Model Answer
0 min readIntroduction
Meningitis, an inflammation of the meninges – the protective membranes covering the brain and spinal cord – is a serious medical emergency. It can be caused by various infectious agents, most commonly bacteria and viruses, but also fungi and parasites. Early diagnosis and prompt treatment are critical to prevent significant morbidity and mortality. Globally, bacterial meningitis remains a major public health concern, particularly in sub-Saharan Africa (the “meningitis belt”). This response will detail the clinical manifestations, diagnostic approaches, and management strategies for acute meningitis, focusing primarily on bacterial and viral forms.
Clinical Manifestations
The clinical presentation of acute meningitis varies depending on the causative agent, the patient’s age, and their immune status. Common symptoms include:
- Fever: Often high and persistent.
- Headache: Severe and unrelenting, often accompanied by photophobia (sensitivity to light).
- Nuchal Rigidity: Stiffness of the neck muscles, making it difficult to flex the neck forward. This is a hallmark sign, but may be absent in infants and the elderly.
- Altered Mental Status: Confusion, drowsiness, lethargy, or even coma.
- Nausea and Vomiting: Frequently present, especially in children.
- Seizures: Occur in approximately 20-30% of cases.
- Rash: A petechial or purpuric rash (small, non-blanching red or purple spots) is characteristic of meningococcal meningitis.
In infants, symptoms may be more subtle and include irritability, poor feeding, bulging fontanelle, and high-pitched cry.
Diagnosis
A rapid and accurate diagnosis is essential. The diagnostic process typically involves:
1. History and Physical Examination
A thorough history focusing on recent illnesses, travel, exposure to sick contacts, and vaccination status is crucial. A detailed neurological examination is performed to assess mental status, cranial nerve function, motor strength, and reflexes.
2. Lumbar Puncture (LP)
LP is the gold standard for diagnosing meningitis. Cerebrospinal fluid (CSF) is collected and analyzed for:
- Cell Count: Elevated white blood cell count (WBC), particularly neutrophils in bacterial meningitis and lymphocytes in viral meningitis.
- Protein Level: Increased protein levels.
- Glucose Level: Decreased glucose levels in bacterial meningitis.
- Gram Stain and Culture: To identify the causative organism in bacterial meningitis.
- PCR: Polymerase chain reaction (PCR) can detect viral DNA/RNA.
3. Blood Tests
Blood cultures, complete blood count (CBC), electrolytes, and coagulation studies are performed.
4. Neuroimaging
CT or MRI of the brain may be indicated if there are signs of increased intracranial pressure, focal neurological deficits, or immunocompromised status.
Management
Management depends on the suspected etiology of meningitis.
1. Bacterial Meningitis
This is a medical emergency requiring immediate intravenous antibiotic therapy. Empiric antibiotic coverage should be initiated before culture results are available, targeting common pathogens like Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae type b (Hib).
- Adults: Ceftriaxone or cefotaxime plus vancomycin.
- Infants and Children: Ampicillin plus cefotaxime or ceftriaxone.
Dexamethasone may be administered prior to or with the first dose of antibiotics to reduce inflammation and improve outcomes, particularly in pneumococcal meningitis.
2. Viral Meningitis
Viral meningitis is usually self-limiting and supportive care is the mainstay of treatment. This includes rest, fluids, and analgesics for headache and fever. Acyclovir is used for herpes simplex virus (HSV) meningitis.
3. Fungal Meningitis
Requires prolonged treatment with antifungal medications, such as amphotericin B and flucytosine.
4. Supportive Care
Regardless of the etiology, supportive care is crucial. This includes managing fever, maintaining hydration, controlling seizures, and monitoring for complications like cerebral edema and shock.
Conclusion
Acute meningitis is a potentially life-threatening infection demanding swift recognition and intervention. Accurate diagnosis through lumbar puncture and CSF analysis is paramount, guiding appropriate antimicrobial therapy. While bacterial meningitis necessitates immediate antibiotic administration, viral meningitis often resolves with supportive care. Continued research into novel diagnostic tools and vaccine development remains crucial for reducing the global burden of this devastating disease. Public health measures, including vaccination programs, are vital for preventing outbreaks and protecting vulnerable populations.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.