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* From General Internal Medicine (Drs. Vanacker, Knockaert, and Blockmans) and Medical Intensive Care Unit (Drs. Meersseman and Wilmer), University Hospital, Leuven, Belgium.
Correspondence to: W. Meersseman, MD, Department of General Medicine, Herestraat 49, B-3000 Leuven, Belgium; e-mail: wouter.meersseman{at}uz.kuleuven.ac.be
A 42-year-old woman presented to the emergency department with acute-onset dyspnea and severe low back pain. The pain started abruptly while lifting a relatively light object. Within a few minutes, she had acute severe dyspnea and her sputum was blood streaked. Her medical history was remarkable only for pheochromocytoma of the right adrenal gland 5 years ago that was resected. Recent follow-up in the outpatient clinic did not reveal any abnormalities.
Physical Findings
Clinical examination revealed an anxious woman in acute respiratory distress. Heart rate was 150 beats/min, BP was 170/80 mm Hg, and respiratory rate was 35 breaths/min. Oxygen saturation was 92% with a nonrebreathing mask that delivered oxygen at 15 L/min. Auscultation revealed diffuse crackles in the lower two thirds of both lung fields. She had no malleolar edema. Central venous pressure was normal. Muscle strength and tendon reflexes of the lower limbs were normal, and patient was fully conscious.
Laboratory and Radiographic Findings
Blood gases showed a pH 7.26; PO2, 44 mm Hg; PCO2, 42 mm Hg; oxygen saturation, 70%; bicarbonate, 18 mEq/L; and lactate, 4.4 mmol/L. There was a marked increase of WBC count with predominantly neutrophils: 29.0 x 109/L (normal, 4.0 to 10.0 x 109/L); serum creatinine, 130 µmol/L (normal, 53 to 97 µmol/L); creatinine kinase-MB, 3.6 µg/L (normal up to 3.5 µg/L); troponin I level, 1.42 µg/L (normal up to 0.13 µg/L); and cholesterol level was within normal limits. The ECG and chest radiograph are shown in Figures 1,2 , respectively. CT scan of the chest showed diffuse alveolar infiltrates especially in the lower parts of both lungs. Echocardiography on day 1 showed a severe impairment of the left ventricular function with an ejection fraction of 35%, and akinesia of the apical and anteroseptal segments. Culture findings from a BAL sample were negative for bacteria and fungi.
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The trachea was intubated and the lungs were ventilated mechanically shortly after arrival. On day 2, vital signs had normalized with resolution of the acidosis. The patient could be extubated successfully. Chest radiography showed almost complete resolution of the infiltrates. T-wave inversions had disappeared on ECG.
What is your diagnosis?
Diagnosis: Flash pulmonary edema caused by a surge of catecholamine release secondary to vertebral collapse of a metastatic pheochromocytoma lesion.
Flash pulmonary edema is a clinical syndrome characterized by the sudden development of respiratory distress associated with the rapid accumulation of fluid within the lung interstitial space as a result of acutely elevated venous filling pressure. It typically comes on abruptly and resolves rapidly. It can be caused by myocardial stunning due to acute ischemia, acute valvular insufficiency, or malignant hypertension. The main differential diagnosis of sudden respiratory distress includes pulmonary embolism, pneumonia, acute pulmonary edema, and inhalation injury.
One of the rare causes of flash pulmonary edema is pheochromocytoma. This is a catecholamine-producing neuroendocrine tumor arising from chromaffin cells of the adrenal medulla (80 to 85%) or extra-adrenal paraganglia (15 to 20%) The clinical presentation is highly variable, but the classic pentade of symptoms consists of pain, perspiration, palpitations, pallor, and high BP. Other symptoms include acute heart failure, orthostatic hypotension, polyuria, polydipsia, anxiety or panic attack, hyperglycemia, lactate acidosis, and weight loss. These symptoms are caused by the release of norepinephrine, epinephrine, and dopamine, which can be measured in a 24-h urine sample. This is diagnostic in > 95% of symptomatic patients. Acute episodes of pheochromocytoma may be difficult to diagnose and give normal values because of the transient rise in catecholamine levels in the urine. Chromogranin levels are elevated in 80% of cases. Identification of a mass can be achieved by use of 123I-metaiodobenzylguanidine (MIBG) scanning. MIBG is a compound resembling norepinephrine that is taken up by adrenergic tissue.
Approximately 5 to 10% of all catecholamine-secreting tumors are malignant; they are histologically and biochemically similar to the benign type, but there is local invasion or distant metastases, sometimes 15 years after resection. The most common metastatic sites are the bones, lungs, liver, and lymph nodes. Occasionally, a surge of catecholamines with bone compression in areas of metastases can cause a life-threatening spell. Patients with metastatic lesions are treated with 131I-MIBG, although this has rather disappointing results (5% complete remission and 30% partial remission), with only short-lasting remissions.
Takotsubo or stress-induced cardiomyopathy is a reversible left ventricular dysfunction with acute myocardial infarction-like ST-segment changes (usually ST-segment elevation in leads V3 and V4, followed in a later stage by T-wave inversions), without critical coronary lesions. It is characterized by a transient dysfunction of the apical portion of the left ventricle ("apical ballooning"), with compensatory hyperkinesis of the basal walls. Cardiac catheterization usually reveals no major stenosis of coronary vessels. The most common presenting symptom is acute substernal chest pain, but sometimes patients present with dyspnea, shock, or ECG abnormalities alone. Acute complications include tachyarrhythmias, bradyarrhythmias, pulmonary edema, and cardiogenic shock. Postmenopausal women are predominantly affected. Patients who survive the acute episode (in-hospital mortality, 0 to 8%) typically recover with almost complete resolution of left ventricular dysfunction in a few days to weeks.
Although the exact cause of the syndrome is unknown, episodes are often preceded by a heightened adrenergic state secondary to psychological or emotional stress. A similar phenomenon can occur during a crisis of pheochromocytoma. The physiopathologies of the two conditions, stress-induced cardiomyopathy and pheochromocytoma-induced cardiomyopathy, are believed to be similar and mediated by catecholamines. An excess of catecholamines and its metabolites can provoke oxidative damage and lead to myocardial stunning. In this regard, a pheochromocytoma, of which one of the hallmarks is raised cathecholamines, might cause a Takotsubo-like phenomenon. However, this concept is difficult to prove since catecholamine results vary widely, especially when it is not measured at the peak moment of symptoms.
Although the diagnosis of pheochromocytoma in our patient was made a long time ago, we nevertheless considered a relapse in view of the presenting symptoms. Twenty-four-hour urine catecholamine values were 103.5 µg/mL epinephrine (normal < 20 µg/mL), 88.9 µg norepinephrine (normal, 10 to 100 µg), and 153.9 µg dopamine (normal, 90 to 500 µg) in a 24-h urine collection. Urinary vanillyl mandelic acid (a catecholamine metabolite) was 11.0 mg/g creatinine (normal, 1.0 to 7.0 mg/g). These tests were done on day 3 after symptoms had resolved, which may explain why some of the values were within normal limits. Chromogranin level in the plasma was 439 µg/L (normal, 40 to 170 µg/L). A CT scan revealed an irregular mass in the region of the right adrenal gland, and 123MIBG scintigraphy showed bone metastases in the manubrium sterni, the lumbar spine, the left orbita, the sacroiliacal joints, and the right hip, and a mass in the right adrenal region. The strong increment in plasma catecholamines was provoked by severe acute low back pain, probably due to the metastatic lesion in the lumbar spine seen on scintigraphy.
Because of the ECG findings of severely impaired left ventricular function and apical akinesia, the chest radiograph compatible with pulmonary edema, the rapid recovery of left ventricular contractility, as well as the transient T-inversions in the anterior leads of the ECG, the cardiologist considered stress-induced cardiomyopathy (Takotsubo cardiomyopathy) in our patient. A repeat echocardiogram 2 days after presentation showed normalization of the apical and midventricular regional wall motion abnormalities. Three months later, the patient is still alive, remains asymptomatic, and is receiving treatment with 131I-MIBG.
Clinical Pearls
Footnotes
The authors have no potential conflicts of interest or sources of financial support to disclose.
Received for publication July 17, 2006. Accepted for publication August 2, 2006.
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