Objective: The aim of this report was to present a patient with Parkinson’s disease (PD) treated with continuous subcutaneous foslevodopa/foscarbidopa infusion (CSFLI) who developed axonal-demyelinating polyneuropathy.

Background: Parkinson’s disease is the second most common neurodegenerative disorder. Initially symptoms response well to levodopa; however, as the disease progresses, patients may develop dyskinesias and motor fluctuations. These complications may lead to the use of advanced therapies, including CSFLI. Although this treatment may be well tolerated, specific complications can occur during therapy.

Method: The patient underwent standard neurological examination, imaging, and laboratory testing. An autoimmunological panel was performed in cerebrospinal fluid (CSF) and serum. Electromyography and nerve conduction studies were also carried out.

Results: A 75-year-old woman with an eight-year history of Parkinson’s disease was treated for asymmetrical bradykinesia, tremor, and severe freezing of gait. At the age of 74 due to troublesome fluctuations and a high levodopa equivalent daily dose (LEDD = 2510), the patient was qualified for CSFLI, which was initially well tolerated.

The patient was subsequently admitted to the Neurology Department with a history of more than one month of hypoesthesia affecting all extremities, weakness in the lower limbs and weight loss. One week before admission, she had suffered from a gastrointestinal infection.

Neurological examination revealed extrapyramidal dysarthria, contractures of the right extremities, and hypoesthesia in the left thigh and distal parts of the lower limbs. Neuroimaging was normal. Laboratory testing showed vitamin B12 folic acid deficiency below the lower threshold of the reference range, positive antisulfatide antibodies in CSF and positive anti-ganglioside antibodies (AGAs) in serum. Electromyography demonstrated axonal-demyelinating sensorimotor polyneuropathy in the left upper limb; the structural changes seen in the lower limbs were so advanced that their interpretation was extremely difficult.

Conclusion: Patients treated with CSFLI should be monitored for peripheral nerve complications and biochemical abnormalities. Regular testing of vitamin B12 and folic acid levels and supplementation in case of their deficiency may contribute to clinical improvement and reduce the risk of potential complications related to hypovitaminosis.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/axonal-demyelinating-polyneuropathy-after-subcutaneous-foslevodopa-foscarbidopa-infusion-case-report/