alcohol and head injury

Case reports in the forensic literature describe the adverse synergistic effect of moderate alcohol intoxication - blood alcohol concentration typically in the region of 200 mg/dL – and moderate head/ facial injury; typically soft tissue injuries sustained from blows from fists or a ‘kicking’.

Concussive brain injury (a transient interruption of brain functions) does not usually result in apnea, whilst  'concussion with alcohol' does, resulting in lethal respiratory depression (Milovanovic and Di Maio 1999).

Ramsay and Shkrum (1995) also postulate that post-traumatic bradycardia may result in sudden death following a mild head injury, possibly exacerbated by alcohol.

links 

alcohol (Wikipedia)