Iran Specialty Board - Internal Medicine key terms

The difference between measured serum sodium and the sum of chloride and bicarbonate, normally 8–12 mEq/L. It flags unmeasured acids such as ketones, lactate, or toxins and guides the workup of metabolic acidosis.

The difference between measured and calculated serum osmolality. A gap above about 10 mOsm/kg suggests unmeasured osmoles such as methanol, ethylene glycol, isopropanol, or mannitol.

The change in anion gap above baseline compared with the fall in bicarbonate. It reveals whether a pure high anion gap acidosis is complicated by a concurrent metabolic alkalosis or non-gap acidosis.

The percentage of filtered sodium excreted in urine, calculated from paired serum and urine sodium and creatinine. Values below 1% favor prerenal azotemia; higher values suggest intrinsic renal injury.

Ischemic or toxic injury to renal tubular epithelium causing acute kidney injury, muddy brown casts, and impaired concentrating ability. It typically follows hypotension, sepsis, or nephrotoxins and usually recovers over days to weeks.

Reversible rise in creatinine from renal hypoperfusion without structural tubular damage. It responds to volume repletion, shows bland urine sediment, and features avid sodium retention with a low fractional excretion of sodium.

Euvolemic hypotonic hyponatremia driven by excessive ADH release or action, with concentrated urine and normal adrenal and thyroid function. Treatment includes fluid restriction and correction of the underlying cause.

Neurologic injury, classically central pontine myelinolysis, caused by overly rapid correction of chronic hyponatremia. It presents with dysarthria, dysphagia, quadriparesis, or locked-in syndrome days after correction.

Metabolic acidosis with elevated unmeasured anions, memorably caused by ketones, lactate, uremia, salicylates, methanol, or ethylene glycol. Management targets the underlying poison or metabolic derangement rather than bicarbonate alone.

Acute coronary occlusion producing persistent ST elevation in contiguous leads with reciprocal changes. Emergency reperfusion by primary percutaneous coronary intervention or fibrinolysis is time-critical to limit infarct size and mortality.

Cardiac contractile protein released into blood after myocyte injury. High-sensitivity assays detect small elevations; serial measurement and clinical context distinguish acute coronary syndrome from chronic or non-ischemic causes.

Heart failure with left ventricular ejection fraction of 40% or less. Guideline-directed therapy with renin-angiotensin system inhibitors, beta-blockers, mineralocorticoid antagonists, and SGLT2 inhibitors reduces mortality and hospitalization.

Hormones such as BNP and NT-proBNP released by stretched ventricular myocardium. They support the diagnosis of heart failure but rise with age, renal impairment, and atrial fibrillation, so interpretation requires clinical context.

Inadequate tissue perfusion from cardiac pump failure, marked by hypotension, cool extremities, oliguria, and elevated lactate. It complicates large myocardial infarctions and requires urgent revascularization, vasopressors, and inotropic support.

Supraventricular arrhythmia with disorganized atrial activation, absent P waves, and irregularly irregular ventricular rhythm. It raises stroke risk, and anticoagulation plus rate or rhythm control forms the core management.

A validated risk tool estimating stroke risk in nonvalvular atrial fibrillation from age, sex, heart failure, hypertension, diabetes, stroke history, and vascular disease. Higher scores favor anticoagulation.

Emergency catheter-based reperfusion of an occluded coronary artery, ideally within 90 minutes of first medical contact in ST-elevation infarction. It is preferred over fibrinolysis when timely expert access exists.

Acute hypoxemic respiratory failure with bilateral infiltrates not explained by cardiac failure, defined by the Berlin criteria using PaO2/FiO2 ratios. Management emphasizes lung-protective ventilation, prone positioning, and treating the trigger.

Repetitive upper airway collapse during sleep causing apneas, hypopneas, oxygen desaturation, and daytime somnolence. Diagnosis uses polysomnography or home testing; positive airway pressure is first-line therapy.

Elevated arterial carbon dioxide tension, reflecting alveolar hypoventilation from airway obstruction, neuromuscular weakness, or reduced respiratory drive. It may cause headache, somnolence, asterixis, and acidemia.

Positive-pressure support of breathing through an endotracheal tube or noninvasive interface. Lung-protective settings with low tidal volumes reduce ventilator-induced injury in acute respiratory distress syndrome.

Hemorrhage proximal to the ligament of Treitz, often from peptic ulcers or varices, presenting as hematemesis or melena. Early resuscitation, risk scoring, and endoscopy guide therapy.

Bleeding from esophageal or gastric varices resulting from portal hypertension, most often in cirrhosis. Management combines vasoactive drugs, prophylactic antibiotics, and endoscopic band ligation.

A prognostic classification in cirrhosis using bilirubin, albumin, prothrombin time, ascites, and encephalopathy. It grades severity as A, B, or C and estimates survival and surgical risk.

Reversible neuropsychiatric dysfunction from liver failure and portosystemic shunting, driven largely by ammonia. It ranges from subtle confusion to coma and is treated with lactulose and rifaximin while precipitating factors are corrected.

A pre-endoscopic risk score for upper gastrointestinal bleeding using blood urea, hemoglobin, systolic pressure, heart rate, and clinical signs. Low scores identify patients suitable for outpatient management.

Acute metabolic emergency of insulin deficiency with hyperglycemia, ketonemia, and high anion gap acidosis. Treatment requires intravenous fluids, insulin infusion, potassium replacement, and correction of the precipitating cause.

Severe hyperglycemia with marked hyperosmolality, profound dehydration, and minimal ketosis, typically in older patients with type 2 diabetes. It carries high mortality and demands aggressive fluid and insulin therapy.

Glycated hemoglobin reflecting average plasma glucose over roughly three months. It diagnoses diabetes at 6.5% or above but is unreliable in anemia, hemoglobinopathy, pregnancy, and recent transfusion.

Low plasma glucose, conventionally below 70 mg/dL, producing adrenergic and neuroglycopenic symptoms. In hospitalized patients it most often results from insulin or sulfonylurea therapy and requires immediate glucose repletion.

Decompensated severe hypothyroidism with hypothermia, bradycardia, altered consciousness, and hypoventilation, often triggered by infection or cold. It is an endocrine emergency treated with intravenous thyroid hormone and stress-dose glucocorticoids.

Life-threatening thyrotoxicosis with fever, tachyarrhythmia, agitation, and multiorgan dysfunction. Treatment combines beta-blockade, thionamides, iodine, glucocorticoids, and supportive care.

Cortisol deficiency from adrenal destruction, causing fatigue, weight loss, hypotension, hyponatremia, hyperkalemia, and hyperpigmentation. Diagnosis relies on morning cortisol and ACTH stimulation testing; treatment is glucocorticoid and mineralocorticoid replacement.

Acute, life-threatening glucocorticoid deficiency with shock, abdominal pain, and electrolyte derangement, often precipitated by infection or surgery. Immediate parenteral hydrocortisone and fluid resuscitation are essential.

Life-threatening organ dysfunction from a dysregulated host response to infection, operationalized by a rise in the SOFA score. Early antibiotics, cultures, and fluid resuscitation improve survival.

Sepsis with persistent hypotension requiring vasopressors and elevated lactate despite adequate fluid resuscitation. Norepinephrine is the first-line vasopressor, and source control plus timely antimicrobials are central.

Fever at or above 38.3°C once or 38.0°C sustained in a patient with absolute neutrophil count below 500/µL. It demands urgent cultures and empiric broad-spectrum antipseudomonal antibiotics.

Oncologic emergency from rapid cell breakdown releasing potassium, phosphate, and nucleic acids, causing hyperkalemia, hyperphosphatemia, hypocalcemia, hyperuricemia, and acute kidney injury. Aggressive hydration and urate-lowering therapy prevent complications.

The combination of fever and severe neutropenia in a patient receiving chemotherapy, signaling high risk of overwhelming bacterial sepsis. Risk stratification guides inpatient versus outpatient antibiotic strategies.

Consumptive coagulopathy with widespread activation of coagulation, causing thrombosis and bleeding with prolonged PT, low fibrinogen, and elevated D-dimer. Treatment targets the underlying cause rather than routine factor replacement.

Immune-mediated platelet activation by heparin-PF4 antibodies causing thrombocytopenia and paradoxical thrombosis. Management requires stopping heparin and starting a non-heparin anticoagulant such as argatroban.

Autoantibody directed against nuclear components, used as a sensitive screening test for systemic lupus erythematosus. It is common in healthy people, so a positive result requires clinical correlation and specific confirmatory antibodies.

Multisystem autoimmune disease with autoantibodies, rash, arthritis, cytopenias, and renal or neurologic involvement. Treatment is tailored to organ severity, from hydroxychloroquine to immunosuppression.

Thrombotic and pregnancy complications associated with lupus anticoagulant, anticardiolipin, or anti-beta2-glycoprotein I antibodies. Long-term anticoagulation is used for thrombotic events.

Immune-complex glomerulonephritis in systemic lupus erythematosus presenting with proteinuria, hematuria, and declining renal function. Kidney biopsy classifies lesions and guides immunosuppressive therapy.

Rapid, systemic IgE-mediated hypersensitivity with airway swelling, bronchospasm, hypotension, and urticaria. Intramuscular epinephrine is the immediate first-line treatment, followed by fluids and adjunctive antihistamines.

Deep dermal and submucosal swelling of lips, tongue, or airway, which may be histaminergic or bradykinin-mediated. Bradykinin forms from ACE inhibitor use or hereditary deficiency and respond poorly to antihistamines and epinephrine.

Sudden focal neurologic deficit from arterial occlusion, requiring urgent imaging to exclude hemorrhage. Intravenous thrombolysis within 4.5 hours and mechanical thrombectomy for large vessel occlusion improve outcomes.

Brief focal neurologic dysfunction without infarction on imaging, signaling high short-term stroke risk. Urgent evaluation for carotid disease, atrial fibrillation, and vascular risk factors prevents recurrence.

Continuous seizure activity or recurrent seizures without recovery lasting five minutes or more. It is a neurologic emergency treated with benzodiazepines followed by second-line anticonvulsants.

Acute fluctuating disturbance of attention and awareness from medical illness, drugs, or withdrawal, common in older hospitalized patients. Nonpharmacologic prevention and treatment of the cause are preferred over sedatives.

Concurrent use of multiple medications, often five or more, raising risks of interactions, adverse effects, and falls in older adults. Regular deprescribing review improves safety.

A consensus list of potentially inappropriate medications for older adults, such as benzodiazepines and anticholinergics, used to guide safer prescribing. It supports deprescribing rather than rigid prohibition.

Chronic daytime hypercapnia and hypoxemia in obese patients without other cause, often with obstructive sleep apnea. Weight loss and positive airway pressure are mainstays of treatment.

Poisoning by methanol, ethylene glycol, or isopropanol causing an osmolal gap, high anion gap acidosis, and organ toxicity. Fomepizole or ethanol blocks metabolism; dialysis removes toxins and metabolites.

Serum sodium below 135 mEq/L, the most common electrolyte disorder, classified by volume status and tonicity. Symptoms range from nausea to seizures, and correction rate must be carefully controlled.