pneumonias

Pneumonia is an infection in one or both of the lungs. It causes the air sacs of the lungs to fill up with fluid or pus. It can range from mild to severe, depending on the type of germ causing the infection, your age, and your overall health.

Bacterial, viral, and fungal infections can cause pneumonia.

Bacteria are the most common cause. Bacterial pneumonia can occur on its own. It can also develop after you've had certain viral infections such as a cold or the flu. Several different types of bacteria can cause pneumonia, including:

• Streptococcus pneumoniae
• Legionella pneumophila; this pneumonia is often called Legionnaires' disease
• Mycoplasma pneumoniae
• Chlamydia pneumoniae
• Haemophilus influenzae

Viruses that infect the respiratory tract may cause pneumonia. Viral pneumonia is often mild and goes away on its own within a few weeks. But sometimes it is serious enough that you need to get treatment in a hospital. If you have viral pneumonia, you are at risk of also getting bacterial pneumonia. The different viruses that can cause pneumonia include:

• Respiratory syncytial virus (RSV)
• Some common cold and flu viruses
• SARS-CoV-2, the virus that causes COVID-19

Fungal pneumonia is more common in people who have chronic health problems or weakened immune systems. Some of the types include:

• Pneumocystis pneumonia (PCP)
• Coccidioidomycosis, which causes valley fever
• Histoplasmosis
• Cryptococcus

Anyone can get pneumonia, but certain factors can increase your risk:

• Age; the risk is higher for children who are age 2 and under and adults age 65 and older
• Exposure to certain chemicals, pollutants, or toxic fumes
• Lifestyle habits, such as smoking, heavy alcohol use, and malnourishment
• Being in a hospital, especially if you are in the ICU. Being sedated and/or on a ventilator raises the risk even more.
• Having a lung disease
• Having a weakened immune system
• Have trouble coughing or swallowing, from a stroke or other condition
• Recently being sick with a cold or the flu

The symptoms of pneumonia can range from mild to severe and include:

• Fever
• Chills
• Cough, usually with phlegm (a slimy substance from deep in your lungs)
• Shortness of breath
• Chest pain when you breathe or cough
• Nausea and/or vomiting
• Diarrhea

The symptoms can vary for different groups. Newborns and infants may not show any signs of the infection. Others may vomit and have a fever and cough. They might seem sick, with no energy, or be restless.

Older adults and people who have serious illnesses or weak immune systems may have fewer and milder symptoms. They may even have a lower than normal temperature. Older adults who have pneumonia sometimes have sudden changes in mental awareness.

Sometimes pneumonia can cause serious complications such as:

• Bacteremia, which happens when the bacteria move into the bloodstream. It is serious and can lead to septic shock.
• Lung abscesses, which are collections of pus in cavities of the lungs
• Pleural disorders, which are conditions that affect the pleura. The pleura is the tissue that covers the outside of the lungs and lines the inside of your chest cavity.
• Kidney failure
• Respiratory failure

Sometimes pneumonia can be hard to diagnose. This is because it can cause some of the same symptoms as a cold or the flu. It may take time for you to realize that you have a more serious condition.

Your health care provider may use many tools to make a diagnosis:

• A medical history, which includes asking about your symptoms
• A physical exam, including listening to your lungs with a stethoscope
• Various tests, such as
  • A chest x-ray
  • Blood tests such as a complete blood count (CBC) to see if your immune system is actively fighting an infection
  • A Blood culture to find out whether you have a bacterial infection that has spread to your bloodstream

If you are in the hospital, have serious symptoms, are older, or have other health problems, you may also have more tests, such as:

• Sputum test, which checks for bacteria in a sample of your sputum (spit) or phlegm (slimy substance from deep in your lungs).
• Chest CT scan to see how much of your lungs is affected. It may also show if you have complications such as lung abscesses or pleural effusions.
• Pleural fluid culture, which checks for bacteria in a fluid sample that was taken from the pleural space
• Pulse oximetry or blood oxygen level test, to check how much oxygen is in your blood
• Bronchoscopy, a procedure used to look inside your lungs' airways

Treatment for pneumonia depends on the type of pneumonia, which germ is causing it, and how severe it is:

• Antibiotics treat bacterial pneumonia and some types of fungal pneumonia. They do not work for viral pneumonia.
• In some cases, your provider may prescribe antiviral medicines for viral pneumonia
• Antifungal medicines treat other types of fungal pneumonia

You may need to be treated in a hospital if your symptoms are severe or if you are at risk for complications. While there, you may get additional treatments. For example, if your blood oxygen level is low, you may receive oxygen therapy.

It may take time to recover from pneumonia. Some people feel better within a week. For other people, it can take a month or more.

Vaccines can help prevent pneumonia caused by pneumococcal bacteria or the flu virus. Having good hygiene, not smoking, and having a healthy lifestyle may also help prevent pneumonia.

NIH: National Heart, Lung, and Blood Institute

Pneumocystis jirovecii is a fungus that is common throughout the world. Many people have been exposed to it as children. Some people have the fungus in their lungs. If you are healthy, it usually will not make you sick. But it can make you sick if you have a weakened immune system, for example if you:

• Have HIV
• Have an autoimmune disease
• Have cancer
• Have a chronic (long-lasting) lung disease
• Had an organ or bone marrow transplant
• Take medicines which weaken your immune system, such as chemotherapy and steroids

Pneumocystis jirovecii can spread from person to person through the air. You can spread it to others even if it isn't making you sick.

The most common type of infection that Pneumocystis jirovecii causes is pneumocystis pneumonia (PCP). Pneumonia is an infection in one or both of the lungs. It causes the air sacs of the lungs to fill up with fluid or pus.

The symptoms of PCP can develop over several days or weeks. They may include:

• Fever
• Cough
• Trouble breathing
• Chest pain
• Chills
• Fatigue

Contact your healthcare provider if you have symptoms that you think are related to PCP. Since PCP can be life-threatening, it's important to get early treatment.

To find out if you have PCP, your provider will take a sample of fluid or tissue from your lungs. You may cough up the sample (called sputum), have fluid collected during a bronchoalveolar lavage, or have tissue taken with a biopsy. They will send the sample to the lab to check for Pneumocystis.

The treatment for PCP is with antibiotics, either by mouth or intravenously (by IV). You need to take them for about 3 weeks. If you have a severe case of PCP, you might need treatment in the hospital.

There is no vaccine to prevent PCP. Some people who are at high risk of getting PCP may need to take antibiotics to prevent it.

Centers for Disease Control and Prevention

Legionnaires' disease is a type of pneumonia caused by bacteria. You usually get it by breathing in mist from water that contains the bacteria. The mist may come from hot tubs, showers, or air-conditioning units for large buildings. The bacteria don't spread from person to person.

Symptoms of Legionnaires' disease include high fever, chills, a cough, and sometimes muscle aches and headaches. Other types of pneumonia have similar symptoms. You will probably need a chest x-ray to diagnose the pneumonia. Lab tests can detect the specific bacteria that cause Legionnaires' disease.

Most people exposed to the bacteria do not become sick. You are more likely to get sick if you:

• Are older than 50
• Smoke
• Have a chronic lung disease
• Have a weak immune system

Legionnaires' disease is serious and can be life-threatening. However, most people recover with antibiotic treatment.

Centers for Disease Control and Prevention

Having HIV/AIDS weakens your body's immune system. It destroys the white blood cells that fight infection. This puts you at risk for opportunistic infections (OIs). OIs are serious infections that take advantage of your weak immune system. These infections are less common and less severe in healthy people.

There are many types of OIs:

• Bacterial infections, including tuberculosis and a serious related disease, Mycobacterium avium complex (MAC)
• Viral infections, such as cytomegalovirus (CMV) and hepatitis C
• Fungal infections, like yeast infections, cryptococcal meningitis, pneumocystis carinii pneumonia (PCP) and histoplasmosis
• Parasitic infections, such as crypto (cryptosporidiosis) and toxo (toxoplasmosis)

Having HIV/AIDS can make infections harder to treat. People with HIV/AIDS are also more likely to have complications from common illnesses such as the flu.

You can help prevent infections by taking your HIV/AIDS medicines. Other things that can help include practicing safe sex, washing your hands well and often, and cooking your food thoroughly.

Staphylococcus (staph) is a group of bacteria. There are more than 30 types. A type called Staphylococcus aureus causes most infections.

Staph bacteria can cause many different types of infections, including:

• Skin infections, which are the most common types of staph infections.
• Bacteremia, an infection of the bloodstream. This can lead to sepsis, a very serious immune response to infection.
• Bone infections.
• Endocarditis, an infection of the inner lining of the heart chambers and valves.
• Food poisoning.
• Pneumonia.
• Toxic shock syndrome (TSS), a life-threatening condition caused by toxins from certain types of bacteria.

Some people carry staph bacteria on their skin or in their noses, but they do not get an infection. But if they get a cut or wound, the bacteria can enter the body and cause an infection.

Staph bacteria can spread from person to person. They can also spread on objects, such as towels, clothing, door handles, athletic equipment, and remotes. If you have staph and do not handle food properly when you are preparing it, you can also spread staph to others.

Anyone can develop a staph infection, but certain people are more likely to get one, including those who:

• Have a chronic condition such as diabetes, cancer, vascular disease, eczema, and lung disease
• Have a weakened immune system, such as from HIV, medicines to prevent organ rejection, or chemotherapy
• Had surgery
• Are in the hospital
• Use a catheter, breathing tube, or feeding tube
• Have an implanted device, such as a pacemaker or artificial joint or heart valve
• Have burns, especially if they are deep or cover a large area of the body
• Are on dialysis
• Inject illegal drugs
• Do contact sports, since you may have skin-to-skin contact with others or share equipment

The symptoms of a staph infection depend on the type of infection:

• Skin infections can look like pimples or boils. They may be red, swollen, and painful. Sometimes there is pus or other drainage. They can turn into impetigo, which turns into a crust on the skin, or cellulitis, a swollen, red area of skin that feels hot.
• Bone infections can cause pain, swelling, warmth, and redness in the infected area. You may also have chills and a fever.
• Endocarditis causes some flu-like symptoms: fever, chills, and fatigue. It also causes symptoms such as rapid heartbeat, shortness of breath, and fluid buildup in your arms or legs.
• Food poisoning typically causes nausea and vomiting, diarrhea, and fever. If you lose too many fluids, you may also become dehydrated.
• Pneumonia symptoms include a high fever, chills, and cough that doesn't get better. You may also have chest pain and shortness of breath.
• Toxic shock syndrome (TSS) causes high fever, sudden low blood pressure, vomiting, diarrhea, and confusion. You may have a sunburn-like rash somewhere on your body. TSS can lead to organ failure.

Your health care provider will do a physical exam and ask about your symptoms. Often, providers can tell if you have a staph skin infection by looking at it. To check for other types of staph infections, providers may do a culture, with a skin scraping, tissue sample, stool sample, or throat or nasal swabs. There may be other tests, such as imaging tests, depending on the type of infection.

Treatment for staph infections is antibiotics. Depending on the type of infection, the antibiotics might be a cream, ointment, medicines (to swallow), or intravenous (IV) medicine. If you have an infected wound, your provider might drain it. Sometimes you may need surgery for bone infections.

Some staph infections, such as MRSA (methicillin-resistant Staphylococcus aureus), are resistant to many antibiotics. There are still certain antibiotics that can treat these infections.

Certain steps can help to prevent staph infections:

• Use good hygiene, including washing your hands often.
• Don't share towels, sheets, or clothing with someone who has a staph infection.
• It's best not to share athletic equipment. If you do need to share, make sure that it is properly cleaned and dried before you use it.
• Practice food safety, including not preparing food for others when you have a staph infection.
• If you have a cut or wound, keep it covered.

Strep is short for Streptococcus, a type of bacteria. There are several types. Two of them cause most of the strep infections in people: group A and group B.

Group A strep causes:

• Strep throat - a sore, red throat. Your tonsils may be swollen and have white spots on them.
• Scarlet fever - an illness that follows strep throat. It causes a red rash on the body.
• Impetigo - a skin infection
• Toxic shock syndrome
• Cellulitis and necrotizing fasciitis (flesh-eating disease)

Group B strep can cause blood infections, pneumonia and meningitis in newborns. A screening test during pregnancy can tell if you have it. If you do, intravenous (IV) antibiotics during labor can save your baby's life. Adults can also get group B strep infections, especially if they are 65 or older or already have health problems. Strep B can cause urinary tract infections, blood infections, skin infections and pneumonia in adults.

Antibiotics are used to treat strep infections.

Bronchitis is an inflammation of the bronchial tubes, the airways that carry air to your lungs. It causes a cough that often brings up mucus. It can also cause shortness of breath, wheezing, a low fever, and chest tightness. There are two main types of bronchitis: acute and chronic.

Most cases of acute bronchitis get better within several days. But your cough can last for several weeks after the infection is gone.

The same viruses that cause colds and the flu often cause acute bronchitis. These viruses spread through the air when people cough, or though physical contact (for example, on unwashed hands). Being exposed to tobacco smoke, air pollution, dusts, vapors, and fumes can also cause acute bronchitis. Less often, bacteria can also cause acute bronchitis.

To diagnose acute bronchitis, your health care provider will ask about your symptoms and listen to your breathing. You may also have other tests.

Treatments include rest, fluids, and aspirin (for adults) or acetaminophen to treat fever. A humidifier or steam can also help. You may need inhaled medicine to open your airways if you are wheezing. Antibiotics won't help if the cause is viral. You may get antibiotics if the cause is bacterial.

NIH: National Heart, Lung, and Blood Institute

Birds, just like people, can get the flu. Another name for bird flu is avian influenza. The viruses that cause bird flu normally only infect birds, including chickens, other poultry, and wild birds such as ducks. But sometimes the viruses can infect other animals and, in rare cases, people.

A few types of these viruses have caused most of the infections in people. They are the H5N1, H7N9, and H5N6 viruses. These infections in people have mainly been in Asia, Africa, Europe, the Pacific, and the Near East. Although it's very rare, there have also been some infections in people in the United States.

The most common ways you can get bird flu are from:

• Touching your eyes, nose, or mouth after handling infected live or dead birds
• Touching surfaces or handling items contaminated by bird flu viruses and then touching your eyes, nose, or mouth
• Breathing in droplets or dust contaminated with the virus

It's also possible (but very rare) to get bird flu from:

• Another type of animal who has bird flu. Bird flu can also infect many other animals, including some dogs, cats, certain wild and zoo animals, and livestock such as cattle. These animals can then spread the flu to people.
• Another person.
• Eating poultry, eggs, and beef that were not properly handled and cooked.
• Drinking raw milk.

Certain people may be more likely to get bird flu, including:

• Poultry workers
• Animal handlers
• Wildlife biologists
• Disease control workers
• Research laboratory workers
• Veterinarians
• People who travel to countries where bird flu is present

Sometimes bird flu doesn't cause any symptoms. But if you do feel sick, your symptoms can range from mild to severe. Often, the symptoms are similar to the (seasonal) flu, such as:

• Fever (but not everyone has a fever)
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Fatigue
• Headaches
• Eye redness (conjunctivitis)
• Trouble breathing
• Diarrhea

People with severe illness from bird flu may have pneumonia and might need to be hospitalized.

Laboratory testing is used to diagnose bird flu. It's usually done with a nasal or throat swab. This testing is more accurate when the swab is collected during the first few days of illness.

For people who are severely ill, health care providers may do testing of a different sample, such as fluid taken during a bronchoalveolar lavage or other procedure.

Bird flu is treated with antiviral medicines. It's important to get them as soon as possible. The medicines may make your illness less severe.

You may also be given antiviral medicines if you were exposed to a person or animal who has the virus. This may help prevent you from getting sick.

There is currently no vaccine available to the public. The government has developed a virus that is similar to some H5N1 viruses. The virus could be used to produce a vaccine for people, if needed.

It's important to take precautions to prevent bird flu:

• If you have a job or pastime that puts you in contact with birds or other animals, make sure to use proper protective equipment.
• Otherwise try to avoid direct contact with wild birds and other animals.
• Wash your hands with soap and water after touching birds or other animals.
• Since it's possible to get bird flu through some foods, make sure to handle and cook your food safely and avoid raw milk.

Centers for Disease Control and Prevention

When you're short of breath, it's hard or uncomfortable for you to take in the oxygen your body needs. You may feel as if you're not getting enough air. Sometimes you can have mild breathing problems because of a stuffy nose or intense exercise. But shortness of breath can also be a sign of a serious disease.

Many conditions can make you feel short of breath:

• Lung conditions such as asthma, emphysema, or pneumonia
• Problems with your trachea or bronchi, which are part of your airway system
• Heart disease can make you feel breathless if your heart cannot pump enough blood to supply oxygen to your body
• Anxiety and panic attacks
• Allergies

If you often have trouble breathing, it is important to find out the cause.

Having a pain in your chest can be scary. It does not always mean that you are having a heart attack. There can be many other causes, including:

• Other heart problems, such as angina
• Panic attacks
• Digestive problems, such as heartburn or esophagus disorders
• Sore muscles
• Lung diseases, such as pneumonia, pleurisy, or pulmonary embolism
• Costochondritis - an inflammation of joints in your chest

Some of these problems can be serious. Get immediate medical care if you have chest pain that does not go away, crushing pain or pressure in the chest, or chest pain along with nausea, sweating, dizziness or shortness of breath. Treatment depends on the cause of the pain.