diagnostic process - history, examination and investigation
Last reviewed 06/2022
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)
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