1.1. Viral respiratory tract infections
Formulating a diagnosis
Components of the diagnosis: - clinical form;
- severity;
- complications
| &hide_Cookie=yes) |
Viral respiratory tract infections (VRTI) are a heterogeneous group of diseases, the etiologic agents of which are various respiratory viruses that mainly affect the upper respiratory tract epithelium.
Upper respiratory tract infections are the commonest infections seen in both pediatric and adult populations, with the majority caused by viruses, such as adenovirus, Epstein–Barr virus, parainfluenza, influenza A, Coxsackie A, respiratory syncytial virus, and herpes simplex, among others.
Nearly all of these viral infections are of short duration and require only symptomatic management.
Clinical form
VRTI clinical presentation can vary significantly depending on the etiology, patient’s age, immune system state, and presence of concomitant diseases. The symptoms of VRTI usually include nasal obstruction, headache, sore throat, sneezing, cough, malaise, nasal discharge, low- or high grade fever, mild myalgias, and fatigue.
The types of VRTI, and clinical manifestations depending on the pathogens are presented at table 1.1.
Table 1.1. Viral respiratory tract infections types and their clinical manifestations
| Disease | Etiologic agent* | Clinical manifestations |
| Influenza** | RNA-viruses of the Orthomyxoviridae family | Symptoms vary from a mild respiratory disease confined to the upper respiratory tract and characterized by fever, sore throat, runny nose, cough, headache, muscle pain and fatigue to severe and in some cases lethal pneumonia owing to influenza virus or to secondary bacterial infection of the lower respiratory tract*** |
| Parainfluenza | RNA-containing paramyxovirus | Systemic signs and symptoms are mild or moderate, catarrhal respiratory syndrome (laryngitis, moderate rhinitis, pharyngitis) |
| Adenovirus infection | DNA-containing viruses from the Adenoviridae family, Mastadenovirus genus | - Systemic signs and symptoms are expressed mildly.
- Catarrhal respiratory syndrome — rhinitis, pharyngitis, conjunctivitis.
- Lymphadenopathy — acute tonsillitis, hepatosplenomegaly; dyspeptic syndrome
|
| Respiratory syncytial infection | Respiratory syncytial virus from the paramyxovirus family | - Systemic signs and symptoms are expressed mildly.
- Catarrhal respiratory syndrome (rhinitis, pharyngitis, bronchiolitis)
|
| Rhinovirus infection**** | RNA-containing Human rhinovirus, Enterovirus genus, Picornaviridae family | - Systemic signs and symptoms are expressed mildly.
- Catarrhal respiratory syndrome (rhinitis, pharyngitis)
|
| Rotavirus infection | RNA-containing virus of the Reoviridae family | - Systemic signs and symptoms are expressed poorly.
- Catarrhal respiratory syndrome (pharyngitis).
- Pain syndrome (cramping pains
in the epigastrium). - Dyspeptic syndrome
|
| Coronavirus infectionConsidering the lack of reliable data on diagnosis, clinical course and treatment of new coronavirus infection COVID-19 (agent of SARS-CoV-2 — severe acute respiratory syndrome coronavirus 2), presence of only «Temporary methodological guidelines for prevention, diagnosis and treatment of new coronavirus infection» (reference is given in the bibliography) at the time of writing this Chapter, the information about this disease is not included in the chapter of the textbook. | RNA-containing virus of the Coronaviridae family | Systemic signs and symptoms are expressed mildly or significantly (depending on the strain of the virus), catarrhal respiratory syndrome (rhinitis, pharyngitis), loss of smell, pneumonia |
| Metapneumovirus infection | Human metapneumovirus | - Systemic signs and symptoms are expressed mildly.
- Catarrhal respiratory syndrome (rhinitis, pharyngitis, bronchiolitis)
|
* There are at least 200 viral types and other infectious agents that can cause the VRTI. The rhinoviruses are the most common and are responsible for 40% of cases: corona viruses causing 10%; respiratory syncytial virus, parainfluenza and influenza virus approximately 10 to 15%; and others 5 to 20%.
** Influenza is an acute respiratory illness caused by influenza A or B viruses that occurs in outbreaks and epidemics worldwide, mainly during the winter season.
*** Initially, nonspecific symptoms predominate, including fever, chills or frank shaking, headaches, myalgia (muscle pain), malaise (discomfort) and anorexia. The onset of these symptoms is sudden, and respiratory symptoms, particularly a dry cough, sore or dry throat (possibly with hoarseness) and nasal obstruction and discharge, are usually also present. Cough can be accompanied by substernal discomfort or burning. Influenza virus infection can also lead to a wide range of non-respiratory complications in some cases — affecting the heart, central nervous system and other organ systems.
**** Rhinoviruses are the most common type of virus and are found in slightly more than half of all patients.
The fig. 1.1 below illustrates the peak incidences of various viruses by season.
&hide_Cookie=yes)
Fig. 1.1. Seasonal variation of selected upper respiratory tract infection viruses
Severity
The severity of the patient’s condition is determined by the severity of systemic signs and symptoms and the presence of complications.
Mild degree — an increase in body temperature of no more than 38,0 °C; moderate headache; heart rate <90 beats/min; systolic blood pressure (SBP) ≥110 mm Hg; respiratory rate (RR) less than 24 per minute; oxygen saturation (SpO2) >95%, no dyspnea, no clinical and auscultation pattern of pneumonia.
Moderate degree — body temperature within 38,1–40 °C; severe headache; hyperesthesia; heart rate 90–120 beats/min; SBP <110 mm Hg; RR 24–28 per minute.
Severe degree — acute onset, body temperature more than 40 °C, severe headache, body aches, insomnia, delirium, anorexia, nausea, vomiting, meningeal symptoms; heart rate over 120 beats/min, pulse of poor volume, possible arrhythmias; SBP <90 mm Hg; muffled heart sounds; respiratory rate >28 per 1 minute.