Lecture Notes: Hyperosmolar Hyperglycemic Non-Ketotic State (HHNS)

Overview

• Diabetes mellitus is the 8th leading cause of death globally.
• Chronic complications: kidney disease, cardiovascular disease.
• Acute complications: Diabetic ketoacidosis (DKA) and Hyperosmolar Hyperglycemic Non-Ketotic State (HHNS).
• HHNS has a high mortality rate (8-20%).

Clinical Presentation of HHNS

• Occurs in individuals with a prior diabetes diagnosis.
• Symptoms develop over days to weeks:
  • Fatigue
  • Weight loss
  • Extreme thirst
  • Frequent urination
  • Signs of dehydration (e.g., tachycardia, hypotension, dry mucus membranes, decreased skin turgor).
  • Severe cases: confusion or altered mental status.

Pathophysiology of HHNS

• Hyperglycemia: Due to insulin deficiency.
  • Type 1 diabetes: absolute deficiency.
  • Type 2 diabetes: relative deficiency (insulin production is present but inadequate response).
• Insulin's role:
  • Pulls glucose from blood into cells for storage/energy.
  • In diabetes, glucose is not appropriately utilized, causing high blood sugar.

Metabolic Details

• Hyperosmolarity:
  • Glucose is osmotically active, causing water to follow it.
  • High glucose in blood pulls water from cells to maintain concentration.
  • Kidneys can't reabsorb excess glucose during severe hyperglycemia, leading to glucose in urine.
  • Water follows glucose into urine, causing rapid fluid loss (osmotic diuresis).
  • Result: dehydration, increased solute concentration in blood.

Differentiation: HHNS vs. DKA

• Non-Ketotic in HHNS:
  • Most HHNS patients have type 2 diabetes (pancreas produces insulin).
  • Insulin inhibits ketogenesis, preventing ketone (ketoacid) production.
  • In DKA (more common in type 1 diabetes), lack of insulin leads to ketone production, causing acidosis.

Treatment of HHNS

• HHNS requires ICU treatment due to severity.
• Major Treatments:
  1. Intravenous (IV) Insulin:
     • Corrects insulin deficit, lowers blood glucose.
     • Reduces osmotic diuresis and blood hyperosmolarity.
  2. Aggressive Rehydration:
     • IV fluids (e.g., normal saline) replenish lost fluids.
     • Alleviates dehydration signs (tachycardia, hypotension, altered mental status).

Conclusion

• HHNS is a serious complication of type 2 diabetes.
• Immediate medical evaluation is crucial for individuals with type 2 diabetes who become very ill.
• Aggressive treatment with IV insulin and fluids is necessary to prevent fatal outcomes.