Human health and medicine

Interamerican Society of Cardiology

Interamerican Society of Cardiology (SIAC/IASC), founded 1944 in Mexico City by Ignacio Chávez, is a federation of 28 national cardiology societies of the Americas plus Spain, with 40,000+ cardiologists, PAHO relations since 2012, annual congresses, and the journal RIAC.

Interaural time difference

Interaural time difference (ITD): the arrival-time difference of a sound at the two ears, the dominant cue for horizontal sound localization at low frequencies, encoded by coincidence-detecting MSO neurons, with human sensitivity near 10 microseconds and a maximum near 763 microseconds.

Interceptive orthodontic treatment

Interceptive orthodontic treatment is the short-term correction of developing malocclusions and jaw discrepancies in children, redirecting growth in 9 to 15 months to reduce or avoid later treatment.

Interceptive Orthodontics

Interceptive orthodontics is the branch of orthodontics that treats a developing malocclusion during the primary or mixed dentition, typically starting no later than age 7, to simplify later care.

Intercostal nerve block

An intercostal nerve block is a regional anesthesia technique that numbs the chest wall, used after chest, breast, or abdominal surgery and for rib fractures.

Intercostal nerves

Intercostal nerves (nervi intercostales) are the anterior rami of thoracic spinal nerves T1-T11 running in the costal grooves; T7-T11 continue as thoracoabdominal nerves, T12 is the subcostal nerve, and T2 gives the intercostobrachial nerve.

Intercostal neuropathy

Intercostal neuropathy (intercostal neuralgia; ICD-10 G58.0, ICD-11 8C12.0) is peripheral neuropathy of the intercostal nerves causing band-like chest wall pain, mainly after thoracotomy or herpes zoster, treated with blocks, RFA, and surgery.

Intercostal pain

Intercostal pain, also called intercostal neuralgia, is neuropathic pain along an intercostal nerve between the ribs, usually band-like or dermatomal, caused mainly by thoracotomy or herpes zoster and diagnosed after excluding cardiac, pulmonary, and gastrointestinal causes.

Intercostal plane block

The intercostal plane block is a regional anesthesia technique targeting the intercostal sulcus to numb nerves. It provides dermatomal numbness for thoracic and upper abdominal pain after surgery.

Interdigitating dendritic cell sarcoma

Interdigitating dendritic cell sarcoma (IDCS), also called interdigitating cell or reticulum cell sarcoma, is an extremely rare aggressive dendritic cell tumor of lymph nodes and extranodal sites, with roughly 100 reported cases, treated mainly by surgical resection.

Interfascial plane block

An interfascial plane block is a regional anesthesia technique that injects local anesthetic between fascial layers to numb nerves, used in abdominal, breast, and thoracic surgery.

Interferon

Interferon (IFN), a group of signaling proteins described by Alick Isaacs and Jean Lindenmann in 1957, are cytokines secreted in response to viruses to inhibit cell growth.

Interferon alfa

Interferon alfa (IFN-α, interferon alpha) is a type I interferon cytokine; recombinant alfa-2a and alfa-2b, FDA-approved since 1986, treat hepatitis B and C, myeloproliferative neoplasms, and cancers.

Interferon alfacon-1

Interferon alfacon-1 (consensus interferon, Infergen) is a synthetic 166-amino-acid type I interferon alpha for chronic hepatitis C, FDA-approved 1997, withdrawn in the EU in 2006.

Interferon beta

Interferon beta (IFN-β), type I interferon; recombinant products Betaseron, Avonex, Rebif, Plegridy; first disease-modifying therapy for relapsing-remitting multiple sclerosis, FDA approved 1993, reducing relapses 15-36%.

Interferon beta-1a

Interferon beta-1a, sold as Avonex, Rebif, and pegylated Plegridy, is a glycosylated type I interferon drug for relapsing multiple sclerosis; FDA-approved from 1996, it reduces relapses about 30% versus placebo.

Oct 20, 2026

Interferon beta-1b

Interferon beta-1b (Betaseron, Betaferon, Extavia) is a recombinant, non-glycosylated 165-amino-acid type I interferon from E. coli, injected 250 µg every other day; the first FDA-approved MS disease-modifying therapy (1993).

Interferon gamma release assay

The interferon gamma release assay, or IGRA, is a blood test that measures interferon-gamma released by T cells exposed to tuberculosis antigens, detecting infection, mainly latent tuberculosis, without BCG interference.

InterHeart study

The INTERHEART study was a case-control study of first heart attacks across 52 countries, finding that nine modifiable risk factors account for more than 90% of heart attack risk worldwide.

Interlaminar discectomy

Interlaminar discectomy is a spine operation removing herniated lumbar disc material through the natural gap between laminae, decompressing nerve roots to relieve sciatic leg pain.

Oct 20, 2026

Intermediate age-related macular degeneration

Intermediate age-related macular degeneration (iAMD), AREDS category 3, is AMD with extensive medium drusen (63–124 μm) or large drusen (≥125 μm); it carries high progression risk to wet AMD or geographic atrophy and is treated with AREDS2 supplements.

Intermediate atrioventricular septal defect

Intermediate atrioventricular septal defect (intermediate or transitional AV canal defect, ORPHA:576242) is a rare congenital AVSD variant with a common atrioventricular junction, primum ASD, and restrictive ventricular shunt; sources disagree on valve orifice number and VSD size, and repair is done in infancy.

Intermediate Care Facilities

Intermediate care facilities are residential health care settings between a hospital and home support, serving people with intellectual disabilities in the US and frail older people in the UK.

Intermediate generalized junctional epidermolysis bullosa

Intermediate generalized junctional epidermolysis bullosa, formerly called JEB mitis or non-Herlitz JEB, is a non-lethal autosomal recessive skin-fragility disorder with blistering from birth that usually improves.

Intermediate osteopetrosis

Intermediate osteopetrosis (ORPHA:210110, intermediate autosomal osteopetrosis, IAO) is a rare genetic bone dysplasia with dense, fracture-prone bones, anemia, and sandwich vertebra radiographs, onset in childhood, genes CLCN7, PLEKHM1, TCIRG1, treated supportively.