FRI218 Von Hippel-Lindau With Pheochromocytoma And Severe Orthostatic Hypotension

Disclosure: N. Ebrahimi: None. C.G. Rivas Pajuelo: None. R. Habibi: None. S. Tariq: None. S.A. Penquite: None. Introduction: Von Hippel-Lindau (VHL) syndrome clinically manifests with benign and malignant tumors across multiple organ systems including the cerebellum, retina, kidney, and adrenal glands. Pheochromocytoma occurs in 25-30% of patients with VHL. Up to 50% of patients with pheochromocytoma present with hypertension or paroxysmal hypertension, although patients can be normotensive on presentation. Patients with pheochromocytoma are often severely volume depleted due to chronic vasoconstriction. Here we present a case of VHL with pheochromocytoma complicated by profound orthostatic hypotension after initiation of alpha-blockade. Case Presentation: A 32-year-old man presented for evaluation of progressive headache and diplopia. Patient was normotensive on initial presentation with BP 129/80mmHg. Brain MRI with contrast subsequently revealed a posterior fossa cystic mass with an avidly enhancing central nodule concerning for hemangioblastoma. Given these findings, a CT chest/abdomen/pelvis was obtained, which demonstrated a 4.6 x 5.0 cm right adrenal mass, several enhancing renal lesions, and multiple cystic lesions throughout the pancreas. This constellation of radiological findings was clinically concerning for VHL. Further endocrinologic work-up revealed plasma metanephrines 663 pg/mL (insert reference range here), plasma catecholamines 770 pg/mL (insert reference range here), which confirmed the diagnosis of pheochromocytoma. Alpha blockade was initiated with doxazosin 4 mg BID, and a high sodium diet (insert g/day). Shortly after initiation of doxazosin, patient developed severe orthostatic hypotension despite salt loading and volume resuscitation. Ultimately doxazosin was discontinued, and surgery was postponed due to severe symptomatic orthostatic hypotension limiting patient’s ability to get out of bed. High sodium diet was continued on hospital discharge and alpha-adrenergic blockade was later re-initiated which patient is tolerating well. Patient is pending adrenalectomy in the coming weeks. Discussion: Orthostatic hypotension in pheochromocytoma is expected due to volume depletion from chronic vasoconstriction. Alpha adrenergic blockade is required to alleviate hypertension, allow for adequate volume expansion, and to prevent a hypertensive crisis intraoperatively. Clinicians should be aware of the commercially available alpha-adrenergic antagonists and when they should be temporarily discontinued. There is no preferred alpha-adrenergic antagonist agent, however doxazosin has shown to cause less orthostatic hypotension and does not have such an antihypertensive effect as of Phenoxybenzamine. Presentation: Friday, June 16, 2023