Acute Respiratory Viral Infection (ARVI)
Summary/Definition
Acute respiratory infections are mainly caused by viruses or bacteria, rarely by fungi, due to a sudden drop in immunity. The incubation period varies depending on the type of the causative virus, and the clinical symptoms of acute respiratory infections may also vary slightly, but most of the symptoms are similar. For this reason, based on these factors alone, it is always difficult to determine which virus caused the infection to occur. Acute respiratory viral infections can be divided into upper respiratory tract infections and lower respiratory tract infections. Upper respiratory tract infections include upper respiratory tract illnesses, with the main symptom being a sore throat, commonly referred to as a “cold.” Lower respiratory tract diseases refer to lower respiratory tract infections. These include bronchitis and pneumonia, which spread further down the respiratory tract. Respiratory viruses can cause both upper and lower respiratory tract infections. However, in most people with healthy immune systems, respiratory viruses cause only upper respiratory tract infections. Lower respiratory tract infections occur less frequently and mostly in the elderly or patients with chronic illnesses. The most common respiratory viruses causing acute respiratory viral infections include adenovirus, human bocavirus, parainfluenza virus, respiratory syncytial virus, rhinovirus, human metapneumovirus, and coronavirus.
Symptoms
General systemic symptoms as well as signs of inflammation in the upper and lower respiratory tract appear after infection with viruses. The symptoms alone cannot indicate which type of respiratory virus the patient is infected with. Symptoms affecting the upper and lower respiratory tract include a sore throat, runny nose, stuffy nose, cough, and discharge (sputum). If there is a lot of yellow or blood- colored sputum, or if there is difficulty breathing and wheezing on auscultation, there is a possibility of pneumonia, so careful early treatment is necessary. And with a strong cough, painful sensations occur in the thoracic part.
Diagnostics
Usually, acute respiratory viral infections in adults are mild and have a favorable prognosis, so separate investigations are not performed. However, in cases of severe infection, such as those hospitalized with severe pneumonia or immunocompromised people, investigations are carried out to determine the cause of the disease. Diagnosis is made by isolation of respiratory viruses from specimens (throat swab, nasopharyngeal swab, nasal aspirate, nasopharyngeal aspirate, alveolar lavage fluid, sputum, etc.) obtained from the respiratory tract or by amplification. Diagnosis is made on the basis of analyses and the identification of a specific gene that only a particular type of respiratory virus possesses. Since it takes a relatively long time to obtain results from virus isolation, a gene amplification test is most often performed to speed up the time frame.
Treatment and course of the disease
When symptoms of acute respiratory viral infections occur in adults with a healthy immune system, if they are controlled by medication, they disappear in a short time. The course of the disease does not cause special complications, and the prognosis for a cure is favorable. In rare cases, the respiratory infection may progress to pneumonia of viral etiology, which requires more specialized treatment in the intensive care unit. In the case of sepsis, the prognosis for the patient may be disappointing. There are no antiviral drugs that completely suppress the growth of certain types of respiratory viruses. And since, in most cases of infection, they do not cause complications, there is no special antiviral treatment. The main method is conservative treatment, including the intake of fluids, antipyretics, and expectorants.
