Human health and medicine

Intrusive thought

Intrusive thought: unwanted, unintended, recurrent thoughts, images, or urges that interrupt thought flow; also called obsessions in OCD. Key concepts include thought-action fusion, suppression rebound effect, and transdiagnostic role in OCD, PTSD, depression.

Intubation

Intubation (endotracheal intubation) is placement of a tube into the trachea to secure the airway, enable ventilation, and protect the lungs; used in over 80% of general anesthesia cases and in emergencies, pioneered by Macewen in 1878 and Jackson in 1913.

Oct 15, 2026

Intuitive SureForm stapler

The Intuitive SureForm stapler is a family of fully wristed, single-use surgical staplers by Intuitive Surgical, controlled from the da Vinci console with SmartFire technology that adjusts tissue compression during firing.

Oct 20, 2026

Intuppukana Curna

Intuppukana Curna (Intuppukana Churna) is a classical Ayurvedic powder from Sahasrayoga made of rock salt, ajamoda, pippali, and haritaki, used for indigestion and studied for anti-inflammatory activity.

Intussusception (medical disorder)

Intussusception: telescoping of proximal bowel into distal bowel, the leading cause of intestinal obstruction in infants aged 3-36 months; diagnosed by ultrasound and treated by air or liquid enema reduction, with surgery for perforation, lead points, or failure.

Intussusception of appendix

Intussusception of the appendix (appendiceal intussusception), ICD-11 DB11.5, ICD-10 K38.8: rare telescoping of the vermiform appendix into itself or cecum, about 0.01% incidence, roughly 200 reported cases since McKidd's 1858 report.

Intussusception of small intestine

Intussusception of small intestine (ICD-11 DA91.0): telescoping of a proximal small bowel segment into a distal segment, causing obstruction and ischaemia; rare in adults, usually lead-point related, often treated surgically.

Oct 20, 2026

Intussusception of the large intestine

Intussusception of the large intestine: telescoping of bowel, usually ileum through the ileocecal valve into the colon. Common in infants, rare in adults, where malignancy is the usual lead point.

Inulin clearance

Inulin clearance is a renal function test that measures the rate at which the kidneys remove inulin from plasma, long considered the gold standard for measuring glomerular filtration rate.

Invasive angiography

Invasive angiography is a medical imaging procedure in which a catheter inside an artery injects iodinated contrast dye, and X-ray fluoroscopy records the contrast filling the vessels.

Invasive aspergillosis

Invasive aspergillosis (IA), a tissue-invading Aspergillus fumigatus-led mold infection of immunocompromised people, acquired by inhaling spores; treated with voriconazole, with 25-59% one-year survival and emerging azole resistance.

Invasive blood pressure monitoring

Invasive blood pressure monitoring measures arterial pressure continuously through a catheter in an artery linked to an electronic transducer, the reference method for major surgery, shock, and ICU care.

Invasive candidiasis

Invasive candidiasis, including candidemia, is severe Candida yeast infection of blood or internal organs in hospitalized, immunocompromised, or device-bearing patients; echinocandins are first-line therapy, with Candida auris an emerging drug-resistant threat.

Invasive carcinoma of breast

Invasive carcinoma of breast (ICD-11 2C61): breast cancer that has spread beyond the ducts or lobules into surrounding tissue. Main types are invasive ductal carcinoma (70-80%) and invasive lobular carcinoma (10-15%).

Invasive ductal carcinoma of breast

Invasive ductal carcinoma (IDC), also called infiltrating ductal carcinoma or invasive breast carcinoma of no special type (IBC-NST), is the most common breast cancer, about 70-80% of cases, starting in milk duct lining and invading surrounding tissue.

Invasive glucose monitoring

Invasive glucose monitoring measures blood glucose by sampling body fluid directly, either fingerstick blood on test strips or subcutaneous continuous glucose monitoring (CGM) sensors reading interstitial fluid.

Invasive lobular carcinoma of breast

Invasive lobular carcinoma (ILC), also called infiltrating lobular carcinoma, is the second most common breast cancer type, arising in milk-producing lobules, marked by E-cadherin loss, diffuse growth, HR-positive disease, unusual metastatic sites, and late recurrence.

Invasive mechanical ventilation

Invasive mechanical ventilation is life support that pushes gas into the lungs through an endotracheal or tracheostomy tube, maintaining gas exchange and protecting the airway in respiratory failure.

Invasive mole

Invasive mole (chorioadenoma destruens) is a malignant gestational trophoblastic neoplasia in which molar villi invade the uterine myometrium, usually after a complete hydatidiform mole, causing persistent hCG; treated with chemotherapy, it may regress spontaneously.

Invasive non-typhoidal salmonellosis

Invasive non-typhoidal salmonellosis (iNTS) is bloodstream infection by non-typhoidal Salmonella enterica serovars such as Enteritidis and Typhimurium, causing an estimated 2.1–6.5 million annual cases, highest in sub-Saharan Africa among children with malaria, malnutrition, or HIV, with 14.5–25% case fatality and no licensed vaccine.

Invasive prenatal testing

Invasive prenatal testing is the set of procedures, chiefly chorionic villus sampling (CVS) and amniocentesis, that sample fetal cells for definitive diagnosis of chromosomal conditions.

Invasive vagus nerve stimulation

Invasive vagus nerve stimulation (VNS) is a neuromodulation treatment in which a surgically implanted pulse generator stimulates the left vagus nerve, FDA-approved for drug-resistant seizures and treatment-resistant depression.

Inverse agonist

Inverse agonist: ligand lowering receptor signaling below constitutive (ligand-independent) activity, unlike neutral antagonists; defined by IUPAC, first shown at delta opioid receptor with ICI174864.

Inverse psoriasis

Inverse psoriasis, also called flexural psoriasis, is psoriasis in the skin folds, forming shiny, smooth red plaques in the groin, armpits, and under the breasts.

Inverted duplicated chromosome 15 syndrome

Inverted duplicated chromosome 15 syndrome, also called idic(15) or inv dup(15), is a rare neurogenetic disorder from a maternally derived supernumerary isodicentric chromosome 15 containing the Prader-Willi/Angelman critical region, causing hypotonia, intellectual disability, autism-like behavior, and epilepsy.