Medicine

Croup (Laryngotracheobronchitis) — causes, symptoms, diagnosis, and treatment Croup Croup is a usually viral upper airway illness in young children causing a barking cough, stridor and hoarseness. Most cases are mild and respond to steroids and supportive care; se…

Cryotherapy: uses, types, history, benefits and risks Cryotherapy Cryotherapy uses very low temperatures—applied locally or to the whole body—for medical, rehabilitative and cosmetic purposes. Methods, claimed benefits, evidence and safety consid…

Cryptorchidism: undescended testicles — causes, diagnosis, and management Cryptorchidism Cryptorchidism (undescended testicle) is when one or both testicles fail to descend into the scrotum. Overview of types, causes, diagnosis, treatment, complications and historical…

Cuboid bone: anatomy, function, and clinical significance Cuboid bone The cuboid is a lateral tarsal bone of the foot that helps form the lateral arch, transmits forces, and articulates with the calcaneus and 4th–5th metatarsals; injuries produce pai…

Cyanosis: causes, recognition, and clinical significance Cyanosis Cyanosis is a bluish discoloration of skin and mucous membranes from reduced oxygen delivery or abnormal hemoglobin. Recognize central vs peripheral forms, causes, assessment, and…

Cyclic vomiting syndrome Cyclic vomiting syndrome (CVS) is a disorder of recurrent, stereotyped episodes of severe nausea and vomiting; most common in children and often linked to migraine and other period…

Cyclospora cayetanensis: biology, transmission, clinical features and prevention Cyclospora cayetanensis Cyclospora cayetanensis is a single-celled coccidian parasite that causes prolonged, sometimes recurrent diarrheal illness in humans; transmitted by ingestion of sporulated oocysts…

Cyclothymia: a clinical overview of mood pattern, diagnosis, and management Cyclothymia Cyclothymia is a chronic mood disorder with fluctuating mild hypomanic and depressive symptoms. This article covers features, diagnosis, treatment approaches, history, and how it d…

Cystic fibrosis: causes, symptoms, diagnosis, and management Cystic fibrosis Cystic fibrosis is an inherited disorder caused by mutations in the CFTR gene. It primarily affects the lungs and digestive system and is managed with airway clearance, medications…

Cystitis: causes, symptoms, diagnosis, treatment and prevention Cystitis Cystitis is inflammation or infection of the urinary bladder. This article explains common causes, symptoms, diagnosis, treatment options, prevention measures, and important distin…

Cytokine storm (hypercytokinemia) Cytokine storm An intense, dysregulated immune reaction in which excess cytokine release causes systemic inflammation, organ injury, and can be fatal; seen in infections and immune disorders.

Cytomegalovirus (CMV) Cytomegalovirus A common herpesvirus (Human Herpesvirus 5) that establishes lifelong latent infection; usually harmless in healthy adults but a major cause of congenital disease and serious illnes…

Dacarbazine (DTIC) — antineoplastic methylating agent Dacarbazine Dacarbazine is a chemotherapy prodrug used mainly for metastatic melanoma and some lymphomas. It methylates DNA, has modest response rates, and is limited by nausea, bone marrow su…

Death by natural causes: definition, classification, and significance Death by natural causes Overview of what 'death by natural causes' means, common medical examples, how it differs from unnatural death, legal and forensic considerations, and typical uses on records and o…

Decompression sickness (the bends) Decompression sickness Decompression sickness: causes, symptoms, history, prevention and treatment of gas-bubble injury that can occur after rapid reduction of ambient pressure.

Decongestant: overview, types, uses, and safety Decongestant Medicines that relieve nasal congestion by narrowing swollen blood vessels in the nasal passages. Covers oral and topical agents, common active ingredients, uses, side effects and…

Deep brain stimulation: overview, components, uses, and risks Deep brain stimulation Deep brain stimulation (DBS) is a neurosurgical therapy that delivers electrical pulses to specific brain targets to relieve movement disorders and select psychiatric conditions.

Defibrillation: restoring coordinated heart rhythm with an electric shock Defibrillation Defibrillation is the controlled delivery of an electric shock to stop dangerous heart arrhythmias and permit restoration of a normal heartbeat. Covers mechanisms, devices, uses, a…

Defibrillator (AED, ICD): devices for treating life‑threatening heart rhythms Defibrillator A defibrillator is an electrical device used to stop malignant heart rhythms like ventricular fibrillation and allow the heart's normal rhythm to resume.

Degenerative disease: causes, types, progression, and management Degenerative disease Progressive deterioration of tissues or organs from ongoing cell damage. Includes neurodegenerative disorders (Alzheimer's, Parkinson's) and musculoskeletal conditions; covers caus…

Dehydration (hypohydration): causes, symptoms, prevention and treatment Dehydration Dehydration is loss of body water that impairs physiological functions. This article explains causes, common signs, vulnerable groups, basic treatments and prevention strategies.

Delirium (acute confusional state) Delirium Delirium is an acute, fluctuating disturbance of attention and awareness caused by a medical condition, substance change, or withdrawal. It commonly affects older or hospitalized p…

Delirium tremens (DTs): severe alcohol withdrawal syndrome Delirium tremens Delirium tremens is a life‑threatening form of alcohol withdrawal marked by sudden severe confusion, tremor, autonomic overactivity and hallucinations that requires urgent medical…

Deltoid muscle Large triangular shoulder muscle that shapes the shoulder, produced by three heads, enabling arm abduction, flexion, extension and rotation. Important in movement, clinical assessm…

Delusional disorder A psychiatric condition defined by persistent non-bizarre delusions with relatively preserved functioning. Covers types, symptoms, causes, differential diagnosis, and typical treat…

Dementia: causes, symptoms, progression, and care Dementia Dementia is a clinical syndrome of progressive cognitive decline from multiple brain disorders. This article explains common types, symptoms, causes, diagnosis, management, history…

Dementia with Lewy bodies (DLB) Dementia with Lewy bodies Progressive neurodegenerative dementia characterized by Lewy body protein deposits, fluctuating cognition, visual hallucinations, parkinsonism and sleep disturbances; second most c…

Dengue fever Mosquito‑transmitted viral illness found in tropical and subtropical regions; symptoms range from fever and severe pain to rare hemorrhagic and shock syndromes; prevention centers…

Dental caries (tooth decay): causes, progression, prevention and treatment Dental caries Dental caries (tooth decay) is the progressive destruction of tooth tissues by acids produced by oral bacteria. This article covers causes, stages, diagnosis, prevention, treatment…

Dentistry: scope, roles, procedures and public health importance Dentistry Overview of dentistry as a medical specialty, common procedures, the team of professionals, historical development, and its role in prevention and overall health.

Depression (major depressive disorder) Depression (mental illness) Major depressive disorder is a common mental health condition characterized by persistent low mood, loss of interest, physical symptoms, and impaired functioning. Diagnosis and tre…

Dermatitis: causes, types, symptoms and management Dermatitis Dermatitis is inflammation of the skin that produces rashes and itching. This article explains major forms, clinical features, causes, diagnosis, treatment approaches and key disti…

Dermatology: medical specialty of the skin, hair, nails and related glands Dermatology Dermatology studies and treats the skin, hair, nails and related glands—covering diagnosis, medical and surgical therapies, prevention, cosmetic care, training, and public-health r…

Designer drug (novel psychoactive substances) Designer drug Synthetic compounds created to mimic controlled drugs’ effects. Also called novel psychoactive substances, they vary widely in chemistry, effects, risks, and legal status.

Dextromethorphan A widely used over-the-counter cough suppressant and psychoactive compound with diverse pharmacology, medical uses, and potential for misuse and interaction with other drugs.

Diabetes insipidus: causes, symptoms, diagnosis and treatment Diabetes insipidus A disorder of water balance caused by deficient vasopressin action, producing excessive dilute urine and thirst. Includes central, nephrogenic and gestational forms with distinct c…

Diabetes mellitus A chronic metabolic disorder caused by impaired insulin action or secretion, leading to high blood glucose and long-term health risks; includes types, causes, diagnosis, treatment,…

Diabetic ketoacidosis Diabetic ketoacidosis (DKA) is an acute, potentially life‑threatening complication of diabetes marked by high blood sugar, ketone production, acid–base disturbance, dehydration and…

Diabetic retinopathy — causes, diagnosis, treatment, and prevention Diabetic retinopathy Diabetic retinopathy is a diabetes-related microvascular disease of the retina that can lead to vision loss. This article explains its types, symptoms, diagnosis, treatments, and p…

Diagnosis: Definition, Process, and Applications Diagnosis An explanation of diagnosis as the identification of a problem's nature or cause, covering methods, history, examples from medicine and science, and how clear diagnosis leads to ef…

Dialysis: purpose, types, how it works, history and limitations Dialysis Medical treatment that substitutes some kidney functions by removing waste and excess fluid; includes hemodialysis and peritoneal dialysis, uses, history, access types and limitati…

Diarrhea: overview, causes, symptoms, treatment and prevention Diarrhea Diarrhea is the passage of loose or watery stools more frequently than usual. This article explains types, common causes, diagnosis, treatment, prevention and when to seek medical…

Diazepam Diazepam is a long-acting benzodiazepine used for anxiety, seizure control, muscle spasm and procedural sedation. It can produce tolerance, dependence and respiratory depression an…

Diclofenac: uses, actions, formulations and safety Diclofenac Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) used for pain, inflammation and fever. This article explains how it works, common uses, formulations, risks and historic…

Dilation and curettage (D&C): procedure, uses, risks, and recovery Dilation and curettage Dilation and curettage (D&C) is a gynecologic procedure to sample or remove uterine lining for diagnosis or treatment. This article covers indications, how it is done, risks, recov…

Dilation and evacuation (D&E) Dilation and evacuation Dilation and evacuation (D&E) is a surgical procedure used most often in the second trimester to remove pregnancy tissue or manage an incomplete miscarriage; it involves cervical d…

Diphtheria: causes, symptoms, treatment, prevention Diphtheria An overview of diphtheria, a bacterial infection caused by Corynebacterium diphtheriae, covering symptoms, complications, diagnosis, treatment (antitoxin and antibiotics) and preve…

Disease (medical condition) Disease A disease is a disturbance of normal body or mental function caused by biological, genetic, environmental, or social factors; it includes causes, symptoms, diagnosis, treatment, pr…