When metals compete: A case of copper-deficiency myeloneuropathy and anemia

Background: A 47-year-old woman with an otherwise unremarkable medical history was referred to the multiple sclerosis clinic by her primary neurologist for evaluation of a 2-3 year history of progressive knee and back pain, weakness, paresthesias, sensory loss, ataxia, and falls. During the same period, she had received blood transfusions for unexplained anemia and leukopenia. She had been wearing dentures for many years. Investigations: Physical examination, neurological examinations (assessments of reflexes, gait, proprioception, and sensitivity to temperature, pinprick and vibration), neurophysiological studies (visual and brainstem somatosensory evoked potentials, nerve conduction studies and electromyography), T₂-weighted MRI of the brain and spine, cerebrospinal fluid analysis and serum evaluations. Diagnosis: Myeloneuropathy and anemia due to copper deficiency, secondary to zinc overload associated with long-term use of denture cream with a high zinc content. Management: Change to a low-zinc denture cream and oral copper replacement.