Metabolism
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Two diabetic patients in coma
Two patients arrive in the Emergency Department at the same time. Both are unconscious, and both wear MedicAlert bracelets stating that they are insulin-dependent diabetics.
The results of blood tests were as follows:
patient CG |
patient GJ |
reference range in fasting |
|
| glucose (mmol /L) | 1.4 |
20 |
3 - 5 |
| non-esterified fatty acids (µmol /L) | 200 |
3000 |
700 - 900 |
| ketone bodies (µmol /L) | not detectable |
3000 |
50 - 300 |
What do you think is the cause of Ms CG's coma?
Ms CG is profoundly hypoglycaemic; we have already seen in the exercise Poisoned by unripe ackee fruit that when plasma glucose falls below about 2 mmol /L it is not possible to maintain normal ion transport in the brain, and loss of consciousness results.
What conclusions can you draw from the other data about this patient in the table above?
What is the most likely cause of her emergency admission?
Non-esterified fatty acid and ketone body concentrations are inappropriately low for someone with a plasma glucose concentration of 1.4 mmol /L. These are concentrations that you would expect in the fed state, not in the fasting state.
It is likely that she injected insulin as usual (or perhaps by accident injected more than usual), but then did not eat.