Letter to the Editor “Malignant” baroreflex failure after surgical resection of carotid body tumor Wing-Sze Chan a , William I. Wei b , Hung-Fat Tse a, ⁎ a Cardiology Division, Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China b Otorhinolaryngology Division, Department of Surgery, University of Hong Kong, Queen Mary Hospital, Hong Kong Received 2 December 2006; accepted 2 January 2007 Available online 29 March 2007 Keywords: Baroreflex failure; Carotid body tumor; Hypertension Carotid body tumour (CBT) is a rare neoplasm arising from carotid body, with occasionally bilateral involvement and malignant potential. Surgical resection is recommended treatment for patients with CBT [1]. However, bilateral damage of the carotid sinus baroreceptors during CBT resection may lead to baroreflex failure [2]. We report a case of malignant hypertension associated with baroreflex failure after surgical resection of bilateral CBT. A 30-year-old woman presented with a right neck mass at the angle of jaw 1 year ago. Computed tomography (CT) of neck showed bilateral CBT, and fine needle aspiration of tumor demonstrated paraganglioma cells. She underwent an un- eventful surgical excision of right CBT 1 year ago. She was readmitted again for surgical excision of left CBT because of progressive enlargement of the tumor. Immediately after excision of the left CBT, she developed hypertensive surges associated with episodes of hypotension and markedly fluctuating pulse rate (Fig. 1). An urgent CT brain revealed no abnormality. She also complained of severe frontal headache and became emotionally labile. Initially, her blood pressure and symptoms improved with oral diazepam and intravenous labetalol infusion. However, 3 days later, she developed generalized tonic–clonic convulsion after a surge of blood pressure (Fig. 2), and repeated CT brain showed massive frontal lobe hemorrhage. Subsequent cerebral arteriogram revealed no intracranial arteriovenous malformation or aneurysm. Her blood pressure remained fluctuating for 3 weeks, and required intermittent IV labetalol together with maintenance oral clonidine to achieve satisfactory blood pressure control. A repeated CT brain 2 weeks later showed no further progression of intracranial hemorrhage, but noted the presence of multiple cerebral lacunar infarction. Although 24 hour urine examination showed elevated norephephrine: 1580 nmol/D (b 440); normetanephrine: 450 nmol/D (b 290); and metanephrine: 450 nmol/D (b 290), subsequent CT abdomen and MIBG scan demonstrated no evidence of pheochromocytoma. Finally, she was discharged and treated with oral clonidine for her hypertension. Unfortunately, her labile hypertension persisted 2 years after the operation, and required intermittent hospital admission for mediation adjust- ment to control her blood pressure. Baroreflex failure is a rare but increasingly recognized syndrome which occurs after iatrogenic bilateral denervation of carotid sinus baroreceptors following bilateral CBT resection or radiation therapy of the neck. The acute phase of baroreflex failure is characterized by unopposed sympa- thetic activation in response to physical and emotional stress [3]. As shown in this case, this lack of tonic inhibitory influence of baroreceptors on sympathetic tone lead to episodes of severe hypertension and tachycardia, accompa- nied by excessive increments in sympathetic tone and catecholamine plasma levels. In addition, emotional insta- bility is another prominent feature of acute phase of baroreflex failure. These changes were usually more dramatic if tonic inhibition is removed suddenly as in the surgical resection of CBT. In this case, the dramatic fluctuation in blood pressure resulted in life-threatening intracranial hemorrhage as well as lacunar infarction. The occurrence of these complications have put up more challenge on our decision for her optimal level of blood pressure control as International Journal of Cardiology 118 (2007) e81 – e82 www.elsevier.com/locate/ijcard ⁎ Corresponding author. Tel.: +852 2855 3598; fax: +852 2855 1143. E-mail address: hftse@hkucc.hku.hk (H.-F. Tse). 0167-5273/$ - see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2007.01.024