Human health and medicine

Kenneth J. Ryan

Kenneth J. Ryan is a physician-scientist known for 1980s research in reproductive endocrinology and obstetric epidemiology, proposing that insulin and luteinizing hormone jointly regulate ovarian androgen production.

Kenny-Caffey syndrome

Kenny-Caffey syndrome (KCS, Kenny syndrome) is a rare inherited bone dysplasia with short stature, medullary stenosis, and hypoparathyroid hypocalcemia; dominant FAM111A (type 2) and recessive TBCE (type 1) forms.

Kenyatta National Hospital

Kenyatta National Hospital (KNH) is Kenya's largest public referral and teaching hospital in Upper Hill, Nairobi, founded in 1901 and sitting at Level 6, the apex of the country's health system.

Kenyon cell

Kenyon cells are the intrinsic neurons of the insect mushroom bodies (corpora pedunculata), named after Kenyon (1896); from about 2,500 in Drosophila to 230,000 in cockroach, they form the parallel learning and memory circuit for olfactory conditioning.

Keppen-Lubinsky syndrome

Keppen-Lubinsky syndrome (KPLBS, OMIM 614098), a rare autosomal dominant KCNJ6/GIRK2 channelopathy causing generalized lipodystrophy, progeroid features, severe intellectual disability, and facial dysmorphism; de novo selectivity-filter mutations, fewer than 1 in 1,000,000 prevalence.

Keratectomy

Keratectomy is a corneal surgical procedure that removes corneal tissue to correct refractive error or treat anterior corneal disease, including laser forms PRK and PTK.

Keratitis

Keratitis, inflammation of the cornea; microbial keratitis (bacterial, fungal, viral, Acanthamoeba) is a sight-threatening infection, with contact lens wear the main risk factor in Western settings.

Keratitis fugax hereditaria

Keratitis fugax hereditaria (keratoendotheliitis fugax hereditaria, KFH) is a rare autosomal dominant corneal autoinflammatory disease caused by the NLRP3 variant c.61G>C, causing recurrent unilateral painful attacks, blurred vision, and corneal opacities, mainly in people of Finnish descent.

Keratoacanthoma

Keratoacanthoma (KA), a rapidly growing hair-follicle-derived skin tumour that often regresses spontaneously over 4-6 months; closely mimics well-differentiated squamous cell carcinoma, driving a classification controversy and surgical excision as standard care.

Keratoconus

Keratoconus, also called conical cornea, is a bilateral noninflammatory ectatic corneal disease causing progressive thinning, cone-shaped bulging, and irregular astigmatism; managed with contact lenses, corneal cross-linking, ring segments, or keratoplasty.

Keratocystic odontogenic tumor

Keratocystic odontogenic tumor (KCOT), the WHO 2005 name for the odontogenic keratocyst, an aggressive parakeratinized jaw cyst linked to PTCH1 mutations and Gorlin syndrome; reclassified back as a cyst in WHO 2017 and 2022.

Keratoderma hereditarium mutilans

Keratoderma hereditarium mutilans, or Vohwinkel syndrome (OMIM 124500), is a rare autosomal dominant mutilating palmoplantar keratoderma with honeycomb keratosis, pseudoainhum, and deafness; classic form from GJB2 (connexin 26), ichthyosiform variant from LOR.

Keratoderma hereditarium mutilans with ichthyosis

Keratoderma hereditarium mutilans with ichthyosis, also called loricrin keratoderma or Camisa disease, is a rare autosomal dominant Vohwinkel syndrome variant caused by LOR mutations, featuring honeycomb palmoplantar keratoderma, pseudoainhum, and ichthyosis.

Keratolytic winter erythema

Keratolytic winter erythema (Oudtshoorn skin disease, erythrokeratolysis hiemalis, OMIM 148370) is a rare autosomal dominant disorder of recurrent winter-worsened palmoplantar peeling and erythema, caused by a duplicated enhancer upstream of CTSB on chromosome 8p22-p23, common in South African Afrikaans-speakers via founder François Renier Duminy.

Keratometry

Keratometry is an ophthalmic measurement technique that determines the curvature of the front corneal surface and converts it to dioptric power, mainly for contact lens fitting and cataract surgery.

Keratomileusis

Keratomileusis, Greek for sculptured cornea, is a family of refractive surgical procedures that reshape the cornea to correct myopia, hyperopia, and astigmatism, including LASIK, PRK, and SMILE.

Keratosis follicularis spinulosa decalvans

Keratosis follicularis spinulosa decalvans (Siemens syndrome, KFSD) is a rare X-linked genodermatosis causing follicular hyperkeratosis, scarring alopecia of scalp, eyebrows, and eyelashes, photophobia, and corneal dystrophy, mainly from MBTPS2 mutations.

Keratosis linearis-ichthyosis congenita-sclerosing keratoderma syndrome

KLICK syndrome (keratosis linearis-ichthyosis congenita-sclerosing keratoderma syndrome, OMIM 601952) is a rare autosomal recessive genodermatosis caused by a c.-95delC deletion in the POMP 5′ UTR, causing palmoplantar keratoderma, linear flexural keratoses, ichthyosis, and finger constrictions.

Keratosis pilaris

Keratosis pilaris (KP, chicken skin) is a common benign follicular hyperkeratosis: keratin plugs hair follicles, causing rough sandpaper-like bumps on upper arms and thighs, worse in winter, treated with urea, lactic acid, salicylic acid, or Nd:YAG laser.

Keratotomy

Keratotomy is eye surgery that cuts incisions in the cornea to change its curvature and correct refractive error; radial keratotomy for myopia peaked in the 1980s before lasers replaced it.

Kerion celsi

Kerion celsi is the severe inflammatory form of tinea capitis, a suppurative fungal scalp infection caused mainly by Trichophyton tonsurans and Microsporum canis, treated with systemic antifungals and prone to scarring alopecia.

Kernicterus

Kernicterus, also called bilirubin encephalopathy and kernicterus spectrum disorder, is irreversible neonatal brain damage from unconjugated bilirubin crossing the blood-brain barrier, causing athetoid cerebral palsy and hearing loss; preventable with phototherapy and exchange transfusion.

Kerry Daynes

Kerry Daynes, British consultant forensic psychologist, author of The Dark Side of the Mind and What Lies Buried, TV's 'The Profiler' on Faking It, and anti-stalking campaigner who survived a six-year stalking campaign.

Ketamine

Ketamine, a phencyclidine-derived dissociative anesthetic and NMDA receptor antagonist (Ketalar; esketamine as Spravato), synthesized 1962, FDA-approved 1970, and repurposed since 2000 as a rapid-acting antidepressant for treatment-resistant depression and acute suicidality.

Oct 15, 2026

Ketanserin

Ketanserin is a selective antagonist of the serotonin 5-HT2A receptor, developed by Janssen Pharmaceutica in 1980, studied clinically as an antihypertensive and antiplatelet agent and widely used in laboratory research.

Ketazolam

Ketazolam (U-28,774; brands Anxon, Marcen, Sedotime, Solatran, Unakalm) is an Upjohn benzodiazepine anxiolytic that converts to diazepam in blood, was trialed as once-daily bedtime anxiety treatment, is UN Schedule IV, and has no FDA-approved product.

Ketchup as a vegetable

Ketchup as a vegetable: 1981 USDA proposal under Reagan to credit ketchup and pickle relish toward school lunch vegetable requirements after budget cuts; ridiculed, cancelled September 25, 1981, never enacted.

Ketoacidosis

Ketoacidosis, including diabetic ketoacidosis (DKA), alcoholic, starvation, and euglycemic forms: ketone accumulation from insulin deficiency makes blood acidic; diagnosed by ketones, pH, bicarbonate; treated with fluids, electrolytes, insulin.

Ketoconazole

Ketoconazole (Nizoral) is a Janssen imidazole antifungal, the first oral broad-spectrum drug for systemic mycoses (announced 1977, FDA-approved 1981); oral use was suspended in the EU in 2013 over hepatotoxicity, while topical forms and Cushing's syndrome use remain.