Treatment of Vincristin-induced bilateral Ptosis

Introduction: Antineoplastic drugs have a series of side effects. Some of these side effects like bone marrow suppression are unspecific and common to most of the chemotherapeutic agents. Other side effects like neurotoxicity depend more on the type of drug used. Vincristine is a vinca alkaloid that binds on intracellular tubulin and induces structural changes in the microtubules. In most cases the neurotoxicity is the dose limiting factor. Typical symptoms are vanishing deep tendon reflexes, hyperaesthesia and neurotic pain, or paresthesias. Risk-factors for the development of vincristin-induced neuropathy are dose-intensity, cumulative dosage, interfering medications or a pre-existing and underlying hepato- or neuropathy. Case report: We present a female infant who developed nystagmus at the age of 3 month. A magnetic resonance imaging (MRI) was performed and yielded an optic glioma. The follow-up MRI at the age of 7 month showed a progression of the glioma. A partial excision was conducted, and the tumor was diagnosed as a pilocytic astrocytoma I°. The surgery was followed by polychemotherapy according to the SIOP-LGG protocol. After 9 weeks of treatment and a cumulative dosage of 3,6mg of vincristine a bilateral ptosis was noticed. The MRI showed no signs of progression. The ptosis was assessed as being vincristin-induced and therapy was started with pyridoxine and pyridostigmin. Additionally we paused one dosage of vincristine and gave once only 50% of the regular dosage. After 6 weeks complete remission of the ptosis was noted. Discussion: Vincristin neuropathy of the N. oculomotorius with bilateral ptosis as isolated symptome as in this case is very rare. In the literature four cases of vincristin-induced ptosis are described with an age distribution between 2 to 5 years, who responded to therapy with either pyridoxine alone or to a combination of pyridoxine and pyridostigmin. Three patients had additional vincristin-induced symptoms. There are inconsitent reports about the treatment with pyridoxine and/or pyridostigmin in other manifestations of antineoplastic agent-induced neuropathy. General guidelines and recommendations regarding the treatment of neuropathy with pyridoxine and pyridostigmin are not established. No evidence-based, effective strategy to cure or prevent chemotherapy-induced neuropathy is to date available.