Morbidity
Generally, with prompt and adequate antimicrobial and supportive therapy, the outcome after acute bacterial meningitis is excellent. However, prognosis does depend on multiple factors such as age, presence of comorbidity, causative pathogen, and severity at presentation. In adults with bacterial meningitis, risk factors associated with a poor prognosis include advanced age, presence of osteitis or sinusitis, low Glasgow Coma Scale score on admission (i.e., low level of consciousness), tachycardia, absence of rash, thrombocytopenia, elevated erythrocyte sedimentation rate, low cerebrospinal fluid cell count, and positive blood culture.[17]van de Beek D, de Gans J, Spanjaard L, et al. Clinical features and prognostic factors in adults with bacterial meningitis. N Engl J Med. 2004 Oct 28;351(18):1849-59.
http://www.nejm.org/doi/full/10.1056/NEJMoa040845#t=article
http://www.ncbi.nlm.nih.gov/pubmed/15509818?tool=bestpractice.com
Up to one third of adults who have had bacterial meningitis have cognitive impairment.[114]Hoogman M, van de Beek D, Weisfelt D, et al. Cognitive outcome in adults after bacterial meningitis. J Neurol Neurosurg Psychiatry. 2007 Oct;78(10):1092-6.
http://jnnp.bmj.com/content/78/10/1092.full
http://www.ncbi.nlm.nih.gov/pubmed/17353256?tool=bestpractice.com
Mortality
The mortality rate of community-acquired bacterial meningitis is approximately 20% for all causes and up to 30% for pneumococcal meningitis. The mortality rate increases with age.[17]van de Beek D, de Gans J, Spanjaard L, et al. Clinical features and prognostic factors in adults with bacterial meningitis. N Engl J Med. 2004 Oct 28;351(18):1849-59.
http://www.nejm.org/doi/full/10.1056/NEJMoa040845#t=article
http://www.ncbi.nlm.nih.gov/pubmed/15509818?tool=bestpractice.com
[115]Chadwick DR, Lever AM. The impact of new diagnostic methodologies in the management of meningitis in adults at a teaching hospital. QJM. 2002 Oct;95(10):663-70.
http://www.ncbi.nlm.nih.gov/pubmed/12324638?tool=bestpractice.com
Delayed antibiotic administration increases mortality.[25]van de Beek D, Cabellos C, Dzupova O, et al. ESCMID guideline: diagnosis and treatment of acute bacterial meningitis. Clin Microbiol Infect. 2016 May;22 (Suppl 3):S37-62.
https://www.clinicalmicrobiologyandinfection.com/article/S1198-743X(16)00020-3/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/27062097?tool=bestpractice.com
[33]Proulx N, Fréchette D, Toye B, et al. Delays in the administration of antibiotics are associated with mortality from adult acute bacterial meningitis. QJM. 2005 Apr;98(4):291-8.
http://www.ncbi.nlm.nih.gov/pubmed/15760921?tool=bestpractice.com
[96]Zasowski EJ, Bassetti M, Blasi F, et al. A systematic review of the effect of delayed appropriate antibiotic treatment on the outcomes of patients with severe bacterial infections. Chest. 2020 Sep;158(3):929-38.
https://journal.chestnet.org/article/S0012-3692(20)31497-5/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/32446623?tool=bestpractice.com