skip to main content
RadInfo Logo Home

Acute Respiratory Illness in Immunocompetent Patients

Acute respiratory illness (ARI) is one of the most common reasons for individuals to seek medical treatment. A person with ARI will have one or more of the following symptoms: cough, phlegm production, chest pain, or trouble breathing. Most cases of ARI are caused by infection that will clear up without treatment. ARI cases caused by bacterial pneumonia require treatment. Imaging is used to determine if there is pneumonia.

A chest x-ray is usually the initial imaging test used for a person with a healthy immune system and no other risk factors.

In individuals with other risk factors, such as abnormal vital signs, a chest x-ray is usually appropriate. Chest ultrasound may be appropriate. If the initial chest x-ray is negative or inconclusive, chest CT without intravenous (IV) contrast is usually appropriate as the next imaging test. In a person with pneumonia and suspected abscess or fluid around the lung on the chest x-ray, chest CT either with or without IV contrast is usually appropriate.

In individuals with acute worsening asthma and no suspected pneumonia or pneumothorax (air around the lung), a chest x-ray may be appropriate. If pneumonia or pneumothorax is suspected, then a chest x-ray is usually appropriate.

In individuals with acute worsening of chronic obstructive pulmonary disease, a chest x-ray is usually appropriate for the initial imaging. Chest CT with or without IV contrast may be appropriate. In people who have symptoms such as chest pain or a history of heart disease, an ultrasound examination may be appropriate.

For more information, see the Pneumonia page.

This page was reviewed on December 15, 2021

Sponsored By

Please note is not a medical facility. Please contact your physician with specific medical questions or for a referral to a radiologist or other physician. To locate a medical imaging or radiation oncology provider in your community, you can search the ACR-accredited facilities database.

This website does not provide cost information. The costs for specific medical imaging tests, treatments and procedures may vary by geographic region. Discuss the fees associated with your prescribed procedure with your doctor, the medical facility staff and/or your insurance provider to get a better understanding of the possible charges you will incur.

Web page review process: This Web page is reviewed regularly by a physician with expertise in the medical area presented and is further reviewed by committees from the Radiological Society of North America (RSNA) and the American College of Radiology (ACR), comprising physicians with expertise in several radiologic areas.

Outside links: For the convenience of our users, provides links to relevant websites., RSNA and ACR are not responsible for the content contained on the web pages found at these links.