functional abnormalities include bronchopulmonary dysplasia, respiratory distress syndrome, bronchiectasis (e.g., in cystic fibrosis or ciliary dyskinesia), congenital or acquired emphysema, and pulmonary fibrosis (e.g., from radiation and chemotherapy) TABLE 71.5 MOST COMMON ACUTE LIFE-THREATENING CAUSES OF RESPIRATORY DISTRESS Foreign body Anaphylaxis Epiglottitis Tension pneumothorax Pericardial tamponade Several biologic and chemical agents that are potential weapons of terrorism or warfare produce respiratory distress as their most predominant effect These include the biologic agents inhalational anthrax, pneumonic plague, pneumonic tularemia, melioidosis; the toxins Staphylococcus enterotoxin B and ricin; and the chemical agents chlorine and phosgene (see Chapter 132 Biological and Chemical Terrorism ) Respiratory findings include cyanosis, chest pain, cough, hemoptysis, dyspnea, tachypnea, stridor, rales, and/or wheeze Chest radiographs may reveal infiltrates, pulmonary edema, pleural effusions, widened mediastinum, abscesses, and/or granulomas Nervous System CNS disturbances may result in hypoventilation or hyperventilation, loss of protective airway reflexes, or airway obstruction from loss of pharyngeal tone These conditions include CNS malformation, immaturity, infection, degenerative disease, seizures, mass, trauma, and intoxication Focal neurologic deficits, visual disturbances, pupillary abnormalities, papilledema, abnormal muscle tone, and altered level of consciousness suggest CNS processes Spinal cord trauma and anterior horn cell disease cause bulbar and respiratory muscle dysfunction, which results in airway obstruction and/or hypoventilation Peripheral neuromuscular disorders (i.e., peripheral nerve, neuromuscular junction, muscle) result in muscle weakness or paralysis Physical findings that suggest chest wall weakness may include hypotonia, hyporeflexia, muscle weakness, weak cry, hoarse voice, cough, gag, shallow or irregular respiratory pattern, and inability to lift the head or extremities (see Chapter 82 Weakness ) Chest Wall/Thoracic Cavity