Lower Respiratory Tract Infections (LRTI)

Lower Respiratory Tract Infections (LRTIs)

• LRTIs, including COPD and acute exacerbation of chronic lung diseases, are the 3rd and 4th most common causes of death worldwide.
• They are caused by viral or bacterial infections, with an annual incidence of 24.8 per 10,000 adults, and a higher incidence in patients over 65 years old.

Pneumonia

• Pneumonia is a bacterial or viral infection of the lungs, causing the alveoli to fill with pus and become solid.
• Pathogens can bypass the normal protective mechanisms to gain access to the lower respiratory tract through inhalation, hematogenous seeding, or aspiration of oropharyngeal contents.
• Impairments in the normal defense mechanism, such as depressed mucociliary transport, can increase the risk of developing pneumonia.

Pneumonia Classification

• Pneumonia can be classified as community-acquired or hospital-acquired, with different types of causative pathogens, including aerobic bacteria, atypical bacteria, and viruses.
• Ventilator-associated pneumonia is a type of hospital-acquired pneumonia caused by pathogens such as Staphylococcus aureus, Pseudomonas aeruginosa, and Enterobacter species.

Community-Acquired Pneumonia (CAP)

• CAP can be classified as typical or atypical, based on patient presentation, clinical observations, and course of the disease.
• Typical CAP is associated with acute fever, chills, pleuritic chest pain, and productive cough, while atypical CAP is associated with myalgias, fever without chills, headache, and unproductive cough.
• Aspiration pneumonia is a type of CAP that occurs when a patient at risk of aspiration develops pneumonia, often with anaerobic pathogens from the digestive tract.

Signs and Symptoms

• Symptoms of pneumonia include respiratory symptoms such as cough, shortness of breath, and difficulty breathing, as well as non-respiratory symptoms such as fever, fatigue, sweats, headache, and myalgias.
• Signs of pneumonia include temperature, increased respiratory rate, cyanosis, and diminished breath sounds.

Diagnosis

• Diagnosis of pneumonia involves laboratory tests, diagnostic tests, and microbiological tests, including chest X-ray, CT scan, sputum gram stain and culture, and blood culture.

Risk Factors

• Risk factors for pneumonia include age, underlying medical conditions, and impaired defense mechanisms.

Complications

• Complications of pneumonia include bacteremia, difficulty breathing, fluid accumulation around the lungs, and lung abscess.

Treatment

• Goals of treatment include eradicating the offending organism, achieving complete clinical cure, and minimizing associated morbidity.
• Treatment involves non-pharmacological therapy, such as oxygen, mechanical ventilation, and fluid resuscitation, as well as pharmacologic therapy, including antibiotics and bronchodilators.
• Antibiotic selection depends on the type of pneumonia, patient factors, and severity of disease presentation.

Monitoring and Prevention

• Monitoring involves tracking improvements or worsening of clinical symptoms and laboratory and diagnostic parameters.
• Prevention involves vaccination, immune prophylaxis, and minimizing the risk of developing ventilator-associated pneumonia.