Meningitis – Causes, Types, Symptoms, Diagnosis, and Treatment

 

Introduction:

*Meningitis* is a serious and potentially life-threatening condition characterized by *inflammation of the meninges*—the protective membranes covering the brain and spinal cord. It can result from infections (bacterial, viral, fungal) or non-infectious causes. Prompt diagnosis and treatment are essential to prevent complications such as brain damage or death.

Pathophysiology:

In meningitis, pathogens enter the *central nervous system* via the bloodstream or direct spread (e.g., ear/sinus infections), triggering an *inflammatory response* in the meninges. This leads to:

- *Increased intracranial pressure (ICP)*

- *Cerebral edema*

- *Decreased cerebral perfusion*

- *Neurological damage*

Types of Meningitis:

1. *Bacterial Meningitis* (most severe)

   - Common pathogens: *Streptococcus pneumoniae*, *Neisseria meningitidis*, *Haemophilus influenzae*

2. *Viral Meningitis*

- Caused by enteroviruses, HSV, mumps virus; usually self-limiting

3. *Fungal Meningitis*

   - Seen in immunocompromised patients (e.g., *Cryptococcus*)

4. *Parasitic and Non-infectious Meningitis*

   - Drug-induced, autoimmune, or cancer-related

Symptoms and Signs:

- *High fever*

- *Severe headache*

- *Neck stiffness*

- *Nausea and vomiting*

- *Photophobia (sensitivity to light)*

- *Altered mental status*

- *Seizures*

- *Skin rash* (especially in meningococcal meningitis)

Diagnosis:

- *Clinical assessment* (fever, neck rigidity, Kernig’s and Brudzinski’s signs)

- *Lumbar puncture (LP)* – CSF analysis is diagnostic

  - ↑ WBCs

  - ↓ Glucose (in bacterial)

  - ↑ Protein

- *Blood cultures*

- *CT/MRI scan* – to rule out increased ICP before LP

- *PCR* for viral identification

Treatment:

*1. Bacterial Meningitis (Medical Emergency)*

*Empiric IV antibiotics* (based on age and risk factors):

| Adults | *Ceftriaxone 2g IV BID + Vancomycin 15 mg/kg IV BID ± Dexamethasone* |

| >50 yrs or immunocompromised | Add *Ampicillin 2g IV Q4H* (for *Listeria*) |

*Dexamethasone* 0.15 mg/kg IV Q6H for 2–4 days to reduce inflammation and neurologic complications

Side Effects:

- *Ceftriaxone* – diarrhea, rash, biliary sludge

- *Vancomycin* – nephrotoxicity, ototoxicity

- *Ampicillin* – hypersensitivity reactions

2. Viral Meningitis

- *Supportive care* (fluids, antipyretics)

- *Acyclovir* for HSV-related meningitis  

  - Dose: 10 mg/kg IV Q8H

3. Fungal Meningitis

- *Amphotericin B + Flucytosine* for Cryptococcal meningitis  

  - Side Effects: Nephrotoxicity, electrolyte imbalance

Prevention:

- *Vaccination*  

  - *H. influenzae* type B (Hib)  

  - *Streptococcus pneumoniae* (Pneumococcal vaccine)  

  - *Neisseria meningitidis* (Meningococcal vaccine)

- *Prophylactic antibiotics* for close contacts (e.g., Rifampin)

Conclusion:

Meningitis is a *medical emergency* requiring rapid recognition and treatment. Understanding the types, symptoms, and available therapies can reduce the risk of long-term complications or death. *Vaccination and early intervention* remain the most effective tools in preventing and managing meningitis.