Bilateral renal artery stenosis and pheochromocytoma an uncommon association : A case report

Pheochromocytoma and bilateral renal artery stenosis have a quite rare association. Although unilateral renal artery stenosis is reported in the literature with Pheochromocytoma but bilateral renal artery stenosis never reported before in Gulf region. A 56-years-old woman primarily referred to our facility for CABG for triple vessel disease but uncontrolled blood pressure and long standing history of hypertension rendered her for further investigations for secondary causes. The technical imaging techniques (USG, abdominal CT, magnetic resonance angiogram (MRA) revealed bilateral renal artery stenosis and left supra-adrenal mass. Further hormonal assays confi rmed high catecholamine and raised rennin and aldosterone secondary to Pheochromocytoma and bilateral renal artery stenosis. Laparoscopic removal of Pheochromocytoma with minimum invasive reconstructive surgery for bilateral renal artery stenosis was planned prior to CABG for triple vessel disease but patient declined any surgery or interventional and opted for conservative management inspite of repeated counselling sessions with the patient. Although these conditions co-existed simultaneously but differ in management.


INTRODUCTION
A pheochromocytoma is a rare, catecholamine-secreting tumor that may precipitate life-threatening hypertension.The tumor is malignant in 10% of cases but may be cured completely by surgical removal. [1]The diagnosis can be established by measuring catecholamines and metanephrines in plasma (blood) or through a 24-hour urine collection.Care should be taken to rule out other causes of adrenergic (adrenalin-like) excess like hypoglycemia, stress, exercise, and drugs affecting the catecholamines like stimulants, methyldopa, dopamine agonists, or ganglion blocking antihypertensives.Various foodstuffs (e.g., coffee, tea, bananas, chocolate, cocoa, citrus fruits, and vanilla) can also affect the levels of urinary metanephrines and VMA (vanillylmandelic acid). [2]Imaging by computed tomography or a T2 weighted MRI of the head, neck, and chest, and abdomen can help localize the tumor.Tumors can also be located using an MIBG scan, which is scintigraphy using iodine-123-marked metaiodobenzylguanidine.Even fi ner localization can be obtained in certain PET scan centers using PET/CT with F-18-fl uorodopamine (FDOPA). [3]Pheochromocytomas occur most often during young-adult to mid-adult life.These tumors can form a pattern with other endocrine gland cancers which is labeled multiple endocrine neoplasia (MEN).Pheochromocytoma may occur in patients with MEN 2 and MEN 3 (MEN 2B).Von Hippel Lindau patients may also develop these tumors. [4]nal artery stenosis (RAS) is the major cause of renovascular hypertension and that it may account for 1-10% of the 50 million people in the United States who have hypertension.Apart from its role in the pathogenesis of hypertension, renal artery stenosis is also being increasingly recognized as an important cause of chronic renal insuffi ciency and end-stage renal disease.In older individuals, atherosclerosis (ATH) is by far the most common etiology of renal artery stenosis. [5,6]The gold standard investigation to diagnose renal artery stenosis is digital subtraction angiography. [7]Van Way et al., proposed that these two causes of surgically correctable hypertension may be associated through a common pathophysiological mechanism mediated by catecholamine secretion. [8] the literature to fi nd a relationship between these two etiologies as a cause of hypetension.To the best of my knowledge, bilateral renal artery stenosis and pheochromocytoma with background history of bronchial asthma, hypothyroidism and triple vessel disease never reported before in Gulf region.

CASE REPORT
A 56-year-old Saudi female referred from Al-Noor hospital to our hospital (King Abdullah Medical City, Makkah, Saudi Arabia) for CABG for triple vessel disease.She gave a history of headache, sweating, anxiety, dizziness, nausea, palpitation and severe hypertension.She has a history of bronchial asthma, hypothyroidism, diabetes mellitus and labeled as resistant essential hypertension since 25 years.Her work up for secondary hypertension was planned inspite of four different antihypertensive groups, her blood pressure was uncontrolled and secondly, she has hypertension at quite young age.Doppler ultrasound of renal arteries suggested bilateral renal artery stenosis which confi rmed by MRA of renal arteries.MRI abdomen revealed left supra-adrenal mass about 2 cm [Figure 1a and b].Work up for Cushing, Conn's and Pheochromocytoma was done which revealed raised catecholamines in the serum, raised plasma renin and mild raised serum and urinary cortisol.Low dose dexamethasone test suppressed the serum cortisol making it pseudo-cushingoids due to obesity.
Bilateral renal reconstructing surgery with laparoscopic adrenalectomy planned prior to CABG but patient declined the idea for surgery or minimum invasive procedure due to pre-operative high risk assessment and adopted conservative management for her condition.

DISCUSSION
Pheochromocytomas have been described to be associated with rare vascular abnormalities, most common of them being renal artery stenosis. [9]Surgical resection of the tumor is the treatment of choice and usually cures the hypertension.Careful preoperative treatment with alpha and beta blockers is required to control blood pressure and prevent intraoperative hypertensive crises. [10]owever, even Pheochromocytoma without renal artery stenosis can be accompanied by elevated plasma renin activity that may be induced by direct stimulator effect of catecholamines on renin release and can lead to secondary hyperaldosteronism.Other factors contributing to hyperreninemia are decreased plasma volume, salt restriction and diuretic usage for control of hypertension. [11]rgical resection of the tumor is either by open laparotomy or else laparoscopy. [12]Given the complexity of perioperative management, and the potential for catastrophic intra and postoperative complications, such surgery should be performed only at centers experienced in the management of this disorder.In addition to the surgical expertise that such centers can provide, they will also have the necessary endocrine and anesthesia resources.It may also be necessary to carry out adrenalectomy, a complete surgical removal of the affected adrenal gland(s).Either surgical option requires prior treatment with the non-specifi c and irreversible alpha adrenoceptor blocker Phenoxybenzamine or a short acting alpha antagonist (e.g., prazosin, terazosin, or doxazosin). [13]gh catecholamine level can cause direct myocardial damage with focal degeneration and contraction band necrosis of the myocytes, monocytic infi ltration, medial thickening of small and medium size coronary arteries and interstitial fi brosis.[16] Minimally invasive techniques are being increasingly used for resection of adrenal tumors and to treat renal artery lesions.Laparoscopic adrenalectomy is performed by either the transperitoneal or retroperitoneal approach. [17]Similarly, percutaneous balloon angioplasty has come to be the fi rst line of treatment for the majority of cases of renal artery stenosis. [18]high index of suspicion is necessary to enable both entities to be diagnosed preoperatively and allow proper planning for surgical therapy.Incomplete diagnosis and subsequent treatment may lead to persistent hypertension post-operatively.So, I recommend careful and thorough work up for secondary hypertension with keeping a possibility of dual etiology in mind before proceeding to any fi nal decision for any intervention.

LIMITATIONS OF STUDY
Study is limited by lack of surgical intervention as patient refused for any surgical intervention.It is not clear wether bilateral renal artery stenosis is main contributor of her hypertension or recent incidental Pheochromocytoma was a hidden cause for years contributing towards her hypertension.
Secondly, comparison of biochemical, angiographic parameters, control o f blood pressure after surgical intervention is was possible as patient denied surgical intervention.
The main controversy arises from the study wether renal artery stenosis leading to secondary hypertension or it is itself a complication of advanced atherosclerosis as evident by tripple vessel coronary disease.As when she was diagnosed hypertensive in her second decade of her life but no renal ultrasound or radiological investigation is available since then.
Further research is required to establish the link between bilateral renal artery stenosis and Pheochromocytoma, a genetic propensity or just incidental proclivity.
I have reviewed International Journal of Medicine and Public Health | Oct-Dec 2014 | Vol 4 | Issue 4

Figures
Figures1a and b: CT angiography of the renal arteries revealed Short segment of narrowing is seen at the origin of both renal arteries more prominent on the left side.Diffuse atherosclerotic changes are seen involving the abdominal aorta.The remaining of the scanned vessels are patent.Small well-defi ned lesion is seen involving the left suprarenal gland.It measured about 2 × 1.5 cm2