ESPE Abstracts

Background: Diabetes insipidus of central origin has been described in association with other endocrine autoimmune diseases as a rare condition in adults. In children this association is extremely rare.

Objective and hypotheses: To present a girl with a concurrent appearance of diabetes insipidus and autoimmune thyroiditis.

Method: Diagnostic approach for both diseases.

Results: A girl of 11 years presented with polyuria and polydipsia of 4–6 l/day. She was a well developed child with a height at the 75‰. She also had enlarged thyroid gland. The urine osmolality was 104 mOs/l for the normal plasma osmolality. Electrolytes, urea, creatinine, renal ultrasound as well as FSH, LH, and cortisol were normal. Test with Adiuretin confirmed diabetes insipidus of central origin. MRI of the pituitary showed normal size of the anterior pituitary, missing bright signal of the neurohypophysis and slight enlargement of the pituitary stalk. Normal β hCG and α-foetoprotein excluded hypothalamic germinoma. No histiocytosis was confirmed. Ultrasound of the thyroid gland was typical for Hashimoto’s thyroiditis. TPO antibodies were >1000 IU/ml, whereas antithyroglobylin antibodies were within normal range as well as T₄, T₃, and TSH. Diabetes insipidus was well controlled with 10 μg of adiuretin two times per day. The evolution of the thyroiditis was unusual. Three years after the diagnosis, significant hyperechogenic nodule with cystic degeneration was seen on ultrasound in the right lobe that was benign on biopsy. One year thereafter due to the growth of the nodule a scintiscan was performed and it showed a ‘cold’ – nonfunctioning nodule in the right lobe. Histology confirmed one group of thyrocytes with oncocytic metaplasia and diffusely dispersed inflammatory infiltration.

Conclusion: Although association of hypophysitis with autoimmune thyroiditis usually appears with affected anterior pituitary, neurohypophysis might be affected also. When no other cause for central diabetes insipidus is found, thorough search for multiple endocrine deficiencies of autoimmune origin should be warranted.