Respiratory - Pneumonia - Midterm Notes PDF

Here is an organized summary of Pneumonia from the provided notes. Each component is categorized according to the following criteria: most likely cause, pathophysiology, disease transmission, and risk factors. Pneumonia Pneumonia is an infec6on of the lower respiratory tract caused by bacteria, vir...

Here is an organized summary of Pneumonia from the provided notes. Each component is categorized according to the following criteria: most likely cause, pathophysiology, disease transmission, and risk factors. Pneumonia Pneumonia is an infec6on of the lower respiratory tract caused by bacteria, viruses, fungi, protozoa, or parasites. It can be classified into: 1. Community-Acquired Pneumonia (CAP) 2. Healthcare-Associated Pneumonia (HCAP) 3. Hospital-Acquired Pneumonia (HAP) 4. Ven6lator-Associated Pneumonia (VAP)【106:0†source】. 1. Most Likely Cause Community-Acquired Pneumonia (CAP) o Streptococcus pneumoniae (most common)【106:0†source】. o Haemophilus influenzae, Staphylococcus aureus, Mycoplasma pneumoniae, Chlamydia pneumoniae, Moraxella catarrhalis, Legionella pneumophila, Influenza virus, Rhinovirus, and Coronavirus【106:0†source】. Hospital-Acquired Pneumonia (HAP) o Pseudomonas aeruginosa, Staphylococcus aureus (including MRSA), Klebsiella pneumoniae, Enterobacter species, and Escherichia coli【106:0†source】. Ven6lator-Associated Pneumonia (VAP) o Same microorganisms as HAP but specifically occurs in paMents who are intubated and mechanically venMlated【106:0†source】. Immunocompromised Hosts o Pneumocys6s jirovecii, Mycobacterium tuberculosis, atypical mycobacteria, respiratory viruses, protozoa, and parasites【106:0†source】. Pneumonia in Children o Infants: Respiratory syncy6al virus (RSV) o Children 5 years: Mycoplasma pneumoniae and Streptococcus pneumoniae o Children with cysMc fibrosis: Staphylococcus aureus【106:0†source】. 2. Pathophysiology The pathophysiology of pneumonia involves infecMon and the subsequent immune response. Here is the step-by-step process: 1. Pathogen Entry o The pathogen bypasses the upper airway defenses (cough reflex, mucociliary escalator) and reaches the alveoli【106:0†source】. 2. Immune Recogni6on o Alveolar macrophages recognize the pathogen via surface receptors like Toll-like receptors (TLRs)【106:1†source】.  o Macrophages release TNF-α and IL-1, which trigger widespread lung inflammaMon【106:0†source】. o Macrophages present anMgens to T-cells and B-cells, promoMng cellular and humoral immune responses【106:0†source】. 3. Neutrophil Recruitment o Neutrophils are recruited to the infected alveoli and release: § An6microbial proteins § Toxic free radicals § Neutrophil extracellular traps (NETs) § Inflammatory mediators【106:0†source】. 4. Tissue Damage o The release of toxic free radicals and other agents damages the bronchiole mucosa and pulmonary capillary membranes, leading to leakage of infec6ous debris and exudate into the alveoli【106:0†source】. 5. Impaired Gas Exchange o The accumula6on of fluid and debris in the alveoli reduces venMlaMon, causing a ven6la6on-perfusion (V/Q) mismatch【106:0†source】. o Hypoxemia and dyspnea result from the impaired gas exchange【106:0†source 】. 3. Disease Transmission Transmission varies depending on the causaMve agent: o Bacterial Pneumonia: Spread by respiratory droplets or contact with contaminated surfaces【106:0†source】. o Viral Pneumonia: Transmission via aerosolized droplets from sneezing, coughing, or talking【106:0†source】. o Hospital-Acquired Pneumonia (HAP) and VAP: Caused by microorganisms that enter through contaminated medical equipment (e.g., venMlators, catheters) or by cross-contaminaMon in healthcare seYngs【106:0†source】. o Immunocompromised Hosts: Transmission varies by organism. For example, Pneumocys6s jirovecii is not transmi[ed person-to-person, but Mycobacterium tuberculosis can spread via airborne droplets【106:0†source】. 4. Risk Factors Risk factors for pneumonia vary based on the type of pneumonia (CAP, HAP, VAP, or immunocompromised-related) but generally include the following: Risk Factors for Community-Acquired Pneumonia (CAP) Age: Infants, young children, and elderly individuals are more suscepMble【 106:0†source】. Chronic diseases: Chronic lung disease (like COPD), asthma, and cys6c fibrosis increase suscepMbility【106:0†source】. Weakened immune system: Immunosuppression due to HIV, cancer, organ transplantaMon, or corMcosteroid use【106:0†source】.  Smoking: Smoking damages the respiratory epithelium and impairs the ciliary clearance of pathogens【106:0†source】. Crowded living condi6ons: Overcrowded housing, homeless shelters, and long-term care faciliMes increase exposure to respiratory pathogens【106:0†source】. Risk Factors for Hospital-Acquired Pneumonia (HAP) Hospitaliza6on: Prolonged hospitalizaMon, parMcularly in an intensive care unit (ICU)【 106:0†source】. Mechanical Ven6la6on: Intuba6on and mechanical ven6la6on increase the risk of venMlator-associated pneumonia (VAP)【106:0†source】. Immobility: Bedridden paMents are at greater risk due to reduced lung expansion and secreMon clearance【106:0†source】. Use of invasive medical devices: Central venous catheters, nasogastric tubes, and endotracheal tubes increase the risk of infecMon【106:0†source】. Prior an6bio6c use: Alters normal flora, promoMng the growth of an6bio6c-resistant organisms like MRSA【106:0†source】. Risk Factors for Ven6lator-Associated Pneumonia (VAP) Mechanical ven6la6on: PaMents on venMlators have a 10-30% chance of developing VAP 【106:0†source】. Supine posi6on: Lying flat reduces lung expansion, encouraging bacterial colonizaMon【 106:0†source】. Inadequate oral hygiene: Increases bacterial colonizaMon in the mouth and oropharynx, leading to aspiraMon of pathogens【106:0†source】. Risk Factors for Immunocompromised-Host Pneumonia HIV/AIDS: Increased risk for Pneumocys6s jirovecii pneumonia (PJP) and Mycobacterium tuberculosis【106:0†source】. Cancer treatment: Chemotherapy and radiaMon weaken immune defenses【 106:0†source】. Organ transplant pa6ents: Use of immunosuppressive medicaMons increases the risk of opportunisMc infecMons【106:0†source】. Summary Table Criteria Pneumonia Bacteria: Streptococcus pneumoniae (most common), Haemophilus influenzae, Staphylococcus aureus, Mycoplasma pneumoniae. Viruses: RSV, Cause Influenza, Coronavirus. Fungi: PneumocysMs jirovecii in immunocompromised paMents【106:0†source】. 1. Pathogen entry → 2. Macrophage ac6va6on → 3. Neutrophil recruitment Pathophysiology → 4. Inflamma6on and debris → 5. V/Q mismatch and hypoxemia【 106:0†source】. Respiratory droplets, healthcare-related contaminaMon, aerosolized viral Transmission parMcles【106:0†source】. Criteria Pneumonia Age (young and old), chronic diseases, immune suppression, smoking, ICU Risk Factors stay, venMlators, crowded housing【106:0†source】. This summary provides a detailed view of Pneumonia from the provided notes. Let me know if you'd like any clarificaMons or addiMonal details.