NMLE Integrated cheat sheet

Osmolarity = 2 × [Na⁺] + [glucose]/18 + [BUN]/2.8 (mg/dL); effective osmolarity (tonicity) excludes urea.

Henderson-Hasselbalch: pH = 6.1 + log([HCO₃⁻]/(0.03 × PaCO₂)); acute respiratory change of 10 mmHg PaCO₂ moves pH ~0.08, chronic ~0.03.

Expected compensation: metabolic acidosis PaCO₂ ≈ 1.5 × HCO₃⁻ + 8 ± 2; each 1 mEq/L fall in HCO₃⁻ lowers PaCO₂ ~1.2 mmHg.

Metabolic alkalosis: PaCO₂ rises ~0.7 mmHg per 1 mEq/L rise in HCO₃⁻; anion gap = Na⁺ − (Cl⁻ + HCO₃⁻), normal 8–12 mEq/L.

Cardiac output = heart rate × stroke volume; stroke volume rises with preload and contractility and falls with rising afterload; mean arterial pressure ≈ DBP + ⅓(SBP − DBP).

Autosomal recessive disease appears in 25% of offspring of two carriers; autosomal dominant in 50% if one parent is heterozygous; X-linked recessive affects males, females are carriers.

Hardy-Weinberg: p² + 2pq + q² = 1; carrier frequency for a disease with incidence q² is approximately 2√q².

Enzyme kinetics: Michaelis-Menten v = Vmax[S]/(Km+[S]); Km equals substrate concentration at half-Vmax; competitive inhibitors raise Km, noncompetitive lower Vmax.

Acute coronary syndrome: ST elevation in two contiguous leads defines STEMI; give aspirin 162–325 mg chewed plus P2Y12 inhibitor and arrange reperfusion (PCI within 90 min of first medical contact).

Heart failure with reduced ejection fraction (≤40%): quadruple therapy - ARNI/ACE inhibitor, beta-blocker, mineralocorticoid receptor antagonist, SGLT2 inhibitor - each reduces mortality.

Diabetic ketoacidosis: pH <7.3, bicarbonate <18, anion gap >10, ketonemia; treat with isotonic saline, insulin infusion 0.1 U/kg/h, and potassium replacement once K⁺ <5.2 mEq/L.

Hyperkalemia with ECG changes: IV calcium gluconate for membrane stabilization, then insulin plus glucose, beta-2 agonist, and dialysis if refractory.

Community-acquired pneumonia severity: CURB-65 (confusion, urea >7 mmol/L, respiratory rate ≥30, BP <90/60, age ≥65); score ≥2 suggests admission.

Thyroid: TSH is the first-line screen; low TSH with high free T4 indicates primary hyperthyroidism; high TSH with low free T4 indicates primary hypothyroidism.

Nephrotic syndrome: proteinuria >3.5 g/day, hypoalbuminemia, edema, hyperlipidemia; nephritic syndrome features hematuria, hypertension, and oliguria with red cell casts.

Cirrhosis complications: ascites managed with spironolactone plus furosemide and sodium restriction; spontaneous bacterial peritonitis diagnosed by ascitic neutrophil count ≥250/mm³.

Acute appendicitis: migration of pain to right lower quadrant, McBurney point tenderness, leukocytosis; Alvarado score ≥7 supports operative management.

Bowel obstruction: air-fluid levels and dilated loops on plain film; initial management is nothing by mouth, nasogastric decompression, and IV fluids; closed-loop or strangulation signs need urgent surgery.

ATLS primary survey sequence: airway with cervical spine protection, breathing, circulation with hemorrhage control, disability, exposure - treat life threats before completing history.

Hemorrhagic shock classes: class I <15% blood loss; class II 15–30% (tachycardia, narrowed pulse pressure); class III 30–40% (hypotension); class IV >40% (obtunded).

Acute cholecystitis: right upper quadrant pain, Murphy sign, fever, leukocytosis; ultrasound shows wall thickening >3 mm and pericholecystic fluid; treat with antibiotics and early laparoscopic cholecystectomy.

Burns: Parkland formula gives 4 mL × body weight (kg) × %TBSA of lactated Ringer in 24 h, half in the first 8 h from injury; rule of nines assigns 9% to each arm and 18% to each leg.

Postoperative fever timing: within 48 h consider atelectasis; days 3–5 consider urinary or wound infection; days 5–7 consider anastomotic leak or abscess; after day 7 consider deep vein thrombosis.

Thyroidectomy risks: recurrent laryngeal nerve injury causes hoarseness; external branch of superior laryngeal nerve injury impairs high pitch; hypocalcemia from parathyroid injury appears 24–72 h postoperatively.

Estimated date of delivery by Naegele rule: first day of last menstrual period minus 3 months plus 7 days; ultrasound dating is more accurate before 14 weeks.

Preeclampsia: blood pressure ≥140/90 after 20 weeks plus proteinuria or end-organ dysfunction; severe features include BP ≥160/110, platelets <100,000, transaminases doubled, pulmonary edema, or visual symptoms.

Magnesium sulfate for eclampsia prophylaxis: 4–6 g IV loading dose then 1–2 g/h; monitor reflexes, respiratory rate, and urine output; calcium gluconate is the antidote.

Postpartum hemorrhage: cumulative blood loss ≥1,000 mL or bleeding with hemodynamic instability; uterine atony is the most common cause - give oxytocin, then tranexamic acid within 3 h.

Fetal heart rate tracing: baseline 110–160 bpm; late decelerations suggest uteroplacental insufficiency; variable decelerations suggest cord compression; prolonged deceleration <10 min is not yet bradycardia.

Ectopic pregnancy: positive hCG with empty uterus and adnexal mass; a discriminatory hCG zone (about 3,500 mIU/mL for transvaginal ultrasound) above which an intrauterine sac should be visible.

Cervical cancer screening: cytology every 3 years from age 21, or co-testing with HPV every 5 years from age 30; stop after age 65 with adequate prior negative screening.

Puerperal mastitis: fever, tender erythematous breast wedge in a breastfeeding woman; Staphylococcus aureus is the usual organism; continue breastfeeding and treat with antibiotics.

APGAR scored at 1 and 5 minutes: appearance, pulse, grimace, activity, respiration; 0–3 indicates need for immediate resuscitation.

Neonatal jaundice: phototherapy thresholds depend on age in hours and risk factors; unconjugated hyperbilirubinemia risks kernicterus; jaundice within 24 h of birth is always pathologic.

Infant weight roughly doubles by 5 months and triples by 12 months; birth weight is regained by 2 weeks; length increases about 25 cm in the first year.

Developmental milestones: social smile 6 weeks, head control 3–4 months, sitting without support 6–8 months, walking 12–15 months, two-word phrases 18–24 months.

Bronchiolitis: respiratory syncytial virus is the most common cause, peak age 2–6 months; treat with supportive oxygen and hydration; bronchodilators and corticosteroids are not routinely indicated.

Kawasaki disease: fever ≥5 days plus four of conjunctivitis, oral mucosal changes, rash, extremity changes, cervical lymphadenopathy; treat with IVIG and aspirin to prevent coronary aneurysms.

Acute otitis media: bulging tympanic membrane or otorrhea plus acute onset; amoxicillin is first-line in most children; watchful waiting is acceptable for mild cases over 6 months.

Dehydration in children: assess by weight loss, capillary refill, skin turgor, and mental status; oral rehydration solution is preferred for mild to moderate dehydration; use isotonic fluids for IV maintenance.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); positive predictive value depends on prevalence and rises as prevalence rises.

Relative risk = incidence in exposed / incidence in unexposed; attributable risk = incidence in exposed minus incidence in unexposed; odds ratio approximates relative risk for rare outcomes.

Number needed to treat = 1/absolute risk reduction; number needed to harm = 1/absolute risk increase.

Cohort studies measure incidence and relative risk directly; case-control studies are efficient for rare diseases but yield odds ratios; randomized trials best control confounding.

Screening criteria: important disease, accepted treatment, detectable preclinical phase, suitable test with acceptable sensitivity and specificity, and evidence that early detection improves outcomes.

Herd immunity threshold ≈ 1 − 1/R₀; for measles with R₀ of 12–18, roughly 92–95% coverage is needed to interrupt transmission.

Levels of prevention: primary (before disease, e.g., vaccination), secondary (early detection, e.g., screening), tertiary (limiting disability, e.g., rehabilitation).

Lead-time bias makes screening appear to prolong survival without changing the time of death; length-time bias favors detection of slow-growing disease.

Informed consent requires capacity, adequate disclosure of risks and alternatives, comprehension, and voluntariness; documented refusal by a capacitated adult must be respected.

Four principles: autonomy, beneficence, nonmaleficence, and justice; when they conflict, autonomy generally prevails for a capacitated patient.

Emergency exception: treatment may proceed without consent when immediate intervention is required to prevent serious harm and no surrogate is available.

Minors: parental or guardian consent is generally required; emancipation, mature-minor statutes, and specific services such as sexually transmitted infection testing vary by jurisdiction.

Confidentiality may be breached when required by law (reportable diseases, gunshot wounds, child or elder abuse) or to prevent imminent serious harm to an identifiable person.

Mandatory reporting duties typically cover suspected child abuse, elder abuse, and specified communicable diseases; reporting is legal protection, not a discretionary courtesy.

Brain death is declared by irreversible coma with absent brainstem reflexes and apnea, with cause established and confounders excluded; it is distinct from persistent vegetative state.

Conflict of interest: disclose financial relationships to patients and institutions; participation in research requires independent ethics review and the ability to withdraw without penalty.

Advanced cardiac life support: high-quality compressions at 100–120/min, depth 5–6 cm, minimize interruptions; shock ventricular fibrillation or pulseless ventricular tachycardia immediately.

Adult cardiac arrest: epinephrine 1 mg IV every 3–5 min; amiodarone 300 mg after the third shock for refractory ventricular fibrillation; treat reversible causes (5 Hs and 5 Ts).

Sepsis: give broad-spectrum antibiotics within 1 h of recognition for septic shock; 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L, then reassess.

Anaphylaxis: intramuscular epinephrine 0.3–0.5 mg (1 mg/mL) into the anterolateral thigh, repeat every 5–15 min; adjuncts are antihistamines and corticosteroids, never first-line.

Tension pneumothorax: hypotension, distended neck veins, absent breath sounds, tracheal deviation; treat with immediate needle decompression before imaging.

Acute ischemic stroke: noncontrast CT excludes hemorrhage; IV thrombolysis within 4.5 h of symptom onset if no contraindication; thrombectomy up to 24 h in selected large-vessel occlusion.

Diabetic ketoacidosis in the emergency setting: isotonic saline, insulin infusion, potassium replacement once K⁺ is below 5.2 mEq/L, and dextrose added when glucose falls below about 200–250 mg/dL.

Acute respiratory distress syndrome: Berlin criteria - onset within 1 week, bilateral opacities not explained by heart failure, PaO₂/FiO₂ ≤300 mmHg on positive end-expiratory pressure ≥5 cmH₂O.