Chapter 413 Extrapulmonary Diseases with Pulmonary Manifestations
Respiratory symptoms commonly originate from extrapulmonary processes. The respiratory system adapts to metabolic demands and is exquisitely responsive to cortical input; therefore, tachypnea is common in the presence of metabolic stress such as fever, whereas dyspnea may be related to anxiety. Cough most commonly arises from upper or lower respiratory tract disorders, but it can originate from the central nervous system, as with cough tic or psychogenic cough, and it can be a prominent symptom in children with gastroesophageal reflux disease. Chest pain does not commonly arise from pulmonary processes in otherwise healthy children but more often has a neuromuscular or inflammatory etiology. Cyanosis can be caused by cardiac or hematologic disorders, and dyspnea and exercise intolerance can have a number of extrapulmonary causes. These disorders may be suspected on the basis of the history and physical examination, or they may be considered in children in whom diagnostic studies have atypical findings or who show poor response to usual therapy. More common causes of such symptoms are listed in Table 413-1 on the Nelson Textbook of Pediatrics website at www.expertconsult.com.