Afghanistan Comprehensive Specialization Exam cheat sheet

Starling equation: Jv = Kf[(Pc − Pi) − σ(πc − πi)]; edema arises from increased capillary hydrostatic pressure, increased permeability, reduced plasma oncotic pressure, or lymphatic obstruction.

Arterial oxygen content: CaO2 = (1.34 × Hb × SaO2) + (0.003 × PaO2); anemia lowers oxygen content even when PaO2 is normal.

Winter's formula for metabolic acidosis: expected PaCO2 = (1.5 × HCO3) + 8 ± 2; a measured PaCO2 outside this range indicates an additional respiratory disorder.

Anion gap = Na − (Cl + HCO3); normal is approximately 8–12 mEq/L, and a high gap suggests ketones, lactate, uremia, or toxins.

Volume of distribution: Vd = dose / plasma concentration; loading dose = (Vd × target concentration) / bioavailability.

Clearance: CL = dose rate / steady-state concentration; half-life: t1/2 = 0.693 × Vd / CL; steady state is reached after about 4–5 half-lives.

Sensitivity = TP/(TP+FN) and specificity = TN/(TN+FP); high sensitivity makes a negative test useful for ruling out disease, and high specificity makes a positive test useful for ruling in disease.

Frank–Starling relationship: increased preload raises stroke volume until a plateau; reduced contractility shifts the curve downward and rightward.

ST-elevation myocardial infarction requires emergency reperfusion; primary percutaneous coronary intervention is preferred if achievable within 90 minutes, otherwise fibrinolysis should begin within 30 minutes of diagnosis.

Heart failure with reduced ejection fraction: four mortality-reducing pillars are an ARNI or ACE inhibitor/ARB, an evidence-based beta-blocker, a mineralocorticoid receptor antagonist, and an SGLT2 inhibitor.

Chronic kidney disease by eGFR: G1 ≥90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 <15 mL/min/1.73 m²; albuminuria category adds prognostic risk.

Diabetic ketoacidosis: glucose usually >250 mg/dL, pH <7.3, bicarbonate <18 mEq/L, and ketonemia/ketonuria; total-body potassium is depleted, so insulin is withheld if K <3.3 mEq/L until potassium is replaced.

Primary hypothyroidism shows high TSH with low free T4; central hypothyroidism shows low or inappropriately normal TSH with low free T4.

CURB-65 for pneumonia: confusion, urea >7 mmol/L, respiratory rate ≥30/min, systolic BP <90 or diastolic ≤60 mm Hg, and age ≥65 years; score 0–1 supports outpatient care, ≥2 warrants admission assessment.

Cirrhosis severity: Child–Pugh uses bilirubin, albumin, INR, ascites, and encephalopathy; MELD uses bilirubin, INR, creatinine, and sodium.

Acute ischemic stroke: thrombolysis is considered within 3–4.5 hours in selected patients, and thrombectomy up to 24 hours in selected large-vessel occlusion; blood pressure must be <185/110 mm Hg before thrombolysis.

Trauma assessment follows ABCDE; tension pneumothorax is a clinical diagnosis and requires immediate needle decompression before chest imaging.

Damage-control surgery targets the lethal triad of hypothermia, acidosis, and coagulopathy by controlling hemorrhage and contamination before definitive repair.

Acute appendicitis: the Alvarado score includes migration of pain, anorexia, nausea/vomiting, right lower quadrant tenderness, rebound tenderness, fever, and leukocytosis.

Burns: Parkland formula = 4 mL/kg body weight × percent total body surface area of lactated Ringer over 24 hours; half is given in the first 8 hours from burn time.

Bowel obstruction: air-fluid levels and dilated loops support the diagnosis; nasogastric decompression and intravenous fluids are initial measures, while strangulation, closed-loop obstruction, or peritonitis requires surgery.

Acute cholecystitis: right upper quadrant pain, Murphy sign, fever, and leukocytosis; ultrasonography is first-line imaging, and early laparoscopic cholecystectomy is definitive treatment.

Postoperative fever timing: atelectasis and pneumonia occur early, urinary infection around days 3–5, wound infection around days 5–7, and deep vein thrombosis later.

Strangulated hernia: severe pain, tenderness, fever, leukocytosis, and skin changes indicate ischemia and require emergency surgery.

Estimated pediatric weight: age 1–6 years = (2 × age) + 8 kg; age 7–12 years = (7 × age − 5) / 2 kg; use for emergency drug and fluid dosing.

Maintenance intravenous fluids follow the 4-2-1 rule: 4 mL/kg/hour for the first 10 kg, 2 mL/kg/hour for the next 10 kg, and 1 mL/kg/hour for each kilogram thereafter.

Dehydration: mild is <5% weight loss, moderate 5–10%, and severe >10%; oral rehydration solution suits mild-moderate dehydration, while shock requires isotonic intravenous boluses.

Neonatal jaundice: phototherapy thresholds depend on age, gestational age, and risk factors; exchange transfusion is for severe hyperbilirubinemia; conjugated jaundice is always pathologic.

Severe childhood asthma: inhaled short-acting beta-agonist plus ipratropium, early systemic corticosteroids, and intravenous magnesium for refractory severe disease; sedatives are contraindicated.

Infant meningitis: fever, irritability, bulging fontanelle, and poor feeding are clues; empiric therapy includes ampicillin plus cefotaxime or ceftriaxone, with vancomycin added when pneumococcal resistance is a concern.

Failure to thrive: weight below the third percentile or crossing two major growth percentiles downward; assess intake, growth velocity, and organic causes.

WHO immunization schedule: BCG and birth-dose polio at birth; pentavalent vaccine at 6, 10, and 14 weeks; measles vaccine at 9 and 15 months.

Pregnancy dating: crown–rump length + 6.5 gives gestational age in weeks up to 12 weeks; Naegele's rule = last menstrual period + 7 days − 3 months.

Preeclampsia: blood pressure ≥140/90 after 20 weeks plus proteinuria or end-organ dysfunction; severe features include BP ≥160/110, platelets <100,000, liver enzymes >2× normal, creatinine >1.1 mg/dL, pulmonary edema, or cerebral/visual symptoms.

Eclampsia: magnesium sulfate loading dose 4–6 g IV, then 1–2 g/hour; monitor deep tendon reflexes, respiratory rate, and urine output, and keep calcium gluconate available for toxicity.

Postpartum hemorrhage: uterine atony is most common; give oxytocin, then misoprostol, carboprost, or methylergonovine; tranexamic acid should be given within 3 hours of birth.

Gestational diabetes screening at 24–28 weeks uses a 75-g oral glucose tolerance test; thresholds are fasting ≥92, 1-hour ≥180, and 2-hour ≥153 mg/dL.

Combined oral contraceptive contraindications include migraine with aura, smoking ≥15 cigarettes/day at age ≥35, uncontrolled hypertension, prior venous thromboembolism, and breast cancer.

Uterine fibroids: heavy bleeding and bulk symptoms are common; GnRH agonists shrink fibroids temporarily, while hysterectomy is definitive.

Cervical cancer screening: HPV testing every 5 years from age 30–65, or cytology every 3 years; HPV vaccination prevents infection with high-risk types.

Incidence = new cases / population at risk per unit time; prevalence = all existing cases / total population; prevalence ≈ incidence × average disease duration.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); positive predictive value = TP/(TP+FP); negative predictive value = TN/(TN+FN); predictive values depend on disease prevalence.

Relative risk = incidence in exposed / incidence in unexposed; odds ratio = (a/c)/(b/d) = ad/bc for a 2×2 table.

Attributable risk = incidence in exposed − incidence in unexposed; population attributable fraction = (population incidence − unexposed incidence) / population incidence.

Study design: randomized trials best establish causality; cohort studies measure incidence and relative risk; case-control studies suit rare outcomes; cross-sectional studies measure prevalence.

Herd immunity threshold = 1 − 1/R0; measles with R0 12–18 requires approximately 92–95% population immunity to interrupt sustained transmission.

Screening criteria include an important health problem, detectable preclinical phase, acceptable and accurate test, effective early treatment, and cost-effective follow-up.

Health system building blocks: service delivery, health workforce, health information, access to essential medicines and vaccines, financing, and leadership/governance.

Informed consent requires capacity, disclosure, comprehension, voluntariness, and authorization; emergency treatment may proceed without consent when delay would cause serious harm.

Confidentiality exceptions include patient consent, legal requirements, public health reporting, court order, and preventing serious harm to an identifiable third party.

Four ethical principles: autonomy, beneficence, nonmaleficence, and justice; conflicts require balancing benefits, harms, and patient preferences with justification.

Research ethics: the Nuremberg Code, Declaration of Helsinki, and Belmont Report principles (respect for persons, beneficence, justice) require ethics review and informed consent.

Medical error disclosure: patients should be told about harmful errors, receive an apology and explanation, and the event should be reported for system-based root-cause analysis.

Negligence elements: duty of care, breach of the standard of care, causation, and damages; all four must be established.

Minors: emancipated and some mature minors may consent to certain services; emergency exceptions allow treatment when delay would endanger life or health.

End-of-life care: advance directives and DNR orders guide treatment; decisions use patient autonomy when previously expressed and best interests when capacity is lost.