Meningitis

Table of Contents

Meningitis is a serious medical condition in which the protective membranes surrounding the brain and spinal cord become inflamed.
These membranes are known as meninges, and they protect the central nervous system from injury and infection.
When microorganisms such as bacteria, viruses, fungi, or parasites enter these layers, inflammation develops rapidly.
Because the brain and spinal cord are extremely sensitive organs, even a small amount of swelling can disturb normal body functions.
Meningitis is considered a medical emergency because delay in treatment can lead to severe complications or death.
The disease can affect people of all age groups, but infants, young children, elderly people, and individuals with weak immunity are more vulnerable.

Structure of the Meninges

The meninges consist of three protective layers:
- Dura mater (outer tough layer)
- Arachnoid mater (middle thin layer)
- Pia mater (inner delicate layer attached to brain tissue)
These layers also contain cerebrospinal fluid, which cushions the brain.
When infection occurs, inflammatory cells accumulate in this space.
Fluid pressure rises inside the skull.
Increased intracranial pressure can reduce blood supply to the brain.
This may cause neurological symptoms very quickly.

Causes

Meningitis can occur due to several infectious agents.

A. Bacterial Causes

The most dangerous type is bacterial meningitis.

Common bacteria include:

Neisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae

These bacteria often spread through respiratory droplets.

B. Viral Causes

Common viral causes include:

Enteroviruses
Herpes viruses
Mumps virus
Influenza virus

Viral meningitis is usually less severe.

C. Fungal Causes

Fungal meningitis mainly occurs in:

Immunocompromised patients
Cancer patients
Long steroid users

D. Tuberculous Causes

Tuberculosis can cause meningitis through blood spread.
Tuberculous meningitis develops slowly but is serious.

How Infection Reaches the Brain

Infection usually starts in another body part:
- Nose
- Throat
- Ear
- Lungs
From there, organisms enter the bloodstream.
They cross the blood-brain barrier.
Then they infect the meninges.

In some cases, infection occurs directly after:

Head injury
Skull fracture
Brain surgery

Types of Meningitis

Bacterial Meningitis

Sudden onset
Rapid progression
High mortality if untreated
Requires emergency antibiotics

Viral Meningitis

Mild to moderate illness
Often self-limiting
Recovery usually occurs within days

Fungal Meningitis

Slow onset
Seen in weak immunity

Tuberculous Meningitis

Chronic symptoms
Long treatment duration

Common Symptoms

The classic symptoms include:

High fever
Severe headache
Neck stiffness
Vomiting
Sensitivity to light
Altered consciousness

Other symptoms may include:

Confusion
Irritability
Restlessness
Difficulty speaking
Convulsions

Why Neck Stiffness Happens

Inflammation irritates spinal nerves.
Neck muscles become rigid.
Patient cannot bend neck forward easily.
This is one of the most important warning signs.

Symptoms in Infants and Children

Symptoms are often different in babies:

Constant crying
Poor feeding
Refusal to breastfeed
Irritability
Sleepiness
Bulging fontanelle
Fever or low temperature

Danger Signs That Need Immediate Hospital Admission

Repeated vomiting
Seizures
Loss of consciousness
Difficulty breathing
Sudden rash with fever

A rapidly spreading rash can occur in meningococcal infection.

How Meningitis Spreads

Meningitis spreads through close contact:

Coughing
Sneezing
Saliva droplets
Shared utensils
Crowded living conditions

Risk increases in:

Schools
Hostels
Dormitories
Military camps

Who Is at Higher Risk?

High-risk groups include:

Newborn babies
Children below five years
Elderly persons
Diabetic patients
Malnourished individuals
Immunocompromised persons

Diagnosis of Meningitis

Diagnosis requires urgent evaluation.

Important investigations:

Blood count
Blood culture
Lumbar puncture
Cerebrospinal fluid analysis
CT scan if needed

Cerebrospinal Fluid Findings

Doctors examine:

Cell count
Protein level
Sugar level
Bacterial stain
Culture

Typical bacterial meningitis shows:

High protein
Low glucose
Increased neutrophils

Treatment

Bacterial Meningitis

Immediate antibiotics are essential.

Common drugs:

Ceftriaxone
Vancomycin

Additional treatment:

Steroids
Intravenous fluids
Oxygen support
Monitoring in ICU if severe

Viral Meningitis

Usually supportive:

Bed rest
Fluids
Fever reduction
Pain control

Tuberculous Meningitis

Requires prolonged anti-tubercular therapy:

Isoniazid
Rifampicin
Pyrazinamide
Ethambutol

Complications of Meningitis

Untreated meningitis may cause:

Hearing loss
Brain damage
Paralysis
Learning disability
Hydrocephalus
Epilepsy
Death

Prevention of Meningitis

Vaccination is the most effective prevention.

Important vaccines:

Meningococcal vaccine
Pneumococcal vaccine
Haemophilus influenzae type b vaccine

Additional Preventive Measures

Hand washing
Avoid close contact with infected persons
Proper cough hygiene
Good nutrition
Early treatment of respiratory infections