Meningitis Diagnosis and Treatment

Clinical Presentation

The classic signs of meningitis include fever, headache, neck stiffness, and altered mental status, though less than 50% of patients present with all these symptoms simultaneously, making rapid recognition and treatment with appropriate antibiotics essential to reduce mortality and morbidity 1, 2
Fever is present in 74-84% of cases, and vomiting and seizures are also common symptoms 1
A purpuric rash is present in 92% of cases caused by N. meningitidis 1
Elderly patients often present atypically with more altered mental status and less neck stiffness or fever 1

Document presence or absence of headache, altered mental status, neck stiffness, fever, rash, seizures, and signs of shock 1
Consider meningitis even when classic signs are absent, especially in elderly or immunocompromised patients 1
Brain imaging (CT or MRI) before lumbar puncture is indicated in patients with focal neurological deficits, new-onset seizures, severely altered mental status, or severely immunocompromised state 4
If lumbar puncture is delayed, blood cultures should be obtained and empiric antibiotics started immediately 4

Antibiotics should be started as soon as possible, ideally within 1 hour of clinical suspicion 4
Empiric antibiotic therapy for adults aged 18-50 years includes Ceftriaxone or cefotaxime plus vancomycin or rifampicin 4
For adults >50 years or immunocompromised, add ampicillin/amoxicillin/penicillin G to cover Listeria 4
Dexamethasone should be used in patients with bacterial meningitis but stopped if Listeria monocytogenes is confirmed, although the source of this information is not provided in the context

Intensive care referral is indicated for patients with rapidly evolving rash, GCS ≤12, cardiovascular instability, respiratory compromise, frequent seizures, or altered mental state 3
Intubation should be strongly considered for GCS <12 3
Maintain euvolemia with crystalloids as initial fluid of choice and target mean arterial pressure ≥65 mmHg 3

Neurological deficits occur in 50% of adults 5
Hearing loss occurs in 5-35% of patients 5
Cognitive deficits, seizures, motor deficits, and visual disturbances are also potential long-term sequelae 5, 6

Chemoprophylaxis for close contacts of meningococcal meningitis patients and vaccination with pneumococcal vaccine for patients after pneumococcal meningitis and persons with CSF leakage are recommended 7

Relying on the presence of the classic triad for diagnosis, delaying antibiotic treatment, failing to recognize atypical presentations in elderly patients, overlooking the need for ampicillin in older adults, and neglecting to assess for hearing loss and other sequelae before discharge are common pitfalls 1, 4, 6