Acute Respiratory Infection

Written by Christine DiMaria and Matthew Solan | Published on July 25, 2012
Medically Reviewed by Sylvia S. Hanna, MD


Acute respiratory infection is a serious infection that prevents normal breathing function. It usually begins as a viral infection in the nose, trachea (windpipe), or lungs. If the infection is not treated, it can spread to the entire respiratory system.

Acute respiratory infection prevents the body from getting oxygen and can result in death. If you suspect that you or someone else may be suffering from this condition, contact a medical professional immediately.

Also, acute respiratory infections are infectious, which means they can spread from one person to another.

The disease is quite widespread. It is particularly dangerous for children, older adults, and people with immune system disorders. According to the World Health Organization (WHO), acute respiratory infections kill an estimated 2.6 million children annually every year worldwide. (WHO)

What Are The Symptoms of Acute Respiratory Infection?

The early symptoms of acute respiratory infection usually appear in the nose and upper lungs. Other symptoms include:

  • congestion, either in the nasal sinuses or lungs
  • runny nose
  • cough
  • sore throat
  • body aches
  • fatigue

If the disease advances, there may be high fever and chills. Other serious symptoms are:

  • difficulty breathing
  • dizziness
  • low blood oxygen level
  • loss of consciousness

What Causes Acute Respiratory Infection?

Although some causes of the condition are unknown, a few have been identified:


Adenoviruses are a class of microorganisms that can cause acute respiratory infection. Adenoviruses consist of more than 50 different types of viruses known to cause the common cold, bronchitis, and pneumonia.


Pneumococcus is a type of bacterium that causes meningitis. However, it can also trigger certain respiratory illnesses like pneumonia.


Rhinoviruses are the source of the common cold, which in most cases is uncomplicated. However, in the very young, elderly, and people with a weak immune system, a cold can advance to acute respiratory infection.

How Is Acute Respiratory Infection Diagnosed?

In a respiratory exam, the doctor focuses on the patient’s breathing. Breath sounds in the lungs are checked for fluid and inflammation. The doctor may peer into the nose and check the throat. If caught early, over-the-counter medications can help alleviate symptoms while the virus runs its course. However, if the infection is advanced, an X-ray or CT scan (computer tomography) may be needed to check the condition of the lungs.

Lung function tests have shown to be useful as diagnostic tools and for prognosis purposes. Pulse oximetry, also known as pulse ox, may be used to check how much oxygen gets into the lungs. A physician may also need a sputum (material coughed up from the lungs) sample to check for the type of virus causing the disease.

Who Is at Risk for Acute Respiratory Infection?

While it is almost impossible to avoid viruses and bacteria, certain risk factors increase the likelihood of developing acute respiratory infection. The immune systems of children and the elderly are more prone to be affected by viruses. Children are especially at risk because of their constant contact with other kids who could be virus carriers. Children often do not wash their hands regularly, rub their eyes, and put their fingers in their mouths, resulting in the spread of viruses.

People with heart disease or other lung problems are more likely to contract an acute respiratory infection. Anyone whose immune system might be weakened by another disease is at risk. Smokers also are at high risk and have more trouble recovering from it.

How Is Acute Respiratory Infection Treated?

With many viruses, there are no known cures. Your doctor may prescribe medications to manage your symptoms while monitoring your condition. If the viral infection results in a “secondary infection,” caused by bacteria, tests will help your doctor determine what type of antibiotic should be used.

What Are Potential Complications of Acute Respiratory Infection?

Complications of acute respiratory infection are extremely serious and can result in permanent damage and even death. They include:

  • respiratory arrest
  • respiratory failure
  • congestive heart failure

Preventing Acute Respiratory Infection

Most causes of an acute respiratory infection are not treatable. Therefore, prevention is the best method to ward off harmful respiratory infections. Practice good hygiene by doing the following:

  • Wash your hands frequently, especially after you’ve been in a public place.
  • Always sneeze into the arm of your shirt or in a tissue. Although this may not ease your own symptoms, it will prevent you from spreading infectious diseases.
  • Avoid touching your face, especially your eyes and mouth, to prevent introducing germs into your system.

You should avoid smoking and make sure you include plenty of vitamins in your diet, such as vitamin C, which helps boost your immune system.

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