Kuwait Board Internal Medicine cheat sheet

Pretest probability drives testing: order a test only when the result will cross a treatment threshold; likelihood ratios >10 or <0.1 meaningfully change post-test probability.

Sensitivity rules out disease when negative (SnNout); specificity rules in disease when positive (SpPin); predictive values depend on prevalence, likelihood ratios do not.

Number needed to treat = 1/absolute risk reduction; number needed to harm = 1/absolute risk increase; compare NNT with NNH before starting long-term therapy.

Wells score for DVT: +1 each for cancer, paralysis/immobilization, bedridden >3 days or major surgery within 12 weeks, localized tenderness along deep veins, entire leg swelling, calf swelling >3 cm vs contralateral, pitting edema, collateral superficial veins, previous DVT; -2 if alternative diagnosis as likely.

CURB-65 for community-acquired pneumonia: confusion, urea >7 mmol/L, respiratory rate >=30/min, blood pressure (systolic <90 or diastolic <=60 mmHg), age >=65; 0-1 points supports outpatient care.

Corrected calcium (mg/dL) = measured calcium + 0.8 x (4.0 - albumin g/dL); ionized calcium is preferred when albumin is low or in critical illness.

Anion gap = Na - (Cl + HCO3), normal 8-12 mmol/L; add 2.5 mmol/L to the gap for every 1 g/dL fall in albumin below 4 g/dL.

Osmolal gap = measured osmolality - calculated (2Na + glucose/18 + urea/2.8); a gap >10 mmol/L suggests unmeasured osmoles such as methanol, ethylene glycol, or isopropanol.

Acute STEMI: dual antiplatelet therapy plus anticoagulation and reperfusion; primary PCI is preferred if achievable within 120 minutes of first medical contact, otherwise fibrinolysis within 12 hours of symptom onset.

Inferior STEMI with hypotension: obtain right-sided leads; nitrates and other preload-reducing agents are contraindicated in right ventricular infarction.

Heart failure with reduced ejection fraction (<=40%) mortality benefit: ACE inhibitor/ARB or ARNI, beta-blocker, mineralocorticoid receptor antagonist, and SGLT2 inhibitor; add hydralazine/isosorbide dinitrate in self-identified Black patients.

Atrial fibrillation stroke risk by CHA2DS2-VASc (congestive failure, hypertension, age >=75 =2, diabetes, stroke/TIA =2, vascular disease, age 65-74, female sex); anticoagulate when score >=2 in men or >=3 in women.

Pericarditis: diffuse ST elevation with PR depression, positional pleuritic pain, friction rub; high-dose NSAID plus colchicine; avoid anticoagulation if effusion is large.

Aortic stenosis severity: severe if peak velocity >=4 m/s, mean gradient >=40 mmHg, or valve area <=1.0 cm2; symptomatic severe stenosis warrants valve replacement.

Hypertrophic cardiomyopathy: asymmetric septal hypertrophy, systolic murmur increased by Valsalva and decreased by squatting; avoid dehydration, vasodilators, and high-intensity competitive sport.

Hypertension emergency: target mean arterial pressure reduction of no more than 20-25% in the first hour, then gradual lowering over 24-48 hours; exceptions are aortic dissection and eclampsia.

Asthma is characterized by reversible airflow obstruction (FEV1 improvement >=12% and >=200 mL after bronchodilator) and elevated fractional exhaled nitric oxide; COPD shows persistent post-bronchodilator FEV1/FVC <0.70.

Acute severe asthma: inhaled short-acting beta-2 agonist plus ipratropium, systemic corticosteroid, and oxygen titrated to saturation 93-95%; add magnesium sulfate for refractory cases.

COPD exacerbation: controlled oxygen to target saturation 88-92% in those at risk of hypercapnia, short-acting bronchodilators, systemic corticosteroid for 5 days, and antibiotics when sputum purulence or ventilatory support is present.

Light's criteria for exudative pleural effusion: pleural protein/serum protein >0.5, pleural LDH/serum LDH >0.6, or pleural LDH >2/3 the upper limit of normal serum LDH.

Pulmonary embolism: age-adjusted D-dimer threshold (age x 10 mcg/L in patients >50 years) in low/intermediate pretest probability; high pretest probability proceeds directly to CT pulmonary angiography.

Obstructive sleep apnea diagnosis requires apnea-hypopnea index >=5 with symptoms, or >=15 regardless of symptoms; first-line therapy is positive airway pressure.

Tuberculosis: sputum acid-fast bacilli smear and nucleic acid amplification testing are initial tests; latent infection is treated with rifampicin-based regimens after excluding active disease.

Interstitial lung disease: high-resolution CT is the key imaging test; usual interstitial pneumonia pattern shows peripheral, basal, subpleural reticulation with honeycombing and traction bronchiectasis.

Upper GI bleeding: give intravenous proton pump inhibitor after endoscopic hemostasis for high-risk stigmata; variceal bleeding adds vasoactive drug plus prophylactic antibiotics and endoscopic band ligation within 12 hours.

Acute pancreatitis diagnosis requires 2 of 3: characteristic epigastric pain, serum lipase/amylase >3 times the upper limit of normal, and imaging findings; early care is aggressive crystalloid and analgesia, not prophylactic antibiotics.

Hepatitis B serology: HBsAg indicates infection; isolated anti-HBc IgG indicates past infection or occult carriage; anti-HBs alone indicates vaccination.

Spontaneous bacterial peritonitis: ascitic neutrophil count >=250/mm3 is diagnostic; treat with a third-generation cephalosporin and add albumin 1.5 g/kg on day 1 and 1 g/kg on day 3 if creatinine is elevated.

Hepatorenal syndrome: functional renal failure in cirrhosis with urine sodium <10 mmol/L and no improvement after 2 days of albumin; treat with terlipressin plus albumin.

Celiac disease: test tissue transglutaminase IgA with total IgA while on a gluten-containing diet; duodenal biopsy shows villous atrophy and intraepithelial lymphocytosis.

Inflammatory bowel disease: ulcerative colitis is continuous and confined to the colon; Crohn disease is transmural, skip lesions, and may involve any part of the GI tract from mouth to anus.

Hepatic encephalopathy is precipitated by infection, GI bleeding, constipation, hypokalemia, and sedatives; lactulose titrated to 2-3 soft stools daily is first-line therapy.

Acute kidney injury staging (KDIGO): stage 1 creatinine rise >=0.3 mg/dL in 48 hours or 1.5-1.9x baseline; stage 2 2.0-2.9x; stage 3 >=3x, creatinine >=4.0 mg/dL, or initiation of dialysis.

Fractional excretion of sodium <1% suggests prerenal azotemia; >2% suggests intrinsic renal injury; it is unreliable with diuretics, so use fractional excretion of urea (<35% prerenal).

Hyponatremia: assess serum osmolality and volume status; correct chronic hyponatremia by no more than 8-10 mmol/L in 24 hours to avoid osmotic demyelination.

Hyperkalemia with ECG changes: intravenous calcium gluconate for membrane stabilization, insulin with glucose and beta-2 agonist to shift potassium intracellularly, then removal via diuretics, binders, or dialysis.

Metabolic acidosis: calculate the anion gap and delta ratio (delta gap / delta bicarbonate); a ratio <0.4 suggests a concurrent normal-gap acidosis, >2 suggests a concurrent metabolic alkalosis.

Nephrotic syndrome: proteinuria >3.5 g/day, hypoalbuminemia, edema, hyperlipidemia; complications include thrombosis (especially membranous nephropathy) and infection.

Chronic kidney disease mineral-bone disease: hyperphosphatemia and low calcitriol drive secondary hyperparathyroidism; control phosphate with diet and binders and monitor parathyroid hormone.

Urine anion gap = (Na + K) - Cl; a negative gap indicates adequate ammonium excretion, typical of diarrhea-induced bicarbonate loss, whereas a positive gap suggests renal tubular acidosis.

Diabetic ketoacidosis: glucose >250 mg/dL, pH <7.30, bicarbonate <18 mmol/L, ketonemia; treat with isotonic saline, intravenous insulin infusion, and potassium replacement once potassium <5.2 mmol/L.

Hyperosmolar hyperglycemic state: glucose often >600 mg/dL, effective osmolality >320 mOsm/kg, minimal ketosis; fluid replacement is the priority and insulin is started after volume resuscitation.

Hypoglycemia in a patient with diabetes is glucose <70 mg/dL; severe hypoglycemia is <54 mg/dL or any event requiring third-party assistance.

Thyroid storm: Burch-Wartofsky score >=45 is highly suggestive; treat with beta-blocker, thionamide, iodine at least 1 hour after thionamide, corticosteroid, and supportive care.

Primary hypothyroidism shows high TSH with low free T4; subclinical hypothyroidism shows high TSH with normal free T4, and treatment is considered when TSH >10 mIU/L.

Primary hyperaldosteronism screening: aldosterone-to-renin ratio with aldosterone >15 ng/dL; confirm with saline suppression or captopril challenge, then adrenal CT and adrenal vein sampling.

Adrenal crisis: hypotension with hyponatremia, hyperkalemia, and hypoglycemia; draw cortisol and ACTH, then give dexamethasone or hydrocortisone immediately without waiting for results.

Osteoporosis: dual-energy X-ray absorptiometry T-score <=-2.5 defines osteoporosis; a fragility fracture of hip or spine establishes the diagnosis regardless of T-score.

Iron deficiency anemia: low ferritin is the most specific test; if ferritin is normal but suspicion is high, check transferrin saturation (<20%) and soluble transferrin receptor.

Anemia of chronic disease: low serum iron, low transferrin saturation, normal or high ferritin, and normal or low total iron-binding capacity.

Microangiopathic hemolytic anemia with thrombocytopenia and acute kidney injury suggests thrombotic thrombocytopenic purpura; start plasma exchange urgently and do not delay for ADAMTS13 results.

Heparin-induced thrombocytopenia: platelet drop >50% at 5-10 days, thrombosis more often than bleeding; stop heparin and start a non-heparin anticoagulant such as argatroban.

Neutropenic fever: single oral temperature >=38.3 C or >=38.0 C sustained over 1 hour with neutrophils <500/microliter; obtain cultures and start antipseudomonal beta-lactam within 1 hour.

Tumor lysis syndrome: hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcemia; prevent with hydration and allopurinol (or rasburicase in high risk).

Multiple myeloma: CRAB features (hypercalcemia, renal insufficiency, anemia, bone lesions) plus >=10% clonal plasma cells or a biopsy-proven plasmacytoma.

G6PD deficiency: oxidative stress from infection, fava beans, or drugs such as primaquine, dapsone, and nitrofurantoin causes intravascular hemolysis with bite cells and Heinz bodies.

Sepsis: suspected infection plus organ dysfunction (SOFA increase >=2); septic shock is persistent hypotension requiring vasopressors with lactate >2 mmol/L despite adequate fluids.

Community-acquired pneumonia severity drives site of care; CURB-65 >=2 or new hypoxia generally warrants admission, and coverage should include atypical pathogens.

Meningitis: do not delay antibiotics for lumbar puncture; obtain blood cultures, give dexamethasone with or before the first antibiotic dose in suspected pneumococcal disease.

Infective endocarditis: obtain three sets of blood cultures before antibiotics; add surgery consultation for valve dysfunction, large vegetations, or persistent bacteremia.

Clostridioides difficile: test only unformed stool in symptomatic patients; first episode is treated with oral vancomycin or fidaxomicin, and recurrent disease may need fecal microbiota transplantation.

HIV post-exposure prophylaxis: start within 72 hours (ideally within 2 hours) with a three-drug regimen for 28 days; test the source and the exposed person at baseline.

Malaria: thick and thin smears with rapid antigen tests; severe disease (parasitemia >5%, cerebral involvement, acidosis) requires intravenous artesunate.

Tuberculosis infection control: airborne precautions with negative-pressure room and N95 respirator; treatment of active drug-susceptible disease is a 6-month rifampicin-based regimen.

Acute monoarthritis: joint aspiration is mandatory before antibiotics; septic fluid shows >50,000 leukocytes/microliter with >90% neutrophils, and crystals must be sought because gout and infection can coexist.

Gout: negatively birefringent needle-shaped crystals; pseudogout shows positively birefringent rhomboid crystals. Treat acute flares with NSAIDs, colchicine, or glucocorticoids, not urate-lowering therapy initiation alone.

Giant cell arteritis: age >50, new temporal headache, jaw claudication, visual symptoms, and elevated ESR; give high-dose glucocorticoid immediately and confirm with temporal artery biopsy or ultrasound.

Anti-CCP has higher specificity than rheumatoid factor for rheumatoid arthritis; early treatment with methotrexate improves long-term outcomes.

Systemic lupus erythematosus: antinuclear antibody is sensitive but not specific; anti-double-stranded DNA and anti-Smith are specific, and complement falls during active disease.

ANCA-associated vasculitis: c-ANCA/anti-PR3 with granulomatosis with polyangiitis, p-ANCA/anti-MPO with microscopic polyangiitis; induction with cyclophosphamide or rituximab plus glucocorticoids.

Anaphylaxis: intramuscular epinephrine 0.5 mg (1 mg/mL) into the anterolateral thigh, repeat every 5-15 minutes; antihistamines and corticosteroids are adjuncts only.

Hereditary angioedema: C4 is low and C1 inhibitor level or function is low; treat acute attacks with C1 inhibitor concentrate, icatibant, or ecallantide, not epinephrine.

Acute ischemic stroke: noncontrast CT excludes hemorrhage; intravenous thrombolysis within 4.5 hours of onset and mechanical thrombectomy for large vessel occlusion up to 24 hours in selected patients.

Stroke mimics to exclude before thrombolysis include hypoglycemia, seizure with postictal deficit, migraine, and functional deficits; check glucose immediately.

Status epilepticus: benzodiazepine first (lorazepam or midazolam), then a second-line agent such as levetiracetam, valproate, or phenytoin; refractory cases need anesthetic infusion.

Headache red flags: thunderclap onset, fever with neck stiffness, new focal deficit, age >50 with new headache, papilledema, and positional or Valsalva-provoked pain.

Guillain-Barre syndrome: progressive symmetric ascending weakness with areflexia and albuminocytologic dissociation; monitor vital capacity and treat with intravenous immunoglobulin or plasma exchange.

Myasthenia gravis: fatigable weakness, ptosis, and diplopia; anti-acetylcholine receptor antibodies are most common, and respiratory failure requires vital capacity monitoring.

Multiple sclerosis: dissemination in time and space; typical findings include optic neuritis, internuclear ophthalmoplegia, and periventricular or juxtacortical lesions on MRI.

Delirium: acute fluctuating inattention with altered awareness; identify and treat precipitants such as infection, medication, pain, retention, and withdrawal rather than sedating first.

Stevens-Johnson syndrome and toxic epidermal necrolysis: epidermal detachment <10% of body surface is SJS, >30% is TEN; stop the culprit drug, give supportive care in a burn unit, and avoid corticosteroids in unclear cases.

Cellulitis: nonpurulent and usually unilateral with poorly demarcated borders; mark the border, elevate the limb, and treat streptococcal and staphylococcal coverage.

Urticaria: wheals resolve within 24 hours; lesions lasting >24 hours with residual pigmentation suggest urticarial vasculitis and warrant biopsy.

Atopic dermatitis: impaired skin barrier with filaggrin mutations; first-line therapy is emollients plus topical corticosteroid, with calcineurin inhibitors for sensitive sites.

Drug reaction with eosinophilia and systemic symptoms: fever, rash, facial edema, eosinophilia, and organ involvement 2-8 weeks after starting a drug, often an aromatic anticonvulsant or allopurinol.

Allergic rhinitis: intranasal corticosteroid is the most effective single agent; add oral antihistamine for ocular symptoms and consider allergen immunotherapy for refractory disease.

Psoriasis: well-demarcated plaques with silvery scale on extensor surfaces; associated with psoriatic arthritis, metabolic syndrome, and cardiovascular risk.

Contact dermatitis: sharply demarcated lesions confined to the area of exposure; patch testing identifies the allergen, and treatment is topical corticosteroid plus avoidance.

Advanced cardiac life support: high-quality chest compressions at 100-120/min, depth 5-6 cm, full recoil; minimize interruptions and defibrillate shockable rhythms as early as possible.

Anaphylaxis: intramuscular epinephrine is first-line; give oxygen, intravenous fluids for hypotension, and observe for biphasic reactions.

Tension pneumothorax: clinical diagnosis with hypotension, distended neck veins, and absent breath sounds; immediate needle decompression followed by chest tube, without waiting for imaging.

Opioid overdose: titrate naloxone to restore respiration, not full consciousness; the goal is adequate ventilation to avoid withdrawal and agitation.

Carbon monoxide poisoning: pulse oximetry is normal; use carboxyhemoglobin level and give 100% oxygen, with hyperbaric oxygen considered for severe neurologic or cardiac involvement.

Trauma resuscitation: permissive hypotension is used in hemorrhagic shock until bleeding control; massive transfusion protocols use balanced ratios of plasma, platelets, and red cells.

Heat stroke: core temperature >40 C with central nervous system dysfunction; rapid cooling is the priority and antipyretics are ineffective.

Acute poisoning: activated charcoal is considered within 1 hour of a life-threatening ingestion in a patient with a protected airway; urinary alkalinization is used for salicylate toxicity.

Acute respiratory distress syndrome (Berlin definition): onset within 1 week, bilateral opacities not fully explained by heart failure, and PaO2/FiO2 <=300 mmHg on positive end-expiratory pressure >=5 cmH2O; use low tidal volume 6 mL/kg predicted body weight.

Septic shock: fluids 30 mL/kg crystalloid within the first 3 hours for hypotension or lactate >=4 mmol/L, then norepinephrine as the first vasopressor to target mean arterial pressure >=65 mmHg.

Ventilator-associated pneumonia: suspected after >48 hours of mechanical ventilation; obtain cultures and start empirical coverage based on local resistance patterns.

Acute decompensated heart failure with respiratory failure: noninvasive positive pressure ventilation reduces intubation in cardiogenic pulmonary edema.

Sedation in critical illness: target light sedation with daily interruption; the ABCDEF bundle reduces delirium and duration of mechanical ventilation.

Acute kidney injury in the intensive care unit: indications for renal replacement therapy include refractory hyperkalemia, acidosis, volume overload, and uremic complications.

Transfusion threshold in critically ill patients is hemoglobin <7 g/dL; a threshold of <8 g/dL is used for active cardiovascular disease.

Brain death: coma with absent brainstem reflexes and apnea despite adequate PaCO2 rise; confirmatory testing is used when the clinical examination cannot be completed.

Cardiac risk assessment: the Revised Cardiac Risk Index includes ischemic heart disease, heart failure, cerebrovascular disease, diabetes on insulin, creatinine >2 mg/dL, and high-risk surgery.

Functional capacity: >=4 metabolic equivalents without symptoms allows most surgery without further cardiac stress testing; poor or unknown capacity warrants testing if it will change management.

Perioperative beta-blockers should be continued in patients already taking them; starting high-dose beta-blocker on the day of surgery is not recommended.

Anticoagulation: for most procedures, stop warfarin 5 days before and bridge only in high thrombotic risk; direct oral anticoagulants are stopped based on renal function and bleeding risk.

Perioperative hyperglycemia is associated with infection and mortality; target glucose roughly 140-180 mg/dL with insulin and avoid tight control that causes hypoglycemia.

Postoperative fever timing: within 48 hours consider atelectasis and drug reaction; days 3-5 consider pneumonia and urinary infection; after day 5 consider surgical site infection and abscess.

Venous thromboembolism prophylaxis: use risk stratification (Caprini score); mechanical prophylaxis for high bleeding risk and pharmacologic prophylaxis when bleeding risk is acceptable.

Perioperative pulmonary complications: smoking cessation at least 4 weeks before surgery, incentive spirometry, and early mobilization reduce risk in thoracic and abdominal surgery.