Human health and medicine

Active ingredient

An active ingredient, also called an active pharmaceutical ingredient (API), is the substance in a drug intended to cure, treat, or prevent disease; all other components are inactive excipients.

Active surveillance of prostate cancer

Active surveillance of prostate cancer is a management strategy for low-risk disease that uses periodic PSA tests, examinations, MRI, and biopsies, deferring curative treatment unless progression is detected.

ActiveBrains trial

ActiveBrains trial: 20-week randomized clinical trial at the University of Granada (NCT02295072) in 109 children aged 8-11 with overweight/obesity; supervised aerobic plus resistance exercise improved crystallized and total intelligence and cognitive flexibility, with null effects on inhibition, working memory, and hippocampal volume.

Activities of daily living

Activities of daily living (ADLs) are basic self-care tasks like bathing and eating, with instrumental ADLs covering shopping and finances; measured by scales such as Katz, Barthel, and Lawton-Brody.

Acupoint injection

Acupoint injection, also called water-needle therapy (shui zhen), is a technique that injects medication into acupuncture points, used in China, Korea, and the United States.

Acupotomy

Acupotomy, also called the needle knife or xiaozhendao, is a minimally invasive Chinese medicine procedure that uses a knife-tipped needle to cut soft tissue adhesions, mainly for chronic musculoskeletal pain.

Acupressure

Acupressure is a traditional Chinese medicine practice that applies finger, hand, or device pressure to acupoints to control symptoms such as pain, nausea, and vomiting, without needles.

Acupuncture (针灸)

Acupuncture (针灸) is needle-based therapy from traditional Chinese medicine, used worldwide for pain. Evidence shows benefit over no treatment but small or uncertain differences from sham, with placebo effects substantial.

Acupuncture Analgesia

Acupuncture analgesia is pain relief from needle stimulation at acupuncture points, involving small myelinated nerve fibers and opioid mechanisms; first used for surgery in Shanghai in 1958.

Acupuncture stimulation

Acupuncture stimulation is a clinical treatment using thin needles, heat, or electrical current at defined body points to modulate pain, with evidence strongest for chronic pain conditions.

Acustimulation

Acustimulation is a non-invasive technique applying mild electrical current to the P6 (Neiguan) wrist point to treat nausea and vomiting, using wearable stimulator devices instead of needles.

Acute abdomen

Acute abdomen, also called surgical abdomen (ICD-11 MD81.3), is sudden severe abdominal pain possibly requiring urgent surgery; 5–10% of ED visits, mortality 2–12%, appendicitis the leading cause, contrast CT the standard imaging.

Acute ackee fruit intoxication

Acute ackee fruit intoxication, or Jamaican vomiting sickness, is hypoglycin A poisoning from unripe Blighia sapida fruit, causing vomiting, toxic hypoglycemia, seizures, coma, and sometimes death.

Acute alcohol-induced pancreatitis

Acute alcohol-induced pancreatitis (ICD-11 DC31.1) is acute pancreatic inflammation from heavy alcohol use, the second most common cause after gallstones, diagnosed after excluding other etiologies, with highest recurrence risk.

Acute amoebiasis

Acute amoebiasis (ICD-11 1A36.00), also called amebic dysentery or amebic colitis, is acute symptomatic infection with Entamoeba histolytica, causing bloody diarrhea or liver abscess, treated with metronidazole or tinidazole plus a luminal amoebicide.

Acute and transient psychotic disorder

Acute and transient psychotic disorder (ATPD), ICD-10 F23 and ICD-11 6A23, a brief psychotic illness with onset within 2 weeks, rapid symptom fluctuation, remission within 3 months; DSM-5 counterpart is brief psychotic disorder.

Acute annular outer retinopathy

Acute annular outer retinopathy (AAOR) is a rare unilateral outer retinal disorder, a 1995 Gass and Stern variant of AZOOR, marked by acute visual field loss and a peripapillary gray-white intraretinal ring, with possible spontaneous recovery.

Acute aortoiliac occlusion

Acute aortoiliac occlusion (ICD-11 BD30.1), sudden blockage of the distal aorta and iliac arteries by embolism or in-situ thrombosis; a vascular emergency with 17-52% mortality, bilateral acute limb ischemia, and surgical or endovascular revascularization.

Acute atopic conjunctivitis

Acute atopic conjunctivitis (ICD-10 H10.1, ICD-11 9A60.01; Angelucci's syndrome, spring catarrh) is a sudden IgE-mediated allergic inflammation of the conjunctiva from airborne allergens, causing itchy, red, watery eyes, usually self-limiting and treated with topical antihistamines.

Acute bacterial paronychia

Acute bacterial paronychia, also called nail fold infection, is a bacterial infection of the skin around a nail lasting under six weeks, usually Staphylococcus aureus, treated with soaks, topical antibiotics, and abscess drainage.

Acute bacterial pharyngitis

Acute bacterial pharyngitis, mainly group A Streptococcus (strep throat), is a bacterial pharynx infection causing 5-15% of adult and 20-30% of childhood sore throats, diagnosed by Centor scoring, RADT, or throat culture, and treated with penicillin to prevent rheumatic fever.

Acute basophilic leukemia

Acute basophilic leukemia (ABL), a rare acute myeloid leukemia subtype with primary differentiation to basophils; ICD-10 C94.7; metachromatic toluidine blue blasts, CD123-positive and CD117-negative, MYB-GATA1 fusion in sporadic cases, poor prognosis.

Acute biliary pancreatitis

Acute biliary pancreatitis (gallstone pancreatitis, ICD-11 DC31.2): acute pancreatitis from gallstone obstruction of the ampulla of Vater; ERCP reserved for cholangitis, cholecystectomy during same admission prevents recurrence.

Acute bilirubin encephalopathy

Acute bilirubin encephalopathy (ABE), also called bilirubin-induced neurologic dysfunction, is acute neonatal brain injury from unbound unconjugated bilirubin crossing the blood-brain barrier, progressing through early, intermediate, and advanced phases toward kernicterus.

Acute bronchiolitis due to respiratory syncytial virus

Acute bronchiolitis due to respiratory syncytial virus (RSV bronchiolitis) is the leading viral lower respiratory infection of infants, causing cough, tachypnea, and wheezing after a cold-like prodrome. Diagnosis is clinical; treatment is supportive, with monoclonal antibody prophylaxis for prevention.

Acute bronchitis

Acute bronchitis, or chest cold, is transient inflammation of the trachea and major bronchi causing acute cough under 3 weeks, usually viral, self-limiting, and not treated with antibiotics in otherwise healthy people.

Acute bronchitis due to Rhinovirus

Acute bronchitis due to Rhinovirus (ICD-11 CA42.1, ICD-10 J20.6) is rhinovirus-caused inflammation of the large airways, causing cough lasting under 3 weeks, treated supportively without antibiotics.

Acute cholecystitis

Acute cholecystitis (ICD-11 DC12.0) is acute gallbladder wall inflammation, usually from cystic duct obstruction by gallstones. Distinguished by Tokyo Guidelines diagnostic and severity grading criteria and treatment by early laparoscopic cholecystectomy.

Acute coronary syndrome

Acute coronary syndrome (ACS) is the umbrella term for unstable angina, NSTEMI, and STEMI, caused by sudden reduced heart blood flow from plaque rupture and thrombosis; diagnosed by ECG and troponin, treated with antiplatelets and reperfusion.