Human health and medicine

Biportal endoscopy

Biportal endoscopy, also called unilateral biportal endoscopy or UBE, is a minimally invasive spine surgery technique that treats lumbar disc herniation and spinal stenosis through two small portals on one side of the back.

Birch pollen allergen skin prick test solution

白桦花粉变应原皮肤点刺液 (Skin Prick Solution for Betula platyphylla Suk. Pollen Allergens), NMPA-approved May 2023 (国药准字S20230023) by Zhejiang Wolwo Bio-Pharmaceutical; 50000 DU/ml birch pollen extract for skin prick diagnosis of type I birch pollen allergy.

Bird fancier lung

Bird fancier lung (BFL), or pigeon breeder's lung, avian hypersensitivity pneumonitis: immune lung disease from inhaled bird proteins in droppings, feathers, serum; treated mainly by antigen avoidance.

Birdshot chorioretinopathy

Birdshot chorioretinopathy (birdshot retinochoroidopathy, HLA-A29 uveitis) is a rare chronic bilateral posterior uveitis of middle-aged Europeans, strongly linked to HLA-A29, causing cream-colored choroidal spots and progressive vision loss.

Bireociclib tablets

Bireociclib tablets (吡洛西利), brand name Xuanyuening and research code XZP-3287, are an oral CDK4/6 inhibitor developed by Xuanzhu Biopharmaceutical and approved in China in 2025 for HR-positive, HER2-negative advanced or metastatic breast cancer.

Birk-Barel syndrome

Birk-Barel syndrome, or KCNK9 imprinting syndrome (OMIM 612292), is an extremely rare maternally inherited disorder on chromosome 8q24 causing hypotonia, feeding difficulty, and intellectual disability via TASK3 channel variants.

Birt Harvey

Birt Harvey (1928–2021) was an American pediatrician and Stanford professor, president of the American Academy of Pediatrics from 1989 to 1990 and a member of the National Academy of Medicine.

Birt-Hogg-Dubé syndrome

Birt-Hogg-Dubé syndrome, also called BHD or Hornstein-Knickenberg syndrome, is a rare inherited disorder caused by FLCN gene variants, causing skin tumors, lung cysts, and kidney cancer risk.

Birtamimab

Birtamimab (NEOD001, Hu2A4) is a humanized IgG1 monoclonal antibody targeting misfolded light-chain amyloid fibrils for AL amyloidosis. Phase 3 VITAL and AFFIRM-AL trials failed; development discontinued in May 2025.

Birth control

Birth control (contraception): methods to prevent pregnancy, from IUDs and implants (under 1% failure) to pills, condoms, and sterilization; emergency contraception within 5 days; global unmet need 164 million women.

Birth defect

Birth defect (congenital anomaly, congenital disorder): structural or functional abnormality present at or before birth. Affects 1 in 33 US births; leading cause of US infant death; causes mostly unknown; folic acid prevents neural tube defects.

Birth depression

Birth depression (ICD-11 KD30) is cardiorespiratory and neurological depression in a newborn, graded by 5-minute Apgar score (0-3, 4-6) or cord-blood metabolic acidaemia; distinct from maternal perinatal depression.

Birth injury to scalp

Birth injury to scalp (ICD-11 KA42): delivery-related scalp damage including caput succedaneum, subgaleal hemorrhage, cephalhematoma, bruising, and chignon, with layer-specific anatomy, incidence, and outcomes.

Birth weight

Birth weight is a newborn's first weight measured after birth; WHO defines low birth weight as below 2,500 g. In 2020, 19.8 million babies (14.7% globally) were born low birthweight, driving over 80% of neonatal deaths.

Birthmark

Birthmark: a colored or raised skin mark present at birth or shortly after, in vascular (salmon patch, hemangioma, port-wine stain) and pigmented (cafe-au-lait spot, congenital nevus, dermal melanocytosis) types, mostly benign but some signaling syndromes or melanoma risk.

Bisacodyl

Bisacodyl, a diphenylmethane stimulant laxative sold since the 1950s, is a prodrug converted by intestinal mucosal enzymes to BHPM; it treats constipation via dual prokinetic and secretory action, orally (6-12 h onset) or rectally (15-60 min).

Bisantrene

Bisantrene (Zantrene, CL-216942, NSC 337766) is an anthracenyl bishydrazone DNA-intercalating, topoisomerase II-inhibiting anticancer drug with doxorubicin-like activity but low cardiotoxicity, developed in the 1980s and rediscovered as an FTO inhibitor for AML.

Bishop score

Bishop score (cervix score, pelvic score): 0-13 digital cervical assessment of dilation, effacement, station, consistency, and position, devised by Edward Bishop in 1964 to predict labor induction success; simplified and modified variants exist.

Bismuth quadruple therapy

Bismuth quadruple therapy (BQT) is a four-drug regimen of a proton pump inhibitor, bismuth, tetracycline, and metronidazole that eradicates Helicobacter pylori; the 2024 ACG guideline names it the preferred first-line treatment when antibiotic susceptibility is unknown.

Bismuth subsalicylate

Bismuth subsalicylate (BSS, Pepto-Bismol, Kaopectate) is an OTC antidiarrheal and stomach remedy, C7H5BiO4, that converts in the gut to salicylic acid and poorly absorbed bismuth salts; used for diarrhea and travelers' diarrhea prevention.

Bisoprolol

Bisoprolol, a beta1-selective cardioselective beta-blocker (bisoprolol fumarate), treats hypertension and chronic heart failure; CIBIS-II showed mortality reduction (HR 0.66), making it one of three evidence-based heart failure beta-blockers.

Bispecific antibody therapy

Bispecific antibody therapy is a cancer and immune-disorder treatment using engineered antibodies that bind two antigens at once, often directing T cells to kill tumor cells.

Bispectral index monitoring

Bispectral index monitoring is a processed-EEG technique that turns forehead readings into a 0 to 100 score of hypnotic depth, FDA-cleared in 1996 and widely used to guide anesthesia.

Bisphosphonate

Bisphosphonates (diphosphonates) are P–C–P bone-seeking drugs inhibiting osteoclasts; first-line for osteoporosis, Paget's disease, and metastatic bone disease. Key agents: alendronate, risedronate, zoledronate; first clinical use etidronate, 1968.

Bite Force

Bite force, or occlusal force, is the force exerted by the jaw muscles on teeth, measured in newtons; healthy adults reach 300-600 N in the molar region, with male, posterior, and bilateral values higher.

Bitemporal hemianopsia

Bitemporal hemianopsia (bitemporal hemianopia): loss of the temporal half of the visual field in both eyes, classically from a pituitary adenoma or other lesion compressing crossing nasal fibers at the optic chiasm.

Bitewing radiography

Bitewing radiography is a dental X-ray technique in which the receptor is held between the teeth so one exposure records the crowns of upper and lower teeth.

Bithionol

Bithionol (Bitin, Actamer), a chlorinated bisphenol anthelmintic, treated Fasciola, Paragonimus, and tapeworm infections before photosensitivity led to its 1967 FDA withdrawal; now obsolete as a drug but studied for antibacterial and anticancer repurposing.

Bitolterol

Bitolterol (Tornalate, bitolterol mesylate) is a discontinued inhaled beta-2 agonist bronchodilator prodrug of colterol for asthma and COPD, FDA-approved 1984 and withdrawn in 2001.