What are the diagnostic criteria for meningitis (inflammation of the meninges)?

From the Guidelines

To perform a meningitis exam, start with a thorough neurological assessment including mental status evaluation, checking for neck stiffness (Kernig's and Brudzinski's signs), and assessing for photophobia, headache, and fever, as these clinical characteristics have limited diagnostic accuracy, and cerebrospinal fluid analysis remains the principal contributor to the final diagnosis 1.

Key Components of the Exam

• Observe the patient's level of consciousness and orientation
• Test for neck stiffness by having the patient flex their neck forward or by raising their straightened leg while supine (Kernig's sign) - resistance or pain suggests meningeal irritation
• Brudzinski's sign is positive when neck flexion causes involuntary hip and knee flexion
• Examine for rash (especially petechial or purpuric rash suggesting meningococcal infection), cranial nerve abnormalities, and focal neurological deficits

Diagnostic Work-up

• If meningitis is suspected, obtain blood cultures immediately and perform a lumbar puncture to collect cerebrospinal fluid for analysis (cell count, glucose, protein, Gram stain, culture) 1
• Empiric antibiotics should be started promptly before lumbar puncture results if bacterial meningitis is suspected, typically with ceftriaxone 2g IV every 12 hours plus vancomycin 15-20 mg/kg IV every 8-12 hours, with consideration of ampicillin 2g IV every 4 hours for patients at risk for Listeria
• The ESCMID guideline advises to start empiric treatment within one hour of arrival in all suspected meningitis cases, and choice of antibiotics needs to be differentiated according to the patient's age, risk factors, and local resistance rates of pneumococci 1

Important Considerations

• Cranial imaging may be considered to evaluate for signs of brain shift as a precaution in selected patients before lumbar puncture, but should not delay antibiotic treatment 1
• The ESCMID guideline committee advises to strive for treatment of all patients with suspected bacterial meningitis within one hour, irrespective of cranial imaging before the lumbar puncture 1

From the Research

Meningitis Exam Overview

• Meningitis is a life-threatening emergency that requires rapid recognition of symptoms and prompt treatment 2, 3, 4.
• The disease is still associated with high mortality and poor outcome, despite improved healthcare 3.

Diagnostic Measures

• Physical examination may not be sufficient to accurately identify patients with meningitis 4.
• Lumbar puncture is a crucial diagnostic tool, but its results may not always predict bacterial meningitis 4.
• Cerebrospinal fluid parameters remain a vital skill for clinicians to interpret 5.

Treatment Guidelines

• Antibiotics should be administered within 30 minutes after admission 3, 6.
• Empirical therapy may include ceftriaxone and vancomycin, with adjustments based on patient risk factors and local guidelines 5.
• Dexamethasone is recommended as a routine component of empirical therapy to reduce morbidity and mortality from pneumococcal meningitis 5.

Emergency Department Management

• A focused and well-organized procedure is necessary to ensure prompt treatment and minimize delays 3.
• Cerebral CT-scan before lumbar puncture is mandatory for selected patients only 6.
• PCR for viruses in the cerebrospinal fluid can inform diagnosis and treatment, and meningitis caused by enterovirus can usually be managed at home 6.