Introduction
Acute respiratory viral infection can be described as an infection affecting the lungs and causing difficulty in breathing in an individual. This infection can be seen in both the upper and lower respiratory system. The upper respiratory system begins at the nose, nasal cavity, mouth, and throat, and ends at the voice box. The lower respiratory system starts from the windpipe and the lungs, including the bronchi, bronchioles, and alveoli (air sacs). Further, in the lungs, the bronchus branches out into secondary and tertiary bronchi and subdivides into bronchioles. The bronchi and bronchioles are also known as the airways.
Respiratory viral infection is a serious problem in children, individuals with immune system disorders which weaken the immune response, and the elderly. Most kids are at higher risk as they are in contact with other children who could be virus carriers. Most upper respiratory infections are contagious and can spread widely and easily. The infection can spread by inhaling respiratory droplets from sneezing and coughing.
Viral infections mostly affect the upper or lower respiratory tract and result in respiratory infections. It is believed that respiratory infections can be classified by the causative virus (for example - influenza). Still, they are generally classified according to the clinical syndrome (for example - common cold, croup, bronchiolitis, and pneumonia). There are specific pathogens that commonly cause characteristic clinical manifestations; for example, rhinovirus causes the common cold, and the respiratory syncytial virus typically causes bronchiolitis. Each can cause many viral respiratory syndromes.
The seriousness of viral respiratory illness varies widely; severe disease is more likely to be seen in older patients and infants. Viral infection may directly or indirectly result in morbidity. This is mainly due to worsening underlying cardiopulmonary conditions or bacterial superinfection of the lung, paranasal sinuses, or middle ear.
What Are the Causative Agents of Acute Respiratory Viral Infection?
Viral pathogens are the most common cause of respiratory infection, which can be the upper or lower respiratory system. The causative agents include:
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Rhinoviruses.
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Respiratory syncytial.
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Influenza.
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Parainfluenza.
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Human metapneumovirus.
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Measles.
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Adenovirus.
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Coronaviruses.
It should also be noted that viruses are of special concern and are commonly spread through travelers, especially people traveling from Asian countries who are more likely to have Middle East respiratory syndrome (MERS) Coronavirus.
Middle East respiratory syndrome is the differential diagnosis for patients with fever and pneumonia-like symptoms for 14 days after traveling from countries. Therefore, contact with a confirmed or suspected MERS case or healthcare facilities with MERS transmission is of special concern, even in the absence of confirmed pneumonia. It should be kept in mind that regions associated with MERS may expand or change.
Bacterial pathogens are less common than viral but can include Streptococcus pneumonia, Mycoplasma pneumonia, Haemophilus influenzae, and Chlamydophila pneumonia. In addition, Coxiella burnetii and Legionella pneumophila can cause outbreaks and sporadic cases of respiratory illness. Bacterial sinusitis, bronchitis, or pneumonia may occur secondarily after a viral respiratory infection.
What Are the Symptoms of Acute Respiratory Viral Infection?
The symptoms of acute respiratory viral infections are different. But some common symptoms might include:
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Fever.
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Runny nose.
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Sore throat.
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Congestion.
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Fatigue.
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Cough.
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Body aches.
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Pneumonia.
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Difficulty in breathing.
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Nasal congestion.
How Do Respiratory Viruses Spread?
The viruses are spread through aerosols or droplets coughed or sneezed into the air. The drops are inhaled or indirectly infected through contaminated hands, handkerchiefs, toys, and other objects that can come in contact with the eyes and nose.
How Is Acute Respiratory Viral Infection Diagnosed?
The diagnosis depends on the symptoms, the laboratory investigations, and the physical examination:
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The doctors observe breathing.
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The healthcare provider will check for inflammation and fluid in the lungs. They usually do it by listening to the abnormal sounds made when they breathe.
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The doctor will examine the throat, nose, and ears.
The doctor may take a swab from the mouth and nose. The physician may also ask the patient to cough up sputum. This is to check for the type of virus that is causing the disease. In the physical examination of upper respiratory infection, the doctor may look for:
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Redness of the throat.
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Redness in the wall of the nasal cavity.
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White secretions on the tonsils.
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Enlargement of the tonsils.
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Facial tenderness.
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Redness of the eyes.
Moreover, the laboratory test is recommended to diagnose a lower respiratory infection. Blood tests and imaging tests are rarely required. However, a chest X-ray and CT (computed tomography) scan are necessary if the doctor believes the infection is in the lower respiratory system. A useful diagnostic tool is lung function tests. Pulse oximetry helps to check the oxygen levels in the lungs.
The doctor may prescribe medications according to the symptoms while treating a respiratory infection. It is very important to monitor the patient's condition. In case of bacterial infection, the healthcare provider will indicate the administration of antibiotics.
What Is the Treatment for the Common Viral Respiratory Disease?
Infection without any serious complications will generally subside in two to five days. Bacterial complications such as otitis media, pneumonia, and sinusitis may require antibiotics.
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Oseltamivir and Zanamivir are indicated for influenza.
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Ribavirin is a guanosine analog that is indicated to inhibit the replication of RNA and DNA viruses and may be considered for severely immunocompromised patients with lower respiratory tract infections.
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Palivizumab is a type of monoclonal antibody to RSV fusion protein that is being used to prevent RSV infection in certain high-risk children.
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Nirmatrelvir with Ritonavir, Remdesivir, Molnupiravir, or monoclonal antibodies after the onset of symptoms of COVID-19 is considered to prevent the progression to severe disease in patients, and Remdesivir and monoclonal antibodies are indicated for severe COVID-19.
How Is Acute Respiratory Viral Infection Prevented?
Prevention of viral respiratory diseases is very important. Certain good habits can help with the same like:
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Maintaining personal hygiene.
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Covering the mouth when coughing and sneezing.
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Sanitary disposal of discharges from nose and mouth.
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Frequent handwashing.
Vaccines for influenza are developed each year in accordance with the three predominant subtypes anticipated. Unfortunately, developing a vaccine for a constantly mutating virus is difficult. Currently available vaccines significantly reduce the risk of influenza infection. They are specifically recommended each year for persons at greatest risk for life-threatening complications, especially the elderly and patients with chronic underlying health conditions of the heart, lungs, and kidneys.
Adenovirus vaccines are most effective against certain types of adenovirus infections. However, because of the major disruption and economic impact of epidemics on military recruits, vaccines are targeted at this group but are not recommended for the general population.
What Are the Potential Complications of Acute Respiratory Infection?
Complications of acute respiratory viral infection are extremely serious and can result in life-threatening conditions. They include:
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A respiratory arrest.
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Respiratory failure is a rise in carbon dioxide in the blood caused by the lungs not functioning correctly.
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Congestive heart failure.
Conclusion
Acute respiratory viral infections are a leading cause of doctor visits worldwide. They are mostly caused by viruses and affect the nose, sinuses, and throat. These infectious symptoms include a runny nose, congestion, sneezing, cough, and mucus secretion. Most patients recover without any prescribed antibiotics within a few weeks. Preventive measures include frequent handwashing, avoiding close contact with people who are sick, and staying home when a person is not feeling well.
