Pharmacotherapy II - Lower Respiratory Tract Infections - Lecture (4) PDF

New Mansoura University Faculty of Pharmacy Pharm D Program __________________________________________________________ _________________ pharmacotherapy II Lower respiratory tract infections Lecture (4) ...

New Mansoura University Faculty of Pharmacy Pharm D Program __________________________________________________________ _________________ pharmacotherapy II Lower respiratory tract infections Lecture (4)  Pneumonia Pneumonia remains one of the most common causes of severe sepsis and infectious cause of death in children and adults, with a mortality rate as high as 50%. Pneumonia is categorized as either community-acquired (CAP), hospital-acquired (HAP) or ventilator-associated pneumonia (VAP).  Pneumonia Pathophysiology Pneumonia is caused by a variety of viral and bacterial and sometimes fungal pathogens. Respiratory pathogens enter the lower respiratory tract by one of three routes: (1) direct inhalation of infectious droplets; (2) aspiration of oropharyngeal contents; or (3) hematogenous spread from another infection site. The causative pathogen in CAP in adult patients is most commonly viral, with human rhinovirus and influenza most common. Viral pathogens (respiratory syncytial virus (RSV) and human rhinovirus) predominate in CAP among pediatric patients with a prevalence of up to 80% in those less than 2 years of age.  Pneumonia Pathophysiology The most prominent bacterial pathogen causing CAP in otherwise healthy adults is S. pneumoniae accounting for up to 35% of all acute cases. Other common bacterial causes are H. influenzae, the “atypical” pathogens including M. pneumoniae, Legionella species, C. pneumoniae. HAP is predominantly caused by gram-negative aerobic bacilli and S. aureus and is much more likely to be caused by a multidrug-resistant isolate. P. aeruginosa and Acinetobacter spp. are the most common cause of HAP (about 25%–45%) followed by K. pneumoniae and E. coli are also common.  Pneumonia Clinical presentation & Diagnosis Signs and symptoms: Abrupt onset of fever, chills, and productive cough; Rust-colored sputum or hemoptysis; Chest pain; and Dyspnea. Physical examination findings: Tachypnea and tachycardia; Diminished breath sounds over affected area; and Inspiratory crackles during lung expansion. Chest radiograph and sputum examination and culture are the most useful diagnostic tests for gram-positive and gram-negative bacterial pneumonia. Typically, the chest radiograph reveals a dense lobar or lobular consolidated infiltrates. Blood cultures and noninvasive sputum cultures (ie, expectorated sputum, sputum induction, or nasotracheal suctioning) are recommended for all adult patients with suspected HAP or VAP. Laboratory tests: Leukocytosis with predominance of polymorphonuclear cells. Low oxygen saturation on arterial blood gas or pulse oximetry.  Pneumonia Treatment Goal of Treatment: Eradication of the offending organism and complete clinical cure. S e co n d a r y go a l s i n c l u d e m i n i m i za t i o n o f t h e u n i n te n d e d consequences of therapy, including toxicities and selection for secondary infections such a Clostridioides difficile or antibiotic- resistant pathogens, and minimizing costs through outpatient and oral therapy when the patient ’s severity of illness and clin ica l considerations permit. The supportive care of the patient with pneumonia includes the use o f h u m i d i f i e d ox yge n fo r hy p oxe m i a , f l u i d re s u s c i t a t i o n , administration of bronchodilators (albuterol) when bronchospasm is present, and chest physiotherapy with postural drainage if there is evidence of retained secretions. Important therapeutic adjuncts include adequate hydration (by IV route if necessary), optimal nutritional support, and fever control.  Pneumonia Treatment Severity scoring systems such as CURB-65 are used to guide treatment. For CURB-65, patients receive 1 point for each criterion present: Confusion, Uremia (BUN >20 mg/dL, Respiratory rate ≥30 breaths/min, Blood pressure (systolic