Bacterial Meningitis

Bacterial meningitis typically presents with headache, stiff neck, and photophobia in its more advanced stages. Early in the course the presentation may be more subtle. Meningitis should always be considered in patients with fever and altered mental status. Early treatment with antibiotics is imperative and should not be delayed in order to perform any test (including LP). In the few cases when it may be appropriate to delay LP in order to do CT first, blood should be drawn for blood cultures, and antibiotics then given before CT. LP should then be performed if not contraindicated by CT findings. This strategy identifies the cause of bacterial meningitis in most cases, even when LP is performed 1 to 2 hours after the initiation of antibiotics.

Causes

Enteroviruses are the usual cause. These are the viruses that only infect human beings and are spread by the fecal-oral route. They live in the human intestine.

Echovirus and Coxsackie are the two that cause most viral meningitis in the U.S. Polio is also an enterovirus.

Causes of noninfectious meningitis include the following:

• Contaminated water
• Head injury, birth defect of the skull, brain surgery (may result in infection of the meninges or cerebrospinal fluid)
• Carcinomatosis
• Medications such as nonsteroidal anti-inflammatories (e.g., ibuprofen, naproxen) and antibiotics.

Symptoms

• Fever ++++
• Headache +++
• Stiff neck ++
• Vomiting +++
• Photophobia
• Altered mental status

Signs

• Temperature > 38° C ++++
• Classic triad +++: fever, nuchal rigidity, change in mental status
• Meningismus +++: nuchal rigidity, brudzinski's sign, Kernig's sign
• Mental status changes: irritable +++, confused, lethargic +++, decreased responsiveness to pain ++, coma ++, normal
• Seizures ++, much more common with Streptococcus pneumoniae than with Neisseria meningitidis
• Focal CNS findings: cranial nerve palsies, gaze preference,
  aphasia, hemiparesis ++
• Rash: maculopapular, petechial, purpuric (+++ of N. meningitidis)

Treatment

Treatment for meningitis depends on the organism causing the infection, your age, the extent of the infection, and the presence of other medical conditions or complications of meningitis.

Many viral meningitis may require treatment in a hospital, including:

• Antibiotics. This medications usually are given through a vein. Antibiotics are given only when bacteria are causing the infection. Giving antibiotics when they are not needed may cause drug resistance.
• Intravenous antibiotics may be given. Steroids may help decrease the immune reaction and brain swelling.