HHNK (Hyperglycemic, Hyperosmolar Non-Ketotic State)

Overview

• Occurs over several days and can lead to coma.
• Mainly affects elderly individuals with Type 2 diabetes or undiagnosed diabetes.
• Gradual onset—symptoms develop over days or weeks.
• Often missed or mistaken for dementia due to overlapping symptoms.

Cause and Pathophysiology

• Insulin levels are sufficient to prevent ketoacidosis but insufficient to prevent hyperglycemia.
• Common triggers:
  • Biological Stressors: infection, stroke, myocardial infarction.
  • Overindulgence in carbohydrates.
  • Poor management of diabetes or missed medication.
• Counter-regulatory hormones (glucagon, cortisol, epinephrine, norepinephrine) stimulate hepatic gluconeogenesis and glycogenolysis, pushing more glucose into the blood.
• Cells are starved for glucose because insulin response is inadequate, leading to hyperglycemia.

Effects of Hyperglycemia

• High blood glucose (>600 mg/dL).
• Excess glucose pulls water into urine (osmotic diuresis), causing severe dehydration.
• Decreased blood volume leads to low blood pressure (hypovolemia).
• Concentration of red blood cells increases (hemoconcentration): higher hematocrit.
• Reduced urine output over time due to dehydration.

Symptoms and Clinical Signs

• Thirsty and dry skin (loss of turgor).
• Headaches and feeling overheated.
• Low urine output (dehydration phase).
• Hypovolemia causes low blood pressure.
• Neurological signs:
  • Confusion, decreased alertness.
  • Weakness, abnormal reflexes.
  • Difficulty speaking.
  • Abdominal pain.
  • Loss of sensory function, visual disturbances.
  • Symptoms may resemble stroke.
• Decreased neural function can progress to seizures and coma.

Effect on the Body

• Dehydration and low blood volume impair brain function.
• Compensatory mechanisms include increased heart rate and respiration.
• Neuronal damage due to lack of nutrients and oxygen.
• Can lead to seizures, loss of consciousness, and death if not treated promptly.

Diagnosis

• Blood glucose >600 mg/dL.
• Signs of severe dehydration.
• Elevated hematocrit (more concentrated blood).
• Electrolyte imbalance.
• Blood pH typically normal or slightly acidic (no ketoacidosis).
• Urinalysis:
  • Glucosuria (glucose in urine).
  • Usually no ketones (hence non-ketotic).
  • Polyuria initially followed by oliguria.

Treatment

• IV fluids to correct dehydration.
• Electrolyte replacement (potassium, sodium).
• Insulin therapy to reduce blood glucose.
• Address underlying stressors (infection, stroke, etc.).

Summary

• HHNK is a life-threatening complication mainly affecting elderly with Type 2 diabetes.
• Characterized by severe hyperglycemia and dehydration without ketoacidosis.
• Rapid treatment with fluids, electrolytes, and insulin is essential to prevent coma and death.