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Abstract

Case Presentation: A 30-year-old female with no prior comorbidities presented to a nephrology center with polyuria and polydipsia of 2-weeks duration. Her 24-hour urine output was more than 6 L/day, and her serum sodium was 147 mEq/L, serum osmolality 302 mOsm/L, and urine osmolality 108 mOsm/L, consistent with a diagnosis of diabetes insipidus. Her glucose, potassium, and calcium levels were normal. Her thyroid-stimulating hormone was 1.13 mIU/L, thyroxine was 8.7 µg/dL, prolactin 34.6 ng/mL, and an 8 am cortisol was 3 µg/dL. She had two normal pregnancies, with last childbirth 8 years back. Her menstrual cycles were regular. Magnetic resonance imaging (MRI) of the brain showed a thickened stalk and enlarged pituitary gland (Fig. 1). On contrast, there was thickening and abnormal enhancement of the stalk and an enlarged pituitary measuring 15 mm, with abnormal heterogeneous enhancement with a peripheral rim of enhancement and a central nonenhancing area (Fig. 1). A diagnosis of infundibulo-hypophysitis was made, and a detailed set of investigations, including antinuclear antibodies, antineutrophil cytoplasmic autoantibodies (ANCA), IgG4, angiotensin-converting enzyme levels, chest X-ray, and skin tuberculin testing was done, with nonrevealing reports. She was started on intranasal desmopressin and prednisolone 60 mg/day with good resolution of symptoms. Desmopressin was stopped after 3 months; after being on high-dose steroids for 6 months, she presented to our center with weight gain and cushingoid features. A repeat MRI was unchanged. Due to a lack of resolution of the MRI features despite prolonged steroid therapy, a whole-body computed tomography scan with a transnasal biopsy of the pituitary gland was planned. Patient's prednisone dose was reduced to 15 mg/day. Patient presented a month later to the medical emergency with acute hypoxemic respiratory failure and acute renal failure, with serum creatinine of 4.75 mg/dL. Chest X-ray showed “white out” lungs, and urine analysis showed numerous red blood cells. A clinical diagnosis of pulmonary-renal syndrome was made, and the patient was started on high-dose steroids and plasma exchange was attempted. However, the patient succumbed within 48 hours of admission. What is the diagnosis?