Case history
Case history #1
A 72-year-old man is brought to hospital from a nursing home for progressive lethargy. The patient has a history of hypertension complicated by a stroke 3 years previously. This has impaired his speech and rendered him wheelchair-bound. He also has schizophrenia for which he was started recently on clozapine. On presentation, he is disoriented to time and place and febrile, with a temperature of 38.3°C (101°F). Vital signs include a BP of 106/67 mmHg, heart rate of 106 beats per minute, and a respiratory rate of 32 breaths per minute. Initial laboratory work-up reveals a serum glucose of 52.7 mmol/L (950 mg/dL), a serum sodium of 127 mmol/L (127 mEq/L), a serum potassium of 5.7 mmol/L (5.7 mEq/L), a serum urea of 21.1 mmol/L (59 mg/dL), and a serum creatinine of 200 micromol/L (2.3 mg/dL). Total serum osmolality is calculated as 338 mOsm/kg (338 mmol/kg). Urinalysis reveals numerous white blood cells and bacteria. Urine is positive for nitrates but negative for ketones. Serum is negative for beta-hydroxybutyrate (<1.0 mmol/L [<0.01 mg/dL]).[8]
Case history #2
A 45-year-old man with a history of type 2 diabetes is admitted directly from clinic for a serum glucose of 53.8 mmol/L (970 mg/dL). He was started recently on basal bolus insulin therapy after several years of treatment with oral hypoglycaemic agents. However, he reports not having followed his insulin prescription because he struggles to inject himself. For the past 2 weeks he has had polyuria and polydipsia, and has lost 5 kg in weight. He has also noted a progressively worsening cough for approximately 3 weeks that is productive of greenish-brown sputum. On examination, he is febrile, with a temperature of 38.5°C (101.3°F), tachypnoeic (respiratory rate of 24 breaths per minute), and normotensive. Initial laboratory work-up reveals a serum glucose of 53.8 mmol/L (969.4 mg/dL), a serum sodium of 134 mmol/L (134 mEq/L), a serum potassium of 4.3 mmol/L (4.3 mEq/L), a serum urea of 7.1 mmol/L (20 mg/dL), and a serum creatinine of 90 micromol/L (1 mg/dL). Urinalysis reveals trace ketones, but serum beta-hydroxybutyrate is not elevated. Serum bicarbonate is 17 mmol/L (17 mEq/L), venous pH is 7.32, beta-hydroxybutyrate is 1.2 mmol/L (0.01 mg/dL), and calculated total serum osmolality is 326 mOsm/kg (326 mmol/kg).
Other presentations
Up to 20% of patients admitted with hyperosmolar hyperglycaemic state (HHS) have previously undiagnosed diabetes.[1][9] Approximately 27% of patients with hyperglycaemic crises present with a mixed picture of diabetic ketoacidosis and HHS.[5] Coma is a rare presentation of HHS. Typically, coma is associated with serum osmolality levels >340 mOsm/kg (>340 mmol/kg) and is most often due to hypernatraemia rather than hyperglycaemia.[10] Occasionally, patients with HHS may present with seizures, hemiparesis, or hemianopia.[11][12] A mild acidaemia and ketoacidosis may be present.
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