Diabetes insipidus in the context of sarcoidosis: a case report

J Mesquita; P Rodrigues; S Belo; A Sousa; A Varela; A Magalhaes; J L Castedo; N Melo; Patricia Mota; Davide Carvalho

Introduction: Sarcoidosis is a systemic granulomatous disease of unknown etiology with a prevalence of 10–20/100 000 individuals and affects mainly young adults. Neurological involvement occurs in about 5% of the cases and it can affect the hypothalamic–pituitary axis. In this case, the most common endocrine manifestations are hyperprolactinemia and diabetes insipidus.

Case report: A 44-year-old male patient complaining of not feeling well and dyspnea was diagnosed with sarcoidosis about 6 years ago and was medicated with deflazacort 6 mg. He developed diabetes mellitus secondary to corticosteroid therapy about 4 years later and started insulin therapy. He was referred to an Endocrinology consultation due to polyuria and polydipsia for about 1.5 years. He ingested up to 5 l of water in a single day. In physical examination he had a cushingoid phenotype. Analytic baseline study revealed plasma osmolarity=294 mOsmol/kg (n: 282–300), normal renal function, normocalcemia, urine osmolarity=179 mOsmol/kg (n: 50–200), urinary volume=5700 ml, mild hyperprolactinemia=17.9/17.7/17.4 ng/ml (n: 4.0–15.2), hypopituitarism: hypogonadism – FSH=0.70 mIU/ml (n: 1.5–12.4), LH<0.10 mUI/ml (n: 1.7–8.6), total testosterone<0.03 ng/ml (n: 2.8–8.0); hypothyroidism – TSH=2.05 μUI/ml (n: 0.35–4.94), FT₄=0.66 ng/dl (n: 0.7–1.48) and hypoadrenalism – 0900 h. ACTH<1.0 ng/l (n: <63.3), 0900 h. cortisol=1.0 μg/dl (n: 6.2–19.4). It was performed a water restriction test that confirmed the diagnosis of central diabetes insipidus (urinary osmolarity during the test was always less than 200 mOsmol/kg and urinary osmolarity increased about 97.5% at 120′ after administration of s.c. desmopressin) and the patient was discharged with intranasal DDAVP solution 5 μg twice a day. Pituitary MRI showed hypothalamic and pituitary stalk thickening. Contrast administration revealed multiple nodules of contrast uptake consistent with the diagnosis of granulomatous meningitis.

Conclusion: Patients with multisystemic diseases, such as sarcoidosis, should have an appropriate follow-up for early diagnosis of complications.

Endocrine Abstracts

P613