dullness to percussion suggests effusion Unilateral absent/decreased breath sounds are concerning for pneumothorax, pneumonia, foreign body aspiration, or a pulmonary embolism however, the absence of decreased breath sounds does not rule out these diagnoses Crepitus of the neck or chest wall is indicative of pneumomediastinum and/or pneumothorax Tracheal deviation may be seen in severe cases of tension pneumothorax where patients are in obvious distress If breath sounds are equal, yet there is an abnormal heart sound, then a cardiac etiology is most likely Pericardial disease can present with a friction rub, distant heart sounds, neck vein distention, hypotension, impaired circulation, pulses paradoxus, and chest pain worse in supine position and improved by leaning forward Signs of myocarditis include persistent tachycardia and orthostasis, bradycardia, pulsus paradoxus, and a gallop rhythm Physical examination findings such as dyspnea, crackles, wheezes, gallop rhythms, neck vein distention, and peripheral edema are seen in those with heart failure/cardiomyopathy There is a wide range of clinical presentations of children with arrhythmias; they may be stable with irregular heart rates and rhythm or they can present in cardiovascular shock Signs of MI include rate and rhythm disturbances, pallor, dyspnea, diaphoresis, as well as signs of heart failure Patients with a pulmonary embolism may present with a variety of physical findings depending on the degree of arterial obstruction and thus hemodynamic compromise (see Chapter 99 Pulmonary Emergencies ) Tachypnea, tachycardia, decreased breath sounds, crackles, fever, a friction rub, an accentuated S2, unexplained cyanosis, pleural friction rub, and/or cardiovascular collapse In addition to the usual cardiac and pulmonary examination, one should search for “trigger points,” where palpation of the chest wall reproduces the pain suggesting musculoskeletal inflammation Reproduction of the pain by a “hooking maneuver” performed over the lower anterior ribs implicates the “slipping rib syndrome.” Pain following a dermatome unilaterally suggests intercostal neuritis; children with zoster (shingles) may have pain preceding the development of rash When focal, peripheral pain is found without a “trigger point,” the physician should consider pain referred from areas of sensory nerve overlap A relationship of the pain to eating or swallowing suggests esophageal disease, and often, the physical examination may appear normal Some of these patients will have a thin body habitus and/or cardiac findings of mitral valve prolapse Extrathoracic abnormalities, such as a rash or arthritis, may provide clues to collagen disorders (see Chapter 101 Rheumatologic Emergencies ) or other systemic illness Marfan syndrome should be suspected in the tall thin patient