Endocrine Abstracts

Introduction: Pituitary apoplexy (PA) is a rare endocrine emergency with less described entity being its subacute/non-acute presentation. Incidence of PA is difficult to determine, varying 2%-12% of pituitary adenoma. Hypopituitarism in PA is observed in up to 70% of cases with diabetes Insipidus (DI) observed in <5% of cases and mostly transient.

Case description: 82-year old female with pituitary macroprolactinoma (1.5 cm) presented with 3-week history of occipital headaches, fatigue, polydipsia and polyuria. Cabergoline 250 mg weekly was started 3 months prior (prolactin- 4,936 mU/l). Examination revealed normal GCS, neurology and visual fields. Admission bloods revealed 9 am cortisol-60 nmol/l and prolactin-1046 mU/l. Hydrocortisone replacement initiated and Cabergoline dose increased. MRI brain showed new focus of T1 high signal on the left side of pituitary consistent with recent hemorrhage. Non-acute PA was diagnosed. Neurosurgeons opined, patient not for surgical intervention given normal neurology. During inpatient stay, the patient reported polyuria with recurrent episodes of raised urea and creatinine and mild hypernatremia. Water deprivation test showed serum osmolality of 297 mOsm/kg (285-295) with urine osmolality of 305 mOsm/Kg. Post intranasal desmopressin urine osmolality increased to 599 mOsm/kg after 150 minutes with urine output reducing from 154 ml/hr to 30 ml/hr confirming diagnosis of Cranial DI. She responded well to oral desmopressin and was discharged with prednisolone 4 mg OD, Cabergoline 250 mg twice weekly and desmopressin 50 mg OD.

Discussion: Our case illustrates non-acute PA in pituitary macroadenoma complicated by ACTH deficiency and DI thus involving both anterior and posterior pituitary axis. DI is a very rare manifestation of non-acute/sub-acute PA with 4 cases reported in literature, including one pregnant woman. Our case is interesting with respect to patient’s age (the others were younger), relatively low prolactin level and lower dose of Cabergoline on presentation.