Pneumonia: 5 things to know

Sandee LaMotte, CNN | 4/5/2017, 10:15 a.m.
Your chest is tight, and at times, it's hard to catch your breath. You wheeze or cough so hard that ...
Pneumonia

(CNN) -- Your chest is tight, and at times, it's hard to catch your breath. You wheeze or cough so hard that your sides soon ache.

You're so tired, it's as if all the blood has drained from your body. A fever spikes. You get chills and begin to shake.

These are all signs of pneumonia, a serious lung infection that claims the lives of hundreds of thousands of people around the world each year.

Here are five key things to know about this potentially deadly illness.

1. What causes pneumonia?

Pneumonia can be caused by a virus, bacteria or even a fungus. Although pneumonia itself is not contagious, the germs that can cause it are. If caused by a virus, it can easily develop into bacterial pneumonia, which can be quite serious.

Pneumonia occurs when the air sacs, or alveoli, of the lungs fill with fluid or pus. That makes it harder to take a breath and get enough oxygen. Without treatment, oxygen levels can fall to life-threatening levels.

Pneumonia can occur in one lung or both lungs, which is called double pneumonia. Or you can have it and not even know it, a condition known as "walking pneumonia."

2. Risk factors for pneumonia

Most healthy people can fight off pneumonia, but for the young, old, frail or immune-compromised, the disease can be tough to battle. In the United States alone, pneumonia kills about 50,000 people a year, mostly adults over 75 and children under 5.

According to UNICEF, more than 2,500 children a day die from pneumonia around the world, most of those under the age of 2, making it the leading cause of death for little ones.

Anyone with a chronic disease such as diabetes, kidney problems, heart failure, HIV/AIDS or a lung disease like COPD is also at high risk, as is anyone undergoing chemotherapy or taking an immunosuppressant drug. Smoking and drinking too much alcohol can also raise your chances of getting the disease.

3. Pneumonia symptoms

Many of the symptoms of pneumonia mimic those of a cold or the flu. So how do you tell the difference?

In general, colds tend to come on rather slowly, probably with a runny nose and sore throat. If you add fever, body aches and headache that come on quickly, it could be you have the flu. Pneumonia is usually a complication of cold or flu, when the illness lodges in the lungs.

If your pneumonia is caused by a virus, the symptoms will be flu-like for the first few days: dry cough, fever, headache, shaking chills, extreme fatigue, a poor appetite, and muscle pain and weakness. But then the cough will worsen and produce mucus, fever will spike, and breathing will worsen. You might have a sharp or stabbing chest pain. Lips might turn bluish.

People who have viral pneumonia are at high risk of developing bacterial pneumonia.

With bacterial pneumonia, you could also have a very high fever (105 degrees) and profuse sweating, with fast, labored breathing and a higher pulse. Due to lack of oxygen, there could be a bluish tinge under your nails. There could be mental confusion, especially in the elderly.