Coma on admission, multiple, deep, or ruptured abscess, inaccurate diagnosis, and inability to prove the diagnosis were factors contributing to mortality.
In survivors, abscess generally followed cranial injury, surgery, or contiguous infection; in most fatal cases, brain abscess was secondary to a more remote primary infection. Ruptured or multiple abscesses or positive spinal fluid cultures were not found in survivors, and coma was present in only one.
Fatal cases in patients admitted in coma usually did not exhibit focal signs, seizures, or symptoms of meningitis early in the illness; none of these patients had prior cranial injury or surgery. Absence of these delayed their seeking care and accurate diagnosis. Ruptured abscess was frequent in these patients. Most patients not in coma on admission had focal signs, seizures, symptoms or meningitis, or had prior cranial injury or surgery.
Karandanis D, Shulman JA. Factors Associated With Mortality in Brain Abscess. Arch Intern Med. 1975;135(9):1145-1150. doi:10.1001/archinte.1975.00330090017002