This is a hot case where the candidate is launched at a comatose patient, with the objective of discovering the cause of that unconsciousness.
For the candidate, the key is to distinguish between the different flavours of coma. The chapter on the approach to the examination of an unconscious patient contains a long comprehensive list of differentials, and digresses extensively on the examination. For the time-poor candidate, the LITFL entry on this topic is much easier to use for revision.
An abbreviated version of that huge list of differentials would resemble the following:
With focal signs
Without focal signs
Metabolic problem: one of the many encephalopathies (see COATPEGS):
Diffuse cerebral vascular issues
Brainstem problem (eg. stroke)
One can get far using the LITFL TOMES/COATPEGS mnemonics. TOMES stands for "toxins, organ failure, metabolic, endocrine, seizures" and COATPEGS stands for "oxygen, carbon dioxide, ammonia, temperature, pH, electrolytes, glucose and serum osmolality". Sure, some of the causes of non-focal unconsciousness are missing, but if you add them all, you end up with "COMATOSE GREAT APE"
A suggestion made by an ex-examiner is as follows: