Human health and medicine

Insulin, neutral

Insulin, neutral (neutral regular or soluble insulin) is short-acting insulin formulated as a clear solution at neutral pH, unlike early acidic preparations. Known as regular insulin (Humulin R, Novolin R, Insuman Rapid), it acts in 30-60 minutes, peaks at 2-4 hours, and lasts 6-8 hours.

Insulinoma

Insulinoma, a rare insulin-secreting pancreatic beta-cell neuroendocrine tumor (4 per million yearly), causes fasting hypoglycemia; diagnosed by Whipple triad and supervised fast, mostly benign and cured surgically.

Insurance Benefits

Insurance benefits, also called health benefits, are the payments or services an insurance policy or prepayment program must provide when specified conditions are met, defining which medical services are covered and with what cost sharing.

Insys Therapeutics

Insys Therapeutics, Arizona pharmaceutical maker of the fentanyl spray Subsys; founder John Kapoor and executives convicted of racketeering in 2019, $225 million settlement, Chapter 11 bankruptcy, first opioid maker to fail.

Intact dilation and extraction

Intact dilation and extraction (D&X, intact D&E), also called partial-birth abortion, is a second/third-trimester procedure extracting an intact fetus after cranial decompression; devised by Martin Haskell in 1992 and federally banned in the US since 2003.

Integrated Child Development Services

Integrated Child Development Services (ICDS), India's 1975 flagship programme for children 0-6, pregnant women, and lactating mothers, delivering six services through over 1.3 million Anganwadi centres; now subsumed under Mission Saksham Anganwadi and Poshan 2.0.

Integrated information theory

Integrated information theory (IIT), proposed by Giulio Tononi in 2004, identifies consciousness with integrated information measured by Φ, with versions 3.0 and 4.0, a clinical proxy (PCI), critiques by Aaronson and a 124-signer pseudoscience letter, and mixed 2025 adversarial-collaboration results.

Integrated Management of Childhood Illness

Integrated Management of Childhood Illness (IMCI) is a WHO and UNICEF guideline, launched in 1995, for assessing and treating major childhood illnesses at first-level clinics without laboratories.

Integrative Oncology

Integrative oncology (IO) is a patient-centered, evidence-based field of cancer care that combines mind and body practices, natural products, and lifestyle changes with standard treatment, aiming to improve quality of life and symptoms throughout care.

Integumentary system

Integumentary system: the body's outer covering of skin, hair, nails, and glands (MeSH D034582). Largest organ, about 6 pounds; provides barrier, thermoregulation, vitamin D synthesis, and sensation.

Intellectual disability

Intellectual disability: significant limitations in intellectual functioning and adaptive behavior beginning before age 18 (AAIDD: 22). Formerly "mental retardation"; ICD-11 calls it intellectual developmental disorder. Causes include Down syndrome, FASD; US child prevalence 11-13.4 per 1,000.

Intellectual disability-autism-speech apraxia-craniofacial dysmorphism syndrome

Pilarowski-Bjornsson syndrome (PILBOS), also called intellectual disability-autism-speech apraxia-craniofacial dysmorphism syndrome, is a rare autosomal dominant CHD1-related neurodevelopmental disorder with developmental delay, speech apraxia, autism, and mild dysmorphism.

Intellectual disability-cataracts-calcified pinnae-myopathy syndrome

Intellectual disability-cataracts-calcified pinnae-myopathy syndrome, also called Primrose syndrome (OMIM 259050), is a rare autosomal dominant ZBTB20-related disorder with intellectual disability, macrocephaly, calcified external ears, cataracts, and progressive myopathy.

Intellectual disability-coarse face-macrocephaly-cerebellar hypotrophy syndrome

Intellectual disability-coarse face-macrocephaly-cerebellar hypotrophy syndrome, also known as SCAR20, is a rare autosomal recessive disorder caused by SNX14 gene mutations, featuring progressive cerebellar ataxia and intellectual disability.

Intellectual disability-expressive aphasia-facial dysmorphism syndrome

Intellectual disability-expressive aphasia-facial dysmorphism syndrome, also called SETBP1 haploinsufficiency disorder, is a rare neurodevelopmental disorder caused by loss of one working copy of the SETBP1 gene.

Intellectual disability-eye abnormalities-microcephaly-peripheral spasticity syndrome

Intellectual disability-eye abnormalities-microcephaly-peripheral spasticity syndrome, also called CTNNB1 syndrome or CTNNB1 neurodevelopmental disorder, is a rare autosomal dominant disorder caused by de novo loss-of-function CTNNB1 variants, featuring intellectual disability, spasticity, microcephaly, and exudative vitreoretinopathy.

Intellectual disability-facial dysmorphism-joint hypermobility-hearing loss syndrome

Intellectual disability-facial dysmorphism-joint hypermobility-hearing loss syndrome, or Beck-Fahrner syndrome (TET3 deficiency, OMIM 618798), is a rare autosomal dominant chromatinopathy causing developmental delay, hypotonia, hearing loss, and overgrowth, diagnosed by TET3 sequencing and a DNA hypermethylation episignature.

Intellectual disability-hypoplastic corpus callosum-preauricular tag syndrome

Intellectual disability-hypoplastic corpus callosum-preauricular tag syndrome, or Da Silva syndrome (ORPHA:1495), is an extremely rare autosomal recessive disorder with severe intellectual disability, microcephaly, corpus callosum hypoplasia, preauricular skin tags, and recurrent bronchopneumonia.

Intellectual disability-seizures-abnormal gait-facial dysmorphism syndrome

Skraban-Deardorff syndrome (SKDEAS), also WDR26-related intellectual disability, a rare autosomal dominant neurodevelopmental disorder from de novo WDR26 variants, causing developmental delay, seizures, abnormal gait, and facial dysmorphism.

Oct 20, 2026

Intellectual disability-seizures-hypophosphatasia-ophthalmic-skeletal anomalies syndrome

Intellectual disability-seizures-hypophosphatasia-ophthalmic-skeletal anomalies syndrome, also called MCAHS3 or PIGT-CDG, is an autosomal recessive GPI-anchor defect caused by biallelic PIGT variants, presenting in infancy with hypotonia, seizures, intellectual disability, and low alkaline phosphatase.

Intellectual disability, Buenos-Aires type

Intellectual disability, Buenos-Aires type, also called Mutchinick syndrome, is a rare autosomal recessive genetic syndrome marked by microcephaly, growth retardation, distinctive facial features, speech disorder, and organ malformations.

Oct 20, 2026

Intense Pulsed Light Therapy

Intense pulsed light (IPL, flashlamp) therapy: noncoherent, polychromatic 500-1200 nm xenon-flashlamp light using selective photothermolysis to treat vascular and pigmented lesions, unwanted hair, photoaging, and dry eye; FDA-cleared since 1995.

Intensity-modulated proton therapy

Intensity-modulated proton therapy (IMPT) is a radiotherapy technique that optimizes every scanned proton spot, conforming dose to the tumor while sparing healthy tissue, first delivered at PSI in 1999.

Intensity-modulated radiation therapy

Intensity-modulated radiation therapy (IMRT) is an external-beam radiotherapy technique that modulates photon beamlets from multiple angles via computerized inverse planning, conformally targeting tumors while sparing organs at risk.

Intensity-modulated radiotherapy

Intensity-modulated radiotherapy (IMRT) is a radiation therapy technique that modulates the beam into many small beamlets, conforming dose to the tumor while sparing nearby organs at risk.

Intensive care unit

An intensive care unit (ICU), also called a critical care unit, is a hospital unit for critically ill patients, providing intensive monitoring, nursing, and organ support such as mechanical ventilation.

Intensive insulin therapy

Intensive insulin therapy is a diabetes regimen of three or more daily insulin injections or pump therapy with frequent glucose monitoring, the standard of care in type 1 diabetes.

Intention tremor

Intention tremor, also called cerebellar tremor, is shaking that appears during target-directed movement and worsens as the limb nears its target, most often from cerebellar dysfunction.