Final answer:
Crackles, or rales, are abnormal lung sounds often associated with the presence of fluid or infection in the lungs. A chest radiograph and sputum analysis, as ordered for Marsha, further investigate the cause of these sounds.
Step-by-step explanation:
Crackles (also called rales) are abnormal lung sounds characterized by a crackling or popping noise heard during auscultation with a stethoscope. These sounds are typically heard during inhalation and are indicative of fluid in the small airways, infections, pulmonary fibrosis, or other conditions affecting lung tissue. In Marsha's case, her physician noted crepitation in her lungs and ordered further tests, including a chest radiograph and sputum sample for microbiological evaluation and cytology. The radiologic evaluation indicated the presence of cavities and opacities, suggesting a pulmonary disorder that needs medical attention.