Abstract Details

Title A Subacute Combined Degeneration-Like Syndrome in the Setting of Zinc Toxicity with Normal Serum Copper

Topic Movement Disorders

Presentation(s) P07 - (-)

Poster/Presentation
Number 203

Objective

Background BACKGROUND: Copper deficiency is a well-described cause of myelopathy with prominent sensory ataxia. Zinc overload results in excessive elimination of copper in enterocytes.

Design/Methods DESIGN/METHODS: Literature review of comparable reports was performed.

Results RESULTS: A 50-year-old woman developed progressive numbness and paresthesia over a 10 month period. She developed symmetrical numbness and paresthesia in her feet shortly after a minor motor vehicle accident, and noted instability of gait. Her paresthesia gradually spread to involve both hands and the legs to the level of the knees. She reported losing balance with eye closure. Sensory examination showed symmetrical, non-length dependent impairment of vibration in both legs to the knees, as well as a prominent Romberg sign. Proprioception and light touch sensation were intact. She had no weakness or atrophy. Toes were downgoing bilaterally. Gait examination showed a widened base, shortened stride length, and profound unsteadiness with tandem gait. The patient reported taking Vitamin B12 supplements and 250mg of zinc supplements daily for over a year. Serum B12 was greater than 1200pg/ml (reference 200-1200pg/ml). Serum Vitamin B6 was 19.2nmol/L (reference 20-125nmol/L). Serum copper was 86[mu]g/dl (reference 80-155[mu]g/dl). Serum ceruloplasmin was 24mg/dl (reference 14-58mg/dl). Serum zinc was 152[mu]g/dl (reference 60-120[mu]g/dl). Hematocrit, Hemoglobin A1c, Lyme antibody and Syphilis antibody were normal. EMG showed moderate bilateral median neuropathies at or distal to the wrist, without large fiber polyneuropathy or lumbar radiculopathy. MRI of the cervical/thoracic spine showed T2 hyperintense, nonenhancing signal in the dorsal columns. She had spontaneous improvement in her gait with discontinuation of zinc supplementation; on one month follow-up, vibratory sense was diminished at the bilateral toes, with impaired proprioception at the toes and wide-based gait.

Conclusions CONCLUSIONS: Zinc excess should be considered in a differential diagnosis of posterior column dysfunction, even with normal copper levels.

Authors/Disclosures
Karen Rembold, MD PRESENTER	No disclosure on file
Tracy Brandt, PhD (GeneDx, Inc.)	No disclosure on file
Juan E. Small, MD (Lahey Hospital and Medical Center)	No disclosure on file
Matthew E. Tilem, MD (Lahey Clinic)	An immediate family member of Dr. Tilem has received personal compensation in the range of $100,000-$499,999 for serving as a Attorney with Pharmaceutical companies (confidential).

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