The clinical picture of influenza against other respiratory tract infections in a general practitioner practice.

Abstract

Influenza is an acute infectious disease caused by an RNA virus. In Poland, influenza occurs seasonally during the epidemic period lasting from October to April. The peak of influenza incidence in Poland falls in the first quarter of the year, with a comparable number of cases in January, February and March. Influenza can be severe in some patients, requiring hospitalization, or even fatal, especially in high-risk patients. Analysis of the frequency and course of influenza in primary care patients compared to other respiratory tract infections. The study included a group of 631 adult patients with symptoms of respiratory infection who saw their GP (general practitioner) in the period from December 2018 to April 2020. Patients reporting symptoms of respiratory tract infection were included in the study. Special attention was paid to influenza-like symptoms, i.e. sudden onset fever and ≥ 1 respiratory clinical symptom such as cough, sore throat, rhinitis or feeling of stuffy nose and ≥ 1 systemic symptom such as headache, muscle pain, sweating or chills, fatigue persisting < 72 h. Rapid antigen tests were performed in case of influenza-like symptoms. Influenza was diagnosed in patients with the above symptoms and a positive antigen test. In the study group, 356 rapid flu tests were performed. Age, comorbidities, nicotinism, vaccination status, clinical symptoms, ordered x-rays, laboratory tests, the result of the Actim Influenza A&B rapid antigen test (Medix Biochemica) for influenza virus infection, and the final diagnosis were taken into account. Influenza was diagnosed in 91 patients (in one person on the basis of clinical symptoms, without confirmation with a rapid antigen test), including 50 women and 41 men. The mean age of the patients was 47 years, the age range was 22-89 years. In 90 patients the infection with the influenza virus was confirmed with the Actim Influenza A&B test (Medix Biochemica). One patient was diagnosed with influenza on the basis of typical clinical symptoms, despite a negative antigen test, and prior contact with a person with confirmed influenza. Fever, cough, myalgia, tachypnoea, chest pain and reported respiratory disturbances, confirmed by abnormal results of physical examination, were more frequent in patients with symptoms of influenza and a positive antigen test than in other infections. Influenza was significantly more often observed in patients with impaired glucose tolerance, atherosclerosis, and muscle diseases. Influenza was mainly diagnosed in unvaccinated patients.