Hyperosmolar Hyperglycemic State
A critical diabetic emergency marked by extreme high blood sugar and profound dehydration, mostly in type 2 diabetes.
Emergency Management: Severe shock requiring vasopressors (e.g., Norepinephrine). Airway compromise due to coma requiring immediate endotracheal intubation.
Hyperosmolar Hyperglycemic State (HHS) is a life-threatening complication of type 2 diabetes mellitus characterized by severe hyperglycemia, hyperosmolality, and profound dehydration without significant ketoacidosis. It primarily affects the central nervous system, leading to progressive altered mental status.
Detailed Overview
HHS typically develops insidiously over days to weeks, often precipitated by infection, myocardial infarction, or poor adherence to antidiabetic therapy. The profound osmotic diuresis leads to massive total body fluid losses, typically between 8-12 liters, causing severe intravascular volume depletion and renal hypoperfusion. Because enough insulin is present to suppress lipolysis, significant ketogenesis is prevented.
Epidemiology & Demographics
Accounts for <1% of hospital admissions related to diabetes. Most common in elderly patients with type 2 diabetes. Estimated mortality rate ranges from 10-20%, which is significantly higher than diabetic ketoacidosis.
Etiological Mechanism
Result of relative insulin deficiency combined with increased levels of counter-regulatory hormones (glucagon, catecholamines, cortisol, growth hormone) usually triggered by severe physiologic stress.
Primary Causes
Infections (pneumonia, UTI) - most common cause (50-60%)
Nonadherence to diabetes medications
Myocardial infarction or stroke
Medications (corticosteroids, thiazide diuretics, atypical antipsychotics)
Insulin deficiency reduces peripheral glucose utilization, while elevated counter-regulatory hormones stimulate hepatic gluconeogenesis and glycogenolysis, causing severe hyperglycemia. Glucose levels exceed the renal transport maximum (approx 180 mg/dL), leading to profound osmotic diuresis. This causes massive losses of water and electrolytes (Na+, K+). Unlike DKA, there is sufficient portal insulin to inhibit hormone-sensitive lipase in adipose tissue, preventing ketogenesis.
Diagnostic Criteria & Guidelines
Plasma glucose >600 mg/dL (33.3 mmol/L). Effective serum osmolality >320 mOsm/kg. Profound dehydration. Small ketonuria and absent-to-low ketonemia. Arterial pH >7.30 and serum bicarbonate >18 mEq/L.
1. Aggressive IV fluid resuscitation: 0.9% NaCl at 15-20 mL/kg/hr (approx 1-1.5 L) for the first hour. Switch to 0.45% NaCl if corrected serum sodium is normal or high. 2. IV Insulin: Regular insulin continuous infusion at 0.1 units/kg/hr. Do NOT start insulin if serum potassium is <3.3 mEq/L. 3. Potassium replacement: Add 20-30 mEq K+ per liter of IV fluid if serum K+ is 3.3-5.2 mEq/L and urine output is adequate.
Second-Line & Adjunctive Therapy
Addition of Dextrose 5% to IV fluids once plasma glucose reaches 250-300 mg/dL to prevent hypoglycemia while continuing insulin to resolve hyperosmolality. Broad-spectrum antibiotics (e.g., Piperacillin-tazobactam 4.5g IV Q6H) if sepsis is the suspected precipitant.
Surgical & Procedural Management
None generally indicated, unless treating a precipitating surgical emergency (e.g., cholecystitis, bowel ischemia).
Patient Counseling & Advice
Educate the patient and caregivers on 'sick day rules' for diabetes management, emphasizing the need to check blood sugars more frequently (every 4 hours) during illness and never to stop insulin completely without medical advice.
Follow-Up & Monitoring Schedule
Endocrinology follow-up within 2-4 weeks post-discharge. Regular HbA1c testing every 3 months until target (<7.0% or individualized goal) is achieved. Regular comprehensive metabolic panel to monitor renal function.
Preventive Strategies
Early detection of infection. Ensuring elderly patients have access to water. Avoidance of offending medications when possible.
Mortality is 10-20%, heavily dependent on age, severity of dehydration, and underlying precipitating illness. Full neurological recovery is expected if treated promptly before irreversible anoxic brain injury.