What To Know About Double Pneumonia—An Infection in Both Lungs

A pneumonia diagnosis can be a scary thing to hear—it means that you have an infection in your lungs that is causing inflammation and fluid buildup, and it can result in distressing symptoms, like chest pain, fever, and shortness of breath.

When giving a diagnosis of pneumonia, healthcare providers may tell you whether you've got a bacterial or viral infection, whether it's in different spots of the lung, and if it's confined to a single lung or has taken up residence in both.

Pneumonia that affects both lungs is colloquially known as "double pneumonia," but healthcare providers are more likely to call it "bilateral pneumonia." And while double or bilateral pneumonia doesn't differ too much from pneumonia that affects a single lung, when the infection, inflammation, and fluid affect a larger area of the lungs, it is likely to be more serious.

Here's what you need to know about pneumonia that affects both lungs, including the most common symptoms, the likeliest causes, and the treatment options healthcare providers typically use.

Definition of Double Pneumonia

Double or bilateral pneumonia is a term used when there's inflammation caused by an infection in the air sacs in both lungs, Thomas Monaco, MD, assistant professor of pulmonary and critical care medicine at the Baylor College of Medicine, told Health.

The parts of the lungs that are affected by pneumonia—either bilateral (double, or both lungs) or unilateral (single, or one lung)—are called the alveoli. Alveoli are the small, balloon-shaped air sacs in the lungs that move oxygen into and carbon dioxide out of your bloodstream.

When those air sacs become infected and inflamed, they begin to fill up with fluid or pus, according to the National Heart, Lung, and Blood Institute (NHLBI). That, in turn, can cause all of those unwelcome symptoms like cough, fever, chills, and difficulty breathing.

Symptoms

There's no real difference in the type of symptoms of double pneumonia versus pneumonia that affects a single lung, Raymond Casciari, MD, a pulmonologist at St. Joseph Hospital in Orange, California, told Health. But because double pneumonia affects both lungs, it may feel more severe. "With single pneumonia, you can get chest pain, but it will only be on one side," Dr. Casciari said and added, "With double, it may be on both sides."

Generally speaking, the most common symptoms of pneumonia, per the NHLBI, include:

• Chest pain when you breathe or cough
• Chills
• Cough with or without mucus
• Fever
• Low oxygen levels in your blood, measured with a pulse oximeter
• Shortness of breath

Some people with pneumonia may also experience other symptoms like headache, muscle pain, fatigue, nausea, vomiting, and diarrhea, NHLBI says.

Pneumonia is usually caused by bacteria, viruses, or fungi—and that's true whether you have double or single pneumonia, Dr. Casciari said. However, Dr. Casciari added that viral infections are usually more likely to show up in both lungs.

"The list of infections that can cause pneumonia of both lungs is long, but viral infections are a common offender," Dr. Monaco said, citing SARS-CoV-2, or the virus that causes COVID-19, as a prime example.

Dr. Monaco noted a type of bacteria that can also lead to double pneumonia. "There are also a group of atypical bacteria [Mycoplasma pneumoniae] that cause pneumonia, a less severe, more mild case of the illness," Dr. Monaco said.

Another form of bacteria—Legionella pneumophila—is also known to affect both lungs quite extensively, Reynold Panettieri, MD, a pulmonary critical care expert, and director of the Institute for Translational Medicine and Science at Rutgers University, told Health.

But it's not always about the type of microbe that caused the infection—a person's underlying risk factors matter too, Shweta Sood, MD, a pulmonologist and assistant professor of clinical medicine at Penn Medicine, told Health. The following factors, per the NHLBI, can raise your risk of having more severe pneumonia:

• Being a smoker
• Being a heavy drinker
• Having heart disease
• Having lung diseases, like asthma or chronic obstructive pulmonary disease (COPD)
• Being immunocompromised
• Being very young or very old
• Having another underlying disease, like diabetes or cancer

Treatment

Treatment usually depends on what caused your pneumonia in the first place, Dr. Sood said. Here's a breakdown of possible treatments:

• Antibiotics: "If someone is relatively healthy and they get bacterial pneumonia, we can usually treat them as an outpatient with antibiotics," Dr. Sood said. In more severe cases, you'll need IV antibiotics in the hospital.
• Rest: Healthcare providers usually recommend rest and fluids if you have viral pneumonia. If you have viral double pneumonia, you may not need any medication, Dr. Panettieri explained.
• Antivirals: In severe situations, an antiviral medication like remdesivir may help, Dr. Casciari said.
• Antifungals: An antifungal medication can help treat fungal pneumonia, Dr. Sood said. And, like antibiotics, if you have a more severe form of double pneumonia, you may be given the medication through an IV.
• Breathing support: "Patients with pneumonia in both lungs are more likely to need supplemental oxygen or possibly support from a mechanical ventilator," Dr. Monaco added.

As far as prognosis goes, it's important to note that pneumonia is one of the top 10 causes of death in the United States, per the Centers for Disease Control and Prevention—and "it's serious, but even worse when it involved both lungs," Dr. Casciari cautioned.

When To See a Healthcare Provider

If you develop double pneumonia, though, don't panic. "Fortunately, most patients with pneumonia will recover without any long-lasting effects," Dr. Monaco said.

If you do begin to feel any of the symptoms most commonly associated with pneumonia, it's best to let a healthcare provider know. Healthcare providers will want to take a thorough look if you come in with symptoms of pneumonia.

Symptoms that signal an emergency include severe trouble breathing, a very high fever, or extreme chest pain. If you are feeling any of these symptoms, seek medical care immediately.