History and exam

Key diagnostic factors

common

headache

Present in 87% of adults with bacterial meningitis.[27]

neck stiffness

A stiff neck with resistance to passive neck flexion (nuchal rigidity) is a classic sign of meningitis.

Present in 30% of children and 83% of adults with bacterial meningitis.[27][38]​​​[41]

The classic triad of fever, neck stiffness, and altered mental status occurs in only 41% to 51% of patients. However, in one study, 95% had at least two of the four symptoms of headache, fever, neck stiffness, and altered mental status.[27]

fever

Present in 77% of adults with bacterial meningitis.[27]

The classic triad of fever, neck stiffness, and altered mental status occurs in only 41% to 51% of patients. However, in one study, 95% had at least two of the four symptoms of headache, fever, neck stiffness, and altered mental status.[27]

altered mental status

Present in 69% of adults with bacterial meningitis.[27]

In older patients, this may be the only presenting sign of meningitis.[1]

The classic triad of fever, neck stiffness, and altered mental status occurs in only 41% to 51% of patients. However, in one study, 95% had at least two of the four symptoms of headache, fever, neck stiffness, and altered mental status.[27]

confusion

Present in adults with bacterial meningitis.[27]

In older patients, this may be the only presenting sign of meningitis.[1]

photophobia

Well-recognized symptom of bacterial meningitis.

vomiting

Well-recognized symptom of bacterial meningitis.

seizures

Can occur in children and adults.

Children have seizures more frequently when infected with Streptococcus pneumoniae and Haemophilus influenzae type b than with meningococcal disease.[1]

hypothermia (infants)

In infants the signs and symptoms can be nonspecific and may include hypothermia.[1]

irritability (infants)

In infants the signs and symptoms can be nonspecific and may include irritability.[1]

lethargy (infants)

In infants the signs and symptoms can be nonspecific and may include lethargy.[1]

poor feeding (infants)

In infants the signs and symptoms can be nonspecific and may include poor feeding.[1]

apnea (infants)

In infants the signs and symptoms can be nonspecific and may include apnea.[1]

uncommon

focal neurologic deficit

Focal neurologic deficits, including aphasia, hemiparesis, or cranial nerve palsies, may be present.[40]

May also include dilated nonreactive pupil, abnormalities of ocular motility, abnormal visual fields, gaze palsy, arm or leg drift.

Suggests increased intracranial pressure.

abnormal eye movement

Suggests cranial nerve palsy (III, IV, VI) and increased intracranial pressure.

facial palsy

Cranial nerve VII may be involved and damaged due to increased intracranial pressure and inflammation. This damage may lead to facial palsy.

balance problems/hearing impairment

Cranial nerve VIII may be involved and damaged due to increased intracranial pressure and inflammation. This damage may lead to balance problems and hearing impairment.

bulging fontanel in infants

Indicates raised intracranial pressure.

Other diagnostic factors

common

high-pitched cry (infants)

In infants the signs and symptoms can be nonspecific and may include high-pitched cry.[1]

uncommon

rash

A petechial or purpuric rash is typically associated with meningococcal meningitis. However, it may be present with any type of bacterial meningitis.[1][9]

papilledema

On visual field exam, an enlarged blind spot may be elicited.

Indicates raised intracranial pressure.

Kernig sign

With the patient supine and the thigh flexed to a 90° right angle, attempts to straighten or extend the leg are met with resistance.

Present in 53% of children and 11% of adults with bacterial meningitis.​[38]​

Brudzinski sign

Flexion of the neck causes involuntary flexion of knees and hips.

Alternative sign is passive flexion of the leg on one side causing contralateral flexion of the opposite leg.

Present in 66% of children and 9% of adults with bacterial meningitis.​[38]​

Risk factors

strong

age ≤5 or ≥65 years

People at the extremes of age are commonly affected because of impaired or waning immunity.[5] Infants and neonates are particularly susceptible.[1]

crowding

Provides an ideal environment for transmission of the bacteria. Outbreaks have been reported in dormitories at US colleges and in training camps for military recruits.[1][25][26]

exposure to pathogens

Risk of acquiring bacterial meningitis is increased after exposure to infection within the household or close contact with a patient who has meningitis.[1]

nonimmunized infants

High risk of contracting Haemophilus influenzae type b, pneumococcal, or meningococcal meningitis.[9]

immunodeficiency

About 50% of patients with bacterial meningitis have predisposing conditions, one third of whom have an immunodeficiency.[27]

Patients with HIV infection become increasingly susceptible to bacterial meningitis, particularly if they develop AIDS. Risk is increased approximately eightfold compared with the general population.[28] Bacterial meningitis in this population is primarily caused by Streptococcus pneumoniae, but Salmonella meningitis is also possible.[28][29][30]

Congenital immunodeficiencies, such as complement deficiencies, X-linked agammaglobulinemia, immunoglobulin G subclass deficiency, or interleukin 1 receptor-associated kinase 4 deficiency, have been associated with bacterial meningitis.[31]

cancer

Patients with leukemia and lymphoma are susceptible to bacterial meningitis, especially meningitis caused by Listeria monocytogenes. These patients present with low cerebrospinal fluid leukocyte counts and are at increased risk for adverse outcomes.[29][32]

asplenia/hyposplenic state

Increases risk of overwhelming bacterial infections with encapsulated bacteria, particularly Streptococcus pneumoniae, Neisseria meningitidis,and Haemophilus influenzae.[31]

cranial anatomic defects

Congenital or acquired cranial anatomic defects may increase risk.[1] Anatomic defects should be suspected in cases of recurrent meningitis.[29]

cochlear implants

Cochlear implant recipients are at higher risk of bacterial meningitis than the general population.[33]

weak

contiguous infection

Infections such as sinusitis, pneumonia, mastoiditis, and otitis media increase the risk of meningitis.[1]

smoking

Smoking has been associated with increased risk of meningococcal meningitis.[34]

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