Interstitial Pneumonia

Pneumonia is the infection of the lung parenchyma, resulting from the spread of pathogens and accompanied by the host inflammatory response. This condition is the most common infectious cause of death. Multiple organisms cause pneumonia, including bacteria (of which Streptococcus pneumoniae is the most common), viruses, and fungi. The infection can be acquired while hospitalized (hospital-acquired) or outside the hospital setting (community-acquired). Common symptoms include fever, chills, cough, chest pain, and dyspnea. Chest X-ray usually shows consolidation and/or infiltrates. Diagnosis can be made with clinical presentation and imaging, but in severe cases, microbiological testing (sputum and cultures, molecular testing) and routine blood tests are needed. Empiric treatment with antibiotics is recommended, with regimen depending on the setting, risk factors for multidrug-resistant organisms, and individual comorbidities. Identification of the causative pathogen helps narrow down the antibiotics. Preventive measures include vaccinations (pneumococcal and influenza) and smoking cessation.

Diagnostic modalities such as chest X-rays provide static images of the thoracic cavity, including the lungs and airways. While providing a wealth of anatomical information necessary for the diagnosis of pulmonary disease, chest X-rays do not give much information about the individual's respiratory function. Pulmonary function tests are a group of diagnostic procedures yielding useful, quantifiable information about the rate of the flow of air through the individual's airways, lung capacity, and the efficiency of gas exchange in relation to time. The most commonly utilized tests include spirometry (before and after bronchodilator use), lung volumes, and quantitation of diffusing capacity for carbon monoxide (CO). The tests can be influenced by the individual's effort/fatigue, disease state, or anatomical malformation.

Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy.

Pulmonary, or chest, imaging includes imaging of the lungs and surrounding structures in the thorax. Imaging of the chest represents a substantial portion of the imaging tests that are routinely performed. Common imaging methods include X-ray, CT, MRI, and ultrasonography (US). Each imaging method has advantages and disadvantages. Radiology exams, once completed, are read and interpreted by board-certified, fellowship-trained radiologists; however, most physicians should know the basics of how to interpret these images.