Pituitary apoplexy diagnosed by magnetic resonance imaging: a case report.

Pituitary apoplexy is a neuroendocrine emergency produced by hemorrhage or infarction of pituitary tumors, and its accurate diagnosis has relied mainly on clinical manifestations and computed tomography (CT) scan of sella in the past. A case is reported of pituitary apoplexy which was demonstrated on magnetic resonance imaging (MRI). The 72-year-old male patient was admitted to the Nephrology Section of VGH-Taipei with symptoms of general malaise, poor appetite for four months and apparent hyponatremia (Na 102 mEq/L) on laboratory findings. Under the impression of syndrome of inappropriate secretion of antidiuretic hormone (SIADH), fluid restriction and infusion of isotonic saline were prescribed, but in vain. The patient was transferred to the Endocrinology Section because of lowered serum cortisol, T3, T4, and hs-TSH levels. Dynamic pituitary function tests confirmed the diagnosis of panhypopituitarism. Contrast enhanced CT scan of sella revealed displacement of the pituitary stalk to the right side. T1-weighted MRI showed persistent high intensity in left sella and T2-weighted MRI showed persisting isointense to white matter. The hyponatremia and clinical symptoms resolved within a few days after replacement therapy with glucocorticoid and thyroid hormone. It was concluded that MRI is more sensitive than CT scan for detecting subacute or chronic pituitary apoplexy.