• Eosinophilic Granulomatosis with Polyangiitis
• Diabetes Insipidus
• Methylprednisolone
• Secondary Hypophysitis

A 54-year-old man with a history of allergic rhinitis, chronic productive cough and shortness of breath presented with symptoms of ophthalmalgia, polydipsia, polyuria, ≥8 L daily urine output and 5 kg weight loss within 2 months. Physical examination revealed a haemorrhage under the sclera on the temporal side of the left eye (figure 1). The results of the fluid deprivation–vasopressin test showed central diabetes insipidus. Laboratory investigations showed circulating eosinophilia: 560×10⁶/L (normal 50–300×10⁶/L ), 5% (normal 0.5–5%); plasma antineutrophil cytoplasm antibodies (ANCA) …