Treatment-resistant hypertension in a post-transplant patient with cystic fibrosis: a rare case of phaeochromocytoma
Authors: Tansey David Joseph , Egan Jim John , Murray Michelle , Padfield Katie , Conneely John , Hatunic Mensud 
Published: June 2021

Summary
Phaeochromocytoma is a rare catecholamine-producing tumour. We present the case of phaeochromocytoma in a young man with a background history of a double-lung transplant for cystic fibrosis (CF). Clinical case: A 25-year-old man, with a background history of CF, CF-related diabetes (CFRD) and a double-lung transplant in 2012 was presented to the emergency department with crampy abdominal pain, nausea and vomiting. He was diagnosed with distal intestinal obstructions syndrome (DIOS). Contrast-enhanced CT imaging of the abdomen and pelvis showed a 3.4 cm right adrenal lesion. This was confirmed by a subsequent MRI of adrenal glands that demonstrated moderate FDG uptake, suggestive of a diagnosis of phaeochromocytoma. The patient was noted to be hypertensive with a blood pressure averaging 170/90 mm/Hg despite treatment with three different anti-hypertensive medications – amlodipine, telmisartan and doxazosin. He had hypertension for the last 3 years and had noted increasingly frequent sweating episodes recently, without palpitations or headache. Laboratory analysis showed elevated plasma normetanephrines (NMN) of 3167 pmol/L (182–867) as well as elevated metanephrines (MN) of 793 pmol/L (61–377) and a high 3-MT of 257 pmol/L (<185). Once cathecholamine excess was identified biochemically, we proceeded to functional imaging to further investigate. MIBG scan showed a mild increase in the uptake of tracer to the right adrenal gland compared to the left. The case was discussed at a multidisciplinary (MDT) meeting at which the diagnosis of phaeochromocytoma was made. Following a challenging period of 4 weeks to control the patient’s blood pressure with an alpha-blocker and beta-blocker, the patient had an elective right adrenalectomy, with normalisation of his blood pressure post-surgery. The histopathology of the excised adrenal gland was consistent with a 3 cm phaeochromocytoma with no adverse features associated with malignant potential.

Learning points

Five to ten per cent of patients have a secondary cause for hypertension. Phaeochromocytomas are rare tumours, originating in chromaffin cells and they represent 0.1–1.0% of all secondary hypertension cases.

Secondary causes should be investigated in cases where:

Patient is presenting <20 years of age or >50 years of age,

There is refractory hypertension, or

There is serious end-organ damage present.

Patients may present with the triad of headache, sweating and palpitations or more vague, non-specific symptoms.

Patients with suspected phaeochromocytoma should have 24-h urinary catecholamines measured and if available, plasma metanephrines measured. Those with abnormal biochemical tests should be further investigated with imaging to locate the tumour.

Medical treatment involves alpha- and beta-blockade for at least 2 to 3 weeks before surgery as well as rehydration.

There is a possibility of relapse so high-risk patients require life-long follow-up.