EMERGENCY:If any of these happen to a child with suspected or diagnosed Rasmussen encephalitis: a long seizure (over 5 minutes) or repeated seizures without recovery; continuous jerking of one side of the body that does not stop (epilepsia partialis continua); sudden new weakness, drowsiness, difficulty speaking, or vision changes; high fever with seizures; loss of consciousness following a seizure, or difficulty breathing. Status epilepticus and EPC need urgent inpatient care — do not wait for the jerks to settle. —call040-46324365immediately — 24 hours, 7 days— 24/7
Rasmussen Encephalitis — Diagnosis & Surgical Treatment in Hyderabad at KIMS
Rasmussen encephalitis is a rare, slowly progressive brain disease that affects one side of the brain in children. It causes frequent seizures, gradual weakness on one side of the body, and a slow decline in thinking and learning. The exact cause is not fully understood but most experts agree it is an immune-driven inflammation — the body's own immune system attacking one half of the brain. There is no simple cure, but early diagnosis, immunotherapy in the early stage, and — in the right child — surgery to disconnect or remove the affected half of the brain can stop the seizures and protect the rest of the brain.
Rasmussen encephalitis (RE) is a rare, progressive, unilateral inflammatory disease of one cerebral hemisphere, causing intractable focal seizures (epilepsia partialis continua), progressive hemiparesis, and cognitive decline. RE is caused by CD8+ cytotoxic T cell-mediated destruction of neurons and astrocytes in one hemisphere, producing progressive cortical atrophy visible on serial MRI. The cause of the immune attack is not fully established; an unidentified viral trigger initiating an autoimmune response is the leading hypothesis. GluR3 antibodies (antibodies against the AMPA glutamate receptor subunit) have been proposed but lack diagnostic specificity. Clinical hallmark: epilepsia partialis continua (EPC) — continuous or near-continuous focal clonic jerking of one body part (typically the face or hand contralateral to the affected hemisphere), lasting weeks to months. This continuous seizure activity is refractory to antiseizure medications. Immunotherapy (IV methylprednisolone, IVIG, rituximab, tacrolimus) may temporarily slow the inflammatory process but does not prevent hemisphere destruction. The only treatment that reliably controls seizures is hemispherectomy (surgical disconnection or removal of the affected hemisphere), producing >80% seizure freedom. In young children, the remaining hemisphere compensates for language and motor function through neuroplasticity.
- Epilepsia partialis continua — the defining and most distressing feature
- Continuous or near-continuous clonic jerking of one body part (typically the hand, face, or foot) persisting for hours, days, weeks, or even months. In RE this comes from continuous epileptiform activity in the motor cortex of the affected hemisphere, driven by the ongoing inflammatory destruction. EPC is refractory to standard antiseizure medications and is the most distressing symptom for families.
- Progressive unilateral atrophy — the MRI trajectory
- Subtle T2 signal change and cortical swelling early; over months to years, progressive cortical thinning and volume loss preferentially affecting perisylvian and frontal regions. The contralateral hemisphere is normal. This progressive, asymmetric, unilateral atrophy on serial MRI is pathognomonic for RE.
- CD8+ T cells — the immunopathology
- Biopsy of the affected hemisphere shows infiltrating CD8+ cytotoxic T cells attacking neurons and astrocytes (granzyme B-induced neuronal apoptosis), microglial activation, and astrogliosis. The CD8+ T cell invasion is antigen-driven though the specific antigen has not been identified. GluR3 antibodies are non-specific. Immunotherapy can dampen but cannot reverse already-destroyed neurons.
- Immunotherapy — slowing progression, not stopping it
- Options used at KIMS: IV methylprednisolone (monthly pulses or high-dose courses), IVIG, rituximab (anti-CD20 B-cell depletion), and tacrolimus. Important limitation: immunotherapy does not stop the underlying immune-mediated destruction and does not prevent progressive hemisphere atrophy. Delaying hemispherectomy while trying more immunotherapy means more hemisphere lost.
- Hemispherectomy — the seizure-control operation
- Surgical disconnection (anatomical or functional) of the affected hemisphere — eliminates the epileptogenic zone and produces >80% seizure freedom. Motor: contralateral hemiplegia (often already developing pre-operatively). Language: early hemispherectomy in young children (typically <6–8 years) allows language transfer to the contralateral hemisphere via neuroplasticity. Decision at KIMS: fMRI language lateralisation, Wada test, PET, detailed neuropsychology.
- When to refer — earlier is better for outcome
- The principal prognostic factor is age at hemispherectomy: the younger the child, the more neuroplastic the brain, the better the language and cognitive outcomes. Waiting for the disease to 'stabilise' prolongs hemisphere destruction. Refer for assessment as soon as: (1) diagnosis confirmed by clinical, MRI, and EEG criteria; (2) seizures refractory to antiseizure medications and ≥1 course of immunotherapy; (3) unilateral hemisphere involvement confirmed.
- Language transfer after hemispherectomy in children
- In a child with left-hemisphere RE who undergoes left hemispherectomy before age 6–8, the right hemisphere progressively takes over language processing. Post-operatively, language is initially impaired and then recovers over 12–24 months. Older children and adults have much less capacity for this transfer — another reason to operate earlier rather than later.
| Fact | Details |
|---|---|
| Definition | Progressive unilateral hemisphere inflammation · CD8+ T cells attacking neurons and astrocytes · One hemisphere affected · Progressive cortical atrophy on serial MRI |
| Epilepsia partialis continua | Continuous or near-continuous focal clonic jerking of one body part · Refractory to antiseizure medications · Hallmark feature of RE · Persists for weeks to months |
| Immunotherapy | IV methylprednisolone · IVIG · Rituximab (anti-CD20) · Tacrolimus · May slow progression temporarily but does not stop hemisphere destruction |
| Hemispherectomy | >80% seizure freedom · Earlier = better language and cognitive outcomes (neuroplasticity) · Decision requires fMRI + Wada test + PET + neuropsychology |
| Earlier surgery | The younger the child at surgery, the better the language transfer and cognitive outcome · Delaying surgery = more hemisphere destroyed, less neuroplastic, worse outcome |
| Diagnosis criteria | EPC + progressive unilateral hemisphere atrophy on MRI + unilateral EEG seizures + clinical hemiparesis progression + CD8+ T cell pathology on biopsy |
| Contact | 040-44885000 (Rasmussen / epilepsy surgery clinic) · 040-46324365 (emergency: prolonged seizure or breathing difficulty) |
About This Condition
Rasmussen Encephalitis at a Glance
What is it?
A rare, progressive inflammation of one half of the brain (one hemisphere), causing seizures, weakness, and cognitive decline.
Who gets it?
Rasmussen encephalitis predominantly affects children (median onset ~6–7 years, most cases before age 10) but can also present in adolescents and adults. Adult-onset RE is less common but well-documented, typically with a similar but sometimes slower clinical course; the Bien et al. (2005) diagnostic criteria apply across age groups.
How common?
Rare — estimated at 2–4 per 10 million children per year worldwide. India sees several cases each year in major referral centres.
Cause
Believed to be autoimmune — the body's immune system attacking one half of the brain. The exact trigger is unknown; viral infection or genetic predisposition may play a role.
Hallmark
Drug-resistant focal seizures, often turning into continuous jerking of one side of the body (epilepsia partialis continua) within the first year.
Key tests
MRI of the brain (often showing shrinkage of one side), EEG (focal slowing and seizures from one hemisphere), and sometimes brain biopsy.
Early treatment
Antiseizure medicines plus immunotherapy — IVIG, steroids, plasmapheresis, or rituximab. May slow progression early on.
Definitive treatment
Hemispheric surgery (functional hemispherotomy or hemispherectomy) — disconnects or removes the affected hemisphere; stops seizures in 70–90% of cases.
Diagnosis at KIMS
A Rare Immune-Driven Hemispheric Epilepsy of Childhood — Diagnosed, Treated, and Operated at KIMS
Rasmussen encephalitis is a rare, slowly progressive brain disease that affects one side of the brain in children. It causes frequent seizures, gradual weakness on one side of the body, and a slow decline in thinking and learning. The exact cause is not fully understood but most experts agree it is an immune-driven inflammation — the body's own immune system attacking one half of the brain. There is no simple cure, but early diagnosis, immunotherapy in the early stage, and — in the right child — surgery to disconnect or remove the affected half of the brain can stop the seizures and protect the rest of the brain.
KIMS Neuroscience has a dedicated paediatric epilepsy programme, offering epilepsy surgery including hemispheric procedures. Together with paediatric neurologists, neurophysiologists, and neuropsychologists, we provide end-to-end care — from diagnosis to surgery to long-term rehabilitation.
Book a Rasmussen Consultation
Speak directly with the KIMS paediatric epilepsy team — dedicated, multidisciplinary; on-site video-EEG monitoring unit (paediatric and adult); 1.5T and 3T MRI with epilepsy protocols 24×7; functional MRI and language mapping; Stealth AutoGuide robotic cranial guidance (first in India at KIMS); IVIG, plasmapheresis, and rituximab on site 24×7. Outpatient paediatric epilepsy and epilepsy surgery clinics run Monday to Saturday. Bring: all previous MRI and CT scans (preferably on CD), EEG reports, seizure diary or videos of the seizures, all medications and doses, and school reports.
040-44885000Neuro Emergency: 040-46324365 (24×7)Treatment
Why Rasmussen Encephalitis Happens — and Why Surgery Can Be the Right Answer in a Child
Rasmussen is an immune attack confined to one hemisphere, producing a vicious cycle of seizures and progressive inflammation. The young brain's plasticity means that disconnecting or removing the affected hemisphere — in carefully selected children — protects the good half and gives the best chance of an independent adult life.
Why Rasmussen encephalitis happens
In Rasmussen encephalitis, the immune system mistakenly identifies cells in one half of the brain as foreign and slowly destroys them. T-cells (a type of immune cell) and inflammatory chemicals enter the brain tissue and damage nerve cells over months and years. What is most striking is that the inflammation almost never crosses to the other side — the disease stays in one hemisphere. The reason for this strict one-sidedness is one of the unsolved puzzles of the disease.
Seizures and inflammation — a vicious cycle
Because seizures themselves can further damage the brain, the seizure activity and the underlying inflammation form a vicious cycle. Each makes the other worse. This is why stopping the seizures — by medication, immunotherapy, or surgery — is not just about comfort: it actually protects the rest of the brain.
The young brain has remarkable plasticity
The young brain has remarkable plasticity — the ability to re-wire itself. When the affected half of the brain is disconnected or removed, the other half takes over many of its functions, particularly in children operated before age 10. Children with Rasmussen who have hemispheric surgery often walk, talk, learn, and grow up to lead independent lives.
Trade-offs of hemispheric surgery
Some hand and visual field function on the affected side is lost — but seizure control and protection of the good hemisphere are usually worth the trade-off in carefully selected patients. Surgical decision-making is highly individualised. KIMS uses a multidisciplinary epilepsy surgery conference to plan every case.
Rasmussen Encephalitis — The Three Stages
Rasmussen follows a recognisable three-stage course — from a non-specific prodromal phase often missed as ordinary childhood epilepsy, through the acute stage with drug-resistant seizures, epilepsia partialis continua, weakness, and cognitive decline, to a residual stage of stable but severe damage.
Prodromal stage — weeks to months
Often a non-specific phase — a previously healthy child has occasional seizures. Seizures may be brief, on one side, and respond initially to antiseizure medicines. Sometimes a recent viral illness is noticed, but not always.
Often missed or attributed to ordinary childhood epilepsy.
Acute stage — months to a year or two
Seizures become more frequent and harder to control. Continuous jerking of one side of the body — face, arm, leg — that does not stop even during sleep. This is epilepsia partialis continua (EPC), one of the hallmarks. Weakness on the same side as the jerks. The child stops using the affected arm well, walks with a limp, or drops things. Speech may be affected if the dominant hemisphere is involved. Cognitive abilities — memory, learning, behaviour — gradually decline.
MRI shows shrinkage of one hemisphere on repeat scans.
Residual stage — after the acute phase
The disease slows or stops 'burning' but leaves a stable, severely damaged hemisphere. The child has persistent weakness on one side, visual field loss, sometimes loss of language, and continuing seizures. Cognitive decline plateaus.
Decisions about surgery are usually taken before this stage to preserve as much brain function as possible.
How We Diagnose Rasmussen Encephalitis at KIMS
Rasmussen encephalitis is diagnosed at KIMS through a structured seven-stage workflow that begins with a detailed history, proceeds to a careful neurological examination, then to serial MRI of the brain (the most important test, showing characteristic progressive shrinkage of one hemisphere), EEG (often with long-term video-EEG monitoring), blood and CSF tests to rule out other causes, brain biopsy when needed, and a comprehensive epilepsy surgery work-up once surgery is being considered :
Detailed history
Onset of seizures, type and frequency, recent infections, weakness patterns, changes in school performance, language, and behaviour. Family history of epilepsy or autoimmune disease. Vaccination history and trigger illnesses.
Neurological examination
Side of the body weak, reflexes, vision fields (sometimes hard to test in young children), language assessment, gait, and any continuous jerking.
MRI of the brain — the most important test
Early in the disease, MRI may show only subtle inflammation. Repeat scans over months show characteristic progressive shrinkage of one hemisphere. We use a standardised protocol — including high-resolution T2/FLAIR, contrast-enhanced sequences, and volume measurement. 1.5T and 3T available.
EEG
Seizure activity originating from one hemisphere. Background slowing over the affected side. Long-term video-EEG monitoring may be needed to capture seizures and confirm origin. Done in our dedicated paediatric epilepsy monitoring unit.
Blood and CSF tests
To rule out infections, autoimmune encephalitis with specific antibodies (anti-NMDAR, anti-GAD, MOG, AQP4), and metabolic causes. Anti-GluR3 antibodies — historically described in Rasmussen — are no longer considered specific but are checked in selected cases.
Brain biopsy — sometimes
When the diagnosis is unclear from MRI and EEG, a small piece of inflamed brain tissue is taken and examined under the microscope. Confirms the inflammation, rules out infection or tumour. Done by the KIMS Neuroscience team using image-guided techniques.
Comprehensive epilepsy surgery work-up
Once the diagnosis is confirmed and surgery is being considered, the work-up expands: detailed neuropsychology, language and motor mapping, sometimes functional MRI, and Wada test in selected older patients to test language and memory lateralisation.
Treatment — Three Pillars
Antiseizure medicines
First-line — but rarely enough on their own. Multiple medicines are usually combined. Common choices: levetiracetam, carbamazepine, lacosamide, clobazam, valproate (used cautiously in young children), and topiramate. Doses are pushed to maximum tolerated levels. Many medicines may be tried before surgery is considered.
Immunotherapy — best in the early stage
High-dose intravenous steroids, IVIG, plasmapheresis, and rituximab are used in various combinations. Tacrolimus or other immunosuppressants are used in selected patients for long-term suppression. Immunotherapy may slow progression and delay the need for surgery, especially when started early — but does not usually stop the disease completely. Side effects (infection, growth issues, mood changes) need careful monitoring.
Hemispheric surgery — the definitive treatment
When seizures are uncontrolled and weakness is already established, hemispheric surgery becomes the best option for many children. Two main types: functional hemispherotomy (disconnects the affected hemisphere from the rest of the brain without removing most of it — modern preferred approach) and anatomical hemispherectomy (removes most of the affected hemisphere — rarely needed today). Performed by experienced epilepsy surgeons. KIMS Neuroscience performs epilepsy surgery including hemispheric procedures.
Recovery After Hemispheric Surgery
Recovery after hemispheric surgery follows a predictable arc — from the hospital and ICU phase, through early recovery in weeks 1–6 with physiotherapy/OT/speech therapy beginning in hospital, through structured rehabilitation in months 1–12, and into long-term follow-up at 3–6-monthly intervals during the first 2 years and annually thereafter :
Hospital stay
Usually 7–10 days in hospital — including paediatric intensive care for the first 1–2 days. Pain control, prevention of clots, and watchful nursing.
Early recovery — weeks 1–6
Initial period of weakness, fatigue, and sometimes fever. These usually improve. Early physiotherapy, occupational therapy, and speech therapy begin in hospital. Seizures often stop immediately after successful surgery. Medicines are continued for at least 1–2 years before considering tapering.
Rehabilitation — months 1–12
Daily physiotherapy, hand therapy, and walking practice. Speech and language therapy if needed, especially after dominant-side surgery. Children adapt remarkably well — many learn to walk again within months and develop functional one-handed dexterity.
Long-term follow-up
Every 3–6 months for the first 2 years, then yearly. Repeat MRI and EEG. School performance review. Hormonal screen. Behaviour and mood support. Most children continue to make gains in cognition and skills for years after surgery.
Realistic Outcomes — What Families Should Expect
Hemispheric surgery for Rasmussen aims for seizure freedom and protection of the unaffected hemisphere. The trade-offs — visual field loss on the affected side and limited hand function — are usually outweighed by seizure freedom, cognitive stability, and a substantially better quality of life.
Seizure freedom
70–90% of children completely free of seizures after hemispheric surgery; another 5–10% have a dramatic reduction.
Walking
Most children walk again, often with a limp on the affected side. Many run, swim, cycle, and play sport.
Hand use
The affected hand often functions only as a helper. The unaffected hand becomes very capable.
Vision
A permanent loss of the visual field on the affected side. Most children adapt without obvious difficulty.
Language
If surgery is on the language-dominant side and the child is young (under 6–8 years), language usually transfers to the other side. Older children may have more language difficulty.
Cognition and learning
Many children stabilise or improve after surgery once seizures are controlled. School support is usually still needed. Overall quality of life is substantially better in seizure-free children after hemispheric surgery than in those with continuing seizures and progressive disease.
Special Considerations — Adolescents, Language, and Status / EPC
Rasmussen presents specific challenges in older patients (less plasticity), in language-dominant hemisphere cases (requiring fMRI and Wada testing), and in patients with persistent epilepsia partialis continua, which accelerates the surgical decision.
Adolescents and adults
Rasmussen encephalitis occasionally appears in older patients with a slower, milder course. Hemispheric surgery in adults carries a higher risk of permanent weakness and language difficulty — the adult brain has less plasticity. Immunotherapy and seizure control are often more prominent in management, with surgery reserved for highly selected cases.
Language-dominant hemisphere
When the affected hemisphere controls language (usually the left in right-handed people), the decision to operate is more complex. In young children, language reorganises to the other side after surgery — though some weakness in language remains. Functional MRI and Wada testing help assess language lateralisation. Decisions are made jointly by the family, neurologist, neurosurgeon, and neuropsychologist.
Status epilepticus / EPC management
Continuous jerking that does not stop is an emergency. Treated with intravenous antiseizure medications, sedation, and intensive care if needed. Persistent EPC accelerates surgical decision-making.
KIMS — Rasmussen Service Highlights
Paediatric epilepsy programme
Multidisciplinary, dedicated.
Video-EEG monitoring unit
On site, paediatric and adult.
1.5T and 3T MRI with epilepsy protocols
24×7.
Functional MRI and language mapping
Available.
Stealth AutoGuide robotic cranial guidance
First in India at KIMS.
IVIG, plasmapheresis, rituximab
On site, 24×7.
Hemispheric surgery — seizure freedom
70–90% of carefully selected children.
Emergency line
040-46324365 (24×7).
Related Conditions
Rasmussen encephalitis belongs to the family of neuro-infection complications evaluated and managed at KIMS Neuroscience. Explore related conditions
FAQs
Frequently Asked Questions
A child whose seizures will not stop with any combination of medicines. Continuous jerking of one side of the body. Slow weakness in the same arm and leg. Falling school performance. Rasmussen encephalitis is rare but treatable — early diagnosis, immunotherapy, and in the right child hemispheric surgery can stop seizures and protect the good half of the brain.
At KIMS Neuroscience, Secunderabad, Hyderabad, the dedicated multidisciplinary paediatric epilepsy programme offers epilepsy surgery including hemispheric procedures. On-site video-EEG monitoring unit (paediatric and adult), 1.5T and 3T MRI with epilepsy protocols 24×7, functional MRI and language mapping, Stealth AutoGuide robotic cranial guidance (first in India at KIMS), IVIG, plasmapheresis, and rituximab available on site 24×7. Hemispheric surgery achieves seizure freedom in 70–90% of carefully selected children. Open emergency line: 040-46324365 (24×7). Outpatient paediatric epilepsy and epilepsy surgery clinics run Monday to Saturday. Appointments: 040-44885000. Email: neuroscience@kimshospitals.com. Bring: all previous MRI and CT scans (preferably on CD), EEG reports, seizure diary or videos of the seizures, all medications and doses, and school reports.
International enquiries: info@kimsneurosciences.com