Zocdoc Answers

Medical questions & health advice by board certified doctors

"Can swine flu cause pneumonia? "


A friend of a friend died of pneumonia brought on by swine flu. How did this happen? Are they related?


I am sorry to hear about this situation. Without reviewing the patient's hospital records and x-rays, it is hard to tell whether the death was caused by swine flu directly, or by a complication of having swine flu. Here, I will speculate what you may mean by a "pneumonia brought on by swine flu.

See a doctor who can help

Find a Primary care-doctors near you

" Swine flu is a variant of influenza, which is a respiratory tract VIRUS. This means that the virus infects the cells that line the airways (trachea or windpipe, and smaller airways deeper in the lungs, called bronchioles). When the influenza virus infects these lining cells, they die and cause mucus plugging in the airways. Also, healthy cells have cilia--which are little whip-like structures that help to clear bacteria and debris out of the airway--and the cilia tend to become dysfunctional when the cells are infected with the flu virus. Therefore, the airway cells are not able to clear out the dead cells and mucus. This situation predisposes patients to acquiring a BACTERIAL pneumonia, on top of the influenza virus. What is the difference? Bacterial pneumonias are the result of bacteria getting trapped in part of the lung, with infection-fighting cells coming to the area to try to eliminate it. These infection-fighting cells are called neutrophils, and they are the components of pus. Therefore, a bacterial pneumonia is (crudely put) a collection of pus in part of the lung. In general, if you think you have the flu or a pneumonia, you should see your primary care doctor, who can listen to your lungs, check blood tests, and take an x-ray of your chest if needed.

Zocdoc Answers is for general informational purposes only and is not a substitute for professional medical advice. If you think you may have a medical emergency, call your doctor (in the United States) 911 immediately. Always seek the advice of your doctor before starting or changing treatment. Medical professionals who provide responses to health-related questions are intended third party beneficiaries with certain rights under Zocdoc’s Terms of Service.