ANSWER 53
This man has been unconscious in the open air for an unknown period. Little history is
available, but the tablets in his pocket might suggest that he has a problem with a painful
condition. There are a number of possible causes for his unconsciousness including a cere-
brovascular problem, deliberate or accidental drug overdose, including alcohol poisoning,
metabolic or endocrine disturbance or hypothermia.
If this were an overdose, e.g. of dihydrocodeine, the pupils might well be small. The slow
respiratory rate could be compatible with an opiate excess suppressing ventilation. The
oxygen saturation results show that he is oxygenating himself satisfactorily although it
would be sensible to perform blood gases to measure the arterial partial pressure of CO 2
(paCO 2 ). It would be appropriate to measure the paracetamol level in the blood and it would
be worth giving the opiate antagonist naloxone if there remained a likelihood of overdose.
The blood alcohol level should be measured to exclude alcohol poisoning.
Most cerebrovascular problems would be expected to produce some localizing neuro-
logical signs on careful examination even in an unconscious patient. There are no such
signs here. The absent ankle jerks might be related to his age.
He could have hyperosmolar non-ketotic coma detected by a high glucose and evidence
of haemoconcentration. The blood glucose should be measured together with electrolytes
and haematology but the single'of glucose in the urine makes it unlikely that he has
hyperglycaemic coma. Liver function and renal function should be measured.
He has a slow respiratory rate, low blood pressure and an ECG which shows a wide QRS
complex. The wide complexes on the ECG show an extra deflection at the end of the QRS
complex, the J point. This J-wave is characteristic of hypothermia and disappears after
rewarming as shown by the subsequent ECG (Fig. 53.2). The pulse rate would often be
slower than the 82/min in this man and the ECG may show evidence of a tremor from
shivering. The temperature of 35.1°C does not appear excessively low but this may not be
reliable if it is not a true core temperature or has been measured with a normal mercury
thermometer (mercury thermometers are not reliable at low temperatures). Indeed, in this case,
repeat of the rectal temperature measurement with a low-reading thermometer showed a tem-
perature of 30.6°C. No paracetamol was detected in the blood and his alcohol level was low at
11 m g / 10 0 m L.
IIIIIIVIaVRaVLaVFV1V2V3V4V5V6Figure 53.2Electrocardiogram of resolved hypothermia.