Challenges of Hemodialysis in Patients with Hyperglycemic Hyperosmolar States (HHS)

Nephrologists are often challenged by patients with hyperosmolar states requiring hemodialysis (HD). A 25-year-old man with hypertension and obesity presented with nausea, vomiting, polyuria and blurred vision. He was found to have a blood sugar of 1700, serum sodium of 141 (179 corrected), hydroxyburyrate 5.2, lipase 1028 and a CT concerning for pancreatitis. Blood glucose levels were slowly corrected to the 1200s with insulin. He then required HD for AKI and hyperkalemia, leading to an acute drop in glucose to the 800s and a corrected sodium of 158, associated with acute mental status changes. Blood sugars were allowed to rise back to the 1000s, with corresponding corrected sodium of 169. A CT head saw no intracranial abnormalities. Renal function improved with resuscitation and no additional sessions of HD were required. Blood glucoses and corrected serum sodium was then carefully improved with a net change of tonicity of up to 12 mmol/L per day, leading to resolution of mental status changes. HHS is associated with high mortality. Metabolic derangements result from insulin deficiency, increased counter regulatory hormones (glucagon, catecholamines, cortisol) leading to increased gluconeogenesis, accelerated conversion of glycogen to glucose, and inadequate use of glucose by peripheral tissues. This leads to osmotic diuresis resulting in volume depletion, hypotensive shock, rhabdomyolysis, increased risk of thrombosis, and severe multi-organ failure. During extracellular hyperosmolar states, the brain is thought to protect itself against changes in volume by production of unidentified solutes. Rapid correction in plasma osmolality can lead to osmolar gradients, volume shifts, and cerebral edema. This case exemplifies difficulties in treating hyperglycemia and its resultant hyperosmolar state in a HD dependent patient. To avoid rapid changes in tonicity and intracranial fluid shifts during HD, careful manipulation of sodium and possibly concomitant use of mannitol may be required for cranial protection