Diagnostic process - history, examination and investigation

diagnosis

Unlike diabetic ketoacidosis (DKA) which presents within hours of onset, HHS comes on over many days (1).

• typical patient is an elderly person with undiagnosed diabetes or type 2 diabetes managed by diet and/or oral diabetic medication
• history will reveal one or more of the precipitating factors (often medication) (1,2)

HHS patients may present with:

• weakness
• visual disturbance
• leg cramps
• nausea and vomiting - less frequent than in patients with DKA
• neurological symptoms - degree of neurologic impairment correlates directly to the effective serum osmolarity
  • lethargy, confusion
  • hemiparesis (often misdiagnosed as cerebrovascular accident)
  • seizures - present in up to 25% of cases, can be generalized, focal, myoclonic jerking, or movement induced
  • coma (2)

Physical finding will reveal

• signs of severe dehydration e.g. - poor tissue turgor, dry buccal mucosa membranes; soft, sunken eyeballs; cool extremities; and a rapid, thready pulse
• low grade fever
• abdominal distension - due to gastroparesis induced by hypertonicity (2)

Investigations

• blood glucose - markedly raised (usually 30 mmol/L or more)
• serum osmolarity - elevated >320 mmol/L (normal range is 290 ± 5 mmol/L)
  • serum osmolarity is useful, both as an indicator of severity and for monitoring the rate of change with treatment
  • if measurement of total osmolality is not available, osmolarity should be calculated as a surrogate using the formula 2(Na) + glucose + urea.
• arterial blood gases
• urinalysis
• renal function tests and electrolytes
• creatinine, blood urea nitrogen (BUN)

Reference:

• (1) Joint British Diabetes Societies (JBDS) 2012. Inpatient care group. The management of the hyperosmolar hyperglycaemic state (HHS) in adults with diabetes
• (2) Stoner GD. Hyperosmolar hyperglycemic state. Am Fam Physician. 2005;71(9):1723-30.