Fig. 2

Clinical course. Daily urinary output (ml) and fluid intake (ml) (A); plasma sodium levels (mEq/l) (B); intranasal (times/day) and oral (μg) desmopressin administration (C); and glucocorticoid replacement (mg) (D). Operative days are indicated by a red arrow. Immediately after biopsy, urinary output was > 3000 ml (red dashed line in A) and there was a temporary increase in plasma sodium levels. We temporally administrated glucocorticoid for brain edema treatment (postoperative day 1–6). From postoperative day 9, urinary output was < 3000 ml and plasma sodium levels normalized. Due to possible worsening of brain edema, we administrated glucocorticoid at postoperative day 18 (red wedge arrow). Subsequently, there was a notable increase in daily urinary output. We could determine that central diabetes insipidus was masked by insufficient adrenocorticotropic hormone. Polyuria and plasma sodium levels were improved by desmopressin and glucocorticoid replacement. We instructed the patient to drink according to thirst; therefore, fluid intake volumes subsequently increased following an increased urinary output