IgG4 Disease-Related Ataxia

We describe a male patient presenting with cerebellar ataxia and behavioural frontotemporal dementia in whom imaging showed cerebellar atrophy. He had significantly low N-acetyl aspartate to creatine (NAA/Cr) area ratio on MR spectroscopy of the cerebellum, primarily affecting the vermis. CT body scan showed extensive abnormal tissue within the mesentery, the retroperitoneum and perinephric areas. PET-CT showed increased tracer uptake within the wall of the aorta suggestive of an aortitis and within the perinephric tissue bilaterally. Biopsy of the perinephric tissue confirmed IgG4 disease. Treatment with steroids and mycophenolate improved his clinical state, but he developed symptoms attributed to pericardiac effusion that necessitated treatment initially with drainage and subsequently with pericardial window. After a course of rituximab, he had an episode of sepsis that did not respond to appropriate treatment and died as a result. Both the imaging findings and neurological presentation with cerebellar ataxia and behavioural frontotemporal dementia are novel in the context of IgG4 disease.

Automated summary

We report a male patient with cerebellar ataxia and behavioural frontotemporal dementia, accompanied by cerebellar atrophy detected on imaging. The MR spectroscopy of the cerebellum revealed significantly low N-acetyl aspartate to creatine (NAA/Cr) area ratio, mainly affecting the vermis. CT body scan showed abnormal tissue in the mesentery, retroperitoneum, and perinephric areas. PET-CT showed increased tracer uptake in the aortic wall and perinephric tissue, suggestive of aortitis. Biopsy confirmed IgG4 disease in the perinephric tissue. Treatment with steroids and mycophenolate improved the patient's condition, but complications arose from pericardiac effusion, leading to further interventions. After a course of rituximab, the patient developed sepsis that proved unresponsive to treatment and ultimately resulted in death. The combination of imaging findings and the neurological presentation of cerebellar ataxia and behavioural frontotemporal dementia are rare in the context of IgG4 disease.