Acute Respiratory Infection: Causes, Symptoms & Diagnosis

Acute Respiratory Infection

What Is Acute Respiratory Infection?

Acute respiratory infection is an infection that may interfere with normal breathing. It usually begins as a viral infection in the nose, trachea (windpipe), or lungs. If the infection isn’t treated, it can spread to the entire respiratory system.

Acute respiratory infections are infectious. This means they can spread from one person to another.

The disease is quite widespread. It’s particularly dangerous for children, older adults, and people with immune system disorders.

What Causes Acute Respiratory Infection?

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While 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. It can also trigger certain respiratory illnesses like pneumonia.


Rhinoviruses are the source of the common cold. Colds are uncomplicated in most cases. However, in the very young, older adults, and those with a weak immune system, a cold can lead to acute respiratory infection.

Who Is at Risk for Acute Respiratory Infection?

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It’s almost impossible to avoid viruses and bacteria, but certain risk factors increase your chances of developing acute respiratory infection. The immune systems of children and older adults are more prone to being affected by viruses. Children are especially at risk because of their constant contact with other kids who could be virus carriers. Children often don’t wash their hands regularly. They 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.

What Are the Symptoms of Acute Respiratory Infection?

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

How Is Acute Respiratory Infection Diagnosed?

Risk Factors

In a respiratory exam, the doctor focuses on the patient’s breathing. They will check for fluid and inflammation in the lungs by listening to your breath sounds in the lungs. The doctor may peer into your nose and check your 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 may be necessary to check the condition of the lungs.

Lung function tests have been useful as diagnostic tools. Pulse oximetry, also known as pulse ox, can 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.

How Is Acute Respiratory Infection Treated?

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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 the appropriate type of antibiotic to use.

What Are Potential Complications of Acute Respiratory Infection?

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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

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Most causes of an acute respiratory infection aren’t 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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