title: Hyperthyroidism after parathyroid exploration.
abstract: BACKGROUND
  We hypothesized that hyperthyroidism after parathyroid exploration may be an underreported phenomenon with a course more severe than recognized previously.
  
  
  METHODS
  We examined pre- and postoperative thyroid function and outcomes in 199 consecutive patients who, since March 2000, had parathyroid exploration for primary sporadic hyperparathyroidism (HPTH). We excluded patients with prior thyroid or parathyroid surgery, preoperative thyroid medication, concurrent total thyroidectomy, or follow-up <5 months.
  
  
  RESULTS
  Of 125 patients with normal preoperative serum thyroid-stimulating hormone levels, 39 (31.2%) were hyperthyroid postoperatively. Mean thyroid-stimulating hormone levels (mean +/- SD) dropped with operation from 2.0 +/- 1.1 microIU/mL to 1.2 +/- 1.4 microIU/mL (P < .0001). Nineteen patients (15%) reported symptoms 1 to 2 weeks after operation. The clinical course of hyperthyroidism typically was short, but 5 patients (4%) had symptomatic hyperthyroxinemia requiring medical therapy. Hyperthyroidism was independent of age, severity of HPTH, anatomic/pathologic features, operative time, and other measures of operative difficulty, but was associated with lithium therapy, bilateral exploration, and absence of concurrent thyroid lobectomy.
  
  
  CONCLUSIONS
  Risk of hyperthyroidism may be underappreciated after routine parathyroid surgery for HPTH. Use of lithium and degree of dissection appear contributory. Patients undergoing parathyroid exploration need counseling and surveillance for hyperthyroidism, which may be reduced by minimizing the extent of parathyroid surgery.
authors.affiliation: Department of Surgery, University of Pittsburg School of Medicine, PA 15261, USA.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Stang
authors.forename: John H
authors.initials: JH
authors.lastname: Yim
authors.forename: Sue M
authors.initials: SM
authors.lastname: Challinor
authors.forename: Sachin
authors.initials: S
authors.lastname: Bahl
authors.forename: Sally E
authors.initials: SE
authors.lastname: Carty
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000175:diagnosis / Q000601:surgery*; D006980:Hyperthyroidism / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands / Q000473:pathology / Q000601:surgery*; D016105:Parathyroidectomy / Q000009:adverse effects*; D012189:Retrospective Studies; D013960:Thyroid Function Tests; D020535:Video-Assisted Surgery / Q000009:adverse effects*