Pneumonia is inflammation (swelling) of tissue in one or both lungs. It is a condition which primarily affects the air sacs of lungs called as alveoli. It is usually caused by infection with viruses or bacteria and less commonly other microorganisms, certain drugs.

Pneumonia can range in seriousness from mild to life-threatening. It is most serious for infants and young children, people older than age 65, and people with health problems or weakened immune systems.

Symptoms

Signs and symptoms of pneumonia may include:

Chest pain when you breathe or cough
Confusion or changes in mental awareness (in adults age 65 and older)
Cough, which may produce phlegm
Fatigue
Fever, sweating and shaking chills
Lower than normal body temperature (in adults older than age 65 and people with weak immune systems)
Nausea, vomiting or diarrhea
Shortness of breath

Newborns and infants may not show any sign of the infection. Or they may vomit, have a fever and cough, appear restless or tired and without energy, or have difficulty breathing and eating.

Causes

Pneumonia is primarily due to infections caused by bacteria or viruses and less commonly by fungi and parasites.

Bacterial pnuemonia: Bacteria are the most common cause of community-acquired pneumonia (CAP), with Streptococcus pneumoniae isolated in nearly 50% of cases . Other commonly isolated bacteria include haemophilus influenzae, Chlamydophila pneumoniae, and Mycoplasma pneumoniae .

Viral pnuemonia : Various virus include rhinoviruses, coronaviruses, influenza virus and para influenza .

Fungal pnuemonia: It is most often caused by Histoplasma capsulatum, blastomyces,Cryptococcus neoformans, Pneumocystis jiroveci, and Coccidioides immitis.

Diagnosis

Early diagnosis and treatment is  very important for invasive pneumococcal disease.

If disease, like meningitis or bloodstream infections, is suspected, samples of blood or cerebrospinal fluid are collected and sent to the laboratory for testing. It is important to know the cause and the severity of illness as the treatment will change depending on the cause. In the case of pneumococcal disease, antibiotics can help prevent severe illness.

If pneumococcus bacteria are present with invasive disease, they can be grown (cultured).

Physical examination may sometimes reveal low blood pressure, high heart rate or low oxygen saturation. The respiratory rate may be faster than normal and this may occur a day or two before other signs.

Management

Treatment for pneumonia involves curing the infection and preventing complications. People who have community-acquired pneumonia usually can be treated at home with medication. Although most symptoms ease in a few days or weeks, the feeling of tiredness can persist for a month or more.

Specific treatments depend on the type and severity of your pneumonia, your age and your overall health. The options include:

Antibiotics. These medicines are used to treat bacterial pneumonia. It may take time to identify the type of bacteria causing your pneumonia and to choose the best antibiotic to treat it. If your symptoms don’t improve, your doctor may recommend a different antibiotic.

Cough medicine. This medicine may be used to calm your cough so that you can rest. Because coughing helps loosen and move fluid from your lungs, it’s a good idea not to eliminate your cough completely. In addition, you should know that very few studies have looked at whether over-the-counter cough medicines lessen coughing caused by pneumonia. If you want to try a cough suppressant, use the lowest dose that helps you rest.

Fever reducers/pain relievers. You may take these as needed for fever and discomfort. These include drugs such as aspirin, ibuprofen (Advil, Motrin IB, others) and acetaminophen (Tylenol, others).

Hospitalization

You may need to be hospitalized if:

You are older than age 65
You are confused about time, people or places
Your kidney function has declined
Your systolic blood pressure is below 90 millimeters of mercury (mm Hg) or your diastolic blood pressure is 60 mm Hg or below
Your breathing is rapid (30 breaths or more a minute)
You need breathing assistance
Your temperature is below normal
Your heart rate is below 50 or above 100

You may be admitted to the intensive care unit if you need to be placed on a breathing machine (ventilator) or if your symptoms are severe.

Children may be hospitalized if:

They are younger than age 2 months
They are lethargic or excessively sleepy
They have trouble breathing
They have low blood oxygen levels
They appear dehydrated

Complications

Complications associated with pneumonia are:

1) Pleurisy: Pneumonia can cause pleurisy, which is inflammation of the pleura, the two thin linings between your lungs and your ribcage.
2) Septicemia: Another serious complication of pneumonia is blood poisoning, also known as septicemia.

Prevention

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