History and exam
Key diagnostic factors
common
headache
Present in 87% of adults with bacterial meningitis.[17]
fever
Present in 77% of adults with bacterial meningitis.[17]
altered mental status
Present in 69% of adults with bacterial meningitis.[17]
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.[25][35][36] However, in one study, 95% had at least two of the four symptoms of headache, fever, neck stiffness, and altered mental status.[17]
confusion
May be the only presenting sign of meningitis in older patients.[1]
photophobia
Well-recognised symptom of bacterial meningitis.[16]
seizures
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.[16]
One third of those with predisposing conditions have an immunodeficiency.[17]
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.[20]
Asplenia or hyposplenia increases the risk of overwhelming bacterial infections with encapsulated bacteria, particularly S pneumoniae and Haemophilus influenzae.[20]
HIV infection makes people susceptible to bacterial meningitis, particularly if they develop AIDS.
Malignancy
Patients with leukaemia and lymphoma are susceptible to bacterial meningitis.[18]
Cranial anatomical defects, ventriculoperitoneal shunt
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.[21]
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.[22]
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
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.[17]
papilloedema
Sign of raised intracranial pressure.
An enlarged blind spot may be identified when you examine the visual fields.
Kernig's sign
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