacetylmorphine): chemistry, methods of use, physiological effects, dependence and harms, medical use, legal status, and public-health responses.

Herpes simplex: causes, symptoms, transmission, and management Herpes simplex Herpes simplex (HSV) is a common viral infection causing oral and genital lesions. This article explains types, symptoms, latency, diagnosis, treatment, prevention, complications,…

Herpes zoster (shingles): causes, symptoms, treatment and prevention Herpes zoster Herpes zoster, or shingles, is a reactivation of the varicella‑zoster virus causing a painful, blistering rash. Age, immune status, antivirals, and vaccination affect risk, severit…

Hiccups: causes, mechanisms, common triggers, remedies, and clinical notes Hiccups A concise guide to hiccups: what they are, how they occur, common triggers and home remedies, theories on their origin, and when to seek medical evaluation.

Hip dysplasia: causes, signs, diagnosis and treatment Hip dysplasia Developmental disorder of the hip joint that destabilizes the socket, commonly seen in dogs (especially large breeds). Leads to pain and arthritis; managed by conservative care, su…

Hip replacement (hip arthroplasty) Hip replacement Surgical replacement of the hip joint with a prosthesis to relieve pain and restore function. Covers types, components, indications, procedure, recovery, risks, and historical note…

Histamine: roles, chemistry, physiology, and clinical significance Histamine An accessible overview of histamine: its chemistry, how and where it is made, physiological actions through receptors, roles in allergy and digestion, and clinical implications inc…

Hodgkin lymphoma (Hodgkin's disease) Hodgkin lymphoma Hodgkin lymphoma is a malignant disease of the lymphatic system defined by Reed–Sternberg cells. This article summarizes features, subtypes, presentation, diagnosis, treatment, his…

Homeopathy: principles, history, evidence, and uses Homeopathy Overview of homeopathy, its founding by Samuel Hahnemann, core principles (like cures like, dilution), common preparations, historical spread, scientific assessments, and safety co…

Hospice: compassionate end-of-life care and services Hospice Hospice provides comfort-focused medical, emotional and spiritual care for people nearing the end of life. It emphasizes symptom relief, family support, interdisciplinary teams and…

Hospital A hospital is a health care institution that provides diagnosis, treatment, and continuous care for acute and chronic illnesses, injuries, surgery, emergency care, and rehabilitati…

Human chorionic gonadotropin (hCG): biology, testing, and clinical uses Human chorionic gonadotropin Overview of hCG, a placental glycoprotein hormone: its structure, production in pregnancy and some tumors, laboratory testing, clinical roles, and controversies including weight‑lo…

Human papillomavirus (HPV): causes, types, prevention and treatment Human papillomavirus Comprehensive overview of human papillomavirus (HPV): biology, transmission, disease spectrum, screening and vaccines, plus common treatments and public health importance.

Human penis: anatomy, function, development and cultural notes Human penis Overview of the human penis covering anatomy, physiological roles (urination and reproduction), development, variations, health considerations, and cultural terminology.

Human penis size: measurement, variation, and medical facts Human penis size Overview of how human penis size is defined and measured, typical averages, sources of variation, medical considerations, common misconceptions, and comparative notes with other pr…

Human T-lymphotropic virus (HTLV) Human T-lymphotropic virus Overview of the Human T-lymphotropic viruses: classification, biology, clinical significance, transmission, history, and prevention.

Humorism: the ancient doctrine of four bodily fluids, temperament, and treatment Humorism Humorism (humoralism) is an ancient medical theory that health and temperament depend on balance among four bodily fluids. It shaped Greco-Roman, Islamic, and medieval medicine unt…

Hunger: physiological sensation, causes, and social impact Hunger Hunger is the physiological and psychological drive to eat. This article explains its mechanisms, differences from appetite and satiety, short- and long-term effects, and social im…

Huntington's disease — inherited neurodegenerative disorder Huntington's disease A progressive, autosomal dominant brain disorder causing movement disturbances, cognitive decline and psychiatric changes. Symptoms typically appear in mid-adulthood and worsen ove…

Hygiene: personal and public practices for maintaining health Hygiene Hygiene comprises habits and practices—personal, domestic, and public—aimed at preserving health, preventing infection and contamination, and promoting wellbeing across societies.

Hypercholesterolemia: causes, risks, diagnosis, and management Hypercholesterolemia Hypercholesterolemia is an elevated level of cholesterol in the blood that raises risk for atherosclerosis and cardiovascular disease; causes include genetics and lifestyle and it…

Hyperglycemia — high blood sugar: causes, symptoms, diagnosis, treatment Hyperglycemia Hyperglycemia is elevated blood glucose. This article explains causes, signs, testing, acute dangers, long-term complications, treatment and prevention in clear, practical terms.

Hyperhidrosis — excessive sweating disorder Hyperhidrosis Hyperhidrosis is a condition of abnormally increased sweating that can be focal or generalized, often starting in youth and affecting quality of life. Treatments range from topical…

Hyperkalemia: causes, effects, diagnosis and treatment Hyperkalemia Hyperkalemia is an elevated blood potassium level that can impair cardiac conduction. This article covers causes, symptoms, ECG findings, emergency and long‑term management, and no…

Hyperopia (Farsightedness): causes, symptoms, diagnosis and treatment Hyperopia Hyperopia, or farsightedness, is a common refractive error where distant objects are clearer than near ones. This article explains causes, symptoms, examination, correction options…

Hypersomnia (excessive sleepiness) Hypersomnia Hypersomnia is a sleep disorder marked by persistent or recurrent excessive sleepiness. This entry explains symptoms, common causes, diagnostic tests, treatment approaches, and how…

Hypertension (High Blood Pressure) Hypertension Chronic elevation of arterial blood pressure. Covers definition, measurement, causes, risks, complications, prevention, and common treatments including lifestyle and medicines.

Hyperthermia: causes, symptoms, treatment, and prevention Hyperthermia Hyperthermia is abnormally high body temperature from failed heat regulation. This article explains types, signs, medical response, risk groups, prevention, and distinctions from f…

Hyperthyroidism: overview, causes, symptoms, diagnosis, and treatment Hyperthyroidism Hyperthyroidism is a disorder of excess thyroid hormone production. This article explains causes, symptoms, tests, treatments, complications, and special considerations in plain, m…

Hypnotic (sleep-inducing medication) Hypnotic Hypnotics are drugs that promote sleep or deep sedation. This article explains their types, history, clinical uses, risks like dependence, and notable examples and distinctions.

Hypoactive Sexual Desire Disorder (HSDD) Hypoactive sexual desire disorder HSDD is a persistent reduction or absence of sexual fantasies and desire that causes personal distress or relationship problems. Covers symptoms, diagnosis, causes, history, and tr…

Hypochondriasis (hypochondria): overview, symptoms, causes, and management Hypochondriasis Hypochondriasis (hypochondria) is persistent anxiety about having a serious illness despite medical reassurance. This article covers symptoms, causes, diagnosis, treatment, and dis…

Hypodermic needle A hypodermic needle is a hollow, sharpened tube used with a syringe to deliver or withdraw fluids through the skin; it is central to modern injections, vaccinations and many medica…

Hypoglycemia (Low Blood Sugar): Causes, Symptoms, Diagnosis and Treatment Hypoglycemia Hypoglycemia is abnormally low blood glucose. This article explains causes, symptoms, diagnosis, immediate treatment, prevention and why prompt care is important.