Lower Respiratory Tract Infections
Lower respiratory tract infections are among the most commonly encountered diseases in clinical practice and often occur in people with underlying chronic respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD).
Pneumonia is diagnosed mainly in young children and the elderly. Death rates associated with the so-called community-acquired pneumonia (CAP) vary considerably between countries.
Respiratory viruses, Streptococcus pneumoniae, and Haemophilus influenzae, followed by Mycoplasma pneumoniae, Clamidia trachomatis, Legionella, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli predominate in the aetiology of lower respiratory tract infections. Bronchitis and CAP differ from the hospital acquired forms (nosocomial) with regard to the aetiology; in fact, compared to community-acquired infections, nosocomial respiratory infections are more frequently due to Gram-negative bacteria, anaerobes and Staphylococcus aureus, while viral forms are more rare.
Lower respiratory tract infections may present with a variety of symptoms, including cough (often productive) and dyspnea, i.e. the subjective sensation of shortness of breath that is inappropriate to the level of physical activity that provoked it. Fever is a symptom commonly associated with lower respiratory tract infections, although in many cases it may be mild or absent. The management and treatment of patients with acute bronchitis usually involves a symptomatic treatment (anti-inflammatories, antitussives) and the administration of antibiotics in case of infection with fever and/or if the disease is not resolved in 5 to 6 days. The treatment of infectious pneumonia varies depending on the causative agent and the clinical condition of the patient. With regard to bacterial pneumonia, antibiotic therapy should be ideally based on the isolation of the responsible organism with determination of its antibiotic resistance profile; however, antibiotic therapy is often “empiric,” i.e. based on the aetiological hypothesis formulated according to clinical and epidemiological considerations and possible individual risk factors of the patient. The duration and the route of administration depend on the severity of the clinical picture and the specific conditions of the patient.