S.pneumoniae meningitis featured in Question 9 from the first paper of 2013, as one of the septic complications of the post-splenectomy state. Specifically, the college examiners were interested in predisposing risk factors and specifics of management.

For the time-poor reader, LITFL has an excellent overview of adult bacterial meningitis.

Predisposing factors to pneumococcal meningitis:

  • Immunosuppression
  • Splenectomy
  • Extremes of age (very young and very old)
  • Intracranial implants, eg. cochlear implants
  • A CSF leak, for any reason
  • Cochlear implants
  • Sickle cell disease
  • Unvaccinated patient

Features suggesting a poor outcome:

Apparently, even now this condition has a disturbingly high mortality - almost 30%.

The following seem to be factors associated with a high risk of death:

  • Cranial nerve palsies
  • Low GCS
  • A raised ESR
  • High CSF protein
  • Low CSF leucocytes (less than 1000 per ml)

Utility of the urinary antigen

The urinary antigen in meningitis has a lower sensitivity than in pneumococcal pneumonia.

In pneumonia, the sensitivity is 82% and specificity is 97%.

In meningitis, the sensitivity is about 57% (but it is still highly specific).

However, it looks like you can use it on the CSF. In fact, the sensitivity improves to 95% if you decide to do this. Not all laboratories are going to agree with this.

Immediate management should consist of dexamethasone, vancomycin and ceftriaxone.

References

Kastenbauer, Stefan, and Hans‐Walter Pfister. "Pneumococcal meningitis in adults Spectrum of complications and prognostic factors in a series of 87 cases." Brain 126.5 (2003): 1015-1025.

Selby, C. D., and P. J. Toghill. "Meningitis after splenectomy." Journal of the Royal Society of Medicine 82.4 (1989): 206-209.

Fraser, David W., et al. "Risk factors in bacterial meningitis: Charleston County, South Carolina." Journal of infectious Diseases 127.3 (1973): 271-277.

Reefhuis, Jennita, et al. "Risk of bacterial meningitis in children with cochlear implants." New England Journal of Medicine 349.5 (2003): 435-445.

Lynch 3rd, J. P., and George G. Zhanel. "Streptococcus pneumoniae: epidemiology, risk factors, and strategies for prevention." Seminars in respiratory and critical care medicine. Vol. 30. No. 2. 2009.

Weisfelt, Martijn, et al. "Clinical features, complications, and outcome in adults with pneumococcal meningitis: a prospective case series." The Lancet Neurology 5.2 (2006): 123-129.

Samra, Zmira, et al. "Use of the NOW Streptococcus pneumoniae urinary antigen test in cerebrospinal fluid for rapid diagnosis of pneumococcal meningitis." Diagnostic microbiology and infectious disease 45.4 (2003): 237-240.

Smith, Michael D., et al. "Rapid diagnosis of bacteremic pneumococcal infections in adults by using the Binax NOW Streptococcus pneumoniae urinary antigen test: a prospective, controlled clinical evaluation." Journal of clinical microbiology 41.7 (2003): 2810-2813.