Meningitis – Causes, Symptoms, Treatment

Meningitis;

Overview:

Meningitis, an inflammation of the protective membranes covering the brain and spinal cord, poses a significant health threat worldwide. Timely recognition and management are paramount to prevent severe complications and reduce mortality rates associated with this condition.

Symptoms of Meningitis:

The presentation of meningitis can vary depending on the causative agent and the age of the affected individual. Common symptoms and signs include:

• Headache: Persistent and severe headache is a hallmark symptom of meningitis.
• Fever: High fever is often present and may be accompanied by chills and rigors.
• Stiff Neck: Neck stiffness, especially when trying to touch the chin to the chest, is characteristic.
• Photophobia: Sensitivity to light is common, along with other neurological symptoms such as confusion or altered mental status.
• Nausea and Vomiting: Gastrointestinal symptoms may be present, particularly in children.
• Rash: Meningococcal meningitis can cause a characteristic purpuric rash that does not blanch with pressure.

Causes of Meningitis:

• Bacterial Meningitis:
  • Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae are common bacterial pathogens.
  • Bacterial meningitis is often more severe and can progress rapidly without treatment.
• Viral Meningitis:
  • Enteroviruses, herpesviruses, and adenoviruses are common viral causes.
  • Viral meningitis is typically less severe than bacterial meningitis and often resolves without specific treatment.
• Fungal Meningitis:
  • Cryptococcus neoformans and Histoplasma capsulatum are common fungal pathogens.
  • Fungal meningitis is more common in immunocompromised individuals and may require prolonged treatment.

Clinical Examination in Meningitis:

1. Neurological Assessment:

• Mental Status: Evaluate for altered mental status, confusion, or decreased level of consciousness.
• Cranial Nerves: Assess cranial nerve function, including extraocular movements, facial sensation and symmetry, and gag reflex.
• Motor and Sensory Function: Test muscle strength, tone, and sensation in all extremities.
• Reflexes: Check deep tendon reflexes such as the biceps, triceps, and patellar reflexes for abnormalities.

2. Evaluation of Meningeal Irritation:

• Neck Stiffness: Have the patient attempt to touch their chin to their chest to assess for resistance or discomfort.
• Kernig’s Sign: Flex the patient’s hip and knee to 90 degrees while lying flat, then attempt to straighten the knee. Pain or resistance indicates a positive sign.
• Brudzinski’s Sign: Flex the patient’s neck, and observe for involuntary flexion of the hips and knees. Positive sign suggests meningeal irritation.

3. Assessment of Vital Signs:

• Temperature: Measure body temperature for fever, a common sign of meningitis.
• Heart Rate: Monitor heart rate for signs of tachycardia, which may indicate systemic infection or hemodynamic instability.
• Blood Pressure: Check blood pressure for signs of hypotension or shock, particularly in severe cases of meningitis.
• Respiratory Rate: Assess respiratory rate for signs of respiratory distress or compromise.

4. Skin Examination:

• Rash: Look for a characteristic purpuric rash that does not blanch with pressure, which may suggest meningococcal meningitis.
• Petechiae: Check for tiny, pinpoint red or purple spots on the skin, mucous membranes, or conjunctiva, which may indicate septicemia.

5. Fundoscopic Examination:

• Papilledema: Look for optic disc swelling, which may suggest increased intracranial pressure secondary to meningitis.
• Retinal Hemorrhages: Examine for retinal hemorrhages, which may be present in severe cases of meningococcal meningitis or disseminated intravascular coagulation.

6. Assessment of Systemic Manifestations:

• Respiratory System: Listen for abnormal breath sounds such as crackles or diminished breath sounds, which may indicate associated pneumonia.
• Cardiovascular System: Check for signs of tachycardia, hypotension, or signs of shock, which may indicate systemic involvement or sepsis.
• Gastrointestinal System: Assess for nausea, vomiting, or abdominal pain, which may accompany meningitis, particularly in children.

7. Evaluation of Fontanelle (in infants):

• Bulging Fontanelle: Palpate the infant’s fontanelle for bulging, which may indicate increased intracranial pressure associated with meningitis.
• Sunken Fontanelle: Conversely, a sunken fontanelle may suggest dehydration, which can complicate meningitis in infants.

Laboratory Diagnosis of Meningitis:

• Lumbar Puncture:
  • Cerebrospinal fluid (CSF) analysis is crucial for diagnosing meningitis.
  • CSF findings typically include elevated white blood cell count, elevated protein levels, and decreased glucose levels.

• CSF findings in bacterial, viral, and tuberculous meningitis :

CSF Finding	Bacterial Meningitis	Viral Meningitis	Tuberculous Meningitis
Appearance	Cloudy or turbid	Clear or slightly cloudy	Clear or slightly cloudy
Cell Count (WBC)	Elevated, >1000 cells/mm³, predominantly neutrophils	Mild to moderately elevated, <1000 cells/mm³, predominantly lymphocytes	Moderately elevated, predominantly lymphocytes and monocytes
Glucose Level	Decreased, <40 mg/dL	Normal	Decreased, similar to bacterial meningitis
Protein Level	Elevated, >100 mg/dL	Slightly elevated, typically <100 mg/dL	Elevated, >100 mg/dL
Gram Stain	Positive for bacteria	Not applicable	Not applicable
PCR Testing	Not applicable	Positive for viral DNA/RNA	Not applicable
ADA Activity	Not applicable	Not applicable	Elevated, supporting diagnosis

.

• Microbiological Testing:
  • Gram stain and culture of CSF help identify the causative organism, guiding appropriate antimicrobial therapy.
  • Polymerase chain reaction (PCR) testing can rapidly detect viral or bacterial DNA in CSF samples.

Treatment:

Drugs and Doses for Meningitis Treatment

1. Antibiotics for Bacterial Meningitis:

• Empirical Therapy:
  • Ceftriaxone: 2 grams IV every 12 hours OR
  • Cefotaxime: 2 grams IV every 4-6 hours OR
  • Meropenem: 2 grams IV every 8 hours
• Consider adding Vancomycin: 15 mg/kg IV every 6-8 hours for empiric coverage of resistant Streptococcus pneumoniae or suspected methicillin-resistant Staphylococcus aureus (MRSA) infection.
• Definitive Therapy (Based on Culture and Sensitivity):
• Adjust antibiotics based on culture results and susceptibilities.

2. Antiviral Agents for Viral Meningitis:

• Acyclovir:
  • Adult Dose: 10-15 mg/kg IV every 8 hours for 10-14 days.
  • Pediatric Dose: 20 mg/kg IV every 8 hours for 10-14 days.
• Duration may vary based on the severity of the infection and clinical response.

3. Antituberculous Therapy for Tuberculous Meningitis:

• First-Line Agents:
  • Isoniazid (INH): 5 mg/kg/day orally (maximum 300 mg/day).
  • Rifampin: 10 mg/kg/day orally (maximum 600 mg/day).
  • Pyrazinamide: 25-30 mg/kg/day orally (maximum 2 grams/day).
  • Ethambutol: 15-20 mg/kg/day orally (maximum 1.2 grams/day).
• Adjunctive Therapy:
  • Prednisone: 1-2 mg/kg/day orally for 4-8 weeks, followed by gradual tapering.
• Consideration of additional agents such as Streptomycin or Amikacin in severe cases or drug-resistant TB.

4. Adjunctive Therapy:

• Dexamethasone:
  • Adult Dose: 10 mg IV every 6 hours for 2-4 days, then 4 mg IV every 6 hours for 2-4 days.
  • Pediatric Dose: 0.15 mg/kg IV every 6 hours for 2-4 days, then 0.1 mg/kg IV every 6 hours for 2-4 days.
  • Administer before or concomitantly with the first dose of antibiotics in bacterial meningitis to reduce the risk of neurological complications and mortality.
• Maintenance Fluids:
  • Ensure adequate hydration with intravenous fluids to prevent dehydration and maintain electrolyte balance.

5. Supportive Care:

• Analgesics:
  • Use acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) for headache and fever control.
• Antipyretics:
  • Administer antipyretics such as acetaminophen to reduce fever and alleviate discomfort.
• Antiemetics:
  • Consider antiemetic agents for nausea and vomiting.
• Monitoring and Surveillance:
  • Regular monitoring of vital signs, neurological status, and response to treatment is essential for guiding management and detecting complications.

6. Duration of Treatment:

• Bacterial Meningitis:
  • Antibiotic therapy typically continues for 10-14 days or longer based on clinical response and CSF parameters.
• Viral Meningitis:
  • Antiviral therapy with acyclovir is usually administered for 10-14 days or longer as needed.
• Tuberculous Meningitis:
  • Antituberculous therapy is prolonged, often for 9-12 months or more, depending on the severity of the infection and the patient’s clinical response.

Summary:
Meningitis remains a significant public health concern, with bacterial meningitis posing the greatest risk of morbidity and mortality.