Application of Knowledge for Osteopathic Medical Practice
Application of Knowledge for Osteopathic Medical Practice is the largest domain and where Level 3 diverges most from earlier exams: stems describe outpatients and inpatients with comorbidity, polypharmacy, and ambiguous presentations, and the answer is the next best management step rather than a diagnosis alone.
Emergency management
- Sepsis: cultures and lactate, broad-spectrum antibiotics within one hour, 30 mL/kg crystalloid for hypotension or lactate of 4 or more, norepinephrine first-line for refractory shock.
- STEMI: chewed aspirin, P2Y12 inhibitor, anticoagulation, and PCI within 90 minutes of first medical contact, or fibrinolysis within 30 minutes when PCI is unavailable and no contraindication exists.
- Acute ischemic stroke: IV alteplase within 4.5 hours of last known well after noncontrast CT excludes hemorrhage; thrombectomy in selected large-vessel occlusion up to 24 hours.
- Hyperkalemia with ECG changes: IV calcium first, then insulin with glucose, albuterol, and dialysis.
Chronic disease targets
- Hypertension: below 130/80 for most adults; first-line thiazide, ACE inhibitor or ARB, or dihydropyridine calcium channel blocker; never combine an ACE inhibitor with an ARB.
- Type 2 diabetes: A1c below 7% for most; metformin first; add an SGLT2 inhibitor or GLP-1 agonist when ASCVD, heart failure, or CKD is present.
- Asthma: inhaled corticosteroid-formoterol as both reliever and controller in mild disease; never LABA monotherapy.
- Uncomplicated cystitis: nitrofurantoin for five days, avoiding it when creatinine clearance is very low.
Worked example
A 22-year-old with type 1 diabetes presents with vomiting and Kussmaul breathing. Glucose 486, pH 7.12, pCO2 22, bicarbonate 8, anion gap 30, beta-hydroxybutyrate positive, potassium 3.1. The gap and ketones confirm DKA. Because potassium is below 3.3, insulin is held and potassium repleted first; insulin drives potassium intracellularly and can precipitate fatal arrhythmia. Then isotonic fluids and an insulin infusion, with dextrose added when glucose falls below 200-250 mg/dL. Insulin continues until the anion gap closes, not until glucose normalizes. Bicarbonate is reserved for pH below 6.9.
Traps
Treating the glucose rather than the gap in DKA. Giving insulin before checking potassium. Using bicarbonate routinely. Missing that a normal blood pressure does not exclude sepsis, or that a normal A1c does not exclude diabetes in anemia or hemoglobinopathy.