300+ medical terms, defined.

A fast, irregular ventricular rate during atrial fibrillation, typically >100 bpm, resulting from rapid AV nodal conduction. Leads to hemodynamic compromise and requires urgent rate or rhythm control.

An enzyme produced by neutrophils detected in urine via dipstick; a marker of pyuria (UTI). Positive result suggests bacterial infection but can have false positives and negatives.

An enzyme that degrades collagen, secreted by various cell types (fibroblasts, immune cells, tumor cells). Implicated in tissue remodeling, wound healing, and pathologic processes like inflammation and cancer invasion.

A property where a system's output depends on its history; in pulmonary physiology, the lung's inflation and deflation pressure-volume curves differ due to surface tension and surfactant effects. Clinically relevant in ARDS and mechanica...

The process of transferring oxygen from inhaled air into blood and removing carbon dioxide from blood into exhaled air, occurring primarily at the alveolar-capillary membrane. Essential for aerobic metabolism and CO2 elimination.

A beta-3 adrenergic agonist used to treat overactive bladder by relaxing detrusor smooth muscle. Unlike anticholinergics, it does not cause cognitive or urinary retention side effects.

A diagnostic test for diabetes insipidus by withholding water and observing urine output and osmolality response to exogenous vasopressin. Differentiates central from nephrogenic DI.

Elevated serum potassium (>5.0-5.5 mEq/L) that impairs cardiac conduction and muscle function, potentially causing fatal arrhythmias. Requires urgent treatment based on etiology and severity.

Peptide hormones (IGF-1, IGF-2) that promote growth, metabolism, and differentiation, structurally similar to insulin. Mediate many effects of growth hormone and regulated by GH, nutrition, and thyroid hormone.

A peptide hormone (alpha-MSH, derived from POMC) that stimulates melanin production and darkens skin pigmentation. Also involved in appetite regulation and immune function.

The state of having given birth to more than one child (para >1); associated with increased parity-related health risks including uterine atony, postpartum hemorrhage, and certain cancers.

Inflammation of the arterial intima causing narrowing and thrombosis. Historically associated with tertiary syphilis (vasa vasorum); modern causes include vasculitis and infection.

Heparanase is an endoglycosidase that cleaves heparan sulfate in the extracellular matrix and basement membrane, facilitating cell invasion and metastasis. Overexpressed in malignant tumors and contributes to tumor progression and angiog...

Renal tubular acidosis (RTA) is a normal anion gap metabolic acidosis caused by impaired renal acid secretion or bicarbonate reabsorption despite normal GFR. Four types exist with different mechanisms.

Whispered pectoriloquy is the abnormal transmission of whispered voice through consolidated lung tissue, heard as clear whispering on auscultation. Indicates lung consolidation (pneumonia, atelectasis).

Egophony is a change in voice resonance where the patient says 'E' and it sounds like a nasal 'A' on auscultation, indicating consolidated lung tissue. Reflects altered acoustic properties of consolidation.

Bronchophony is exaggerated transmission of spoken voice sounds through consolidated lung, heard as louder and clearer speech on auscultation. Indicates lung consolidation.

Contraction alkalosis is metabolic alkalosis caused by disproportionate loss of chloride and volume relative to bicarbonate, often from vomiting, NG suction, or diuretic use. The kidneys retain bicarbonate to restore volume, perpetuating...

This equation represents Fick's Law of Diffusion, where gas diffusion rate is proportional to area (A) and pressure gradient (ΔP), and inversely proportional to membrane thickness (Δx). Critical for understanding alveolar-capillary gas e...

PaO2 is the partial pressure of oxygen dissolved in arterial plasma, normally 80-100 mmHg on room air at sea level. Indicates adequacy of lung oxygenation.

SaO2 is the percentage of hemoglobin oxygen saturation in arterial blood, normally 95-100%. Reflects the proportion of hemoglobin bound to oxygen, determined by the sigmoidal oxygen-hemoglobin dissociation curve.

Formic acid is the toxic metabolite of methanol oxidation responsible for methanol's severe toxicity including metabolic acidosis, blindness, and death. Inhibits mitochondrial cytochrome c oxidase.

Oxalic acid is the toxic metabolite of ethylene glycol that precipitates with calcium to form calcium oxalate crystals, causing acute kidney injury, hypocalcemia, and neurologic symptoms.

Isoniazid (INH) is a first-line tuberculosis drug that inhibits mycolic acid synthesis. Major side effects include hepatotoxicity, peripheral neuropathy (prevented by B6), and drug-induced lupus.

Propylene glycol is a pharmaceutical solvent that can cause high anion gap metabolic acidosis, hyperosmolality, and neurologic symptoms in toxicity. Occurs with large IV doses or renal impairment.

DKA is a life-threatening complication of diabetes with hyperglycemia, high anion gap metabolic acidosis, and ketosis, typically in Type 1 diabetes. Requires emergent insulin, fluids, and electrolyte repletion.

Uremia is a clinical syndrome from accumulation of uremic toxins when GFR drops below 10-20 mL/min, causing multi-organ dysfunction. Develops in advanced CKD/ESRD with cardiovascular, neurologic, hematologic, and GI complications.

Salicylates (aspirin) cause toxicity by uncoupling oxidative phosphorylation, leading to mixed respiratory alkalosis and anion gap metabolic acidosis. Present with tachypnea, tinnitus, and altered mental status.

Lactic acidosis is an anion gap metabolic acidosis (lactate >5 mmol/L) classified as Type A (tissue hypoperfusion) or Type B (no hypoxia). Type A is seen in sepsis/shock; Type B with seizures, malignancy, or medications (metformin).

Hyperalimentation (total parenteral nutrition/TPN) is IV delivery of complete macronutrients and micronutrients for patients unable to eat. Risks include catheter infections, hyperglycemia, and TPN-associated liver disease.

Primary adrenal insufficiency with inadequate cortisol and aldosterone from destruction of >90% of the adrenal cortex, most commonly autoimmune. Classic: hypotension, hyponatremia, hyperkalemia, hyperpigmentation.

A potassium-sparing diuretic that competitively blocks aldosterone receptors in the collecting duct, preventing Na+ reabsorption and K+ excretion. Used for heart failure, hypertension, hyperaldosteronism, and cirrhotic ascites.

A carbonic anhydrase inhibitor that impairs bicarbonate reabsorption in the proximal tubule, causing bicarbonate wasting and normal anion gap metabolic acidosis. Used for glaucoma, altitude sickness, and idiopathic intracranial hypertens...

EoE is a chronic immune-mediated inflammatory disorder with eosinophil infiltration (>15/HPF) of the esophageal mucosa, presenting with dysphagia to solids and food impaction. Driven by Th2-mediated allergic inflammation.

Hepatic lipase (HTGL) hydrolyzes triglycerides and phospholipids in chylomicron remnants, IDL, and HDL, playing a critical role in remnant clearance and HDL remodeling. Deficiency causes remnant accumulation and premature atherosclerosis.

Transitional conducting airways marking the beginning of the respiratory zone, distinguished from terminal bronchioles by scattered alveoli budding from their walls. Have simple cuboidal epithelium with Clara cells.

Describes a disease that fails to respond to standard treatments despite appropriate trials. In oncology, indicates initial non-response to chemotherapy (vs. relapsed = responds then recurs).

A surgical procedure for GERD where the gastric fundus is wrapped 360 degrees around the lower esophageal sphincter. Gold-standard surgical treatment for GERD refractory to medical management.

Myocardial diseases causing mechanical/electrical dysfunction. Three main types: dilated (most common, systolic dysfunction), hypertrophic (diastolic dysfunction, sudden death risk), and restrictive (impaired filling).

An oxidized metabolite of vitamin A essential for vision, functioning as the light-sensitive chromophore in rhodopsin. 11-cis-retinal binds opsin; light converts it to all-trans retinal, triggering phototransduction.

Atopy is a genetic predisposition to develop IgE-mediated hypersensitivity reactions to environmental allergens. It manifests as the classic triad of asthma, allergic rhinitis, and atopic dermatitis (eczema). This Type I hypersensitivity...

Hepatocytes are the primary functional cells of the liver, comprising 60-80% of liver mass. They perform essential metabolic functions including protein synthesis, detoxification, glucose metabolism, and bile production. Hepatocyte dysfu...

Empyema is a collection of infected fluid (pus) in the pleural space, typically resulting from pneumonia, chest trauma, or post-surgical complications. It requires immediate drainage and antibiotic therapy to prevent life-threatening com...

The lungs are paired respiratory organs responsible for gas exchange between air and blood. They contain millions of alveoli where oxygen diffuses into pulmonary capillaries and CO2 is removed. Essential for maintaining acid-base balance...

Ceruloplasmin is a copper-carrying glycoprotein synthesized by the liver that transports 90-95% of plasma copper. Decreased levels are pathognomonic for Wilson disease, while elevated levels occur in inflammatory conditions and pregnancy.

Pancoast tumor is a lung cancer located in the superior sulcus (apex) of the lung that invades local structures including the brachial plexus, sympathetic chain, and ribs. It classically presents with shoulder/arm pain, Horner's syndrome...

Superior sulcus tumor (Pancoast tumor) is a lung cancer located in the apex of the lung that invades local structures including the brachial plexus, sympathetic chain, and ribs. It presents with shoulder/arm pain, Horner's syndrome, and...

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder affecting presynaptic voltage-gated calcium channels at neuromuscular junctions, causing proximal muscle weakness that improves with repetitive use. It is strongly associ...

Psammoma bodies are concentrically laminated, calcified structures found in certain neoplasms and some normal tissues. They are pathognomonic findings in papillary thyroid carcinoma, meningioma, papillary serous ovarian carcinoma, and ma...

Glucose is a simple sugar (monosaccharide) that serves as the primary energy source for cellular metabolism. Normal blood glucose levels are tightly regulated (70-100 mg/dL fasting) through hormonal control involving insulin and glucagon...