Pneumococcal meningitis

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.