Human health and medicine

Catalepsy (κατάληψις)

Catalepsy (κατάληψις) is a neuropsychiatric sign of prolonged involuntary posture-holding against gravity, a cardinal motor feature of catatonia in DSM-5, assessed by physical examination and distinct from cataplexy.

Catamenial pneumothorax

Catamenial pneumothorax is recurrent lung collapse in reproductive-age women within 72 hours before or after menstruation, the most common form of thoracic endometriosis syndrome, usually right-sided, treated with VATS, pleurodesis, diaphragm repair, and hormonal therapy.

Cataplexy

Cataplexy: sudden, brief, emotion-triggered bilateral loss of muscle tone with preserved consciousness, the hallmark of narcolepsy type 1; diagnosed clinically, treated with sodium oxybate or pitolisant.

Cataract

Cataract: clouding of the eye's lens, mainly age-related; leading cause of curable blindness (94 million affected). Treated only by surgery, phacoemulsification or manual small incision cataract surgery, with comparable outcomes.

Cataract surgery

Cataract surgery removes the eye's clouded lens and implants an intraocular lens; standard technique is Kelman's 1967 phacoemulsification through sub-3 mm incisions, evolved from couching and Daviel's 1750 extraction.

Cataract-growth hormone deficiency-sensory neuropathy-sensorineural hearing loss-skeletal dysplasia syndrome

CAGSSS (OMIM 616007, ORPHA:436174) is an ultra-rare autosomal recessive mitochondrial disease caused by IARS2 mutations, combining cataract, growth hormone deficiency, sensory neuropathy, sensorineural hearing loss, and spondyloepimetaphyseal dysplasia with normal cognition.

Cataract-intellectual disability-hypogonadism syndrome

Cataract-intellectual disability-hypogonadism syndrome, also called Martsolf syndrome, is a rare autosomal recessive genetic disorder featuring congenital cataract, mild-to-moderate intellectual disability, hypogonadism, and characteristic facial features.

Cataract-microcornea syndrome

Cataract-microcornea syndrome (CCMC, ORPHA:1377) is a rare genetic disorder combining congenital cataract with microcornea under 10 mm, without systemic anomalies; autosomal dominant or recessive, linked to crystallin, GJA8, MAF, ABCA3, and SOX2 genes.

Catarrh

Catarrh, also called postnasal drip, is a build-up of mucus in the nose, sinuses, and throat from infection, allergy, smoke, or nasal polyps; usually self-limiting, but chronic forms last months or years.

Catarrhal gingivitis

Catarrhal gingivitis, also called simple gingivitis (カタル性歯肉炎), is the common red, swollen, easily bleeding form of gum inflammation without attachment loss; ICD-11 code DA0B.1, mapped to ICD-10 K05X/K05.00.

Catastrophic antiphospholipid syndrome

Catastrophic antiphospholipid syndrome (CAPS, Asherson's syndrome): rare, life-threatening variant of antiphospholipid syndrome with multiorgan small-vessel thrombosis within days, ~1% of APS cases, 37% mortality, treated with heparin, steroids, plasma exchange or IVIG.

Catatonia

Catatonia: neuropsychiatric syndrome of abnormal motor behavior, volition, and behavior, first named by Kahlbaum in 1874. Diagnosed by DSM-5-TR (3 of 12 features) or ICD-11; treated with lorazepam and ECT.

Catatonia associated with another mental disorder

Catatonia associated with another mental disorder (ICD-11 6A40) is a catatonia diagnosis occurring with mood disorders, schizophrenia, or autism; diagnosis needs three psychomotor features, treatment is benzodiazepines or ECT.

Catatonic depression

Catatonic depression: major depressive disorder with catatonic features (DSM-5-TR specifier; ICD-11 catatonia associated with another mental disorder). Mutism, stupor, posturing; treated with lorazepam and ECT.

Catecholaminergic polymorphic ventricular tachycardia

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited cardiac arrhythmia syndrome in which exercise or emotional stress triggers ventricular tachycardia in a structurally normal heart.

Catequentinib

Catequentinib, also called anlotinib hydrochloride or AL3818, is an oral multi-target tyrosine kinase inhibitor targeting VEGFR2/3, FGFR1-4, and PDGFR; NMPA-approved in 2018 for advanced NSCLC after two chemotherapy lines.

Catherine Reinis Lucey

Catherine Reinis Lucey is an American physician and medical educator, Executive Vice Chancellor and Provost at UCSF since 2023, elected to the National Academy of Medicine in 2018.

Catheter

Catheter, from Greek kathienai, a flexible tube for delivering or withdrawing body fluids. Covers urinary, vascular (CVC, PICC, PIVC), and cardiac catheters, their history from antiquity, and infection risks like CAUTI and CLABSI.

Catheter ablation

Catheter ablation (radiofrequency ablation) destroys small areas of heart tissue via catheter to treat arrhythmias, especially atrial fibrillation. First done by Scheinman in 1981; Haissaguerre's 1998 pulmonary vein finding; meta-analyses show reduced mortality versus drugs; pulsed field ablation is the newest energy.

Sep 29, 2026

Catheter ablation of atrial fibrillation

Catheter ablation of atrial fibrillation, also known as atrial fibrillation ablation, is a cardiac electrophysiology procedure that uses catheter-delivered energy to electrically isolate the pulmonary veins and suppress AF.

Catheter Obstruction

Catheter obstruction, also called catheter blockage or encrustation, blocks urine flow in indwelling urinary catheters, mainly via Proteus mirabilis crystalline biofilms; affects 40-50% of long-term catheterized patients; saline irrigation shows no benefit.

Catheterization

Catheterization: insertion of a tube into a duct, vessel, hollow organ, or body cavity to inject or withdraw fluids. Covers urinary catheterization from the Ebers papyrus and the Foley catheter, and cardiac catheterization from Forssmann's 1929 self-experiment.

Cathexis

Cathexis (Freud's Besetzung) is the psychoanalytic investment of psychic or libidinal energy in a person, object, or idea; coined by Strachey, with variants hypercathexis, decathexis, and object cathexis.

Sep 29, 2026

Cathodal transcranial direct current stimulation

Cathodal transcranial direct current stimulation (cathodal tDCS) is a noninvasive brain stimulation technique that passes a weak direct current through the scalp, conventionally to reduce cortical excitability.

CATIS trial

CATIS (China Antihypertensive Trial in Acute Ischemic Stroke, NCT01840072) was a 4071-patient randomized trial in 26 Chinese hospitals testing immediate blood pressure lowering in acute ischemic stroke; it was neutral, as was CATIS-2, while CATIS-ICAS tests rivaroxaban plus aspirin.

Catridecacog

Catridecacog (Tretten, NovoThirteen) is Novo Nordisk's recombinant coagulation factor XIII A-subunit made in yeast, given as 35 IU/kg monthly intravenously to prevent bleeding in congenital FXIII A-subunit deficiency.

Catumaxomab

Catumaxomab (Removab, Korjuny) is a bispecific trifunctional rat-mouse anti-EpCAM x anti-CD3 antibody for malignant ascites; EU-approved 2009, withdrawn 2017, reapproved 2025.

Caturbhadra kvatha curna

Caturbhadra kvatha curna (Cāturbhadra kvātha cūrṇa, चतुर्भद्र), an Ayurvedic four-herb decoction powder from Bhaishajya Ratnavali (ginger, Tinospora, Aconitum heterophyllum, Cyperus rotundus) for dyspepsia and Grahani roga; distinct from Balachaturbhadra churna.

Caturbhuja rasa

Caturbhuja rasa (चतुर्भुजरस), also Chaturbhuj Ras, is a Kharaliya herbo-metallic Ayurvedic Rasashastra formulation of mercury, gold, arsenic disulphide, and orpiment, dosed at 125 mg, used classically for psychosis, epilepsy, and Kampavata.