title: Zinc poisoning from excessive denture fixative use masquerading as myelopolyneuropathy and hypocupraemia.
abstract: A 50-year-old man presented with a four-year history of unsteadiness, with recent falls and tingling in his fingers. Neurological examination found an ataxic gait, with a positive Romberg's sign. There was distal wasting and weakness in all four limbs and impaired co-ordination, with pseudoathetosis in the arms. Initial investigations showed a normochromic, normocytic anaemia, leucopenia, neutropenia and a low vitamin B(12) (172 ng/L). Treatment with intramuscular cobalamin injections showed no clinical improvement. Further investigations showed an undetectable caeruloplasmin (<0.085 g/L), a very low serum copper (1.1 μmol/L) and a markedly raised serum zinc concentration (36.2 μmol/L). On detailed questioning it became apparent that he had ill-fitting dentures requiring excessive use of denture fixative with high zinc content. The patient was switched to a non-zinc containing denture fixative and commenced copper supplementation. Although within three months the bone marrow suppression had resolved, there was no clinical improvement in neurological presentation. Questioning a patient about their denture fixative usage and checking if zinc is an ingredient may be considered during an investigation for myelopolyneuropathy when vitamin B(12) deficiency is not a cause.
authors.affiliation: Department of Clinical Chemistry, Royal Cornwall Hospital, Truro, Cornwall, UK. Anna.Barton@rcht.cornwall.nhs.uk
authors.forename: A L
authors.initials: AL
authors.lastname: Barton
authors.forename: R A
authors.initials: RA
authors.lastname: Fisher
authors.forename: G D P
authors.initials: GD
authors.lastname: Smith
mesh_terms: D000740:Anemia / Q000139:chemically induced / Q000175:diagnosis; D002570:Ceruloplasmin / Q000032:analysis; D003300:Copper / Q000097:blood / Q000172:deficiency*; D003738:Dental Cements / Q000506:poisoning*; D003778:Dentures / Q000009:adverse effects*; D003937:Diagnosis, Differential; D000075322:Heavy Metal Poisoning; D006801:Humans; D008297:Male; D008875:Middle Aged; D009503:Neutropenia / Q000175:diagnosis / Q000209:etiology; D011041:Poisoning / Q000175:diagnosis* / Q000209:etiology; D011115:Polyneuropathies / Q000139:chemically induced / Q000175:diagnosis; D014805:Vitamin B 12 / Q000627:therapeutic use; D014806:Vitamin B 12 Deficiency / Q000139:chemically induced / Q000175:diagnosis; D015032:Zinc / Q000378:metabolism / Q000506:poisoning*
chemical_list: D003738:Dental Cements; D003300:Copper; D002570:Ceruloplasmin; D015032:Zinc; D014805:Vitamin B 12