300+ medical terms, defined.

Class of asbestos fibers (e.g., crocidolite, amosite) that are straight, stiff, needle-like, and more carcinogenic than serpentine (chrysotile) asbestos. Strongly linked to mesothelioma.

A mydriatic is an agent that dilates the pupil. Classic mydriatics include muscarinic antagonists (atropine, tropicamide) and alpha-1 agonists (phenylephrine), used for fundoscopic exams and to break posterior synechiae in uveitis.

Amphibole fibers (crocidolite, amosite) are the straight, needle-like form of asbestos that is far more pathogenic than the curly serpentine (chrysotile) fibers. They are strongly linked to malignant mesothelioma and bronchogenic carcinoma.

Caplan syndrome is the coexistence of rheumatoid arthritis and a pneumoconiosis (classically coal worker's pneumoconiosis, but also silicosis and asbestosis), producing multiple peripheral pulmonary nodules. Nodules can cavitate and rese...

In clinical writing, 'presents' refers to how a patient first appears for medical evaluation, i.e., their initial chief complaint and constellation of signs/symptoms. The 'presentation' is the doorway-impression a USMLE vignette gives you.

Emphysema is a chronic obstructive lung disease characterized by permanent enlargement of airspaces distal to the terminal bronchiole with destruction of alveolar walls and loss of elastic recoil. Classic boards split: smoking → centriac...

Vinblastine is a vinca alkaloid antineoplastic that binds beta-tubulin and prevents microtubule polymerization, arresting cells in M phase. Used in Hodgkin lymphoma (the 'V' in ABVD) and testicular cancer; key toxicity is bone marrow sup...

Alpha-fetoprotein (AFP) is a fetal serum glycoprotein analogous to adult albumin, produced by the fetal yolk sac and liver. Clinically it is a tumor marker for hepatocellular carcinoma and yolk sac (endodermal sinus) tumors, and a screen...

Pneumoconiosis (the user has misspelled the term) is a group of restrictive interstitial lung diseases caused by chronic inhalation of inorganic mineral dusts and the resulting fibrotic reaction. Major boards types: coal worker's pneumoc...

Plicae circulares (valves of Kerckring) are permanent circular mucosal-submucosal folds of the small intestine that increase absorptive surface area. They are most prominent in the jejunum and key for radiographic identification of the s...

Methylxanthines (theophylline, theobromine, caffeine) are bronchodilators that nonselectively inhibit phosphodiesterase, increasing cAMP, and block adenosine receptors. Theophylline is rarely used today because of its narrow therapeutic...

Cheyne-Stokes breathing is a pattern of cyclical crescendo-decrescendo hyperpnea alternating with apnea, driven by unstable feedback between PaCO2 and central chemoreceptor response. Classic associations: advanced heart failure, stroke,...

Lupus pernio is the most specific cutaneous manifestation of sarcoidosis: violaceous, indurated plaques on the nose, cheeks, ears, and lips. Despite the name, it is unrelated to lupus erythematosus.

The DASH diet is an evidence-based dietary pattern proven to lower blood pressure: high in fruits, vegetables, whole grains, low-fat dairy, lean proteins, and nuts, and low in saturated fat, sodium, red meat, and sweets. It is a first-li...

Hyaline arteriolosclerosis is thickening of small arteriolar walls by homogeneous pink (hyaline) deposits, narrowing the lumen. Classic associations: benign/essential hypertension and diabetes mellitus; in the kidney it produces benign n...

Anthracosis is the accumulation of inhaled carbon (coal dust, soot) pigment in pulmonary macrophages and hilar lymph nodes. It is essentially asymptomatic and is the mildest end of the spectrum of carbon-related lung disease.

IL-5 receptor alpha (IL-5Rα, CD125) is the cytokine-binding subunit of the IL-5 receptor, expressed on eosinophils and basophils. It is the therapeutic target of benralizumab in eosinophilic asthma.

Benralizumab is a humanized monoclonal antibody against IL-5 receptor alpha (CD125) used for severe eosinophilic asthma. Unlike anti-IL-5 antibodies, it depletes eosinophils directly via NK-cell mediated ADCC.

Leukotriene antagonists are oral anti-asthma drugs that block the cysteinyl leukotriene pathway: montelukast and zafirlukast block the CysLT1 receptor, and zileuton inhibits 5-lipoxygenase. They are particularly useful in aspirin-exacerb...

Epoetin alfa is recombinant human erythropoietin, an erythropoiesis-stimulating agent given for anemia of chronic kidney disease, chemotherapy-induced anemia, and zidovudine-treated HIV. Major boards risk: thromboembolism and hypertensio...

ACS (acute coronary syndrome) is the spectrum of acute myocardial ischemia from coronary plaque rupture and thrombosis, encompassing unstable angina, NSTEMI, and STEMI. It is distinguished by ECG changes and cardiac biomarkers (troponin).

IHD (ischemic heart disease), also called coronary artery disease, is the chronic syndrome of myocardial oxygen demand exceeding supply due to atherosclerotic narrowing of the coronary arteries. It encompasses stable angina, acute corona...

Selective phosphodiesterase-4 (PDE-4) inhibitor used as add-on therapy in severe COPD with chronic bronchitis phenotype and history of exacerbations. Reduces inflammation by increasing intracellular cAMP in immune cells.

SGLT2 inhibitor that blocks glucose reabsorption in the proximal convoluted tubule, causing glucosuria and lowering blood glucose. Provides cardiovascular and renal protection in type 2 diabetes and heart failure.

SGLT2 inhibitor used in type 2 diabetes, heart failure, and chronic kidney disease. Blocks proximal tubule glucose reabsorption, causing glucosuria with cardiovascular and renal protective effects.

Cardioselective (beta-1) beta-blocker with intrinsic sympathomimetic activity (ISA), meaning it acts as a partial agonist. Used for hypertension and ventricular arrhythmias.

Nonselective beta-blocker with significant intrinsic sympathomimetic activity (partial agonist). Used for hypertension; avoided post-MI and in angina.

Non-ST-elevation acute coronary syndrome — encompasses unstable angina and NSTEMI, caused by partial coronary thrombosis with subendocardial ischemia. Lacks ST elevation but may show ST depression or T-wave inversion.

Mortality refers to death; in epidemiology it is typically expressed as a mortality rate (deaths per population per unit time). Key measure of disease burden and intervention effectiveness.

Concentric 'onion-skin' thickening of arteriolar walls due to smooth muscle hyperplasia, classically seen in malignant (severe) hypertension. May progress to fibrinoid necrosis.

Direct arteriolar vasodilator that opens ATP-sensitive K+ channels, causing hyperpolarization and smooth muscle relaxation. Used for severe refractory hypertension and androgenetic alopecia (topical).

Drugs that competitively block muscarinic acetylcholine receptors (M1-M5), producing parasympatholytic effects. Classic toxidrome: 'hot as a hare, dry as a bone, red as a beet, mad as a hatter, blind as a bat.'

Sweet-tasting antifreeze component metabolized by alcohol dehydrogenase to glycolic and oxalic acids, causing high anion-gap metabolic acidosis and acute kidney injury with calcium oxalate crystals.

Iron supplements (ferrous sulfate) treat iron-deficiency anemia but are a common cause of pediatric poisoning. Acute overdose causes GI hemorrhage, metabolic acidosis, and hepatic necrosis.

Bone disease of chronic kidney disease driven by hyperphosphatemia, decreased calcitriol, hypocalcemia, and secondary hyperparathyroidism. Causes osteitis fibrosa cystica, osteomalacia, and adynamic bone disease.

Direct-acting cholinergic agonist with both muscarinic and nicotinic activity; resistant to acetylcholinesterase. Used topically to induce miosis in glaucoma and during ocular surgery.

Intracellular vesicle formed by fusion of a phagosome with a lysosome, where ingested pathogens are degraded by reactive oxygen species and hydrolytic enzymes. Central to neutrophil and macrophage killing.

Enzymes that phosphorylate tyrosine residues on target proteins, transducing signals from growth factor receptors. Dysregulation drives many cancers; common drug target ('-tinib' family).

Drugs blocking dopamine D4 receptors, a subtype of D2-like receptors enriched in the prefrontal cortex and limbic system. Clozapine is the classic high-affinity D4 antagonist.

Class III antiarrhythmic (K+ channel blocker) that also has class I, II, and IV properties. First-line for ventricular arrhythmias and rate/rhythm control of atrial fibrillation; notorious for multi-organ toxicity.

Bacteriostatic antibiotics (azithromycin, clarithromycin, erythromycin) that bind the 50S ribosomal subunit and inhibit protein synthesis. Cover atypicals, gram-positive cocci, and some gram-negatives.

First-generation H2-receptor antagonist that reduces gastric acid secretion. Notable for potent CYP450 inhibition, antiandrogenic effects, and numerous drug interactions; largely replaced by famotidine and PPIs.

Restrictive interstitial lung disease from inhalation of coal dust, with carbon-laden macrophages forming coal macules in upper lobes. May progress to massive fibrosis ('black lung').

Pneumoconiosis caused by inhalation of silica dust, classically in sandblasters, miners, and foundry workers. Produces upper-lobe nodular fibrosis and dramatically increases susceptibility to tuberculosis.

Pneumoconiosis from asbestos fiber inhalation, classically in shipyard workers, plumbers, and insulation/construction trades. Produces lower-lobe interstitial fibrosis and pleural plaques, with markedly increased risk of bronchogenic car...

Atherosclerotic narrowing of the coronary arteries causing myocardial ischemia, the leading cause of death in the United States. Manifests as stable angina, acute coronary syndromes, ischemic cardiomyopathy, and sudden cardiac death.

Pantothenic acid; precursor of coenzyme A (CoA) and the phosphopantetheine arm of fatty acid synthase. Deficiency is rare but causes dermatitis, enteritis, alopecia, and adrenal insufficiency.

Macrophage surface receptor (SR-A) that binds and internalizes modified (oxidized/acetylated) LDL and a variety of polyanionic ligands. Central to foam cell formation in atherosclerosis and to pattern recognition in innate immunity.

Diagnostic procedure in which sterile saline is instilled through a bronchoscope into a lung segment and aspirated to sample alveolar cells, pathogens, and proteins. High yield for diagnosing opportunistic pneumonias, alveolar proteinosi...

The fluid component of blood remaining after coagulation - plasma minus clotting factors (especially fibrinogen). Used for most clinical chemistry, serology, and antibody assays.