What is the diagnosis and treatment for Meningitis (inflammation of the meninges)?

From the Guidelines

For suspected bacterial meningitis, empiric therapy should include ceftriaxone (2g IV every 12 hours) plus vancomycin (10-20 mg/kg IV every 8-12 hours), with ampicillin (2g IV every 4 hours) added for patients over 50 or immunocompromised individuals to cover Listeria, as recommended by the ESCMID guideline 1. Meningitis is a serious infection of the membranes (meninges) surrounding the brain and spinal cord, requiring immediate medical attention as it can be life-threatening. The most common causes are bacterial, viral, and fungal infections. Symptoms include severe headache, stiff neck, fever, confusion, sensitivity to light, and sometimes a rash.

Key Considerations

• Bacterial meningitis is the most dangerous form and requires immediate treatment with intravenous antibiotics.
• For patients between 1 month and 18 years, cefotaxime or ceftriaxone plus vancomycin or rifampicin is recommended, with specific dosing guidelines provided in the ESCMID guideline 1.
• Adjunctive treatment with dexamethasone should be considered in all cases of suspected bacterial meningitis, but may be discontinued if pathogens other than S. pneumoniae or H. influenzae are identified 1.
• Intracranial pressure (ICP)-based treatment strategies, such as drainage of CSF by means of external lumbar or ventricular drains, mannitol, and methylprednisolone, are not recommended for routine care until RCTs have shown additional value of these potentially harmful treatments 1.

Treatment Duration and Prevention

• Treatment duration is typically 7-14 days depending on the causative organism.
• Prevention includes vaccines against common bacterial causes like pneumococcus, meningococcus, and Haemophilus influenzae type b.
• Prompt diagnosis through lumbar puncture and cerebrospinal fluid analysis is crucial for determining the specific cause and appropriate treatment, as the inflammation of the meninges disrupts the blood-brain barrier, allowing pathogens and immune cells to enter the cerebrospinal fluid, which explains the classic symptoms and potential for neurological complications if not treated quickly.

From the FDA Drug Label

In the treatment of meningitis, it is recommended that the initial therapeutic dose be 100 mg/kg (not to exceed 4 grams). Thereafter, a total daily dose of 100 mg/kg/day (not to exceed 4 grams daily) is recommended. MENINGITIS Caused by Haemophilus influenzae, Neisseria meningitidis or Streptococcus pneumoniae Bacterial Meningitis caused by E. coli, Group B Streptococci, and other Gram-negative bacteria (Listeria monocytogenes, N. meningitidis).

Meningitis Treatment:

• The recommended dose of ceftriaxone for meningitis is 100 mg/kg/day (not to exceed 4 grams daily) 2.
• Ceftriaxone is effective against meningitis caused by Haemophilus influenzae, Neisseria meningitidis, or Streptococcus pneumoniae 2.
• Ampicillin is also used to treat bacterial meningitis caused by E. coli, Group B Streptococci, and other Gram-negative bacteria, including Listeria monocytogenes and N. meningitidis 3.

From the Research

Definition and Epidemiology of Meningitis

• Meningitis is a medical emergency that requires prompt recognition and treatment, with mortality remaining high despite the introduction of vaccinations for common pathogens 4.
• The etiologies of meningitis range in severity from benign and self-limited to life-threatening with potentially severe morbidity 4.
• The introduction of protein conjugate vaccines for Haemophilus influenzae type b (Hib), Streptococcus pneumoniae (S. pneumoniae), and Neisseria meningitidis (N. menigitidis) has changed the epidemiology of bacterial meningitis 5.

Diagnosis of Meningitis

• Physical examination may not perform well enough to accurately identify patients with meningitis, and traditionally described lumbar puncture results for viral and bacterial disease cannot always predict bacterial meningitis 6.
• Examination maneuvers such as Kernig sign or Brudzinski sign may not be useful to differentiate bacterial from aseptic meningitis because of variable sensitivity and specificity 4.
• The diagnosis relies on the examination of cerebrospinal fluid obtained from lumbar puncture 4.

Treatment of Meningitis

• Prompt treatment of bacterial meningitis with an appropriate antibiotic is essential, and optimal antimicrobial treatment requires bactericidal agents able to penetrate the blood-brain barrier (BBB), with efficacy in cerebrospinal fluid (CSF) 5.
• Empiric antibiotics should be directed toward the most likely pathogens and should be adjusted by patient age and risk factors 4.
• Dexamethasone should be administered to children and adults with suspected bacterial meningitis before or at the time of initiation of antibiotics 4.
• The use of empiric vancomycin plus a third-generation cephalosporin for suspected bacterial meningitis has been recommended since 1997, and vancomycin should still be included as empiric therapy for bacterial meningitis 7.
• Ceftriaxone is effective in infants and children three months to 18 years old, and in adults, ceftriaxone is effective therapy for presumed bacterial meningitis but must be combined with ampicillin initially 8.

Prevention of Meningitis

• Vaccination against the most common pathogens that cause bacterial meningitis is recommended 4.
• Chemoprophylaxis of close contacts is helpful in preventing additional infections 4.