How should I manage hyperosmolar hyperglycemic state (HHS) in an older adult with type 2 diabetes who presents with infection, dehydration, and medication non‑adherence?

Management of Hyperosmolar Hyperglycemic State (HHS) in Older Adults

Immediately initiate aggressive fluid resuscitation with 0.9% sodium chloride at 15-20 mL/kg/hour in the first hour, withhold insulin until blood glucose stops falling with fluids alone (unless ketones are present), and admit to an intensive care unit with continuous monitoring to prevent cerebral edema and other life-threatening complications. 1

Immediate Recognition and Initial Assessment

HHS is a medical emergency with higher mortality than diabetic ketoacidosis, particularly in elderly patients where age is the strongest prognostic indicator. 2, 3 The syndrome develops over days to a week (unlike DKA which develops in hours) and presents with:

• Severe dehydration with altered mental status – confusion, drowsiness, or reduced consciousness is present in most cases 1, 4
• Extreme hyperglycemia (typically >600 mg/dL) with marked hyperosmolality but minimal ketoacidosis 5, 6
• Precipitating factors – infection is the most common trigger, followed by medication non-adherence, acute cardiovascular events, or stroke 1, 2

Elderly patients are particularly vulnerable because they have impaired thirst mechanisms, reduced ability to recognize symptoms, and often cannot communicate their condition to caregivers. 2

Step 1: Aggressive Fluid Resuscitation (First Priority)

Begin with 0.9% sodium chloride (isotonic saline) at 15-20 mL/kg/hour during the first hour to restore circulatory volume and ensure adequate perfusion of vital organs. 1, 5 This is the absolute first priority before any other intervention.

• Continue isotonic saline until hemodynamic stability is achieved (stable blood pressure, improved mental status, adequate urine output) 7, 5
• Transition to 0.45% sodium chloride (hypotonic saline) after initial resuscitation if serum sodium is normal or elevated 7
• Aim to correct estimated fluid deficits within 24 hours, but avoid overly rapid correction 1

Critical Monitoring Point for Osmolality

The induced change in serum osmolality must not exceed 3-8 mOsm/kg/hour to prevent cerebral edema and central pontine myelinolysis, which are potentially fatal complications. 2, 1, 5 Measure or calculate serum osmolality every 2-4 hours during active treatment. 1

Step 2: Insulin Therapy (Delayed Until Appropriate)

Withhold insulin until blood glucose stops falling with intravenous fluids alone, unless significant ketonemia is present. 5 This is a critical difference from DKA management – early insulin use before adequate fluid resuscitation may be detrimental in HHS. 5

When insulin is indicated:

• Start with 10-15 units regular insulin IV bolus, followed by continuous infusion at 0.1 units/kg/hour 7
• Once blood glucose reaches 250-300 mg/dL, add 5% dextrose to IV fluids and reduce insulin infusion rate 2, 7
• Maintain glucose at 250-300 mg/dL until hyperosmolarity resolves and mental status improves – do not aggressively lower glucose below this range during acute HHS 2

Step 3: Electrolyte Management

Monitor serum potassium every 2-4 hours as insulin therapy drives potassium intracellularly and can cause life-threatening hypokalemia. 1

• Begin potassium replacement when serum levels fall below 5.2-5.5 mEq/L, provided adequate urine output is present 1
• Do not start insulin if potassium is <3.3 mEq/L – replace potassium first to avoid cardiac arrhythmias 1
• An initial rise in sodium is expected and normal during treatment – this is not an indication to switch to hypotonic fluids prematurely 5

Step 4: Identify and Treat Precipitating Causes

Infection is the most common precipitating factor in HHS, followed by medication non-compliance, acute myocardial infarction, stroke, and other acute illnesses. 2, 1

• Obtain cultures (blood, urine, sputum) and chest X-ray to identify occult infections 2
• Review medication list for drugs that worsen hyperglycemia (thiazides, steroids, beta-blockers, phenytoin) 7, 3
• Assess for acute cardiovascular or cerebrovascular events 2

Appropriate management of precipitating illnesses is essential to limit the high mortality associated with HHS. 7

Critical Monitoring Parameters

These patients require intensive care unit admission with continuous monitoring by experienced staff. 1, 5

Monitor the following parameters:

• Blood glucose every 1-2 hours initially 1
• Electrolytes, BUN, creatinine, and serum osmolality every 2-4 hours 1
• Vital signs and mental status continuously 1
• Urine output hourly to guide fluid and potassium replacement 1

Common Pitfalls to Avoid

Do not use hypotonic fluids initially – start with isotonic saline regardless of sodium level to restore circulating volume first. 5

Do not correct osmolality too rapidly – the maximum safe reduction is 3-8 mOsm/kg/hour to prevent cerebral edema. 2, 1, 5

Do not aggressively lower glucose below 250-300 mg/dL during acute HHS – maintain this range until mental status normalizes. 2

Do not start insulin before adequate fluid resuscitation unless significant ketones are present – fluid replacement alone will lower glucose initially. 5

Be especially cautious in elderly patients with heart failure or prior stroke – aggressive fluid replacement may be difficult to balance with these comorbidities, which are frequent causes of death in this population. 3

Transition and Prevention

After stabilization, many older adults with HHS will not require long-term insulin therapy and can be managed with oral agents or diet modification. 7

Prevention is paramount and requires:

• Adequate supervision for elderly patients who cannot recognize or communicate evolving dehydration 2
• Education of caregivers about signs of hyperglycemia and when to seek medical attention 2
• Never discontinue insulin during intercurrent illness – this is a common and preventable precipitant 1
• Ensure adequate fluid intake during illness, especially in nursing home residents 3

Structured discharge planning must address the underlying precipitating cause and include sick-day management education to prevent recurrence. 1