Encephalitis means inflammation of the brain. It is a medical emergency that can affect anyone-children, young adults, or the elderly. On World Encephalitis Day, observed on February 22, it is important for everyone to understand the warning signs, because early diagnosis and timely treatment can make a huge difference between full recovery and lifelong disability.
How common is encephalitis?
Globally, encephalitis affects an estimated 4–8 people per 100,000 population per year, though the numbers vary across regions. Every 20 seconds, someone somewhere in the world is diagnosed with encephalitis.
In India, the burden is higher in certain states due to viral infections such as Japanese Encephalitis. During seasonal outbreaks, especially in parts of Uttar Pradesh, Bihar, Assam, and other northeastern states, hundreds of cases may be reported.
While encephalitis is not as common as stroke or heart disease, it is one of the most serious neurological emergencies, particularly in children.
What are the symptoms?
Encephalitis can start like a simple viral illness. But the key is to recognise when it is more than 'just fever'.
Common symptoms include:
- Fever
- Severe headache
- Vomiting
- Altered behaviour or confusion
- Drowsiness or difficulty waking up
- Seizures (fits)
- Weakness of limbs
- Difficulty speaking
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In children, irritability, refusal to feed, or persistent crying may be early signs. Any patient with fever plus altered mental status or seizures should be evaluated urgently.
What causes encephalitis?
Many people assume encephalitis is always due to infection, and often, it is.
Viral infections
Viruses are the most common cause. These include:
- Herpes simplex virus (HSV)
- Japanese Encephalitis virus
- Enteroviruses
- Dengue and other mosquito-borne viruses
Japanese Encephalitis (JE)- a major concern in India
Japanese Encephalitis, sometimes called Japanese B encephalitis, is transmitted by mosquitoes. It primarily affects children in rural and semi-rural areas. Although many infections are mild, severe cases can lead to high fever, seizures, coma, and even death. Survivors may be left with long-term neurological problems.
Vaccination programmes in India have significantly reduced cases, but outbreaks still occur. Mosquito control and vaccination remain critical preventive measures.
Autoimmune encephalitis- an emerging cause
In recent years, doctors have been diagnosing autoimmune encephalitis more frequently. In this condition, the body’s immune system mistakenly attacks the brain. It may present with:
- Sudden behavioural changes
- Memory loss
- Psychosis-like symptoms
- Seizures
- Abnormal movements
Unlike viral encephalitis, autoimmune encephalitis requires immunotherapy, such as steroids or other immune-modulating treatments. Early recognition dramatically improves outcomes.
How is encephalitis diagnosed?
Diagnosis requires urgent medical evaluation. Doctors may perform:
- MRI brain scan
- Lumbar puncture (spinal fluid test)
- Blood tests
- EEG (brain wave test)
These tests help identify whether the cause is viral, bacterial, autoimmune, or unknown.
Importantly, doctors often start treatment before test results are confirmed, especially when herpes encephalitis is suspected, because delay can lead to irreversible brain damage.
How is it treated?
Treatment depends on the cause:
- Antiviral drugs (such as acyclovir) for suspected herpes encephalitis
- Supportive care in ICU (for breathing, seizures, swelling of brain)
- Antibiotics if bacterial infection is suspected
- Steroids and immunotherapy for autoimmune encephalitis
Time is critical. Studies show that early initiation of appropriate therapy significantly reduces death and long-term disability.
What is the outcome?
Outcomes vary:
- Some patients recover completely.
- Others may develop long-term problems such as epilepsy, memory difficulties, speech problems, behavioural changes, or weakness.
- Severe cases can be fatal.
Early diagnosis and prompt treatment are the strongest predictors of better recovery.
Can encephalitis be prevented?
While not all cases can be prevented, risk can be reduced by:
- Vaccination (especially for Japanese Encephalitis in endemic areas)
- Mosquito control and use of mosquito nets
- Good hygiene to reduce viral spread
- Early treatment of infections
- Seeking immediate medical care for a fever with confusion or seizures
Encephalitis is rare but devastating. It may begin like an ordinary fever, but fever plus confusion, seizures, or altered behaviour should never be ignored.
On this World Encephalitis Day, let us spread awareness: Recognise early. Investigate early. Treat early. Because when it comes to brain inflammation, every hour matters.
The opinions expressed in this article are those of the author and do not purport to reflect the opinions or views of THE WEEK.
