CNS Infections

A central nervous system infection is an infection of the brain, the spinal cord, or the membranes that wrap around them — including meningitis, encephalitis and brain abscess — and it is treated as a medical emergency, because inflammation and pressure inside the skull can cause lasting harm within hours.

These infections are uncommon, but they are the ones where time matters most. The symptoms below are worth knowing precisely, because recognising them early changes what can be done.

Symptoms of CNS infections

• A severe headache that feels different from any you have had before
• Fever together with a stiff neck, or pain on bending the chin to the chest
• Confusion, drowsiness, or behaviour that seems out of character
• Discomfort in bright light
• A seizure, particularly a first-ever seizure
• A rash that does not fade when pressed under a glass

When should you see a specialist for a CNS infection?

• Fever with a stiff neck, confusion or drowsiness — go to an emergency department immediately. Do not wait for a clinic appointment
• A first seizure accompanied by fever or headache
• A sudden, severe headache reaching maximum intensity within moments
• New weakness, facial droop, difficulty speaking, or double vision alongside fever
• Headache and fever in anyone whose immune system is suppressed, or who has a ventricular shunt

Frequently asked questions about CNS infections

What is the difference between meningitis and encephalitis?

Meningitis is inflammation of the membranes surrounding the brain and spinal cord. Encephalitis is inflammation of the brain tissue itself and more often affects thinking, behaviour and consciousness. The two can occur together.

Is meningitis always contagious?

No. Some causes spread from person to person, others do not spread at all. Which one is involved determines whether close contacts need any precaution, and that is decided once the cause is identified.

Why is a lumbar puncture needed?

Examining the fluid around the brain and spinal cord is usually the only way to confirm what is causing the infection. It is a routine procedure performed under local anaesthetic, and identifying the organism is what allows treatment to be targeted properly.

Are vaccines available?

Vaccines exist against several organisms that cause meningitis, and some are part of routine immunisation schedules. Which are relevant depends on age, health conditions and travel plans, and is worth discussing individually.

How quickly does treatment need to start?

Urgently. When a CNS infection is suspected, treatment is generally begun straight away on clinical grounds and refined once test results arrive — waiting for confirmation first is not the approach taken.

Conditions related to CNS infections

Where fever is prolonged and no source has been found, see Fever of Unknown Origin. Several infections acquired in tropical regions can involve the nervous system — see Tropical Infections. Transplant recipients face a distinct set of causes, covered under Transplant Related Infections.

Our infectious disease specialist follows a comprehensive diagnostic approach using detailed history, clinical examination, and advanced investigations to identify the root cause and provide effective treatment.