A 56-year-old male, with a previous splenectomy, presents with an altered mental state but a stable cardiorespiratory status. He is pyrexial with a temperature of 38.4°C.
Blood cultures taken on admission show gram-positive cocci in both bottles.
- What is the likely diagnosis and what other specific investigations would you order?
- Outline your specific treatment for this condition.
- List five factors that predispose to this condition.
- What follow-up treatment will you recommend for this man on hospital discharge?
College Answer
Pneumococcal bacteraemia – probably meningitis
Investigations:
CT head ± lumbar puncture
PCR for pneumococcus
Urine pneumococcal antigen (Routine bloods)
b)
Empiric antibiotics – ideally within 30 minutes
3rd generation cephalosporin + vancomycin (steroids may limit penetration to CSF) or rifampicin
May change to penicillin if susceptible
Alternative regime – any reasonable combination
Dexamethasone before or with first dose of antibiotics
c)
Age <2 or >65 years
Chronic lung disease
Asplenic – functional or post splenectomy
Immunosuppression
Transplant recipient
CSF leak
Cochlear implants
d)
Vaccination and re-vaccinate at 5 year intervals
Empiric antibiotics if develops temperature and consider life long antibiotic therapy in this patient.
Discussion
a) The asplenic man is prone to infections by encapsulated organsisms. S.pneumoniae is the likely culprit. One would want a CT brain and LP; a urinary pneumococcal antigen should confirm the pathogen.
b) Immediate management should consist of dexamethasone, vancomycin and ceftriaxone.
c) 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
d) Post splenectomy vaccination and chronic oral suppression antibiotics will be required.
The specific details of precisely which vaccinations are required are available in the splenectomy chapter of the Required Reading section. A lot of spleen-associated wank is there, including references to such hard-hitting medical sources as the Japanese Journal of Ichthyology.
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.