CASE 89: LOSS OF CONSCIOUSNESS
History
A 40-year-old man is admitted to the emergency department having been found uncon-
scious at home by his wife on her return from work in the evening. He has suffered from
insulin-dependent diabetes mellitus for 18 years and his diabetic control is poor. He has
had recurrent hypoglycaemic episodes, and has been treated in the emergency department
on two occasions for this. Over the past few weeks he has developed pain in his right foot.
His general practitioner diagnosed cellulitis and he has received two courses of oral
antibiotics. This has made him feel unwell and he has complained to his wife of fatigue,
anorexia and feeling thirsty. In his medical history he had a myocardial infarction 2 years
ago. He has had bilateral laser treatment for proliferative diabetic retinopathy. He was a
builder but is now unemployed. He smokes 25 cigarettes per week and drinks 30 units of
alcohol per week. His treatment is twice-daily insulin, he checks his blood glucose irregu-
larly at home.
Examination
He is clinically dehydrated with reduced skin turgor and poor capillary return. His pulse
is regular and 116/min. His blood pressure is 92/70 mmHg lying, 72/50 mmHg sitting up.
He seems short of breath with a respiratory rate of 30/min. Otherwise, examination of his
respiratory and abdominal systems is normal. He has an ulcer on the third toe of his right
foot and the foot looks red and feels warm. He is rousable only to painful stimuli. There
is no focal neurology. Funduscopy shows bilateral scars of laser therapy.
NormalHaemoglobin 15.2 g/dL 11.7–15.7 g/dL
White cell count 16.3% 109 /L 3.5–11.0% 109 /L
Platelets 344 % 109 /L 150–440% 109 /L
Sodium 143 mmol/L 135–145 mmol/L
Potassium 5.5 mmol/L 3.5–5.0 mmol/L
Chloride 105 mmol/L 95–105 mmol/L
Urea 11.3 mmol/L 2.5–6.7 mmol/L
Creatinine 114 &mol/L 70–120&mol/L
Bicarbonate 12 mmol/L 24–30 mmol/LUrinalysis:''protein;''ketones;'''glucoseBlood gases on air
pH 7.27 7.38–7.44
paCO 2 3.0 kPa 4.7–6.0 kPa
paO 2 13.4 kPa 12.0–14.5 kPaINVESTIGATIONS
Questions
- What is the cause for this man’s coma?
- How would you manage this patient?