Coma
Coma results from sustained impairment of awareness of self and of the environment. It can simply be defined as a state of unconsciousness or numerically categorised as a GCS score of<8.
Causes
Trauma
Figure 11 CT of the head.
There is a left-sided extradural haematoma (arrow). The haematoma is confined giving rise to its characteristic biconvex shape, with a well-defined margin.
Metabolic
Organ Failure
Infective
Toxin/Drug-Induced
History
The history for the comatose patient is usually obtained co-laterally from relatives, friends, witnesses or ambulance crew. Other sources of information are previous hospital notes, records kept by general practitioners and tablets or prescriptions that have been found at the patient’s premises.
Presentation
The circumstances regarding discovery of the patient is usually the first piece of information to be reported. Trauma patients may have been transported from sites of road traffic accidents, fire or have been found assaulted on the street. When teenagers are brought in unconscious from a night club, it is important to exclude alcohol intoxication, epilepsy, hypoglycaemia and the effects of illicit drugs (e.g. malignant hyperthermia with ‘ecstasy’). Attempted suicides may have an accompanying note or drug bottles may have been recovered from the scene. Carbon monoxide poisoning occurs with suicide attempts in enclosed areas with running engines or may be a complication in victims involved with fires. Patients who have been brought in from cold environments may also have hypothermia in addition to the primary event.
