02 November 2011
Tison F, Le Masson G
Is it conceivable
that for 40 years we have overlooked an insidious long-term levodopa treatment
adverse effect, such as neuropathy, in idiopathic Parkinson disease (IPD)? In
this issue of Neurology(®), Rajabally and Martey(1) take up the already
controversial question, recently mooted by Toth et al.,(2) of the increased
prevalence of neuropathy in chronic levodopa-treated IPD and its potential but
tenuous link to elevated plasma levels of homocysteine (Hcy) and methylmalonic
acid (MMA) and to reduced vitamin B(12) levels.
Even though the role of
levodopa in neuropathy is still hypothetical, the clinical relevance is
evident, as sensory neuropathy may contribute to impaired balance and
neuropathic pain in advanced IPD. Furthermore, vitamin B(12) deficiency and
increased Hcy and MMA levels can be easily determined in blood, suggesting that
neuropathy as a treatment-related complication may be prevented or treated by
vitamin B(12) and folate supplementation.
