Dados do Trabalho

Título

Extensive spinal Wallerian degeneration in a paraneoplastic ganglionopathy case

RESUMO

CASE REPORT:
A 52-year-old woman presented a three-month history of weight loss and incoordination that turned her bedridden. She was a longstanding smoker without comorbidities. Neurological evaluation unveiled severe appendicular and axial sensitive ataxia, uncomfortable paresthesia, despite preserved strength. Previous electroneuromyography endorsed the hypothesis of ganglionopathy. Etiologic investigation disclosed a small cell lung cancer (SCLC) and the final diagnosis was a paraneoplastic syndrome. Intravenous pulse steroid therapy was prescribed without symptomatic change, and the patient was referred to Oncology. After 2 months of chemotherapy, surveillance exams revealed lung response though the appearance of dorsal spine hyperintensity, not seen in the first MRI. Neurological examination was unchanged. Patient was submitted to radiotherapy and a 3rd MRI still showed the hyperintensity. Nine months after the treatment beginning, the oncologic disease remains under control without neurological gain.
DISCUSSION:
Paraneoplastic ganglionopathy is most associated to SCLC indeed. The main antibodies involved are: anti-Hu, anti-CRMP5 and anti-amphiphysin. MRI dorsal column hyperintensities have been reported in ganglionopathy, a differential diagnosis for tabes dorsalis, vitamin B12 and copper deficiency and nitrous oxide toxicity. In ganglionopathy, it has been reported a precocious emergence of this spine hypersignal, besides a radiological improvement after immunomodulatory therapy. However, in most cases, MRI finding represents irreversible damage due to gliotic injury. This latter scenario reinforces the physiology basis of Wallerian degeneration (WD) started from dorsal root ganglia (DRG), pseudobipolar neurons that ramify into the peripheral branch and the central branch which carries the somatosensory information to the spinal cord. Although the underlying cause has been addressed, the lesion of the DRG, namely the proximal cell body, triggered a cascade to distal axonal degeneration. Therefore, first MRI was unremarkable but the following exams testified a permanent finding.
FINAL COMMENTS:
Our case highlights WD in central afferent tracts, secondary to disrupted synapse at the dorsal-horn. The persistence of the novel hyperintensity and the absent recovery from sensitive ataxia supports MRI as a tool for chronicity ascertainment. Moreover, MRI was able to illustrate the pathogenesis behind the natural history of ganglionopathy.

Palavras Chave

paraneoplastic ganglionopathy, Wallerian degeneration, dorsal root ganglia,