23 August,2026 10:29 PM IST | Mumbai | Vinod Kumar Menon
SSPE is a rare, progressive, usually fatal neurological disease caused by persistent measles infection. (Pics/ Special Arrangement)
A child recovers from measles. The fever disappears, the rash fades, and the family believes the illness is over. Years later, however, the child may begin forgetting lessons, losing previously acquired skills or behaving differently. School performance deteriorates. Falls become frequent. Then come sudden jerking movements, seizures and progressive loss of movement, speech and vision.
In severe cases, the child can eventually lose the ability to walk, swallow, communicate or remain conscious. This is subacute sclerosing panencephalitis (SSPE), a rare, progressive and usually fatal neurological disease caused by persistent, altered measles virus infection in the brain.
Dr Fazal Nabi, director of paediatrics at Jaslok Hospital, in part seven of mid-day's nine-part series on SSPE, highlights how the disease is a stark reminder that measles is not simply a childhood infection that ends when the fever and rash disappear.
Dr Fazal Nabi, director of paediatrics at Jaslok Hospital. (Pic/ Special Arrangement)
"In rare cases, the virus can persist in the brain and, years later, lead to a devastating and progressive neurological illness," the expert said.
SSPE generally appears several years after the original measles infection. That long interval can make the connection difficult to recognise. The disease usually begins insidiously, with symptoms that may initially be mistaken for behavioural, psychological or educational problems.
"When a child develops unexplained behavioural or cognitive regression, particularly when it is followed by myoclonic jerks or seizures, SSPE should be considered, especially if there is a history of measles," Dr Nabi said.
"Subacute sclerosing panencephalitis, or SSPE, remains a rare but devastating consequence of natural measles infection. Recent Indian research published in 2025 and a 2026 systematic review of neuroimaging underline the disease's varied presentation, severe outcomes and the urgent need for early recognition and prevention," Dr Nabi said.
SSPE is commonly described clinically as a progressive four-stage disorder, although the speed and exact pattern can vary between patients.
The child may still appear physically well, but parents and teachers notice that something has changed.
This is often the stage at which diagnosis is most easily missed.
Neurological abnormalities become unmistakable.
The child progressively loses purposeful activity.
In the final stage, the patient may develop:
SSPE is not simply a second episode of ordinary measles. Research indicates that the virus persists inside the central nervous system in an altered form.
Mutations in viral proteins, particularly those involved in viral assembly and release, allow the virus to persist and spread from cell to cell while limiting the conventional release of infectious virus.
The process can produce chronic inflammation, neuronal injury, demyelination, gliosis and progressive cerebral atrophy.
The important distinction is that SSPE is a delayed complication of a person's earlier natural measles infection; it is not an infection transmitted from a patient with SSPE to another person.
One of the most important recent Indian datasets was published in 2025 by researchers from AIIMS New Delhi. The study examined 144 patients with SSPE, offering a contemporary hospital-based picture of the disease in India.
It found substantial variation in clinical presentation and progression, while confirming the severe functional and survival burden associated with the disease. The study was hospital-based and therefore should not be interpreted as a national incidence estimate for India. Nevertheless, it demonstrates that SSPE continues to impose a significant neurological burden.
The findings included:
A 2026 systematic review examining the neuroimaging spectrum of SSPE analysed 461 reported cases.
Neuroimaging was available in 456 cases, with MRI performed in 394. The review found that:
The findings are important because SSPE does not always produce one fixed MRI appearance. Imaging abnormalities can change with disease progression, and some patterns may mimic autoimmune, metabolic, inflammatory or other neurodegenerative disorders.
Doctors generally combine the clinical history with EEG, cerebrospinal fluid testing and brain imaging.
CSF measles antibodies: Elevated measles-specific IgG in CSF is a major diagnostic clue and can demonstrate intrathecal antibody production.
EEG: Periodic, stereotyped, high-amplitude complexes are characteristic, particularly when they correspond with myoclonic jerks.
MRI: MRI may be normal early but can later reveal white-matter abnormalities and cerebral atrophy.
A normal early scan or nondiagnostic EEG should therefore not automatically exclude SSPE when the clinical picture is strongly suggestive.
SSPE remains difficult to treat because the virus is persistently embedded within the brain and conventional antiviral strategies have limited evidence. Some patients may receive combinations of antiviral and immunomodulatory therapy, particularly during the earlier stages.
However, there is no proven cure. Treatment responses are inconsistent; evidence comes largely from small studies and observational experience; large randomised controlled trials are lacking, and advanced disease is particularly difficult to reverse.
Supportive treatment is therefore crucial and may include seizure control, physiotherapy, occupational therapy, swallowing assessment, nutritional support, aspiration prevention, respiratory care and palliative care.
The disease is rare, but its early symptoms can be deceptively ordinary.
A previously healthy child who develops progressive loss of cognitive or behavioural abilities, followed by myoclonic jerks, seizures, movement problems or visual deterioration, warrants neurological evaluation, particularly if there is a history of measles.
"There is currently no universally effective curative treatment for SSPE. The objective is to slow progression where possible, control seizures and other symptoms, preserve function and provide comprehensive supportive care. Ensuring that children receive their recommended measles-containing vaccines is critical to reducing risk. Prevention remains our strongest weapon. By preventing measles infection in the first place, we can prevent the devastating neurological legacy that SSPE can leave years later," Dr Nabi said.
