From the Guidelines
Lobar broncho-pneumonia is primarily caused by bacterial infections, most commonly Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Klebsiella pneumoniae. The infection typically begins when these pathogens are inhaled into the lungs or aspirated from the upper respiratory tract, leading to inflammation and infection in the bronchioles and surrounding alveoli within specific lobes of the lung. According to the guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia 1, common pathogens include aerobic gram-negative bacilli, such as P. aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Acinetobacter species.
Key Points
- Risk factors that increase susceptibility include weakened immune systems, chronic lung diseases like COPD, smoking, advanced age, recent viral respiratory infections, and aspiration of stomach contents.
- The infection process involves bacteria multiplying in the lungs, triggering an inflammatory response that causes fluid accumulation, mucus production, and infiltration of white blood cells.
- The body's immune response to the infection contributes to the symptoms, which typically include fever, cough with sputum production, chest pain, difficulty breathing, and sometimes systemic symptoms like fatigue and confusion in severe cases.
- The clinical strategy emphasizes prompt empiric therapy for all patients suspected of having HAP, with the selection of initial antibiotic therapy based on risk factors for specific pathogens, modified by knowledge of local patterns of antibiotic resistance and organism prevalence 1.
Pathogenesis
The pathogenesis of lobar broncho-pneumonia involves the adherence of bacteria to the respiratory epithelium, followed by invasion and multiplication of the bacteria in the lung tissue. This leads to an inflammatory response, which causes damage to the lung tissue and impairs gas exchange. The infection can spread through the lung, causing consolidation and abscess formation.
Diagnosis and Treatment
The diagnosis of lobar broncho-pneumonia is based on clinical presentation, radiographic findings, and microbiological results. The treatment of lobar broncho-pneumonia involves the use of antibiotics, with the choice of antibiotic depending on the suspected or confirmed pathogen and the severity of the infection. According to the guidelines 1, the selection of initial antibiotic therapy is based on risk factors for specific pathogens, modified by knowledge of local patterns of antibiotic resistance and organism prevalence.
From the Research
Causes of Lobar Broncho-Pneumonia
The causes of lobar broncho-pneumonia can be attributed to various bacterial infections. Some of the key causes include:
- Streptococcus pneumoniae, which is the most common cause of community-acquired pneumonia, meningitis, and bacteremia in children and adults 2
- Klebsiella pneumoniae, which can cause pulmonary infection, particularly in patients with certain demographic features and laboratory results, such as lower platelet count, leucopenia, and higher serum albumin 3
Risk Factors
Certain risk factors can increase the likelihood of developing lobar broncho-pneumonia, including:
- Chronic heart and lung disease
- Cigarette smoking
- Asplenia
- Age, with the highest incidence in children under 2 years old and adults over 65 years old 4, 2
Transmission and Colonization
Streptococcus pneumoniae can be transmitted through the mucosal surface of the upper airways of carriers and can colonize the host, leading to invasion and disease 5
- The bacterium can evade or take advantage of the host's inflammatory and immune responses to cause disease
- Vaccination can help prevent invasive pneumococcal disease, but can also lead to the emergence of new serotypes with heightened virulence 2