Emergency and complex management requires the clinician to rapidly assess, diagnose, and initiate treatment for life-threatening conditions. The approach follows the systematic ABCDE framework: Airway, Breathing, Circulation, Disability (neurologic), and Exposure. Sepsis and Septic Shock: Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection (Sepsis-3 criteria using SOFA score ≥2). Septic shock adds persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg AND serum lactate >18.0 mg/dL despite adequate volume resuscitation. The Surviving Sepsis Campaign Hour-1 Bundle includes: measure lactate, obtain blood cultures before antibiotics, administer broad-spectrum antibiotics, begin 30 mL/kg crystalloid for hypotension or lactate ≥4, and apply vasopressors for MAP <65 despite fluids. Acute Coronary Syndromes: The spectrum includes unstable angina (no biomarker elevation), NSTEMI (troponin elevation without ST elevation), and STEMI (troponin elevation with ST elevation in ≥2 contiguous leads). Time-dependent management for STEMI targets door-to-balloon <90 minutes for primary PCI or door-to-needle <30 minutes for fibrinolytics when PCI unavailable. Diabetic Emergencies: DKA presents with hyperglycemia (usually >250 mg/dL), metabolic acidosis (pH <7.3, HCO3 <18), ketonemia/ketonuria, and anion gap elevation. The...