Pneumonia can be mild or life-threatening and is caused by inflammation of the small air sacs in the lungs. If left untreated, it can have fatal consequences, such as lack of oxygen and blood infections.
national geographic spoke to several experts to better understand the different types of pneumonia and the risk of contracting different forms of the disease.
Pneumonia is an infection of the lower respiratory tract, specifically of the tiny air sacs called alveoli, which are the exchange points that supply oxygen to the blood and remove carbon dioxide. This infection can be triggered by a variety of factors, starting in the upper respiratory tract and then moving deeper into the lungs.
Some common symptoms of pneumonia are cough, shortness of breath, chest pain, and general fatigue. Wu Tianshi, a pulmonary specialist at Baylor College of Medicine in Texas, USA, said that when diagnosing pneumonia, the doctor will use a stethoscope to check the patient’s breathing and listen for a unique creaking sound, similar to the sound of paper crinkling. “That’s all you need to diagnose pneumonia,” Wu said, adding that if the doctor is still unsure, he or she can also order a lung X-ray, which will confirm the diagnosis.
In most cases, “it’s impossible to tell whether pneumonia is caused by bacteria, viruses or fungi just by looking at it,” Wu said. “Most pneumonias are never diagnosed.” Instead, doctors treat pneumonia based on a patient’s symptoms and medical history, using that information to determine the best treatment.
Bacterial pneumonia is the most common and is caused by bacteria, which means it is easily treated with antibiotics. For many patients, treating pneumonia with antibiotics will help relieve symptoms and start feeling better within a few days of starting treatment. “The sooner treatment starts, the better,” Wu said. There is also a vaccine that protects against the most important strain of bacteria that causes pneumonia, and it’s approved for use in certain groups, such as patients over 65 and those with certain pre-existing conditions.
Less commonly, viral pneumonia is caused by viruses such as influenza, SARS-CoV-2 (the virus that causes COVID-19), or RSV (a respiratory virus that often causes mild cold-like symptoms). Many viral infections start in the upper respiratory tract and then travel down to the lungs.
Viral infections can also weaken a patient’s immune system, leading to bacterial pneumonia, leaving them susceptible to secondary infections. Although no viruses can be treated with antibiotics, there are vaccines that can help prevent infection: the annual flu shot, the COVID-19 vaccine, and the new RSV vaccine for those who qualify.
Fungal pneumonia is rare and usually occurs in patients with pre-existing medical conditions, such as a weakened immune system. Fungal pneumonia often affects people with autoimmune diseases, those undergoing chemotherapy or other chronic conditions that may affect the body’s immune system, said pulmonologist Lucas Kimmig of the University of Chicago Medicine. Fungal pneumonia requires a different treatment strategy and can often be more severe due to the complications of pneumonia and other underlying conditions in the patient.
Hospital-acquired pneumonia is considered a separate category because the hospital environment often exposes patients to different bacteria, including strains that are more likely to become resistant to antibiotics. Cases of hospital-acquired pneumonia may impact treatment of the disease. “They’re at risk for other bacterial infections that don’t normally affect outpatients,” Kimig explained. “This affects antibiotic choice.”
The risk with pneumonia is that if left untreated, it can cause serious complications and may spread to other parts of the body.
“If you have a bacterial or viral infection in the lungs, there’s really no way to clear it out,” said Jason Turowski, a pulmonologist at the Cleveland Clinic in the United States. “The infection keeps growing.”
The main risk of pneumonia is that it can damage the lungs, affecting a person’s ability to get the oxygen they need. This damage usually occurs because inflammation causes a buildup of inflammatory cells in tiny sacs in the lungs, preventing oxygen from reaching and carbon dioxide from being released. “When you’re injured, you won’t be able to get the vital oxygen you need or release the carbon dioxide your body produces,” Tulowski said.
A secondary risk is that the infection spreads to other parts of the body, such as the space between the lungs and chest wall, or into the bloodstream. When this infection begins to spread to other parts of the body, it can develop into a condition called sepsis, which is an uncontrolled systemic response to the infection. Sepsis can quickly become a life-threatening disease.
Those most at risk for serious complications from pneumonia are children under five, adults over 65, and people with pre-existing conditions such as heart and lung disease, or those with weakened immune systems due to chemotherapy or organ transplants .
Other risk factors include uncontrolled diabetes or heavy smoking or drinking.
“Most forms of pneumonia are ultimately mild and self-limiting,” Wu said. “If it’s severe enough to require hospitalization, there could be something else going on.”
For patients who have been diagnosed with pneumonia and are recovering at home, some major warning signs that they may need to seek additional medical care include worsening of the condition even after treatment, either a fever that does not go away, or chest pain or shortness of breath that does not go away. , or shortness of breath, which may indicate a failure to get enough oxygen.
“It’s important to contact your doctor when you notice something unusual,” Turowski said. “When we get involved early, we can provide you with guidance and help prepare you at the hospital if we get a follow-up call that I’m getting worse.”