Lower respiratory tract infections are among the most frequent pathologies encountered in clinical practice and often appear in subjects with underlying chronic respiratory diseases, such as in particular asthma and chronic obstructive pulmonary disease (COPD).
Pneumonia is diagnosed especially in young children and in elderly subjects.
In the etiology of lower respiratory tract infections, respiratory viruses predominate, Streptococcus pneumoniae and Haemophilus influenza, followed by Mycoplasma pneumonia, Chlamydia trachomatis, Legionella, Staphylococcus aureus, Klebsiella pneumonia, Pseudomonas aeruginosa, and Escherichia coli. Bronchitis and CAP have differences in terms of etiology compared to hospital-acquired forms (nosocomial). In fact, the nosocomial respiratory infectious forms are compared to the “community” ones more frequently due to Gram-negative, anaerobic and to the Staphylococcus aureus, while viral forms are rarer.
Lower respiratory tract infections can show various types of symptoms, including cough (often productive) and dyspnea, that is the subjective feeling of shortness of breath that is excessive both for the entity and for the type of physical activity it follows. Fever is a symptom commonly associated with lower respiratory tract infections, although in many cases it may be mild or absent. For the management and treatment of patients with acute bronchitis, symptomatic treatment (anti-inflammatory, cough suppressants) is generally used, and antibiotics are administered in case of severe infection with fever and/or if the condition does not resolve in 5 -6 days.
The treatment of infectious pneumonia varies according to the causative agent and the patient’s clinical conditions. As for infectious bacterial pneumonia, ideally antibiotic therapy should be based on the isolation of the microbial agent with definition of the specific antibiotic-resistance profile; often, however, antibiotic therapy must necessarily be set on an “empirical” basis, i.e. according to the etiological hypothesis formulated on the basis of clinical-epidemiological assessments and any individual risk factors of the patient.