How to manage Hyperosmolar Non-Ketotic Coma (HONK)?

Management of Hyperosmolar Nonketotic Coma (HONK)

Begin immediate fluid resuscitation with 0.9% sodium chloride at 15-20 mL/kg/hour during the first hour to restore circulatory volume and tissue perfusion, followed by insulin therapy once hemodynamic stability is achieved. 1

Initial Stabilization and Assessment

Immediate priorities:

• Secure airway, breathing, and circulation; intubate if necessary for airway protection in obtunded patients 1
• Establish intravenous access and begin aggressive fluid resuscitation before detailed laboratory workup 2
• Draw initial labs: glucose, electrolytes (especially potassium), BUN, creatinine, serum osmolality, venous pH, and complete blood count 1
• Monitor vital signs continuously and assess for precipitating causes (infection most common, followed by MI, stroke) 1, 2

Key diagnostic features to confirm:

• Severe hyperglycemia (typically >600 mg/dL) with marked hyperosmolality 2
• Absence of significant ketoacidosis (distinguishes from DKA) 3
• Profound dehydration with typical water deficit of 9 liters 1

Fluid Resuscitation Protocol

First hour:

• Administer 0.9% normal saline at 15-20 mL/kg/hour to restore intravascular volume 1
• Continue isotonic saline until hemodynamic stability achieved (stable blood pressure, adequate urine output) 2

After hemodynamic stabilization:

• Switch to 0.45% (half-normal) saline to address free water deficit 2
• Continue fluid replacement to correct estimated deficits within 24 hours 1
• Critical safety parameter: Ensure osmolality decrease does not exceed 3-8 mOsm/kg/hour to prevent cerebral edema 1

Pitfall to avoid: Overly aggressive fluid resuscitation with crystalloids increases risk of cerebral edema and adult respiratory distress syndrome; if hypovolemia persists despite adequate crystalloid administration, consider colloid solutions like albumin 3

Insulin Therapy

Timing and dosing:

• Delay insulin until after initial fluid resuscitation has begun (unlike DKA, insulin is not first-line) 3, 2
• Administer IV bolus of regular insulin 0.1 units/kg body weight 1
• Follow with continuous infusion at 0.1 units/kg/hour 1

Glucose management during treatment:

• When glucose reaches 250-300 mg/dL, add 5% dextrose to IV fluids 1
• Reduce insulin infusion rate but continue to prevent rebound hyperglycemia 1
• Maintain glucose initially around 250 mg/dL (14 mmol/L) as rapid lowering increases cerebral edema risk 3

Transition to subcutaneous insulin:

• Administer basal insulin 2-4 hours before stopping IV insulin to prevent rebound hyperglycemia 1
• Many elderly patients with HONK will not require long-term insulin and can be managed with diet or oral agents after recovery 2

Electrolyte Management

Potassium replacement (critical priority):

• Monitor potassium levels every 2-4 hours as insulin therapy drives potassium intracellularly, causing potentially fatal hypokalemia 1, 4
• Begin potassium replacement when serum level falls below 5.5 mEq/L, assuming adequate urine output 1
• Warning: Hypokalemia can cause respiratory paralysis, ventricular arrhythmia, and death if untreated 4

Phosphate and magnesium:

• Replace when serum concentrations fall below normal range, particularly in critically ill patients 3
• While clinical benefit not definitively established, replacement is justified given potential for complications 3

Monitoring Protocol

Glucose monitoring:

• Check blood glucose at least every 2-4 hours 1

Laboratory monitoring:

• Draw blood every 2-4 hours for: electrolytes, glucose, BUN, creatinine, osmolality, venous pH 1
• Pay particular attention to potassium given rapid shifts with insulin therapy 1

Clinical monitoring:

• Assess mental status frequently for improvement or deterioration 2
• Monitor urine output to ensure adequate renal perfusion 1
• Watch for signs of cerebral edema (headache, altered consciousness, seizures) especially in younger patients 1

Identify and Treat Precipitating Causes

Most common precipitants:

• Infection (most frequent cause) - obtain cultures, start empiric antibiotics if suspected 1, 2
• Myocardial infarction - obtain ECG and cardiac biomarkers 1
• Stroke - perform neurological examination and imaging as indicated 1
• Medications: diuretics, corticosteroids, beta-blockers, phenytoin increase risk 2

Critical point: Associated diseases cause most fatalities in HONK, not the metabolic derangement itself; aggressive management of precipitating conditions is essential 5

Special Populations and Complications

Elderly patients:

• HONK predominantly affects elderly patients with type 2 diabetes 2, 5
• Higher risk of thromboembolic complications; two-thirds of deaths result from thrombosis and infection 3
• Monitor for congestive heart failure with aggressive fluid administration 5

Pediatric patients (rare):

• Greater risk of fatal cerebral edema compared to adults 6
• Fluid therapy takes priority over insulin in initial management 6
• Focus on slowly returning serum tonicity to normal 6

Mortality considerations:

• Overall mortality remains 20-30% despite treatment, primarily due to severe underlying conditions 3
• Thromboembolic disorders are leading cause of death alongside infections 3

Discharge Planning

Develop structured discharge plan including:

• Diabetes education to prevent recurrence 1
• Medication reconciliation (discontinue precipitating drugs if possible) 2
• Follow-up arrangements to reduce readmission rates 1