Clinical meaning
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 >2 mmol/L 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 pathophysiology involves absolute insulin deficiency leading to lipolysis and ketogenesis. HHS (hyperosmolar hyperglycemic state) presents with extreme hyperglycemia (>600 mg/dL), hyperosmolarity (>320 mOsm/kg), and minimal ketosis, typically in type 2 diabetes.
Electrolyte Emergencies: Severe hyponatremia (<120 mEq/L) risks cerebral edema and seizures. Correction must not exceed 8-10 mEq/L in 24 hours to prevent osmotic demyelination syndrome (central pontine myelinolysis). Severe hyperkalemia (>6.5 mEq/L) with ECG changes (peaked T waves, widened QRS, sine wave) is immediately life-threatening. Treatment sequence: (1) calcium gluconate for cardiac membrane stabilization, (2) insulin + D50 to shift potassium intracellularly, (3) sodium bicarbonate if acidotic, (4) kayexalate or patiromer for GI elimination, and (5) emergent dialysis if refractory.