USMLE Step 2 CK cheat sheet

STEMI: aspirin 325 mg chewed, P2Y12 inhibitor, anticoagulant, and primary PCI within 90 min of first medical contact; fibrinolysis if PCI unavailable within 120 min and no contraindications.

Heart failure with reduced EF: ARNI/ACEi/ARB, evidence-based beta-blocker, MRA, and SGLT2 inhibitor improve mortality; loop diuretics relieve congestion.

DKA: isotonic IV fluids, insulin infusion, and potassium repletion; if K <3.3 mEq/L, hold insulin and give potassium first; add dextrose when glucose <200-250 mg/dL.

AKI: FeNa <1% favors prerenal; FeNa >2% favors intrinsic injury; urgent bladder decompression for obstructive uropathy with hydronephrosis.

COPD exacerbation: target SpO2 88-92%, give short-acting bronchodilators, systemic corticosteroids, and antibiotics if sputum purulence or increased dyspnea; NIV for hypercapnic acidosis.

Cirrhosis with ascites: sodium restriction, spironolactone plus furosemide, and albumin 6-8 g per liter of ascites removed for large-volume paracentesis >5 L.

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

Graves disease: diffuse goiter, ophthalmopathy, suppressed TSH, elevated free T4, and TSH receptor antibodies.

Nephrotic syndrome: proteinuria >3.5 g/day, hypoalbuminemia, edema, hyperlipidemia; minimal change disease is most common in children.

Trauma ABCDE; tension pneumothorax needs immediate needle decompression then chest tube; cardiac tamponade shows Beck triad and needs pericardiocentesis.

Massive hemothorax: chest tube output >1500 mL immediately or >200 mL/h for 2-4 h suggests need for thoracotomy.

Burns: Parkland formula 4 mL LR × kg × %TBSA in 24 h; half in first 8 h from burn time; urine output 0.5 mL/kg/h in adults.

Acute appendicitis: periumbilical pain migrates to RLQ with McBurney tenderness and leukocytosis; CT or ultrasound helps; appendectomy is definitive.

Small bowel obstruction: air-fluid levels, NG decompression, IV fluids; fever, tachycardia, peritoneal signs, acidosis, or closed loop suggest strangulation and need surgery.

Acute cholecystitis: RUQ pain, Murphy sign, ultrasound wall thickening or pericholecystic fluid; IV antibiotics and cholecystectomy.

Acute pancreatitis: lipase >3× ULN, aggressive LR fluids, analgesia, early enteral feeding; ERCP for cholangitis or persistent biliary obstruction.

Postoperative fever: atelectasis first 24-48 h, urinary infection 3-5 days, wound infection 5-7 days, drug fever 7-10 days.

Breast cancer: sentinel node biopsy for clinically node-negative disease; axillary dissection for node-positive; ER/PR-positive receive endocrine therapy, HER2-positive receive trastuzumab.

Pediatric vital signs: newborn HR 100-160 and RR 30-60; infant HR 100-160 and RR 30-60; toddler HR 90-150 and RR 24-40; school-age HR 70-120 and RR 18-30.

Maintenance fluids use 4-2-1 rule: 4 mL/kg/h for first 10 kg, 2 mL/kg/h for next 10 kg, 1 mL/kg/h for each additional kg.

Dehydration: mild <5%, moderate 5-10%, severe >10%; give 20 mL/kg isotonic IV bolus for shock and oral rehydration for mild-moderate.

Croup: barky cough, inspiratory stridor, steeple sign; dexamethasone for all, nebulized epinephrine for moderate-severe.

Bronchiolitis: RSV most common, wheeze/crackles, apnea in young infants; supportive care; no routine bronchodilators, steroids, or antibiotics.

Kawasaki disease: fever ≥5 days plus ≥4 of conjunctivitis, oral changes, rash, extremity changes, cervical lymphadenopathy; IVIG plus aspirin; risk of coronary aneurysms.

Newborn jaundice: use hour-specific bilirubin nomogram; phototherapy for threshold levels; exchange transfusion for severe hyperbilirubinemia.

Intussusception: colicky pain, currant-jelly stool, sausage mass, target sign on ultrasound; air or contrast enema reduction.

Febrile seizure: age 6 months-5 years, generalized, <15 min, once in 24 h; routine EEG and neuroimaging are not indicated.

Pregnancy dating: crown-rump length is most accurate at 7-13 weeks; Naegele rule is LMP plus 7 days minus 3 months.

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

Severe preeclampsia at ≥34 weeks: delivery is recommended; before 34 weeks, corticosteroids for fetal lung maturity and magnesium sulfate for seizure prophylaxis.

Eclampsia: magnesium sulfate 4-6 g IV load then 1-2 g/h; monitor reflexes, respiratory rate, and urine output.

Gestational diabetes: screen at 24-28 weeks with 50-g glucose challenge; abnormal results followed by 100-g 3-hour OGTT; first-line therapy is diet and exercise, then insulin or metformin.

Postpartum hemorrhage: uterine atony most common; massage, oxytocin, methergine (avoid with hypertension), carboprost (avoid with asthma), misoprostol, tranexamic acid.

Combined oral contraceptives are contraindicated with migraine with aura, smoking at age ≥35, hypertension, VTE history, or breast cancer.

Ovarian torsion: sudden unilateral pelvic pain, nausea, adnexal mass; Doppler may be normal; immediate laparoscopy is required.

Cervical cancer screening: start at 21 with cytology every 3 years; age 30-65 can use co-testing every 5 years or cytology every 3 years.

Major depressive disorder: ≥5 symptoms for ≥2 weeks including depressed mood or anhedonia; SSRI first-line; assess suicide risk.

Bipolar mania: elevated/irritable mood plus increased energy for ≥1 week with ≥3 symptoms; treat with mood stabilizer plus antipsychotic; avoid antidepressant monotherapy.

Serotonin syndrome: clonus, hyperreflexia, hyperthermia, autonomic instability; stop serotonergic drugs; cyproheptadine for severe cases.

Neuroleptic malignant syndrome: rigidity, fever, autonomic instability, altered mental status; stop antipsychotic; dantrolene or bromocriptine.

Alcohol withdrawal: benzodiazepines are first-line; give thiamine before glucose; CIWA guides treatment.

Opioid use disorder: buprenorphine/naloxone, methadone, or naltrexone; naloxone reverses overdose.

Schizophrenia: ≥2 core symptoms for ≥6 months with ≥1 month active symptoms and functional decline; clozapine for treatment-resistant cases with ANC monitoring.

ADHD: inattention or hyperactivity before age 12 for ≥6 months with impairment; stimulants first-line plus behavioral therapy.

Anorexia nervosa: low BMI, fear of weight gain, body image disturbance; amenorrhea is not required; watch for refeeding syndrome.

USPSTF colorectal cancer screening: average-risk adults ages 45-75; options include colonoscopy every 10 years or annual fecal immunochemical test.

USPSTF breast cancer screening: mammography every 2 years for women ages 40-74.

USPSTF lung cancer screening: annual low-dose CT for adults 50-80 with ≥20 pack-year history who currently smoke or quit within 15 years.

USPSTF cervical cancer screening: ages 21-65; cytology every 3 years, or co-testing every 5 years for ages 30-65.

USPSTF statin: adults 40-75 with ≥1 risk factor and 10-year ASCVD risk ≥10% should receive a statin.

USPSTF diabetes screening: adults 35-70 who are overweight or obese; repeat every 3 years if normal.

USPSTF HIV screening: all adults 15-65 at least once; repeat for increased risk; PrEP for high-risk HIV-negative persons.

USPSTF hepatitis C screening: all adults 18-79 once; hepatitis B screening for pregnant patients and high-risk groups.

Adult immunizations: influenza annually; Tdap every 10 years; recombinant zoster for ≥50 years; pneumococcal for ≥50 or risk conditions.