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mise à jour du
23 septembre 2004
Am J Cardiol
2004; 94; 701-702
lexique
Repetitive yawning associated with cardiac tamponade
Mori J. Krantz, Jenny K. Lee, David H. Spodick
From the Department of Medicine, Cardiology Division, Denver Health Medical Center and the University of Colorado Health Sciences Center, Denver, Colorado

Chat-logomini

Cardiac tamponade is a clinical syndrome caused by the accumulation of fluid in the pericardial space that limits ventricular filling and subsequently reduces stroke volume and cardiac output.1 The principal abnormality is an increase in intrapericardial pressure that leads to a reduction in diastolic compliance and equalization of diastolic pressure in each chamber.
Neoplastic disease, infection, uremia, idiopathic pericarditis, and trauma are among the most common causes of tamponade in the United States. Although dyspnea is the most frequent presenting complaint, patients may also complain of chest discomfort, cough, air hunger, anorexia, and fatigue. We report a case of cardiac tamponade temporally associated with repetitive yawning, a phenomenon not previously described.
 
A 59-year-old Latino man with a history of stage IV non-small cell lung carcinoma presented to the emergency department with a 3-day history of progressive dyspnea and malaise. The patient's family reported that he had been yawning repeatedly over the preceding 24 hours. The patient also complained of increasing chest discomfort for 2 weeks. Two months before admission, a transthoracic echocardiogram revealed a smallto- moderate sized pericardial effusion with a suggestion of epicardial tumor studding, but no evidence of tamponade physiology. In the emergency department, the patient's blood pressure was 105/69 mm Hg with a 16 mm Hg pulsus paradoxus.
 
His heart rate was 112 beats/min and respiratory rate was 25 breaths/min with an oxygen saturation of 92% while breathing room air (normal in Denver is 90% to 95%). He was mildly agitated and displayed repetitive, exaggerated yawning every few minutes. Neck examination demonstrated jugular venous distension to the angle of his jaw when he was sitting upright. Cardiac auscultation revealed tachycardia with severely diminished heart sounds. Pulmonary examination was remarkable for basilar crackles and diminished breath sounds at the right lung base. Dullness to percussion and bronchial breathing were also noted over the angle of the left scapula (Ewart's sign).
 
The patient's lower extremities had mild pitting edema bilaterally. Chest x-ray showed a markedly enlarged cardiac silhouette with obliteration of the retrosternal airspace, absence of pulmonary vasculature in the hilum, and a right-sided pleural effusion. Electrocardiography revealed sinus tachycardia, low QRS voltage, and electrical alternans. A transthoracic echocardiogram confirmed the presence of a massive pericardial effusion with fluid surrounding both atria. In addition, there was evidence of right ventricular diastolic collapse and marked dilation of the inferior vena cava.
 
Emergency pericardiocentesis with catheter placement was performed at the bedside under echocardiographic guidance and 2 liters of serosanguinous fluid was removed. Immediately after drainage, the patient's repetitive yawning resolved completely. Computed tomography of the brain showed no cerebral metastases. Follow-up electrocardiography demonstrated resolution of electrical alternans and an increase in QRS voltage. Repeat echocardiography showed minimal residual effusion and resolution of right ventricular diastolic collapse. The drainage catheter was removed within 24 hours, and the patient was discharged home 2 days after hospital admission.
tamponnade
The pathophysiology and purpose of yawning are not known. The existing reports on this subject are sparse, consisting almost entirely of letters, case reports, and small series. Although generally attributed to boredom and fatigue, yawning has been observed in a limited number of neurologic conditions, including migraine, hemiplegia, coma, encephalitis, brain hypoxia, pontine and fourth ventricle tumors, progressive supranuclear palsy, and multiple sclerosis. In addition, psychiatric disorders such as schizophrenia, psychosis, and involutional depression have been associated with yawning.5 Yawning has also been observed in patients who have overdosed on naloxone and imipramine, as well as in opioid-dependent patients withdrawing from heroin.
 
The mechanism underlying the frequent yawning observed in our patient with tamponade is unknown. Inhalation to total lung capacity during a yawn may reverse the microatelectasis associated with breathing at low lung volumes as might occur when the lung is compressed by the expanded pericardial sac (explaining the pathophysiology of Ewart's sign). Alternatively, repetitive yawning in tamponade may be secondary to phrenic nerve irritation.
 
The yawning center is a complex neuronal reflex system located at the level of the reticular brainstem, close to the ascendant activatory reticular system with connections to the phrenic nerves.5 The right phrenic nerve passes along the pericardium over the right atrium, whereas the left phrenic nerve runs along thefrequent yawning observed in our patient with tamponade is unknown. Inhalation to total lung capacity during a yawn may reverse the microatelectasis associated with breathing at low lung volumes as might occur when the lung is compressed by the expanded pericardial sac (explaining the pathophysiology of Ewart's sign). Alternatively, repetitive yawning in tamponade may be secondary to phrenic nerve irritation.
 
The yawning center is a complex neuronal reflex system located at the level of the reticular brainstem, close to the ascendant activatory reticular system with connections to the phrenic nerves. The right phrenic nerve passes along the pericardium over the right atrium, whereas the left phrenic nerve runs along the resolution of yawning and pericardial drainage links it to some effect of the rapid change in volume of the pericardial sac, cardiac chambers, or lung.