title: Recovery from SIADH-associated osteoporosis: a case report.
abstract: BACKGROUND
  Recent studies show an association between hyponatremia and osteoporosis. We have previously reported a case of severe male osteoporosis due to chronic syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Here, we provide a follow-up on this case after cure of the condition that further supports the causal relationship.
  
  
  METHODS
  A 38-year-old man had been diagnosed with severe osteoporosis most likely due to chronic SIADH. The SIADH was believed to be idiopathic. A magnetic resonance imaging scan, however, revealed a tumor in the sinus, and biopsies showed an esthesioneuroblastoma, immunohistochemically positive for antidiuretic hormone (ADH). After the tumor was removed, ADH and sodium levels normalized. A dual-energy x-ray absorptiometry scan performed 7 months after the patient's last surgery showed a significant spontaneous improvement in bone mineral density in the lumbar vertebrae.
  
  
  CONCLUSIONS
  This case provides evidence for a causal relationship between SIADH and chronic hyponatremia and impaired bone metabolism that can lead to severe secondary osteoporosis. The effect on bone metabolism is at least partially reversible.
authors: Department of Cardiology, Nephrology, and Endocrinology (A.-S.S., A.-L.T., U.P.-B., P.E.), Nordsjællands Hospital, DK-3400 Hillerød, Denmark; Faculty of Health Sciences (A.-S.S.), University of Southern Denmark, DK-5000 Odense, Denmark; and Faculty of Health Sciences (U.P.-B., P.E.), University of Copenhagen, DK-2200 Copenhagen, Denmark.
authors: Anne-Sophie
authors: AS
authors: Sejling
authors: Anne-Luise
authors: AL
authors: Thorsteinsson
authors: Ulrik
authors: U
authors: Pedersen-Bjergaard
authors: Pia
authors: P
authors: Eiken
mesh_terms: D000328:Adult; D018304:Esthesioneuroblastoma, Olfactory / Q000150:complications* / Q000175:diagnosis; D006801:Humans; D007010:Hyponatremia / Q000209:etiology; D007177:Inappropriate ADH Syndrome / Q000150:complications*; D008297:Male; D064847:Multimodal Imaging; D009296:Nasal Cavity; D009669:Nose Neoplasms / Q000150:complications* / Q000175:diagnosis; D010024:Osteoporosis / Q000209:etiology*