Diabetes insipidus presentation before renal and pulmonary features in a patient with Wegener's granulomatosis

We report a case of a 47-year-old woman with Wegener's granulomatosis complicated by central diabetes insipidus. The patient had initially seronegative polyarthritis which mostly responded well to methotrexate and steroid therapy. Eight months later the patient suffered from polyuria and polydipsia. There were no abnormalities of the anterior pituitary hormones. MR images showed only loss of brightness of the posterior pituitary. Extensive evaluation of the patient revealed the presence of ANCA, in c-ANCA pattern and also PR3 positivity. Three months later findings of glomerulonephritis, as suggested by an active urine sediment and gradual proteinuria, and, finally, asymptomatic pulmonary nodules completed the clinical picture of Wegener's disease within 1 year. Renal biopsy showed crescent formation in two glomeruli, consistent with ANCA-related glomerulonephritis which showed pauci-immun depositions by direct immunofluorescence. Diabetes insipidus symptoms mostly regressed; renal and pulmonary findings completely disappeared with glucocorticoid and pulse cyclophosphamide treatment. These findings show that diabetes insipidus may rarely develop early in the disease process and ANCA positivity was directly indicative of Wegener's granulomatosis before the classic clinical signs of the disease.