Pneumonia: Symptoms, causes, diagnosis, treatments

2021-07-22 03:41 PM

Pneumonia can range from mild to life-threatening. The pneumonia mortality rate is lower if getting the right treatment. Pneumonia is often a complication of another illness, such as the flu.


Pneumonia is an inflammation usually caused by an infection. Bacteria, viruses, fungi, or parasites can cause pneumonia. Bacteria viruses and fungi are examples of microbes. Pneumonia is a particular concern if you are over 65 years old or have a chronic illness, or weakened immune system diseases. It can also occur in children or otherwise healthy people.

Pneumonia diagnosisbook: Main symptoms

Pneumonia: Main symptoms

Pneumonia can range from mild to life-threatening. The pneumonia mortality rate is lower if getting the right treatment. Pneumonia is often a complication of another illness, such as the flu. Antibiotics can treat the most common forms of pneumonia bacteria, but increasingly resistant strains are a problem. The best approach is to try to stop the infection.


Symptoms of pneumonia can be very much different, depending on the possible underlying condition and the type of organism causing the illness. Pneumonia often mimics the flu, starting with a cough and fever, so you may not realize there's a more serious condition.

Common signs and symptoms of pneumonia may include:



Shortness of breath.



Acute pleuritic chest pain.


Muscle pain.


Ironically, people in vulnerable high-risk groups such as the elders and those with chronic illnesses or weakened immune system diseases may have fewer or milder symptoms. And instead of having the high fevers that are often characteristic of pneumonia, elderly people may even have lower-than-normal temperatures.

Because pneumonia can be life-threatening, see your doctor as soon as possible if you have a persistent cough, shortness of breath, chest pain, unexplained fever - especially a fever that persists at 38.90C or higher with chills and sweating, or if you suddenly feel worse after a cold or flu.
Seek medical attention if you are elderly or smoke, drink alcohol excessively, have an injury, are undergoing chemotherapy, or take medication such as prednisone, which suppresses the immune system. For some elders and those with heart or lung disease, pneumonia can quickly become a life-threatening condition.


The body has many ways to protect the lungs from infection. In fact, frequent exposure to bacteria and viruses can cause pneumonia, but the body usually protects itself, such as coughing and normal microorganisms in the body to prevent harmful organisms from entering and respiratory damage. However, under many conditions, including malnutrition and systemic diseases, the defense may be lower and allow harmful organisms to bypass the body's defenses and enter the lungs.

Once the organisms get into the lungs, white blood cells function, as an important part of the immune system, begin to attack. White blood cells attack and destroy bacteria, viruses, and other organisms causing a lung infection. Bacteria, white blood cells, and immune system proteins cause inflammation of the alveoli and fluid-filled sacs, leading to the shortness of breath that characterizes many types of pneumonia.

Classification of pneumonia

Pneumonia classification diagnosisbook

Pneumonia classification

Pneumonia is sometimes classified according to the causes:

Pneumonia in the community. Refers to pneumonia present in the course of everyday life - at school, work, or the gym, for example. The most common cause is Streptococcus pneumonia. Less common is Mycoplasma pneumonia, a less common organism that usually causes milder signs and symptoms than other types of pneumonia. Walking pneumonia, a term used to describe not pneumonia severe enough to require bed rest may be caused by Mycoplasma pneumonia.
Hospital pneumonia. If you're hospitalized, you're at high risk for pneumonia, especially if you're on a ventilator in an intensive care unit or have a weakened immune system. This type of pneumonia can be extremely serious, especially in the elderly, young children, and people with chronic obstructive pulmonary disease (COPD) or HIV/AIDS.

Nosocomial pneumonia develops at least 48 hours after admission. This category includes postoperative pneumonia - most common in people older than 70 years, who have had surgery on the abdomen or chest - and related to pneumonia acquired in long-term care facilities, centers, where drugs are given intravenously (infusion) and dialysis is done.

A common factor for this type of pneumonia is gastroesophageal reflux disease (GERD). This happens when stomach juices enter the esophagus. From there, gastric juices can be inhaled into the trachea and then into the lower respiratory tract. Even small amounts of gastric juice can lead to pneumonia.

Aspiration pneumonia. This type of pneumonia occurs when foreign substances enter the lungs - most often when stomach contents enter the lungs after vomiting. This usually occurs when a brain injury or other condition affects the normal reflexes of the mouth.

Another cause of aspiration pneumonia is heavy drinking. Choking occurs when an intoxicated person vomits and inhales.

Difficulty swallowing, which occurs with diseases such as amyotrophia (ALS), Parkinson's disease, stroke, can also lead to aspiration pneumonia.

Pneumonia by opportunistic organisms. This is a type of pneumonia in people with weakened immune systems. Organisms that are not harmful to healthy people can be dangerous to people with AIDS and other conditions with weakened immune systems, as well as people with organ transplants. Drugs that suppress the immune system, such as corticosteroids or chemotherapy, can also put you at risk for opportunistic pneumonia.

Other pathogens. H5N1 flu (avian flu) and severe viral acute respiratory syndrome (SARS) have caused severe pneumonia, deadly pneumonia that sometimes occurs, even in previously healthy people. Although anthrax - rare, bubonic plague and tularemia can also cause pneumonia. Some fungi, when inhaled, can cause pneumonia. Tuberculosis in the lungs can also cause pneumonia.

Dust pneumonia. Dust pneumonia is a chronic fibrous lung disease caused by the inhalation of coal dust and inert, inorganic, or silicate dust. Dust pneumonia due to inhalation of inert dust is usually an asymptomatic disorder with diffuse nodular infiltrates on radiographs. Clinically important dust mite diseases include pneumoconiosis in coal miners, silicosis, and asbestosis.

Risk factors

Pneumonia risk factor diagnosisbook

Pneumonia risk factor 

Age. If you're 65 or older, especially if there are other conditions that make pneumonia more likely to develop. Infants, whose immune systems are not fully developed, are also at risk for pneumonia.

Some diseases. These include immunocompromised diseases such as HIV/AIDS and chronic diseases such as cardiovascular disease, emphysema, other lung diseases, and diabetes. There is also an increased risk if the immune system is weakened by chemotherapy or long-term use of immunosuppressive drugs.

Smoking, alcohol abuse. Millions of tiny hairs cover the surface of the cells lining the bronchial tubes. The hairs clear the airways of normal secretions, but irritants such as cigarette smoke paralyze the cilia. If the secretions contain bacteria, they can develop into pneumonia. Alcohol interferes with normal reflexes as well as with the function of white blood cells that fight infection.

Hospitalization in an intensive care unit. Hospital-acquired pneumonia tends to be more severe than other types of pneumonia. People requiring mechanical ventilation are, particularly at risk.

COPD and inhaled corticosteroid use for more than 24 weeks. Research indicates that this greatly increases the risk of developing pneumonia, which can be serious.

Exposure to chemicals or pollutants. The risk of developing pneumonia may be increased if you work in agriculture, construction, or around industrial chemicals or animals. Exposure to polluted air or toxic gases can also contribute to pneumonia.

Injury. People who have surgery or who are immobilized from an injury or trauma are at high risk of developing pneumonia from surgery or a serious injury can relieve coughing - making it harder to clear the lungs, and lying flat can allow mucus to build up in the lungs, creating a breeding ground for bacteria.

Nation. If you are an Alaskan or certain Native American tribe, there is a greater risk of pneumonia.


The severity of pneumonia often depends on your overall health and the type and extent of pneumonia.

If young and healthy, pneumonia can be successfully treated. However, some organisms that cause pneumonia are so dangerous that they overwhelm defense mechanisms, even in healthy people.

If you have heart failure or lung disease, especially if you smoke, or are older, pneumonia can be very difficult to treat successfully. There's also a greater chance of developing complications, some of which can be life-threatening.

Complications of pneumonia can include:

Bacteria in the blood. Pneumonia can be life-threatening when it infects many of the alveoli in the lungs and interferes with the ability to breathe. In some cases, the infection can enter the bloodstream. It can then spread rapidly to other organs.

Peripheral effusion and infection. Sometimes fluid builds up between the lungs and pleura, which is called a pleural effusion. Normally, the pleura is smooth, allowing the lungs to move easily along the chest wall when breathing in and out. But when the pleura becomes inflamed (pleurisy) — usually from pneumonia — fluid can accumulate and possibly become infected (empyema).

Lung abscess. A pus-filled cavity (abscess) in the area affected by pneumonia is a potential complication.

Acute respiratory distress syndrome (ARDS). Pneumonia in both lungs. Pneumonia covers most areas of both lungs, making breathing difficult and hypoxemia. Any underlying lung disease, but especially COPD, predisposes to ARDS.

Tests and diagnostics

Your doctor may suspect pneumonia based on your medical history and examination. You may undergo some or all of these tests:

Clinical examination. The doctor listens to the lungs to check for abnormal sounds or rales and signal the presence of fluid.

X-ray. X-rays can confirm the presence of pneumonia and determine the extent and location of the infection.

Blood and mucus tests. Blood tests may be done to measure white blood cell counts and look for the presence of viruses, bacteria, or other organisms. Your doctor may also test a sample of mucus or blood to help identify the specific microorganisms that are causing the illness.

Treatments and drugs

Treatments for pneumonia are different, depending on the severity of your symptoms and the type of pneumonia.

Bacteria. Doctors usually treat bacterial pneumonia with antibiotics. Although you may start to feel better soon after you start taking it, be sure to complete the entire dose of antibiotics. Stopping the medication too soon can cause pneumonia to return. It also helps create antibiotic-resistant strains of bacteria.

Viruses. Antibiotics are not effective against most viral pneumonia. And although some viruses that can cause pneumonia are treated with antiviral drugs, the recommended treatment is usually rest and plenty of fluids.

Mycoplasma. Pneumonia Mycoplasma is treated with antibiotics. Even so, there may not be an immediate recovery. In some cases, fatigue can continue long after the illness has gone into remission. Many cases go undiagnosed and untreated. Signs and symptoms mimic those of a cold, so some people never seek medical attention. Symptoms usually go away on their own.

Fungus. If the pneumonia is caused by a fungus, it can be treated with antifungal medications.

Coping with the symptoms

Besides treatments, your doctor may recommend over-the-counter medications to reduce fever, treat aches and pains, and soothe coughs associated with pneumonia. However, because coughing helps clear the lungs so it may not need to eliminate coughing completely. If it must be used to relieve a cough, use the lowest dose that provides rest.

When hospitalization is necessary

If pneumonia is severe, you will need to be hospitalized and treated with intravenous antibiotics and possibly oxygen. If oxygen is unnecessary, a quick recovery at home with oral antibiotics is possible, as in hospitals, especially if there is adequate access to home health care. It can sometimes be three or four days in the hospital with intravenous antibiotics and then continue to recover at home with oral medications.

Follow up treatment

Your doctor will most likely recommend a schedule of radiological follow-up and follow-up visits after initial diagnosis and treatment. By that time the infection is gone, but it's important for your doctor to watch, even if you're feeling better. Following appointments and radiographs is especially important in smokers.

If you don't feel better, your next visit is an opportunity for your doctor to determine the effectiveness of your treatment and do further testing to get more information about your condition.

Lifestyle and Remedies

If you have pneumonia, the following measures can help you recover faster and reduce your risk of complications:

Rest much. Even when starting to feel better, be careful and don't overdo it.

Stay home until the temperature returns to normal and the coughing up mucus stops. This advice depends in part on how sick it is. If unsure, ask your doctor. Because pneumonia can recur within a week or so.

Drink a lot of water. The fluid keeps you from becoming dehydrated and helps loosen mucus in your lungs.

Take the full dose of any prescribed medicine. Stopping the medication too soon can cause pneumonia to return and contribute to the development of antibiotic-resistant bacteria.

Keep all appointments. Even if you feel better, your lungs can still become infected. It is important to have a follow-up doctor.


Pneumonia is it contagious?


Because pneumonia can be a complication of the flu, a yearly flu shot is a good way to prevent pneumonia caused by the flu virus, which can lead to bacterial pneumonia. In addition, although there is some controversy over its effectiveness, especially in older adults, doctors recommend getting the pneumococcal pneumonia vaccine at least once after age 50, and if any risk factors, every five years thereafter. Your doctor will recommend the pneumonia vaccine even if you are younger than 50 if you are a smoker if you have lung cancer, heart disease, certain types of cancer, diabetes, or sickle cell anemia, if your system compromised your immune system, or if the spleen has been removed.

A vaccine called pneumococcal conjugate vaccine can help protect children against pneumonia. It is recommended for all children under 2 years of age and for children ages 2 to 5 years who are at particular risk for pneumococcal diseases, such as those with immune system deficiencies, cancer, cardiovascular disease, or sickle cell anemia, or those attending a daycare group. Side effects from the pneumococcal vaccine are usually mild and include mild pain or swelling at the injection site.


Hands are constantly in contact with most of the germs that can cause pneumonia. These germs enter the body by touching the eyes or rubbing the inside of the nose. Washing hands frequently and thoroughly can help reduce the risk. When washing is not possible, use alcohol-based hand sanitizer, which can be more effective than soap and water at killing disease-causing bacteria and viruses.

No smoking

Smoking often damages the defense system against respiratory infections.

Take care of yourself

Proper rest and a diet rich in fruits, vegetables, and whole grains along with moderate exercise can help keep the immune system strong.

Treatment of Gerd

Treat GERD symptoms, and lose weight if you are overweight.

Protect others from infection

If pneumonia, try to stay away from anyone with a compromised immune system. When that's not possible, you can help protect others by wearing a mask and always coughing into a tissue.

Related articles:

Pneumonia is an infection that inflames the air sacs in one or both lungs.

The germs that cause pneumonia are contagious.

Medications for Pneumonia.

Related books: 

1. Streptococcus Pneumoniae: Molecular Mechanisms of Host-Pathogen Interactions: Download here.

2. Community-Acquired Pneumonia: Strategies for Management: Download here.

3. Clinical Management of Bacterial Pneumonia: Download here.

4. Severe Pneumonia (Lung Biology in Health and Disease, Volume 206): Download here.

5. Community-Acquired Pneumonia: Download here.