Paraganglioma causing a myocardial infarction.

Paragangliomas, extra-adrenal pheochromocytomas, are rare and classically associated with sustained or paroxysmal hypertension, headache, perspiration, palpitations, and anxiety. A 49-year-old male, parachute instructor, likely developed a hypertensive emergency when deploying his parachute leading to a myocardial infarction. A para-aortic tumor was incidentally discovered during the patient's emergency department work-up and was eventually surgically resected. He had no evidence of coronary disease during his evaluation. This case shows that a myocardial infarction may be the initial manifestation of these neuroendocrine tumors. Hypertensive emergency, much less elevated blood pressure may not be present at time of presentation.

INTRODUCTION

A paraganglioma, or pheochromocytoma, presenting with myocardial infarction (MI) is rare. We report a case of a non-hypertensive asymptomatic male without coronary artery disease who presented with an MI likely associated with a paraganglioma causing end organ ischemia. Conclusions/Summary: Uncommon etiologies of MI may be encountered in emergency department (ED) settings. A paraganglioma or pheochromocytoma may present as paroxysmal hypertensive crisis that leads to MI.

CASE REPORT

A 49-year-old male, parachute instructor by profession, presented to the ED with complaint of non-radiating substernal chest pain following chute deployment. During the episode, he noted associated headache, diaphoresis, and palpitations, which subsequently spontaneously resolved after landing. The parachute jump was described as standard: there was no unusually traumatic parachute opening or landing. The patient denied significant environmental conditions, such as a high altitude jump or extreme cold exposure. There was no change in intensity, location, or character of his pain during the remainder of his parachute ride to landing. There was no change in pain with position, movement, or deep inspiration. He subsequently had two hours of continuous chest pain prior to arrival.

His pain was described as dull, non-radiating, and rated 7/10 improving to a 5-6/10. No prior history of similar chest pain, associated shortness of breath, nausea, change in sensation, or weakness was reported. He was a non-smoker and denied personal cardiac or pulmonary disease history. The patient did admit to a history of gastroesophageal reflux and was intermittently compliant with his prescribed ranitidine. His family history was unremarkable for coronary disease, sudden, or early death.

The patient arrived to the medical center via his private vehicle. Upon presentation, the glasgow coma scale (GCS) was 15 with pulse of 80, blood pressure (BP) of 132/87, respirations of 16, temperature of 100.5 degrees Fahrenheit, and room air saturation of 96%. His physical exam was unremarkable on presentation. The ED management included sublingual nitroglycerine, which resolved his chest pain after one dose, followed by nitroglycerine paste and aspirin. Initial troponin was 0.01. Remainder of laboratory evaluation was unremarkable. Dynamic electrocardiogram (ECG) changes were noted and Cardiology consultation was made. [Figure 1] Differential diagnosis included a traumatic aortic dissection, so a cardiac gated computed tomography (CT) was obtained that did not demonstrate this etiology as a source for his chest pain. However, an incidental retroperitoneal mass below the level of the left kidney was discovered, which appeared to be highly vascular, with central necrosis, and had at least one feeding artery coming directly off of the aorta [Figure 2]. A rising second troponin was noted in the ED at 0.08. He was started on low weight molecular heparin with clopidogril and admitted for further observation to the cardiac intensive care unit with a planned diagnostic cardiac catheterization. The catheterization showed no angiographic evidence of coronary artery disease (CAD) and normal left ventricular function. Over the course of the hospitalization the patient's BP was intermittently hypertensive without report of associated chest pain. A neuroendocrine work-up for the para-aortic mass demonstrated a normal catecholamine metabolites, normetanephrine (329 mcg/24 hours [reference range: 88-649 mcg/24 hours]) and metenephrine (164 mcg/24 hours [reference range: 58-203 mcg/24 hours]) on 24-hour urine. His troponin peaked at 0.31.

Figure 1(a-b)

Electrocardiograms (1st [symptomatic] and 2nd [asymptomatic] during ED stay)

Figure 2(a-b)

CT demonstrating para-aortic mass later found to be a paraganglioma

The patient was discharged home with atenolol and atorvastatin after a four-day hospitalization. He underwent laparoscopic retroperitoneal mass excision one month after presentation. Intravenous fluids, phentolamine, and metoprolol were utilized for presurgical treatment in this patient. Induction of anesthesia was done with fentanyl, lidocaine, propofol, and rocuronium. The anesthesia maintenance agent was isoflurane. No adverse complications such as hypertensive episodes or bleeding were reported. He returned to his profession as a full-time parachute instructor three months later and subsequently discontinued antihypertensive medications.

DISCUSSION

This case illustrates an unusual cause of MI, rarely reported in the literature.[1-4] Extra-adrenal pheochromocytomas, better known as paragangliomas, are neuroendocrine tumors that produce, store, and secrete catecholamines. These neoplasms may occur in all age groups but are most common in young and middle-aged adults. Signs and symptoms of these tumors are listed in Table 1.[5] Hypertension is the most common sign, and hypertensive paroxysm, or crisis, occurs in more than half of all cases. Hypertensive crises may be precipitated by any activity that displaces the abdominal contents, and tachyarrhythmias are the most common cardiac manifestation.[5] Angina and acute myocardial infarction may occur in the absence of coronary artery disease due to increased oxygen consumption, coronary spasm, and increased afterload contributing to ischemia.[3]

Table 1

Signs and symptoms of paraganglioma/pheochromocytoma

Diagnosis may be made from elevated plasma catecholamines metabolites, only if drawn during a hypertensive crisis. A 24-hr urine sample may demonstrate increased excretion of metanephrine, normetanephrine, and vanillymandelic acid (VMA). Levels of these metabolites may be normal when the patient is asymptomatic.[5]

Treatment of associated hypertension is with phenoxybenzamine, an irreversible alpha-blocker with a long half-life. Hypertensive emergencies may be treated with intravenous phentolamine before adequate alpha-blockade is achieved. Nitroprusside, calcium channel blockers, and angiotensin-converting-enzyme inhibitor (ACE) inhibitors will also reduce blood pressure in these patients. Surgical resection of the tumor is the definitive treatment. Five-year survival after surgery is usually over 95%, and the recurrence rate is under 10%.[5] Removal of tumor cures hypertension in the majority of patients though residual tumor may cause persistent symptoms. Patients with persistent hypertension after tumor resection may be managed with standard anti-hypertensive therapy. Primary care follow-up includes 24-hour urine, which should be reassessed annually, even in asymptomatic post-surgical patients.

CONCLUSION

This case shows that cardiac chest pain leading to a myocardial infarction may be the initial manifestation of a paragangliomas in the absence of prior symptoms or significantly elevated blood pressure.