Diagnostic Testing and Procedures for Pneumonia
Optimal management of pneumonia depends on a rapid and accurate diagnosis of the causative agent. In cases of delay, morbidity and mortality rates will increase. However, the initial stage in a diagnosis involves obtaining an accurate history from the patient and then performing a thorough physical examination such as checking for crackling or bubbling sounds. This helps narrow the differential diagnosis and guide on choosing the tests to perform to rule in or out the differential diagnosis. The diagnostic procedures and tests performed for pneumonia include pleural fluid cultures, blood tests, sputum tests, chest x-rays, and CT scans.
Pleural Fluid Culture
The procedure entails culturing the pleural fluid to identify the causative agent. Cultures are the gold standard in identifying bacterial, fungal, and viruses though they take a long time (Mattila et al., 2014). The pleural fluid is obtained via thoracentesis, which involves inserting a needle into the pleural space between the chest wall and lungs. The fluid is then cultured on a growth media and incubated at 370C for two days. The growth is examined, and for further identification, a stain is made and inspected using a microscope.
A complete blood count is a basic test done in a laboratory. In cases of bacterial pneumonia, leukocytosis is present, while viral infections exhibit leukopenia. The number of circulating eosinophils increases in the cases of parasitic infections. Blood can also be cultured to identify the germ and indicate if it has spread into the blood. The downside of blood tests is that they do not identify the causative agent.
Sputum refers to the thick phlegm released from the lower respiratory tract when a person coughs. The sample collection involves induction or expectoration, and care should be taken to ensure the sample is from the bronchi and lungs. The sputum is then cultured to detect bacterial pneumonia, and a Gram stain follows it to identify the bacteria causing the disease. The normal flora should be distinguished from pathogenic organisms, as sputum is not sterile. Sputum cultures’ diagnostic yield varies from 10% to 86%, depending on previous use of antibiotics and the specimen’s quality (Harris et al., 2017). Besides, sputum can be visually examined by color; a dark yellow or green color indicates a bacterial infection. Other aspects inspected are the amount, odor, and consistency of the sputum. It is scanty and watery in atypical pneumonia, rusty in pneumococcal bacteria, and mucopurulent for bacterial pneumonia. Sputum with a foul smell is seen in cases of necrotizing pneumonia.
It involves using ionizing radiation, known as x-rays, to create an image of a part of the body. When focused on the chest region, it forms images of the lungs, heart, blood vessels, airways, bones, and spine. In addition to the body organs, x-rays reveal the presence of fluid or gas. The images formed take different shades of white and black, depending on the organs or substances presents. A typical lung appears dark because it has air. In cases of pneumonia, there will be whitish spots on the lungs.
This specialized imaging technique utilizes x-rays to take cross-sectional images of an organ or part of the body. This procedure provides finer details of the lungs, which are difficult to see when using plain x-ray. It also expresses significant details of the bronchi and trachea. Therefore, with a CT scan, it is easier to identify the pathology’s specific location and any complications related to pneumonia.
Harris, A. M., Bramley, A. M., Jain, S., Arnold, S. R., Ampofo, K., Self, W. H., Williams, D. J., Anderson, E. J., Grijalva, C. G., McCullers, J. A., Pavia, A. T., Wunderink, R. G., Edwards, K. M., Winchell, J. M., & Hicks, L. A. (2017). Influence of antibiotics on the detection of bacteria by culture-based and culture-independent diagnostic tests in patients hospitalized with community-acquired pneumonia. Open Forum Infectious Diseases 4(1), 1-7. Web.
Mattila, J. T., Fine, M. J., Limper, A. H., Murray, P. R., Chen, B. B., & Lin, P. L. (2014). Pneumonia. Treatment and diagnosis. Annals of the American Thoracic Society, 11(Supplement 4), S189-S192. Web.