Internal Medicine · Year 3 · from Internal Medicine

Case 3: Hyperosmolar Hyperglycemic State

Patient Presentation

A 68-year-old man with type 2 diabetes is brought to the emergency department by his daughter who found him confused and difficult to arouse. She reports he has had decreased oral intake due to a "stomach bug" for the past week and has been less responsive over the past 2 days. His medications include metformin and glipizide, which he has not been taking due to nausea.

Vital Signs

  • Blood Pressure: 92/58 mmHg
  • Heart Rate: 108 bpm
  • Respiratory Rate: 18/min
  • Oxygen Saturation: 96% on room air
  • Temperature: 37.8°C

Physical Examination

  • General: Obtunded, arousable to painful stimuli only
  • HEENT: Extremely dry mucous membranes
  • Cardiovascular: Tachycardic, weak pulses
  • Pulmonary: Clear
  • Abdomen: Non-tender
  • Skin: Tenting, no rashes
  • Neurologic: GCS 10 (E2V3M5), no focal deficits

Initial Workup

  • Glucose: 1,150 mg/dL
  • Sodium: 152 mEq/L
  • Potassium: 4.2 mEq/L
  • Bicarbonate: 22 mEq/L
  • BUN/Creatinine: 68/3.2 mg/dL
  • Serum osmolality: 385 mOsm/kg (calculated: 378)
  • Arterial pH: 7.32
  • Serum ketones: Trace

Clinical Image

Figure 3: Comparison table of diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS) highlighting key differentiating features.

Image Source: Educational illustration for teaching purposes.

Questions

  1. What are the diagnostic criteria for hyperosmolar hyperglycemic state (HHS)?
  • A) Glucose >400, osmolality >300, pH >7.30, minimal ketones
  • B) Glucose >600, osmolality >320, pH >7.30, minimal ketones
  • C) Glucose >500, osmolality >310, pH <7.30, positive ketones
  • D) Glucose >800, osmolality >350, pH >7.25, no ketones
  1. What is the estimated fluid deficit in HHS?
  • A) 2-3 liters
  • B) 4-6 liters
  • C) 8-12 liters
  • D) 1-2 liters
  1. What is the most important difference in management between HHS and DKA?
  • A) Insulin dose is higher in HHS
  • B) Bicarbonate is always needed in HHS
  • C) Fluid resuscitation is more critical in HHS
  • D) Potassium replacement is not needed in HHS
  1. What is the significance of the neurologic findings in HHS?
  1. What precipitating factors should be investigated?

Answers

  1. B) Glucose >600, osmolality >320, pH >7.30, minimal ketones - HHS is characterized by severe hyperglycemia (>600 mg/dL), hyperosmolality (>320 mOsm/kg), minimal or no ketosis, and absence of significant acidosis (pH >7.30).
  1. C) 8-12 liters - Patients with HHS typically have profound volume depletion (8-12 L deficit) due to osmotic diuresis occurring over days to weeks. This is greater than the typical 5-7 L deficit in DKA.
  1. C) Fluid resuscitation is more critical in HHS - While both require aggressive fluid replacement, HHS requires even more emphasis on volume repletion. Glucose often drops significantly with fluids alone, and insulin requirements may be lower than in DKA.
  1. Neurologic findings significance:
  • Mental status changes (confusion, lethargy, coma) are more common in HHS than DKA
  • Correlate with degree of hyperosmolality (typically >320-330 mOsm/kg causes obtundation)
  • Focal neurologic deficits may occur and mimic stroke
  • Usually reversible with treatment
  • Rate of correction should avoid cerebral edema (gradual reduction in osmolality)
  1. Precipitating factors to investigate:
  • Infection (most common): pneumonia, UTI, sepsis
  • Medication non-adherence
  • New diagnosis of diabetes
  • Myocardial infarction or stroke
  • Medications: steroids, thiazides, antipsychotics
  • Gastrointestinal illness with dehydration
  • This patient likely had viral gastroenteritis leading to dehydration and medication non-adherence

Learning Points

  1. DKA is characterized by hyperglycemia, ketosis, and metabolic acidosis; treatment priorities are fluids, insulin, potassium replacement, and identification of precipitant.
  1. HHS features severe hyperglycemia and hyperosmolality without significant ketosis; fluid resuscitation is paramount.
  1. Potassium monitoring is critical in both conditions as total body potassium is depleted despite normal or elevated serum levels.
  1. Diabetes management should be individualized based on cardiovascular and renal comorbidities; SGLT2 inhibitors and GLP-1 agonists offer benefits beyond glucose control.
  1. HbA1c goal of <7% is appropriate for most patients; less stringent goals may be appropriate for those with limited life expectancy or high hypoglycemia risk.

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