EMERGENCY:ADEM is a neurological emergency. After a recent infection: sudden confusion, drowsiness, or unusual behaviour 1–4 weeks after a viral fever, sore throat, stomach upset, or vaccination; new weakness in the limbs, especially spreading or affecting both sides; a first seizure with fever or behaviour change; sudden vision loss, double vision, or difficulty speaking/swallowing; inability to walk, severe drowsiness, or trouble breathing; loss of bladder or bowel control with leg weakness. Time matters — children and adults treated early often recover fully. —call040-46324365immediately — 24 hours, 7 days— 24/7
Post-Infectious Encephalomyelitis (ADEM) — Treatment in Hyderabad at KIMS
Post-infectious encephalomyelitis — usually called ADEM (Acute Disseminated Encephalomyelitis) — is a sudden, dramatic inflammation of the brain and spinal cord that follows an infection or, less commonly, a vaccination by 1 to 3 weeks. The immune system, switched on by the infection, mistakenly attacks the protective covering (myelin) of nerves in the brain and spinal cord. Children are affected more often than adults. Most patients recover well — sometimes completely — with prompt treatment, but ADEM is a medical emergency that needs urgent hospital care.
Acute Disseminated Encephalomyelitis (ADEM) is an immune-mediated inflammatory demyelinating disease of the brain and/or spinal cord, occurring 1–4 weeks after a viral fever, respiratory or gastrointestinal infection, or (rarely) vaccination. It is primarily a disease of children but occurs in adults. The pathological mechanism: the immune system, primed against a viral antigen, cross-reacts with myelin components through molecular mimicry, producing widespread perivenous demyelination throughout the central white matter. MRI: bilateral, asymmetric T2-hyperintense lesions in the cerebral white matter, basal ganglia, brainstem, cerebellum, and spinal cord — typically larger and more asymmetric than MS lesions. Clinical features: sudden onset of encephalopathy (confusion, altered consciousness), fever, headache, multifocal neurological deficits (weakness, vision loss, sensory loss, ataxia), and seizures. Diagnosis: post-infectious encephalopathy + multifocal MRI lesions + CSF mild pleocytosis. Testing for MOG-IgG: patients with MOG-IgG may have recurrent ADEM-like episodes (MOGAD spectrum, which requires long-term immunotherapy). Treatment: high-dose IV methylprednisolone; IVIG for steroid-refractory cases; plasmapheresis for severe disease. Prognosis: most cases (>70%) recover fully over weeks to months.
- 1–4 weeks after infection — the diagnostic timing window
- ADEM often follows an infection or vaccination by 1–4 weeks. Confusion and multifocal deficits during the acute fever → think encephalitis. The same picture 2 weeks after the fever has resolved → think ADEM. A preceding trigger cannot be identified in some patients (roughly 20–30% of published series) despite careful history-taking — that does not exclude the diagnosis, which rests on the clinical features and MRI pattern. Commonest triggers: upper respiratory infections, GI infections, chickenpox, measles, mumps, rubella. Post-vaccination ADEM: most commonly after rabies vaccine; rarely after MMR or influenza.
- MRI bilateral asymmetric lesions — the radiological signature
- T2-hyperintense lesions that are BILATERAL, ASYMMETRIC, LARGE (1–5 cm), involving deep white matter, basal ganglia, thalami, cerebellum, brainstem, and often spinal cord simultaneously. Distinguishes ADEM from MS (periventricular, ovoid, Dawson's fingers) and from encephalitis (grey-matter predominant). MRI may be subtle in the first 24–48 hours.
- ADEM vs MS vs MOGAD — the critical prognostic distinction
- ADEM is typically monophasic. Multiphasic ADEM in children raises MOGAD (MOG-IgG antibody disease) — relapsing, requires long-term immunotherapy. Paediatric MS usually begins as a first relapse with ovoid periventricular lesions, Dawson's fingers, and oligoclonal bands. MOG-IgG testing at KIMS in all ADEM and all recurrent inflammatory demyelination.
- IV methylprednisolone — first-line treatment
- Children: 20–30 mg/kg/day (max 1 g/day) for 3–5 days. Adults: 1 g/day for 3–5 days. Most children show dramatic improvement within 24–72 hours. Steroid-refractory: IVIG 2 g/kg total over 2–5 days. Plasmapheresis 5–7 sessions reserved for the most severe, life-threatening cases.
- Post-vaccination ADEM in India — the rabies vaccine context
- Historically associated with the Semple-type rabies vaccine (brain-tissue-derived). Modern VERO cell-derived rabies vaccines do not carry this risk. Post-MMR ADEM risk is extremely low (~1–2 per million doses) and dramatically lower than the ADEM risk from natural measles, mumps, or rubella infection.
- Prognosis — good in most, ongoing monitoring in all
- >70% of children recover fully or nearly fully over weeks to months. Residual cognitive impairment, persistent weakness, epilepsy, or mood problems in the minority. MOGAD-positive children need long-term immunotherapy. Repeat MRI at 3 months, neuropsychology at 6 months, annual follow-up for 5 years, MOG-IgG retesting at 6 months if relapse occurs.
- Post-ADEM epilepsy — when seizures persist
- Acute-phase seizures occur in 30–50% of children; most resolve as encephalitis resolves. A minority develop persistent post-ADEM epilepsy. EEG at 3–6 months identifies residual epileptiform activity. Persistent seizures despite adequate medication → re-image to exclude new inflammatory lesions (MOGAD or MS relapse).
| Fact | Details |
|---|---|
| ADEM definition | Immune-mediated CNS demyelination · Often 1–4 weeks after infection or vaccination, though no trigger is identified in some patients — this does not exclude the diagnosis · Bilateral asymmetric T2 lesions (white matter, basal ganglia, thalami, brainstem, spinal cord) |
| Clinical features | Sudden encephalopathy + multifocal deficits + seizures · Follows fever by 1–4 weeks · Children more commonly than adults · Emergency presentation |
| Diagnosis | Clinical picture + MRI (bilateral asymmetric T2) + CSF (mild pleocytosis) + MOG-IgG testing · Exclude encephalitis (HSV PCR in CSF) and MS (clinical course + oligoclonal bands) |
| Treatment | IV methylprednisolone 20–30 mg/kg/day (children) or 1 g/day (adults) for 3–5 days · IVIG for steroid-refractory cases · Plasmapheresis for severe refractory disease |
| MOGAD distinction | MOG-IgG positive = may have recurrent ADEM-like episodes (MOGAD spectrum) · Requires long-term immunotherapy · MOG-IgG tested in all ADEM cases at KIMS |
| Prognosis | >70% recover fully over weeks to months · Minority: residual cognitive impairment, epilepsy, weakness · Follow-up MRI at 3 months to exclude new lesions (MS or MOGAD) |
| Contact | 040-46324365 (emergency: sudden confusion after fever, spreading weakness, new seizure) · 040-44885000 (outpatient post-ADEM follow-up) |
About This Condition
ADEM at a Glance
What is it?
An autoimmune attack on the myelin (insulation) of nerves in the brain and spinal cord, usually triggered by a recent infection or vaccination — though in some patients no preceding trigger can be identified, and the diagnosis then rests on the clinical picture and MRI pattern.
Who gets it most?
Children aged 3–10 years are the classic group. Adults can also be affected — often with a more severe course.
How quickly does it start?
Symptoms come on over hours to a few days. Where a trigger illness is identified, the lag is usually 1–3 weeks; in a proportion of patients no preceding infection or vaccination is found, and ADEM is still the diagnosis if the clinical features and MRI pattern fit and other conditions are excluded.
Common triggers in India
Viral fevers, chickenpox, measles, mumps, dengue, COVID-19, Mycoplasma pneumonia, Epstein-Barr virus, and occasionally vaccinations.
Key tests
Urgent MRI of the brain and spine, lumbar puncture, blood tests for infection and antibodies.
First-line treatment
High-dose intravenous methylprednisolone for 3–5 days, followed by a tapering oral dose over 4–6 weeks.
Second-line
IVIG or plasmapheresis when steroids alone are not enough.
Outlook
About 70–80% of children recover completely or nearly so; remaining have mild residual symptoms. Adults have somewhat lower full-recovery rates.
Post-Infectious Encephalomyelitis (ADEM) — An Autoimmune Demyelinating Emergency
Post-infectious encephalomyelitis — usually called ADEM (Acute Disseminated Encephalomyelitis) — is a sudden, dramatic inflammation of the brain and spinal cord that follows an infection or, less commonly, a vaccination by 1 to 3 weeks. The immune system, switched on by the infection, mistakenly attacks the protective covering (myelin) of nerves in the brain and spinal cord. Children are affected more often than adults. Most patients recover well — sometimes completely — with prompt treatment, but ADEM is a medical emergency that needs urgent hospital care.
Nerves in the brain and spinal cord are wrapped in a fatty insulation called myelin — like the plastic coating on an electrical wire. Myelin lets nerve signals travel quickly and reliably. In ADEM, after an infection has switched on the immune system, antibodies and immune cells mistake the body's own myelin for the germ they were fighting. They attack it across many areas of the brain and spinal cord at the same time — that is why the condition is called 'disseminated' (spread out) encephalomyelitis (inflammation of the brain and spinal cord). This causes patches of inflammation, swelling, and slowing of nerve signals. On MRI these patches look like bright spots scattered through the brain's white matter, the deep grey matter, and the spinal cord. Once the immune attack is controlled, the body repairs much of the myelin and most patients recover well. Some patches may leave behind small permanent scars.
Book an ADEM Consultation
Speak directly with the KIMS neurology, paediatric neurology, and neuro-ICU teams — 24×7 cover, on-site MRI 1.5T and 3T, IV methylprednisolone protocol, IVIG, and plasmapheresis available on site. Outpatient paediatric neurology and adult neurology clinics, Monday to Saturday. Bring: hospital records of the trigger illness, vaccination card, imaging CDs, blood reports, and the list of current medicines.
040-44885000Neuro Emergency: 040-46324365 (24×7)What Is Happening in ADEM — and the Typical Picture
ADEM is an autoimmune attack on myelin that follows an infection or vaccination by 1–3 weeks. It is usually a one-time event, distinct from MS, NMOSD, and MOG antibody disease — distinctions that shape long-term management. The clinical picture combines encephalopathy (almost always present) with variable focal neurological signs.
WHY ADEM IS USUALLY A ONE-TIME EVENT
ADEM is what doctors call a monophasic illness — it has one attack and does not come back. This is different from multiple sclerosis (MS), which has repeated attacks throughout life.A small minority of children have a relapse within 3 months while still on or just after stopping steroids — this is called multiphasic ADEM and is treated similarly.Repeated, separate attacks months or years apart are not ADEM and usually point to MS, neuromyelitis optica spectrum disorder (NMOSD), or MOG antibody disease. The distinction matters because the long-term treatment is different. We monitor every ADEM patient with repeat MRI and antibody testing (MOG, AQP4) to make sure the diagnosis stays correct.
The first warning — the trigger illness
A viral fever, sore throat, cough, stomach upset, rash, or vaccination 1 to 3 weeks before. By the time ADEM starts, the original infection is usually gone or nearly so. Parents often say their child was 'completely back to normal after the fever' for a week or two before suddenly becoming unwell again.
Brain-related (encephalopathic) symptoms
Drowsiness, irritability, confusion, or unusual behaviour. The child may not respond normally to the family. Severe headache, vomiting, fever. Seizures — in 20–35% of children with ADEM. Personality change, agitation, or hallucinations in severe cases. Encephalopathic features are almost always present in ADEM.
Focal (one-area) neurological signs
Weakness on one or both sides; unsteady walk. Difficulty speaking or swallowing. Vision loss in one or both eyes (optic neuritis component). Double vision, drooping eyelid. Numbness, tingling, or pain. Bladder or bowel trouble (when the spinal cord is involved).
Triggers — What Brings On ADEM
ADEM follows a recognisable set of infectious and vaccine-related triggers. Identifying the trigger helps confirm the diagnosis and shapes any ongoing treatment of a smouldering source infection.
Viral fevers (non-specific)
Very common in India.
Most common identified trigger.
Chickenpox (varicella)
Common.
Reduced by vaccination.
Measles
Still occurs in India.
One of the most severe triggers.
Mumps, rubella
Less common since vaccination.
Vaccination protects.
Influenza, COVID-19
Both well described.
Either the infection itself or rarely the vaccine.
Mycoplasma pneumonia
Common.
Look for atypical pneumonia history.
Epstein-Barr virus
Common in adolescents.
After glandular fever.
Dengue, chikungunya
Reported in India.
Seasonal — monsoon peak.
Vaccinations
Rare — but reported.
Risk is much lower than the diseases the vaccines prevent.
No identifiable trigger
20–30% of cases.
Treated the same way.
Diagnosis at KIMS
How We Diagnose ADEM at KIMS
ADEM is diagnosed at KIMS through a structured seven-stage workflow that begins with a detailed history of the trigger illness and timeline, moves to a careful neurological examination, then to an urgent MRI of the brain and full spine (the single most important test), a bedside lumbar puncture, blood tests for infection and antibodies (including MOG-IgG and AQP4-IgG), EEG when seizures occur, and visual and other supportive testing :
Detailed history and timeline
Exactly when did the trigger illness happen, when did the new symptoms begin, and how have they progressed? The 1–3 week gap is the most useful clue. Vaccinations, travel, sick contacts, pet exposures, and current medicines are all relevant.
Neurological examination
Level of consciousness, language, vision, eye movements, facial movements, strength, sensation, coordination, gait, and reflexes — all charted carefully so improvement can be tracked.
Urgent MRI of the brain and full spine
The single most important test. ADEM typically shows multiple bright patches in the deep white matter, sometimes the deep grey matter, brainstem, cerebellum, and spinal cord — usually large and 'fluffy' rather than small and round. All MRIs are done with contrast unless contraindicated. We use 1.5T or 3T scanners available 24×7.
Lumbar puncture (CSF)
Examining the fluid around the brain and spinal cord. Helps confirm inflammation and rule out infection. Done at the bedside after MRI confirms it is safe. ADEM CSF typically shows mildly raised cells and protein; specific bands (oligoclonal bands) seen in MS are usually absent.
Blood tests for infection and antibodies
Tests for the suspected trigger infection — dengue, chikungunya, mycoplasma, EBV, herpes viruses. MOG-IgG and AQP4-IgG antibodies — important because some MOG-positive cases that look like ADEM can later relapse and need long-term immunotherapy. We test in every Indian patient. Vitamin B12, thyroid function, and inflammatory markers.
EEG when seizures occur
Records electrical activity of the brain. Used to confirm seizures and guide antiseizure treatment.
Visual and other supportive testing
Visual evoked potentials for suspected optic neuritis. Audiology when hearing is affected. Vision field tests when feasible.
Treatment
Treatment — Early and Aggressive
Step 1 — Intravenous methylprednisolone
The first-line treatment. High-dose IV methylprednisolone (usually 20–30 mg/kg for children, 1 g daily for adults) for 3–5 days. Most patients begin to improve within days. Children often show dramatic improvement. Followed by oral steroids tapered over 4–6 weeks to prevent rebound.
Step 2 — IVIG (Intravenous immunoglobulin)
Used when steroids have given an incomplete response, or as the first-line in patients who cannot have steroids. Given as a daily infusion over 2–5 days (total 2 g/kg). Generally well tolerated. Common in paediatric practice in India.
Step 3 — Plasmapheresis (plasma exchange)
Used for severe or steroid-unresponsive ADEM — the patient's blood is run through a machine that removes the antibodies attacking myelin. Usually 5–7 sessions on alternate days. Available on site at KIMS 24×7.
Supportive care
Neuro-intensive care with airway and breathing support when needed. Antiseizure medicines when seizures occur. Treatment of any ongoing infection (sometimes the trigger is still smouldering). Nutrition, prevention of pressure sores, physiotherapy from day 1.
Recovery and Rehabilitation
Recovery from ADEM follows a predictable arc — from rapid improvement in alertness and limb strength in the first 1–2 weeks of treatment, through the steroid taper and rehabilitation phase, to repeat MRI and final mapping at 6–12 months and annual surveillance for late relapse :
Week 1–2 of treatment
Most rapid improvement in alertness and limb strength. Children often go from drowsy and not recognising parents to chatty and alert within days.
Week 2–6
Steroid taper. Physiotherapy and occupational therapy. Schoolwork begins to be reintroduced gently.
Month 2–6
Most major neurological deficits have resolved or are clearly recovering. Repeat MRI shows shrinking patches. We watch for cognitive and behavioural issues that may only become obvious now.
Month 6–12
Final mapping of any lasting effects. Plans for school reintegration, sports return, and any long-term medication review. Repeat MOG-IgG testing — persistently positive children may need ongoing follow-up for relapse.
Annual review
Long-term watching for relapses (very rare in classical ADEM) and developmental progress in children.
ADEM Has a Good Outlook in Most Patients
ADEM carries a good prognosis when treated early. Most children make a full recovery; a minority have mild or more significant residual issues; mortality is now uncommon with modern intensive care and immunotherapy. Relapse in classical ADEM is rare — persistently positive MOG-IgG antibodies signal the children who need longer follow-up.
Full recovery
60–70% of children, 50–60% of adults make a full recovery.
Mild residual symptoms
Another 20–25% have mild residual symptoms — subtle weakness, attention or behaviour change, mild visual changes.
More significant residual disability
10–15% are left with more significant residual disability.
Mortality
Death is now uncommon (less than 5%) with modern intensive care and immunotherapy.
Relapse
Relapse in classical ADEM is rare — most patients have one attack only.
MOG-IgG persistence
Children with persistently positive MOG-IgG antibodies need long-term follow-up because some develop a relapsing condition that responds to ongoing treatment.
KIMS — ADEM Service Highlights
24×7 neurology and neuro-ICU cover
Yes.
MRI availability (1.5T and 3T)
24×7 on site.
IV methylprednisolone protocol
Standardised, paediatric and adult.
IVIG availability
On site, 24×7.
Plasmapheresis on site
Yes — 24×7.
MOG and AQP4 antibody testing
Routinely tested in every patient.
Paediatric neurology team
Dedicated, multidisciplinary.
Surgical experience (the KIMS Neuroscience team)
30+ years.
Emergency line
040-46324365 (24×7).
Related Conditions
Post-infectious encephalomyelitis (ADEM) belongs to the family of neuro-infection complications evaluated and managed at KIMS Neuroscience. Explore related conditions
FAQs
Frequently Asked Questions
A viral fever weeks ago. Then sudden confusion, drowsiness, new weakness, or a first seizure. ADEM is a neurological emergency — and most children and adults treated early recover well, sometimes completely. The window matters.
At KIMS Neuroscience, Secunderabad, Hyderabad, ADEM is managed under 24×7 neurology and neuro-ICU cover with on-site MRI 1.5T and 3T, a standardised IV methylprednisolone protocol for paediatric and adult patients, IVIG and plasmapheresis available 24×7, routine MOG-IgG and AQP4-IgG testing in every patient, a dedicated paediatric neurology team, and 30+ years of experience under the KIMS Neuroscience team. Open emergency line: 040-46324365 (24×7). Outpatient paediatric neurology and adult neurology clinics run Monday to Saturday. Appointments: 040-44885000. Email: neuroscience@kimshospitals.com. Bring: hospital records of the trigger illness, vaccination card, imaging CDs, blood reports, and the list of current medicines.
International enquiries: info@kimsneurosciences.com