Egyptian Board Internal Medicine key terms

The difference between measured serum sodium and the sum of chloride and bicarbonate, normally about 8-12 mEq/L. It estimates unmeasured anions and separates high-gap from normal-gap metabolic acidosis.

The change in anion gap from baseline compared with the fall in bicarbonate. A ratio near 1 suggests pure high-gap acidosis; deviation suggests a coexisting metabolic alkalosis or normal-gap acidosis.

The difference between measured serum osmolality and calculated osmolality. An elevated gap suggests unmeasured solutes such as methanol, ethylene glycol, mannitol, or isopropanol.

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

An abrupt decline in kidney function, defined by a rise in serum creatinine or fall in urine output over hours to days. Staging guides fluid, medication, and dialysis decisions.

A reversible rise in creatinine caused by reduced renal perfusion, with avid tubular sodium reabsorption. It improves with volume or perfusion correction and typically shows a low fractional excretion of sodium.

Ischemic or toxic injury to renal tubular cells causing acute kidney injury with muddy brown casts and impaired concentrating ability. Sodium wasting gives a high fractional excretion of sodium.

Serum potassium above the normal range, risking cardiac conduction delay and arrhythmia. Management addresses membrane stabilization with calcium, intracellular shift, and definitive potassium removal.

A calculated index comparing urine and serum potassium with osmolality, estimating aldosterone-driven potassium secretion in the distal nephron. It helps distinguish renal from extrarenal causes of hyperkalemia.

Falsely elevated potassium caused by cell lysis during blood sampling or processing, as in hemolysis, prolonged tourniquet use, or marked thrombocytosis. Repeat sampling without stasis confirms the artifact.

Serum sodium below normal, reflecting a disturbance of water balance rather than total body sodium. Assessment of volume status and urine osmolality guides safe correction and avoids osmotic demyelination.

Euvolemic hypotonic hyponatremia from excessive antidiuretic hormone activity, with concentrated urine and normal volume status. Diagnosis requires excluding thyroid, adrenal, renal, and diuretic causes.

Neurological injury from overly rapid correction of chronic hyponatremia, causing pontine and extrapontine demyelination. It presents with dysarthria, dysphagia, quadriparesis, or altered consciousness days after correction.

Acute coronary occlusion producing persistent ST elevation in contiguous leads, requiring urgent reperfusion by primary percutaneous coronary intervention or fibrinolysis. Time from symptom onset to reperfusion determines myocardial salvage.

A myocardial contractile protein released into blood after myocyte injury. High-sensitivity assays detect small rises; serial change and clinical context distinguish acute infarction from chronic elevation.

A pre-infarction pattern of deep, symmetric T-wave inversion or biphasic T waves in anterior leads during pain-free periods. It signals critical proximal left anterior descending stenosis and warrants urgent angiography.

Emergency catheter-based reopening of an occluded coronary artery as the preferred reperfusion strategy in ST-elevation infarction. It is preferred when it can be delivered promptly by an experienced team.

Heart failure with symptoms and elevated filling pressures despite a normal or near-normal ejection fraction. It commonly accompanies hypertension, obesity, diabetes, and atrial fibrillation, and is diagnosed with natriuretic peptides and echocardiography.

A hormone released by stretched myocardium, measured as BNP or NT-proBNP. Low values help exclude heart failure; elevated values require clinical interpretation because age, renal function, and obesity modify levels.

Impaired ventricular relaxation or increased stiffness that raises filling pressures at normal volumes. Echocardiographic indices of mitral inflow, tissue Doppler, and left atrial size support the diagnosis.

Inflammation of heart muscle, often viral or immune-mediated, presenting with chest pain, arrhythmia, or heart failure. Troponin may rise, and cardiac magnetic resonance or biopsy supports diagnosis.

Repeated upper airway collapse during sleep causing intermittent hypoxemia and arousals. It worsens hypertension and cardiovascular risk and is confirmed by polysomnography or home sleep testing.

Daytime hypercapnia and hypoxemia during wakefulness in a patient with obesity, after excluding other causes. It reflects impaired ventilatory drive and chest mechanics and is treated with weight loss and positive airway pressure.

Delivery of positive pressure through a mask to support ventilation without intubation. It reduces work of breathing and intubation rates in acute hypercapnic exacerbations of chronic obstructive pulmonary disease.

Persistent airflow obstruction from airway and parenchymal damage, usually related to tobacco smoke. Diagnosis requires post-bronchodilator spirometry showing a reduced forced expiratory volume to forced vital capacity ratio.

Abnormal fluid accumulation in the pleural space. Thoracentesis with fluid protein, lactate dehydrogenase, glucose, and cell count separates transudates from exudates and guides further investigation.

A set of pleural fluid measurements used to classify an effusion as exudative. Exudate is suggested when fluid protein or lactate dehydrogenase exceeds two-thirds of serum values or exceeds absolute thresholds.

Bleeding proximal to the ligament of Treitz, presenting as hematemesis or melena. Resuscitation precedes endoscopy, and risk scores guide timing of intervention and disposition.

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

Bleeding from esophageal or gastric varices caused by portal hypertension. Management combines vasoactive drugs, prophylactic antibiotics, and endoscopic band ligation, with rescue shunt procedures for refractory bleeding.

Infection of ascitic fluid without an obvious intra-abdominal source, diagnosed by an absolute neutrophil count of 250 or more per microliter. It requires prompt antibiotics and albumin in high-risk patients.

Pathological fluid accumulation in the peritoneal cavity, most often from portal hypertension. Diagnostic paracentesis with cell count, albumin, and culture distinguishes infection, malignancy, and cardiac causes.

A hyperglycemic emergency with ketosis and high-anion-gap metabolic acidosis, driven by insulin deficiency. Treatment requires fluids, insulin, and careful potassium replacement, with attention to precipitating illness.

Severe hyperglycemia with marked hyperosmolality, profound dehydration, and minimal ketosis. It occurs mainly in older patients with type 2 diabetes and requires gradual fluid and insulin correction.

Hemoglobin with glucose bound irreversibly, reflecting average glycemia over roughly the preceding two to three months. It is used for diagnosis and monitoring, but anemia and hemoglobin variants distort results.

Thyroid hormone deficiency arising from thyroid gland failure, showing low free thyroxine with elevated thyroid-stimulating hormone. Autoimmune thyroiditis is the commonest cause in iodine-sufficient regions.

A life-threatening exaggeration of thyrotoxicosis with fever, tachyarrhythmia, agitation, and multiorgan dysfunction. Treatment blocks hormone synthesis and release, controls heart rate, and treats precipitants.

Simultaneous reduction of red cells, white cells, and platelets. Marrow examination distinguishes failure of production, such as aplastic anemia, from peripheral destruction or splenic sequestration.

Red cell fragmentation from fibrin or platelet-rich microthrombi in small vessels, producing schistocytes and hemolysis. It is a hallmark of thrombotic thrombocytopenic purpura and hemolytic uremic syndrome.

Insufficient cobalamin causing macrocytic anemia and neurological dysfunction from subacute combined degeneration of the cord. Causes include pernicious anemia and ileal disease; treatment replaces the vitamin.

Antibodies directed against nuclear components, used as a screening test for systemic lupus erythematosus. High sensitivity but low specificity means positive results require specific autoantibody testing and clinical correlation.

A multisystem autoimmune disease with autoantibodies, rash, arthritis, cytopenias, and renal or neurological involvement. Diagnosis combines clinical criteria with serology, and treatment depends on organ severity.

An autoimmune thrombophilia defined by vascular thrombosis or pregnancy morbidity plus persistent antiphospholipid antibodies. Long-term anticoagulation is central to management of thrombotic disease.

A metabolic emergency after rapid cancer cell breakdown, producing hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcemia. It threatens acute kidney injury and arrhythmia and requires hydration and urate-lowering therapy.

Life-threatening organ dysfunction caused by a dysregulated host response to infection. Recognition uses clinical scores, cultures, and early antibiotics alongside fluid resuscitation and source control.

Sepsis with persistent hypotension requiring vasopressors and elevated lactate despite adequate fluid resuscitation. It carries high mortality and demands rapid antibiotics, source control, and hemodynamic support.

A peptide precursor that rises in bacterial infection and falls with recovery. It can support antibiotic stewardship decisions but should not replace clinical judgment.

Infection by Mycobacterium tuberculosis, most often pulmonary, with cough, fever, night sweats, and weight loss. Diagnosis uses sputum microscopy, culture, and nucleic acid amplification, and treatment requires multidrug regimens.

Sudden focal neurological deficit from cerebral arterial occlusion. Urgent imaging excludes hemorrhage, and thrombolysis or thrombectomy is offered within defined time windows.

A brief episode of focal neurological dysfunction without infarction on imaging. It signals high short-term stroke risk and prompts urgent evaluation and secondary prevention.

Continuous seizure activity or recurrent seizures without recovery between them, lasting five minutes or more. It is a medical emergency treated with staged benzodiazepine and antiseizure drug therapy.

The relationship between a drug's toxic and effective doses, indicating how much margin exists before harm occurs. Narrow-index drugs such as digoxin, lithium, and warfarin require monitoring.

Changes in drug metabolism when one agent induces or inhibits hepatic enzyme isoforms, altering concentrations of co-administered drugs. Inhibitors raise levels and toxicity risk; inducers lower efficacy.

An acute fluctuating disturbance of attention and awareness, usually triggered by illness, drugs, or metabolic derangement. It is common in older inpatients and requires identifying and treating the underlying cause.

Use of multiple medications, often defined as five or more, raising risks of interactions and adverse events. Structured medication review and deprescribing improve safety, especially in frail older adults.