Meningitis medical therapy


 * Associate Editor(s)-In-Chief:

Bacterial meningitis
Bacterial meningitis is a medical emergency and has a high mortality rate if untreated. All suspected cases, however mild, need emergency medical attention. Empiric antibiotics must be started immediately, even before the results of the lumbar puncture and CSF analysis are known. Antibiotics started within 4 hours of lumbar puncture will not significantly affect lab results. Adjuvant treatment with corticosteroids reduces rates of mortality, severe hearing loss and neurological sequelae.

The choice of antibiotic depends on local advice. In most of the developed world, the most common organisms involved are Streptococcus pneumoniae and Neisseria meningitidis: first line treatment in the UK is a third-generation cephalosporin (such as ceftriaxone or cefotaxime). In those under 3 years of age, over 50 years of age, or immunocompromised, ampicillin should be added to cover Listeria monocytogenes. In the U.S. and other countries with high levels of penicillin resistance, the first line choice of antibiotics is vancomycin and a carbapenem (such as meropenem). In sub-Saharan Africa, oily chloramphenicol or ceftriaxone are often used because only a single dose is needed in most cases.

Staphylococci and gram-negative bacilli are common infective agents in patients who have just had a neurosurgical procedure. Again, the choice of antibiotic depends on local patterns of infection: cefotaxime and ceftriaxone remain good choices in many situations, but ceftazidime is used when Pseudomonas aeruginosa is a problem, and intraventricular vancomycin is used for those patients with intraventricular shunts because of high rates of staphylococcal infection. In patients with intracerebral prosthetic material (metal plates, electrodes or implants, etc.) then sometimes chloramphenicol is the only antibiotic that will adequately cover infection by Staphylococcus aureus (cephalosporins and carbapenems are inadequate under these circumstances).

Once the results of the CSF analysis are known along with the Gram-stain and culture, empiric therapy may be switched to therapy targeted to the specific causative organism and its sensitivities.
 * Neisseria meningitidis (Meningococcus) can usually be treated with a 7-day course of IV antibiotics:
 * Penicillin-sensitive -- penicillin G or ampicillin
 * Penicillin-resistant -- ceftriaxone or cefotaxime
 * Prophylaxis for close contacts (contact with oral secretions) -- rifampin 600 mg bid for 2 days (adults) or 10 mg/kg bid (children). Rifampin is not recommended in pregnancy and as such, these patients should be treated with single doses of ciprofloxacin, azithromycin, or ceftriaxone
 * Streptococcus pneumoniae (Pneumococcus) can usually be treated with a 2-week course of IV antibiotics:
 * Penicillin-sensitive -- penicillin G
 * Penicillin-intermediate -- ceftriaxone or cefotaxime
 * Penicillin-resistant -- ceftriaxone or cefotaxime + vancomycin
 * Listeria monocytogenes is treated with a 3-week course of IV ampicillin + gentamicin.
 * Gram negative bacilli -- ceftriaxone or cefotaxime
 * Pseudomonas aeruginosa -- ceftazidime''
 * Staphylococcus aureus
 * Methicillin-sensitive -- nafcillin
 * Methicillin-resistant -- vancomycin
 * Streptococcus agalactiae -- penicillin G or ampicillin
 * Haemophilus influenzae -- ceftriaxone or cefotaxime

Viral meningitis
Unlike bacteria, viruses cannot be killed by antibiotics. Patients with very mild viral meningitis may only have to spend a few hours in a hospital, while those who have a more serious infection may be hospitalised for many more days for supportive care. Patients with mild cases, which often cause only flu-like symptoms, may be treated with fluids, bed rest (preferably in a quiet, dark room), and analgesics for pain and fever. Serious cases, especially in the case of young children or neonates, may require the use of antiviral drugs, such as acyclovir. The physician may also prescribe anticonvulsants such as phenytoin to prevent seizures and corticosteroids to reduce brain inflammation. If inflammation is severe, pain medicine and sedatives may be prescribed to make the patient more comfortable.

Fungal meningitis
This form of meningitis is rare in otherwise healthy people, but is a higher risk in those who have AIDS, other forms of immunodeficiency (an immune system that does not respond adequately to infections) and immunosuppression (immune system malfunction as a result of medical treatment). In AIDS, Cryptococcus neoformans is the most common cause of fungal meningitis; it requires Indian ink staining of the CSF sample for identification of this capsulated yeast. Fungal meningitis is treated with long courses of highly dosed antifungals.