Polyneuropathy while on duodenal levodopa infusion in Parkinson’s disease patients: we must be alert

submitted by Hicivilmiff

Some reports have emerged describing the occurrence of Guillain-Barré syndrome and polyneuropathy related to vitamin B12 deficiency in some patients with Parkinson’s disease (PD) treated with continuous duodenal levodopa infusion. We describe five PD patients who developed axonal polyneuropathy and vitamin B12 deficiency while on treatment with duodenal levodopa infusion... One case of Guillain-Barré syndrome and at least 12 cases of polyneuropathy related to vitamin B12 deficiency have been reported in PD patients treated with duodenal levodopa infusion. Levodopa gel infusion may induce a decrease in vitamin B12 levels, leading to peripheral neuropathy. Additional pathogenetic mechanisms include alterations related to the metabolism of l-dopa, abnormal l-dopa absorption, and direct neurotoxicity of l-dopa at high doses.... Vitamin B12 deficiency in patients on duodenal levodopa infusion therapy may be more frequent than the published data suggest..

http://scienceindex.com/stories/2081..._be_alert.html


Rajabally YA, Martey J. Neuropathy in Parkinson disease: prevalence and determinants. Neurology 77(22), 1947–1950 (2011).

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Peripheral neuropathy and levodopa therapy in Parkinson’s disease (PD) are two unlikely bedfellows. Despite decades of levodopa use in thousands of patients, this association has not previously been noted until recently [1]. Case reports of Guillain–Barré syndrome (acute demyelinating neuropathy) have been reported in subjects with intraduodenal infusions of levodopa. The potential pathogenesis may be due to catabolic pathways involving levodopa that could reduce S-adenosylmethionine and lead to lowered vitamin B12, elevated methylmalonic acid and elevated homocysteine.

This is a second cross-sectional case–control study in 37 PD patients (with no risk factors for neuropathy). Of these PD subjects, 37.8% had a predominantly axonal peripheral neuropathy (measured with the Utah Early Neuropathy Scale) versus 8.1% in non-PD neurological controls. Ten out of 14 PD subjects with neuropathy reported symptoms. Low vitamin B12 levels were found in 57% of these PD subjects with neuropathy, which was more likely to be the sole cause in 50%, compared with <25% in a second control group of consecutive non-PD subjects with neuropathy. Cumulative levodopa exposure was inversely correlated with vitamin B12 levels in PD patients with neuropathy.

The issue of peripheral neuropathy in PD remains unresolved and larger studies are needed. At present, measuring vitamin B12 in PD subjects complaining of sensory symptoms or with clinical features of a peripheral neuropathy, appears to be a sensible approach, but whether all PD subjects need to be screened remains unanswered.

– Article suggested and written by Susan Fox

http://www.futuremedicine.com/doi/fu...2217/nmt.12.10