History and exam

Key diagnostic factors

common

headache

Present in 87% of adults with bacterial meningitis.[16]​ Headache is harder to identify in adults with cognitive impairment.[22]

neck stiffness

Present in 83% of adults with bacterial meningitis.[16][23][32]

  • The classic triad of fever, neck stiffness, and altered mental status occurs in only 41% to 51% of patients.[23][33][34] However, in one study, 95% had at least two of the four symptoms of headache, fever, neck stiffness, and altered mental status.[16]

  • Neck stiffness are harder to identify in adults with cognitive impairment.[22]

fever

Present in 77% of adults with bacterial meningitis.[16]

  • The classic triad of fever, neck stiffness, and altered mental status occurs in only 41% to 51% of patients.[23][33][34] However, in one study, 95% had at least two of the four symptoms of headache, fever, neck stiffness, and altered mental status.[16]

  • Fever is less common in older adults.[22]

altered mental status

Present in 69% of adults with bacterial meningitis.[16]

  • May be the only presenting sign of meningitis in older patients.[1]

  • The classic triad of fever, neck stiffness, and altered mental status occurs in only 41% to 51% of patients.[23][33][34] However, in one study, 95% had at least two of the four symptoms of headache, fever, neck stiffness, and altered mental status.[16]

  • Altered level of consciousness or cognition may be missed in young adults and older adults.[22]

vomiting

Present in 45% to 74% of patients with bacterial meningitis.[16][33]

confusion

May be the only presenting sign of meningitis in older patients.[1]

photophobia

Well-recognised symptom of bacterial meningitis.[15]

seizures

Present in 15% of patients with bacterial meningitis.[16]

  • Associated with worse outcomes.[16]

presence of risk factors

Your history should cover risk factors including the following.

  • Advanced age

    • Older people are commonly affected because of impaired or waning immunity.[2]

  • Crowding

    • Ideal for bacterial transmission. Outbreaks have been reported in US college dormitories and in training camps for military recruits.[1]

  • 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]

  • Immunocompromising conditions

    • About 50% of patients with bacterial meningitis have a predisposing condition.

      • Includes chronic conditions such as diabetes, alcohol misuse, or eculizumab therapy.[15]

    • One third of those with predisposing conditions have an immunodeficiency.[16]

      • Bacterial meningitis is primarily caused by Streptococcus pneumoniae, but Salmonella meningitis is also possible in this population.[17][18]

    • Congenital immunodeficiencies, such as complement deficiencies, X-linked agammaglobulinaemia, IgG subclass deficiency, or interleukin 1 receptor-associated kinase 4 deficiency, have been associated with bacterial meningitis.[19] 

    • Asplenia or hyposplenia increases the risk of overwhelming bacterial infections with encapsulated bacteria, particularly S pneumoniae and Haemophilus influenzae.[19]

    • HIV infection makes people susceptible to bacterial meningitis, particularly if they develop AIDS.

    • Malignancy

      • Patients with leukaemia and lymphoma are susceptible to bacterial meningitis.[17]

  • Cranial anatomical defects, ventriculoperitoneal shunt

    • Congenital or acquired cranial anatomical defects may increase risk.[1] 

    • Suspect anatomical defects in cases of recurrent meningitis.[17] 

  • Cochlear implants

    • Recipients of cochlear implant are at higher risk of bacterial meningitis than the general population.[1]

  • Sickle cell disease

    • Patients are more likely to get meningitis due to impaired splenic function and impaired complement cascade among other mechanisms.[20]

  • Contiguous infection

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

  • Genetic predisposition 

    • Deficiencies affecting the complement system may increase the risk of bacterial meningitis.[21]

Other diagnostic factors

uncommon

focal neurological signs

May include dilated non-reactive 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).

  • Suggests increased intracranial pressure.

facial palsy

Cranial nerve VII may be damaged.

  • Due to increased intracranial pressure and inflammation.

balance problems/hearing impairment

Cranial nerve VIII may be damaged.

  • Due to increased intracranial pressure and inflammation.

rash

Examine the patient’s skin very carefully for a rash. Always document its presence or absence.[22]​ Rashes may be petechial or purpuric.

  • May be present with any type of bacterial meningitis.

    • Typically associated with meningococcal meningitis.

    • A petechial rash is identified in 20% to 52% of patients and indicates meningococcal infection in more than 90% of patients.[16]

    • In the initial phases there may be only 1 or 2 petechiae.

    • Rashes can be hard to detect on brown, black, or tanned skin (look for petechiae in the conjunctiva).[22]

papilloedema

Sign of raised intracranial pressure.

  • An enlarged blind spot may be identified when you examine the visual fields.

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