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BMJ Case Reports 2018; doi:10.1136/bcr-2017-222741
  • Unusual association of diseases/symptoms
  • CASE REPORT

‘If there were water we should stop and drink’: neurofibromatosis presenting with diabetes insipidus

  1. Orna O' Toole1
  1. 1Department of Neurology, Mercy University Hospital, Cork, Ireland
  2. 2Department of Endocrinology, Mercy University Hospital, Cork, Ireland
  1. Correspondence to Dr Rachel Barry, rachelbarry91{at}gmail.com
  • Accepted 22 January 2018
  • Published 11 February 2018

Summary

A 58-year-old right-handed woman presented to our institution with a 1-month history of polydipsia and polyuria. She had a remote history of neurofibroma excision by dermatology and, on examination, was noted to meet the clinical diagnostic criteria for neurofibromatosis type 1. Laboratory investigations revealed hypernatraemia and elevated serum osmolality, accompanied by reduced urinary osmolality. A subsequent water deprivation test confirmed central diabetes insipidus, which responded to treatment with desmopressin. MRI of the brain showed pituitary enlargement, which raised the possibility of an underlying pituitary adenoma or, alternatively, lymphocytic hypophysitis. Both conditions have rarely been described in neurofibromatosis.

Footnotes

  • RB and AO’C contributed equally.

  • Contributors RB (neurology Senior House Officer) involved in following the patient during her initial presentation; arranging and interpreting of investigations; write-up of case report. AO’C (neurology Specialist Registrar) involved in following the patient during her initial presentation; arranging and interpreting of investigations; write-up of case report. MHA (endocrinology registrar) involved in following the patient during her initial presentation; arranging and interpreting of investigations; arranging patient consent. OO’T (neurology Consultant) consulted on the patient during her initial presentation for expert neurological opinion; provided diagnostic advice; proof-reading of case write-up; provided follow-up for the patient in neurology outpatient clinic.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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