A case of acute cerebellar ataxia without any prodromal illness showed cerebellar hypoperfusion on 123I-iodoamphetamine single photon emission computed tomography. The symptoms did not resolve spontaneously or with methylprednisolone pulse therapy but disappeared rapidly with intravenous immunoglobulin therapy.
Conclusion: Intravenous immunoglobulin therapy is worth considering in acute cerebellar ataxia that does not respond to high-dose steroid therapy.