Pneumonia is an inflammation of the lung. It is mainly caused by infection with bacteria, viruses, and other organisms. Pneumonia may also occur from chemical or physical injury to the lungs, or indirectly due to another medical illness, such as lung cancer or alcohol abuse.

Causes

Your lungs are two spongy organs surrounded by a moist membrane (the pleura). When you inhale, air is carried through the windpipe (trachea) to your lungs in two major airways called bronchi. Inside your lungs, the bronchi subdivide nearly 20 times into a million smaller airways (bronchioles), which finally end in clusters of tiny air sacs called alveoli. There are five main causes of pneumonia :-

Bacteria

Viruses, such as influenza A (the flu virus) and respiratory syncytial virus (RSV) can cause pneumonia.

Mycoplasmas

Other infectious agents, such as fungi -- including pneumocystis

Various chemicals

More unusual bacteria are sometimes found, especially in those people who have an underlying problem with their immune system. Fungal pneumonia is almost always linked to an immunodeficiency.

Symptoms

Most cases of pneumonia started with a cold in the head or throat. In this illness the patient generally feels a chill, shivering fever, difficulty in breathing, and sharp pain in the chest. This may be followed by a cough with pinkish sputum, which may later become brownish. In young children, the disease may cause delirium and convulsions. The temperature may rise to 40.6 degree C and the pulse may go upto 150 beats per minute.

At last the common symptoms of pneumonia indicating a medical emergency include the following:

A rapid heart rate.

Bluish-toned (cyanotic) skin.

Labored and heavy breathing.

Mental confusion.

Coughing up sputum containing pus or blood.

Treatment

If the cause is bacterial, then the goal of treatment is to cure the infection with antibiotics, which can typically be taken orally at home if the infection is not severe. If the infection is severe, if the person is having difficulty breathing, or has other chronic medical conditions, then intravenous antibiotics may be needed and are usually administered in a hospital.

Your doctor will choose your antibiotic based on a number of things, including your age, your symptoms and how severe they are, and whether you need to go to the hospital.

If you do not have to go to the hospital, your doctor may use any of the following antibiotics:

Macrolides, such as Ery-Tab, Biaxin, Biaxin XL, and Zithromax.

Tetracyclines, such as doxycycline (Vibramycin, Doryx).

Fluoroquinolones, such as Levaquin, Avelox, and Tequin.