How to manage Hyperglycemic Hyperosmolar Syndrome (HHS) in high blood glucose?

Management of Hyperglycemic Hyperosmolar Syndrome (HHS)

Begin immediate fluid resuscitation with 0.9% sodium chloride at 15-20 mL/kg/hour in the first hour, followed by intravenous insulin therapy once hypokalemia is excluded, and immediately evaluate for precipitating causes—HHS requires inpatient treatment due to severe volume depletion and typically presents with acute illness. 1, 2

Immediate Recognition and Assessment

HHS develops over days to a week and commonly presents with altered mental status, unlike DKA which develops over hours. 1 The clinical presentation includes:

• Severe dehydration with polyuria, polydipsia, and weight loss 1
• Change in cognitive state is common (ranging from confusion to coma) 1
• Often copresenting with other acute illness 1
• One-third of hyperglycemic emergencies have a hybrid DKA-HHS presentation 1

Immediately measure blood glucose, serum electrolytes, ketones, arterial or venous pH, and serum osmolality. 3 The total body water deficit in HHS is typically 9 liters (approximately 100-200 mL/kg). 2

Step-by-Step Treatment Algorithm

Step 1: Aggressive Fluid Resuscitation (First Priority)

Start with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour during the first hour to restore circulatory volume and tissue perfusion. 3, 4, 2 This is the most critical initial intervention as HHS is characterized by profound volume depletion. 1

• Fluid replacement should correct estimated deficits within the first 24 hours 2
• After stabilizing vital signs, consider switching to 0.45% NaCl for ongoing hydration 5
• The induced change in serum osmolality should not exceed 3-8 mOsm/kg/hour to prevent cerebral edema 4, 2

Step 2: Insulin Therapy (After Excluding Hypokalemia)

Administer an intravenous bolus of regular insulin at 0.1-0.15 U/kg body weight, followed by continuous infusion at 0.1 U/kg/hour. 3, 4, 2 Do not start insulin until hypokalemia is excluded and fluid resuscitation has begun. 2

• When blood glucose reaches 250-300 mg/dL, add dextrose to IV fluids while continuing insulin infusion at a reduced rate 4, 2
• This prevents hypoglycemia while allowing continued insulin administration to resolve hyperosmolarity 2

Step 3: Electrolyte Management

Monitor serum potassium levels every 2-4 hours as insulin therapy drives potassium intracellularly and can cause life-threatening hypokalemia. 3, 4, 2

• Begin potassium replacement when serum levels fall below 5.2-5.5 mEq/L, provided adequate urine output is present 4, 2
• Draw blood every 2-4 hours for electrolytes, glucose, BUN, creatinine, osmolality, and venous pH 3, 4

Step 4: Glycemic Targets During Treatment

Target blood glucose of 140-180 mg/dL (7.8-10.0 mmol/L) for most hospitalized patients once stabilized. 1 During acute management:

• Check blood glucose every 1-2 hours until stable 2
• For noncritically ill patients after stabilization, target pre-meal glucose <140 mg/dL and random glucose <180 mg/dL 3

Transition to Subcutaneous Insulin

Transition from intravenous to subcutaneous insulin 2-4 hours before stopping IV insulin to prevent rebound hyperglycemia. 3 Common pitfalls include:

• Premature termination of IV insulin therapy 6
• Insufficient timing or dosing of subcutaneous insulin before discontinuing IV insulin 6

Use a basal-bolus insulin regimen (basal insulin plus prandial rapid-acting insulin) for patients with adequate oral intake. 1 Sliding-scale insulin alone without basal insulin is strongly discouraged. 1

Identify and Treat Precipitating Causes

Infection is the most common precipitating factor in HHS development. 4, 2 Other causes include:

• Medication non-compliance or new-onset diabetes 2
• Acute illness (sepsis, myocardial infarction, stroke) 3, 4
• Stressful events (trauma, surgery) 1, 2
• Medications that worsen glycemic control (corticosteroids, diuretics) 5

Identify and treat any underlying correctable cause simultaneously with metabolic correction. 3, 4

Critical Monitoring Parameters

Continuous monitoring by experienced physicians is essential during HHS treatment. 6 Monitor:

• Blood glucose every 1-2 hours initially 2
• Electrolytes, BUN, creatinine, osmolality, and venous pH every 2-4 hours 3, 4
• Vital signs and mental status continuously 3
• Urine output to ensure adequate renal perfusion before potassium replacement 2

Special Considerations and Complications

Cerebral edema is a rare but potentially fatal complication, particularly in children and young adults. 2 To minimize risk:

• Avoid excessively rapid correction of osmolality (keep changes <3-8 mOsm/kg/hour) 4, 2
• Monitor for deteriorating level of consciousness during treatment 1

Be aware of euglycemic DKA risk in patients taking SGLT2 inhibitors. 2 These patients may present with lower glucose levels but still have significant ketoacidosis.

Discharge Planning and Prevention

Develop a structured discharge plan addressing the underlying cause and ensuring patient education on sick-day management. 3 Key prevention strategies include:

• Never discontinue insulin during intercurrent illness 1, 3
• Educate patients on when to contact healthcare providers during illness 1
• Ensure adequate supervision for elderly patients who may not recognize evolving dehydration 1
• Review sick-day management periodically, including blood glucose goals and use of supplemental insulin 1
• Establish close follow-up after discharge 3

Many cases of HHS can be prevented by better access to medical care, proper education, and effective communication during intercurrent illness. 1