title: [Pseudohyperthyroxinemia in endemic sprue--reversibility with a gluten-free diet].
abstract: METHODS
  An increased concentration of free T3 (fT3) with normal TSH was repeatedly measured in a 58-year-old man with diarrhoea. Hyperthyroidism was diagnosed and he was treated with thyrostatic drugs.
  
  
  METHODS
  Referred to our clinic, fT4 concentration, determined by routine ELISA, was found to be raised to 33.9 pmol/l, while fT3 and TSH levels were within normal limits. But the equilibrium-dialysis method gave a normal serum level also for fT4. Gastroscopy suggested coeliac disease, confirmed histologically.
  
  
  METHODS
  The symptoms quickly improved on a gluten-free diet and the fT4 level returned to normal values even on routine measurement.
  
  
  CONCLUSIONS
  The raised fT4 level with non-suppressed TSH was only revealed as a false finding by special non-routine laboratory methods. The reversibility and the close time relationship of the reported laboratory data with the clinical manifestations of the concomitant coeliac disease strongly suggested that changes in serum in the course of the latter disease played a role in these misleading laboratory results. An interference of coeliac disease with some laboratory tests has been previously described.
authors.affiliation: Medizinische Klinik I, Medizinische Universität zu Lübeck.
authors.forename: B
authors.initials: B
authors.lastname: Bätge
authors.forename: W
authors.initials: W
authors.lastname: Langsteger
authors.forename: I
authors.initials: I
authors.lastname: Bos
authors.forename: A
authors.initials: A
authors.lastname: Peters
mesh_terms: D002446:Celiac Disease / Q000097:blood / Q000150:complications / Q000178:diet therapy*; D003937:Diagnosis, Differential; D003967:Diarrhea / Q000209:etiology; D004797:Enzyme-Linked Immunosorbent Assay; D005773:Gastroscopy; D005983:Glutens / Q000008:administration & dosage; D006801:Humans; D006981:Hyperthyroxinemia / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D013974:Thyroxine / Q000097:blood*
chemical_list: D005983:Glutens; D013974:Thyroxine
vernacular_title: Pseudohyperthyroxinämie bei einheimischer Sprue--Reversibilität unter glutenfreier Diät.