Human health and medicine

Hyaluronidase deficiency

Hyaluronidase deficiency (MPS IX, Natowicz syndrome) is an ultra-rare autosomal recessive lysosomal storage disease caused by HYAL1 deficiency, with hyaluronan storage, periarticular masses, and joint disease; only four patients reported.

Oct 22, 2026

Hyangyak Jipseongbang

Hyangyak Jipseongbang (향약집성방) is an 85-volume Korean medical encyclopedia completed in 1433 under King Sejong, gathering prescriptions based on medicinal herbs produced in the Korean peninsula.

Hybrid ablation

Hybrid ablation is a treatment for atrial fibrillation that combines minimally invasive surgical ablation on the outside of the heart with catheter ablation on the inside, so lesions extend through the full atrial wall.

Hybrid argon plasma coagulation

Hybrid argon plasma coagulation (HAPC, also HybridAPC) is an endoscopic technique that combines submucosal saline injection with argon plasma coagulation through one catheter, mainly for Barrett's esophagus ablation.

Hybrid coronary revascularization

Hybrid coronary revascularization (HCR) combines minimally invasive LIMA-LAD bypass grafting with PCI for non-LAD lesions in multivessel coronary disease; introduced in the mid-1990s, it lowers perioperative morbidity versus CABG but raises repeat revascularization.

Hybrid imaging

Hybrid imaging is a medical imaging approach combining an anatomical scan (CT or MRI) with a functional scan (PET or SPECT), with main pairs PET/CT, PET/MRI, and SPECT/CT.

Hybrid Renal Replacement Therapy

Hybrid renal replacement therapy (SLED, PIRRT, extended daily dialysis) combines CRRT-like slow solute and fluid removal with intermittent hemodialysis equipment; trials show mortality and hemodynamic outcomes comparable to CRRT at lower cost.

Hybrid repair

Hybrid repair is a vascular surgical technique that combines open debranching of aortic branch vessels with endovascular stent-graft exclusion of the aneurysm, avoiding parts of full open repair.

Hybridoma technology

Hybridoma technology is a laboratory method for producing monoclonal antibodies by fusing short-lived antibody-producing B cells with immortal myeloma cells; described in 1975, it earned the 1984 Nobel Prize.

Hybutimibe

Hybutimibe (海博麦布, hyzetimibe, HS-25; brand Saisimei) is an oral NPC1L1 cholesterol absorption inhibitor made by Zhejiang Hisun, approved in China June 2021 for primary hypercholesterolemia, dosed 10 or 20 mg daily, adding about 16% LDL-C reduction to statins.

HYCOR study

HYCOR (Hybrid-sensor Breath Analysis for Colorectal Cancer Screening, NCT05173077) is a University of Latvia ERDF-funded project, 2021-2023, testing a MOX-plus-IR hybrid breath sensor analyzer and GC-MS VOC markers for colorectal cancer screening, distinct from the unrelated Hycor Biomedical allergy company.

Hydralazine

Hydralazine, a direct arteriolar vasodilator antihypertensive introduced in 1951, treats severe hypertension in pregnancy, resistant hypertension, and, with isosorbide dinitrate, Black patients with heart failure; key risk is drug-induced lupus.

Hydralazine/isosorbide dinitrate

Hydralazine/isosorbide dinitrate (BiDil) is a fixed-dose vasodilator combination for heart failure with reduced ejection fraction, best evidenced in self-identified Black patients by A-HeFT, which showed 43% lower mortality.

Hydranencephaly

Hydranencephaly is a rare congenital malformation in which the cerebral hemispheres are absent and replaced by a cerebrospinal fluid-filled sac, usually caused by blocked carotid arteries in the womb.

Oct 20, 2026

Hydroa vacciniforme

Hydroa vacciniforme (Bazin's hydroa vacciniforme) is a rare childhood photodermatosis causing vesicles on sun-exposed skin that heal with permanent varioliform scars; severe EBV-associated forms (HVLPD) can progress to lymphoma.

Hydroa vacciniforme-like lymphoma

Hydroa vacciniforme-like lymphoma (HVLL), now hydroa vacciniforme lymphoproliferative disorder, is a rare EBV-positive T/NK-cell lymphoproliferative disease of childhood, mainly in Asia and Latin America, with ulcerative skin lesions and risk of systemic lymphoma.

Hydrocele

Hydrocele, also called hydrocele of the tunica vaginalis or canal of Nuck hydrocele in females, is serous fluid collection around the testis causing scrotal swelling; common in newborns, treated by hydrocelectomy or aspiration with sclerotherapy.

Hydrocele or spermatocele

Hydrocele or spermatocele (ICD-11 GB00; ICD-10 N43): scrotal fluid collections. Hydrocele is serous fluid in the tunica vaginalis or spermatic cord; spermatocele is an epididymal cyst containing dead sperm, usually painless and untreated.

Hydrocele testis

Hydrocele testis, fluid collection in the tunica vaginalis around the testis, causes painless scrotal swelling; common in newborns (at least 5%), often resolving by age 1, with communicating, noncommunicating, and filarial forms treated by observation, hydrocelectomy, or sclerotherapy.

Hydrocephalus

Hydrocephalus, "water on the brain," is abnormal CSF build-up in the brain's ventricles. Treated by shunt surgery or endoscopic third ventriculostomy (ETV), often with CPC; congenital, acquired, and NPH types.

Hydrochlorothiazide

Hydrochlorothiazide (HCTZ) is a thiazide-type diuretic inhibiting the renal NCC transporter, used for hypertension and edema; the most prescribed US thiazide (~31.8 million 2023 prescriptions), with electrolyte, metabolic, and small skin-cancer risks.

Hydrocodone

Hydrocodone (dihydrocodeinone) is a semi-synthetic opioid analgesic and antitussive, a full mu-opioid agonist, sold mainly in combination products like Vicodin and Tussionex; DEA Schedule II since October 2014, with about 136 million US prescriptions in 2011.

Hydrocodone/paracetamol

Hydrocodone/paracetamol, also called hydrocodone/acetaminophen and formerly sold as Vicodin, is a prescription tablet combining the opioid hydrocodone with acetaminophen, prescribed in the United States for severe pain.

Hydrocortamate

Hydrocortamate (CAS 76-47-1) is a synthetic glucocorticoid, a hydrocortisone diethylaminoacetate ester, glucocorticoid receptor agonist used topically for dermatoses; marketed as Magnacort 0.5% ointment, US-approved 1956, now discontinued.

Hydrocortisone

Hydrocortisone (cortisol) is the synthetic form of the adrenal glucocorticoid cortisol, used for cortisol replacement in adrenal insufficiency (15–25 mg/day divided) and as an anti-inflammatory; discovered as Compound F at Mayo Clinic, 1950 Nobel Prize context.