CNS, Central nervous system.
expiratory (use of abdominal muscles to actively exhale). In children, increased inspiratory effort is also manifested by nasal flaring. Grunting (forced expiration against a partially closed glottis) suggests respiratory distress, but it may also be a manifestation of pain.
Causes of increased work of breathing during inspiration include extrathoracic airway obstruction (laryngomalacia, croup, subglottic stenosis) and/or decreased pulmonary compliance (pneumonia, pulmonary edema). Increased expiratory work of breathing usually indicates intrathoracic airway obstruction (see Table 133-2).
Stridor is a harsh sound caused by a partially obstructedextrathoracic airway, more commonly heard on inspiration.Wheezing is produced by partial obstruction of the lower airways, more commonly heard during exhalation. Wheezes canbe monophonic and low-pitched (usually from large, centralairways) or high-pitched and musical (from small peripheralairways). Secretions in the intrathoracic airways may producewheezing but more commonly result in irregular sounds calledrhonchi. Fluid or secretions in small airways may produce sounds characteristic of crumpling cellophane (crackles or rales). Having the child take a deep breath and exhale forcefullywill accentuate many abnormal lung sounds. Decreased breathsounds may be due to atelectasis, lobar consolidation (pneumonia), thoracic mass, or a pleural effusion. Observation of respiratory rate, work of breathing, tracheal and cardiac deviation,and chest wall motion, combined with percussion and auscultation, helps to identify intrathoracic disease (Table 133-3).
Digital clubbing is seen in CF and in other, less common chronic pulmonary diseases (such as interstitial lung disease). It is generally not seen in asthma, so its presence should heighten concern for other diagnoses. Clubbing may also be present in nonpulmonary chronic diseases (cardiac, gastrointestinal, or hematologic) or, rarely, as a familial trait.
Pleural effusion Deviation to Reduced over None or Dull None Egophony Muffled opposite side area reduced
Interstitial No Reduced Normal to Normal Normal Inspiratory None process
Adapted from Andreoli TE, Bennett JC, Carpenter CJ, et al, editors: Cecil Essentials of Medicine, ed 4, Philadelphia, 1997, WB Saunders, p 115. PMI, Point of maximum impulse. *In egophony, e sounds like a (may be a sign of consolidation but also is associated with moderate-sized pleural effusions).
†In pectoriloquy, words/voice sounds clearer over the affected site (associated with consolidation and cavitary lesions).