Anti-GABA-A Receptor Encephalitis Presenting as Fulminant Hemicerebellitis in a 5-Year-Old Girl
Kellie Krohn1, Rebecca Luke2, Adrian Lacy2, Sandy Cope3, John Honeycutt4, Jonathan Santoro5, Alfred Balasa2
1Texas College of Osteopathic Medicine, 2Department of Neurology, 3Department of Pathology, 4Department of Neurosurgery, Cook Childrens Medical Center, 5Division of Neurology, Children’s Hospital Los Angeles
Objective:
To report a child with anti-GABAA receptor encephalitis presenting as fulminant hemicerebellitis without early seizures, an atypical phenotype, and to describe the response to early, aggressive immunotherapy with timely decompression.
Background:
Fulminant cerebellitis is a rare pediatric emergency; autoimmune etiologies, including anti-GABAAR encephalitis, may present atypically and deteriorate rapidly. Early recognition and timely therapy escalation can be life-saving.
Design/Methods:
Single-patient case with clinical, radiographic, EEG, CSF cytokine, and antibody data collected during PICU admission.
Results:
A previously healthy 5-year-old presented with fever, lethargy, and right cerebellar edema effacing the fourth ventricle. Emergent posterior-fossa decompressive craniectomy with C1 laminectomy was performed. CSF showed mild pleocytosis; MRI revealed right cerebellar T2/FLAIR hyperintensity with scattered cortical foci. Empiric high-dose IV methylprednisolone began on day 2 and tocilizumab on day 3. Despite antimicrobials, deterioration with new seizures occurred by day 5. A modified plasma-exchange/IVIG “zipper” and a second tocilizumab dose were given. Rising CSF interleukin-6 and continued clinical decline prompted escalation to daily intrathecal dexamethasone and high-frequency tocilizumab (8 mg/kg q12 h). Treatment led to clinical stabilization and extubation, with falling CSF IL-6 and radiographic improvement on MRI. On day 32, expanded serum/CSF testing detected anti-GABAA receptor antibodies. By day 37, the child showed substantial recovery of language, motor function, and cognition, with mild residual hemineglect at discharge.
Conclusions:
Anti-GABAA receptor encephalitis can manifest as fulminant hemicerebellitis and progress to brain-stem compression within hours. Early, coordinated management, including posterior-fossa decompression when indicated; escalation beyond steroids/IVIG/PLEX when clinical status, EEG, or neuroimaging worsens despite typical therapy; CSF IL-6–informed intrathecal/targeted therapy; and expanded antibody panels (including anti-GABAA), can stabilize the disease course before antibody confirmation and enable meaningful recovery.
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