This patient’s presentation of myeloneuropathy, normocytic anemia, leukopenia, and history of gastric bypass is consistent with likely copper deficiency precipitated by recent zinc supplementation. Acquired copper deficiency is most commonly due to gastric surgery; other causes include prolonged total parenteral nutrition, excessive zinc ingestion, and malabsorptive enteropathies (eg, celiac disease, inflammatory bowel disease). Increased zinc intake can lead to copper deficiency as zinc competes with copper absorption in the GI tract.
Patients typically present with leukopenia, anemia (normo- , micro-, or macrocytic), and neurological symptoms similar to vitamin B12 deficiency (eg, ataxia, spasticity with weakness, positive Romberg maneuver, dorsal column disease). Low serum copper and ceruloplasmin levels confirm the diagnosis. Neurologic symptoms improve in most patients with oral copper supplementation and stopping zinc supplements.
Gastric bypass surgery is associated with many nutritional deficiencies. Typical monitoring includes CBC, electrolytes, iron studies (including ferritin), liver function tests, albumin, lipid profile, 25-hydroxyvitamin D and parathyroid hormone levels, thiamine, vitamin B12, and folate levels. All patients with gastric bypass surgery should have laboratory monitoring for these at 3 months, 6 months, and annually after surgery.