Acute respiratory infections (ARIs) are illnesses that interfere with normal breathing, affecting the air passages from the sinuses down to the lungs. These infections are a significant global health concern, accounting for millions of deaths annually and placing a burden on healthcare systems. ARIs can range from mild, self-resolving conditions to severe diseases, especially in vulnerable populations.
Classification of Acute Respiratory Infections
ARIs are categorized based on the anatomical location of the infection. The two main classifications are upper respiratory infections (URIs) and lower respiratory infections (LRIs). Upper respiratory infections affect the breathing passage from the nostrils to the vocal cords, including the nose, sinuses, pharynx, and larynx. Examples of URIs include the common cold, sinusitis, and pharyngitis, which is a sore throat.
Lower respiratory infections involve the airways below the vocal cords, including the trachea, bronchial tubes, and the lungs. These infections are more severe than URIs. Common examples of LRIs are bronchitis, which is the inflammation of the bronchial tubes; bronchiolitis, an infection of the small airways in the lungs; and pneumonia, an infection that inflames the air sacs in the lungs.
Causative Agents and Transmission
The primary causes of acute respiratory infections are a wide variety of viruses and bacteria. Viruses are responsible for the vast majority of ARIs, especially those affecting the upper respiratory tract. Common viral culprits include rhinoviruses, influenza viruses, respiratory syncytial virus (RSV), and coronaviruses.
Bacterial infections, while less frequent, can cause more severe ARIs. Key bacterial pathogens include Streptococcus pneumoniae, a common cause of pneumonia, and Haemophilus influenzae. Fungal infections can also cause ARIs but affect individuals with weakened immune systems.
Transmission occurs by inhaling respiratory droplets from an infected person’s cough or sneeze. It also spreads through contact with contaminated surfaces, followed by touching one’s own mouth, nose, or eyes.
Recognizing Symptoms and Seeking Diagnosis
The symptoms of an ARI vary depending on the infection’s location. Common signs include coughing, sneezing, a sore throat, a runny or stuffy nose, body aches, headaches, and fatigue. A mild fever may also be present with upper respiratory infections.
Certain symptoms signal a more severe infection that requires medical attention. These include a high fever, shortness of breath, chest pain, or wheezing. Bluish lips or face and feelings of confusion are also warning signs that necessitate immediate care.
Diagnosis begins with a physical examination and a review of symptoms. A doctor may take a nasal or throat swab to identify pathogens like influenza. If pneumonia is suspected, a chest X-ray or CT scan might be ordered to view the lungs.
Management and Treatment Approaches
The management of most viral ARIs centers on supportive care to help the body fight the infection. This approach includes getting plenty of rest, staying well-hydrated, and using a humidifier to ease congestion and soothe the throat.
Over-the-counter medications can provide symptom relief. Pain relievers like acetaminophen or ibuprofen manage body aches and fever. Decongestants can help with a stuffy nose, and cough suppressants may offer temporary relief from a persistent cough.
Antibiotics are only effective against bacterial infections and have no impact on viruses, so they are not prescribed for viral illnesses like the common cold. Overuse of antibiotics contributes to antibiotic resistance, so they are reserved for cases where a bacterial infection is confirmed. In some viral cases, such as influenza, antiviral drugs may be prescribed if the infection is diagnosed early.
Prevention Strategies and Risk Factors
Preventing the spread of ARIs involves several proactive measures. Vaccinations against influenza, COVID-19, and pneumococcal disease reduce the risk of severe outcomes. Good hygiene, including frequent handwashing and coughing into an elbow, also helps contain infectious droplets.
Certain populations are at a higher risk of developing severe complications from ARIs. These include young children, older adults, and people with weakened immune systems. Other risk factors include chronic conditions like asthma, heart disease, or other lung problems, as well as being pregnant.