Bacterial pneumonia after the flu is a big problem in patients that get the flu. It is different from getting pneumonia as a result of the flu itself. If you would like to understand the difference between pneumonia from the flu (a type of viral pneumonia) and pneumonia after the flu (a type of bacterial pneumonia), please visit “different types of pneumonia and their symptoms.”
When you get the flu, you may have viral pneumonia. However, as you are recovering from the flu, you may get sick again. While recovering from the flu, your lungs are vulnerable to an invasion by bacteria that may be more serious than the original influenza infection. I have personally treated many patients with bacterial pneumonia after the flu.
In this article, I will explain:
- How bacterial pneumonia develops after the flu
- When you need to be concerned about pneumonia after the flu
- Who is at risk of getting pneumonia after the flu
- What you need to look out for when diagnosed with pneumonia after the flu
How bacterial pneumonia develops after the flu
Bacterial pneumonia after the flu usually starts between day 4 and day 14 of the onset of flu symptoms. Most of the time, bacterial pneumonia starts after the flu virus has cleared. The flu viruses damage the lining of your lungs, making them vulnerable to an invasion by bacteria. When your body fights the viruses, it does so by removing the virus-infected cells in your lungs. The flu viruses mostly attack the outer “skin” layer of the lungs. When this protective layer is removed by the body, the underlying vulnerable layer is exposed.
The outer linings of “skin” in your lungs also have tiny hair-like objects called cilia. These cilia not only trap small particles that fall into your lungs, but they also help get rid of them by gently sweeping them out of the lungs. Without the trapping and sweeping action of the damaged layer, bacteria can easily invade your lungs and cause pneumonia.
In addition to the direct damage to the lung lining, the flu virus also weakens your immune system for days after the flu has cleared. This makes you even more vulnerable to bacterial pneumonia after the flu.
When you need to be concerned about bacterial pneumonia after the flu
It is estimated that 11% to 35% of people with the flu develop pneumonia after it. It is very important to look out for the symptoms of bacterial pneumonia after the flu. Pneumonia after the flu can progress rapidly and make you very sick very quickly.
Here are the signs and symptoms you need to pay attention to:
- Recurrence of high fevers and chills
- Worsening cough with blood-tinged phlegm
- Chest pain when breathing
- Feeling weak and tired
- Shortness of breath
- Low oxygen levels
- Feeling dizzy and lightheaded
- Low blood pressure
- Abnormal labs with high white blood cell counts
- Confusion and disorientation
If you have any of those signs and symptoms suggesting pneumonia after the flu, you need to call your doctor right away. If you are too sick, call 911 and get yourself to the ER right away. You need to be started on appropriate antibiotics as soon as you are diagnosed with pneumonia after the flu. Without a quick diagnosis and treatment, you may get sepsis, and that could be life-threatening. To learn more about sepsis, visit “low blood pressure and fever: think sepsis”.
Who is at risk for getting pneumonia after the flu?
Simply put, everyone is at risk of getting pneumonia after the flu. However, if you meet any of the following criteria, your risk of getting pneumonia after the flu is significantly higher:
- If you have a history of existing lung diseases such as COPD
- If you are getting chemotherapy for cancer
- If you had a recent major surgery
- If you have decreased mobility
- If you have uncontrolled diabetes
- If you are getting dialysis treatment for kidney failure
- If you have a history of liver problems
- If you are a smoker
- If you are malnourished
- If you are on immune-suppressing medications after an organ transplant
What you need to look out for when diagnosed with pneumonia after the flu
Pneumonia, by itself, can be a serious life-threatening illness, and you may need hospitalization. If you want to read who needs hospitalization when diagnosed with pneumonia, visit “hospitalization for pneumonia.” Pneumonia after the flu has a higher chance of making you seriously ill. When you are diagnosed with pneumonia after the flu, you need to be very vigilant. Things can get worse quickly, even when you are taking the appropriate antibiotics at home.
The bacteria that infect your lungs when you have pneumonia after the flu can easily invade your lungs with the decreased defenses. If the antibiotics did not kill them right away, those bacteria could multiply rapidly and overwhelm your body and immune system.
You need to look out for these signs:
- Feeling dizzy or lightheaded
- Increased heart rate with a pounding sensation in the chest
- Fainting or feeling like you are fainting
- Decreased urine output
- Continued high fevers with shaking chills
- Confusion and disorientation
- Worsening pain with breathing
- Shortness of breath
- Rapid and shallow breathing
- Running out of breath with minimal activity
If you have any of those signs, it is a good idea to call 911 or have someone drive you to the ER. You will most likely need hospitalization.
In conclusion, if you are worried about getting pneumonia after the flu, you are right. Pneumonia after the flu is a real concern. Your lungs are very vulnerable to an invasion by pneumonia-causing bacteria after the flu. Pneumonia after the flu can get worse quickly; despite treatment, you need to look out for any worsening symptoms, as you may need hospitalization.
References:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5481322/