Human health and medicine

Bietti crystalline dystrophy

Bietti crystalline dystrophy (BCD, Bietti crystalline corneoretinal dystrophy) is a rare autosomal recessive retinal disease caused by CYP4V2 mutations, marked by yellow-white retinal crystals, night blindness, and progressive vision loss.

Bifascicular block

Bifascicular block, also called bifascicular heart block, is an ECG conduction disorder affecting two of three His-Purkinje fascicles (RBBB plus LAFB or LPFB, or LBBB), risking complete AV block, syncope, and pacemaker decisions.

Bifendate

Bifendate (联苯双酯, DDB, CAS 73536-69-3) is a Chinese synthetic ALT-lowering hepatoprotective drug derived from schisandrin C of Schisandra chinensis, developed in the 1970s and marketed in the early 1980s.

Bifeprunox

Bifeprunox (DU 127090), an unapproved dopamine D2 and serotonin 5-HT1A partial agonist antipsychotic for schizophrenia; FDA rejected it in 2007 and Solvay-Lundbeck stopped development in 2009.

Bifid nose

Bifid nose (cleft nose, double nose, internasal dysplasia) is a rare congenital midline nasal cleft, Tessier 0, ranging from a columellar groove to two half noses; airway usually adequate, associated with frontonasal dysplasia and hypertelorism.

Oct 20, 2026

Bifid rib

A bifid rib, also called a bifurcated or forked rib, is a congenital anomaly where a rib splits into two branches at its sternal end.

Bifid scrotum

Bifid scrotum, also called scrotal cleft, is a congenital midline cleft of the scrotum from incomplete labioscrotal fold fusion, usually with severe hypospadias, sometimes signaling a disorder of sex development requiring genetic evaluation.

Bifid uvula

Bifid uvula (cleft uvula, uvular cleft): a congenital split of the uvula, the mildest form of cleft palate, seen in roughly 2% of people. Usually isolated and harmless, but a marker for possible submucous cleft palate and syndromes such as Loeys-Dietz.

Bifonazole

Bifonazole (Canespor, Mycospor) is a halogen-free imidazole topical antifungal, ATC D01AC10, marketed since 1982. Its 1% cream, gel, solution, and powder are applied once daily for dermatophytoses, cutaneous candidiasis, and pityriasis versicolor.

Bifunctional enzyme deficiency

Bifunctional enzyme deficiency (D-bifunctional protein deficiency, DBIF, pseudo-Zellweger syndrome) is a rare autosomal recessive peroxisomal beta-oxidation disorder caused by HSD17B4 mutations, causing neonatal hypotonia, seizures, and VLCFA accumulation.

BIG 1-98 trial

BIG 1-98 (NCT00004205), a phase III trial by IBCSG/Breast International Group, randomized 8,010 postmenopausal women with hormone receptor-positive early breast cancer to letrozole or tamoxifen, alone or sequenced, showing letrozole improved disease-free survival.

Bigeminy

Bigeminy: a heart rhythm in which every normal beat is followed by a premature ectopic beat, atrial or ventricular. Also called bigeminal rhythm. Causes include heart disease, stimulants and electrolyte imbalance; diagnosed by ECG and Holter; ablation succeeds in 75% or more of cases.

Bikini waxing

Bikini waxing removes pubic hair by pulling it from the root with wax; the Brazilian variant removes all or most hair. Results last three to four weeks. Key risks are burns, folliculitis, and infection; waxing causes fewer repeated injuries than razor shaving.

Bikram Yoga

Bikram Yoga: a 90-minute hot yoga sequence of 26 postures and 2 breathing exercises at 105°F, 40% humidity, created by Bikram Choudhury in 1970s America; rebranded by many studios after abuse lawsuits.

Bilastine

Bilastine (Bilaxten) is a second-generation, non-sedating H1-antihistamine approved in Europe in 2010 for allergic rhinoconjunctivitis and urticaria, dosed 20 mg daily, not metabolized, excreted unchanged, and affected by grapefruit juice and P-gp inhibitors.

Bilateral acute depigmentation of the iris

Bilateral acute depigmentation of the iris (BADI) is a rare eye disorder causing sudden pigment loss in both irises, with photophobia and red eye that usually resolves on its own.

Bilateral cochlear implantation

Bilateral cochlear implantation is the surgical placement of cochlear implants in both ears, improving speech understanding in noise and sound localization beyond what one implant provides.

Bilateral diffuse uveal melanocytic proliferation disease

BDUMP (bilateral diffuse uveal melanocytic proliferation, paraneoplastic uveal melanocytic hyperplasia) is a rare paraneoplastic syndrome of benign uveal melanocyte proliferation from occult cancer, causing bilateral vision loss, cataracts, and retinal detachment.

Bilateral lung transplant

Bilateral lung transplant is surgery that replaces both of a patient's lungs with donor lungs, the dominant form of lung transplantation, used to treat end-stage lung disease.

Bilateral stimulation (psychology)

Bilateral stimulation is the rhythmic alternating left–right presentation of a sensory signal, most often guided eye movements, taps, or tones, used in psychotherapy to accompany recall of distressing memories.

Bilateral striopallidodentate calcinosis

Bilateral striopallidodentate calcinosis, also known as primary familial brain calcification or Fahr's disease, is a rare inherited disorder marked by calcium deposits in the basal ganglia.

Bile

Bile (gall) is the yellowish-green digestive fluid made by the liver (800–1,000 mL/day), stored in the gallbladder, and released into the duodenum; its bile salts emulsify fats, carry bilirubin out, and recycle via enterohepatic circulation, while bile acids signal through FXR and TGR5.

Bile acid malabsorption

Bile acid malabsorption (BAM, bile acid diarrhea/BAD): chronic watery diarrhea from excess colonic bile acids due to ileal reabsorption failure or excess synthesis; types 1–3; diagnosed by SeHCAT, serum C4, FGF19; treated with bile acid sequestrants.

Bile acid sequestrant

Bile acid sequestrants (BAS, bile acid resins): cholestyramine, colestipol, colesevelam. Non-absorbed cationic polymer gels binding bile acids in the gut, lowering LDL-C 15-30%, also improving glycemic control.

Bile duct

Bile ducts are the tubular channels that carry bile from the liver to the gallbladder and small intestine; their main trunk is the common bile duct, about 10 cm long, whose obstruction can cause cholangitis or cholangiocarcinoma.

Bile duct resection

Bile duct resection is a surgical procedure removing part or all of the bile duct, usually with reconstruction of biliary drainage, to treat cancer, strictures, and other biliary disease.

Biliary atresia

Biliary atresia is a neonatal disease in which intra- and extrahepatic bile ducts are scarred and blocked, causing cholestasis and cirrhosis; treated by Kasai portoenterostomy, ideally before 30–90 days of life, often followed by liver transplant.

Biliary atresia with splenic malformation syndrome

Biliary atresia with splenic malformation syndrome (BASM), also called biliary atresia splenic malformation, is a syndromic form of biliary atresia with polysplenia, asplenia, situs inversus, preduodenal portal vein, and cardiac defects, affecting about 10–15% of European and American BA infants.

Biliary colic

Biliary colic: pain from the gallbladder or bile duct contracting around a gallstone; epigastric, steady pain lasting 2 to 4 hours; treated with laparoscopic cholecystectomy.