Central diabetes insipidus due to Langerhans’ cell histiocytosis in an adolecent nigerian girl

Central diabetes insipidus (CDI) is rare and that due to Langerhans’ cell histiocytosis (LCH) is even rarer. We report on an 11-yearand-4-month old post-menarcheal Nigerian girl who presented with pain in the left thigh for 8 weeks, extending to the left hip joint after 4 weeks, polyuria, polydipsia, nocturia for 3 weeks and fever for 2 weeks. She had a urine osmolality of 64mOsm/kg and a serum osmolality of 301mOsm/kg, representing urine-to-plasma osmolality ratio of 0.2. Following vasopressin administration, 3.5-fold elevation of urine osmolality level over the baseline was observed. The urine was hyposthenuric, with a urine specific gravity of 1.000 (the same as for distilled water). Pelvic and left thigh radiograph revealed left acetabular fracture with left femoral head protrusio and underlying left hemipelvis osteopenia. Histology result of a biopsy specimen of joint capsule showed evidence of chronic inflammation. A diagnosis of central diabetes insipidus, presumably due to Langerhans’ cell histiocytosis (LCH) was made. She was treated with fluid and electrolyte replacement and vasopressin injections. Later she was discharged on desmopressin. Non-availability proper diagnostic tools such as brain imaging and immunohistochemistry staining were challenges that we had to face when managing this patient.