A useful way of approaching the unconscious patient is to use these three categories:
- Coma with focal or lateralizing signs
- Coma without focal or lateralizing signs but with meningism
- Coma without either focal or lateralizing signs or meningism
Coma with focal or lateralizing signs
- Cerebrovascular events (ischemic or hemorrhagic)
- Space-occupying lesions (infective or non-infective, e.g. tumours)
Coma without focal or lateralizing signs but with meningism
- Subarachnoid haemorrhage
Coma without either focal or lateralizing signs or meningism (TOMES P)
- Numerous causes including sedatives, narcotics, alcohol, psychotropics, carbon monoxide
- Organ failure
- Uremic encephalopathy, hepatic encephalopathy
- hypoxia, hypercapnoea, hyponatraemia, hyperglycaemia, hypoglycaemia, hypothermia, hyperthermia, hypoosmolality, hyperosmolarity, nutritional disorders (e.g. thiamine deficiency)
- Adrenal insufficiency, hypopituitarism, hypothyroidism
- Seizures (including non-convulsive epilepsy, postictal states and eclampsia)
- Acidosis/ Alcohol
- Trauma to head
- Insulin: too little or or too much
- Units of insulin
- CO2 and CO excess
- Overdose: TCAs, Benzos, EtOH, insulin, paracetamol, etc.
- Metabolic: BSL, Na+, K+, Mg2+, urea, ammonia, etc.
- Apoplexy: stroke, SAH, extradural, subdural, Ca, meningitis, encephalitis, cerebral abscess, etc.