Viral meningitis

Patients with viral meningitis usually have mild to moderately-severe, non-specific symptoms,

often presenting with general illness, muscle aches, and other flu-like symptoms.

Common symptoms include headache, a stiff neck (as opposed to nuchal rigidity), sensitivity to bright light, sleepiness or trouble waking up from sleep, nauseau, vomiting, lack of appetite and lack of energy.

 

Different clinical manifestations may suggest different pathogens in viral meningitis:

- Diffuse maculopapular exanthem in a mildly ill patient may be consistent with enteroviral infection, primary HIV, or syphilis.

- Parotitis may be a sign of mumps meningitis when the patient is unvaccinated

- Look for vesicular and ulcerative genital lesions suggestive of primariy HSV-2 infection.

- Cervical lymphadenopathy and oropharyngeal trush may be consistent with HIV

- An asymmetric flaccid paralysis may be associated with West Nile virus meningitis.

 

Bacterial meningitis

Patients with bacterial meningitis are usually quite ill and often present soon after symptom

onset. In a series of 301 adults, the median duration of symptoms before admission was only 24 hours (range one hour to 14 days). The classic triad of acute bacterial meningitis consists of fever, nuchal rigidity, and a change in mental status, although an appreciable number of patients do not have all three features. Most patients have high fevers, often greater than 38ºC, but a small percentage have hypothermia. Almost no patients have a normal temperature. Headache is also common. The headache is typically described as severe and generalized. It is not easily confused with a normal headache.

 

- Fever is present in 95 percent of patients upon presentation, another 4 percent develops fever within the first 24 hours.

- Nuchal rigidity is present in 88 percent of patients upon initial examination and may

persist for more than seven days in patients despite overal improvement.

- Altered mental status is present in 78 percent of patients. Most are confused or lethargic. 22

percent of patients are only responsive to pain, 6 percent are unresponsive to all stimuli.

 

Only 44 percent of patients presents with the classic triad of fever, altered mental status,

and nuchal rigidity. The classic triad is much more likely to occur in patients with pneumococcal compared with meningococcal meningitis (58 versus 27 percent). It must be noted that older adults (especially those with underlying conditions such as diabetes mellitus or cardiopulmonary disease) may present insidiously with lethargy or obtundation, no fever, and variable signs of

meningeal inflammation.

 

Virtually all patients have at least one of the findings of the classic triad of fever, neck

stiffness, and altered mental status (sensitivity 99 to 100 percent for the presence of at least one finding in a 1999 critical appraisal of 10 studies of 845 episodes of meningitis).

Similarly, 99 percent had at least one classic feature in the 2004 series of 696 cases.

 

Thus, the absence of all of these findings essentially excludes the presence of

bacterial meningitis.

 

In addition to the classic findings, a number of other manifestations, both neurologic and

nonneurologic, can occur in patients with bacterial meningitis, and some findings may be suggestive of a particular bacterial etiology. Neurologic complications such as seizures, focal neurologic deficits (including cranial nerve palsies), and papilledema may be present early or occur later in the course:

 

- Seizures have been described in 15 to 30 percent of patients and focal neurologic deficits in

10 to 35 percent.

- Hearing loss is a late complication

- Papilledema is observed in <5 percent of patients at the time of initial presentation

- Cerebral infarction may occur in up to 25 percent of episodes and in 36 percent of

patients with pneumococcal meningitis.

- Patients with Listeria meningitis have an increased tendency to have seizures and focal neurologic

deficits early in the course of infection, and some patients may present with a syndrome of rhombencephalitis (manifested as ataxia, cranial nerve palsies, and/or nystagmus).

- Skin manifestations, may be present, especially in certain bacteria, particularly N. meningitidis, which can cause characteristic  petechiae and palpable purpura.

- Arthritis occurs in some patients with bacterial meningitis

Bacterial meningitis tends to spare other organs unless severe sepsis ensues. However, if meningitis is the sequela of an infection elsewhere in the body, there may be features of that infection still present at the time of diagnosis of meningitis (eg, otitis or sinusitis).