Bronchiolitis Midterm Notes PDF

Here is an organized summary of Bronchioli)s from the notes provided. Each component is categorized according to the following criteria: most likely cause, pathophysiology, disease transmission, and risk factors. Bronchioli)s Bronchioli=s is a viral infec)on that causes inflamma)on and obstruc)on of...

Here is an organized summary of Bronchioli)s from the notes provided. Each component is categorized according to the following criteria: most likely cause, pathophysiology, disease transmission, and risk factors. Bronchioli)s Bronchioli=s is a viral infec)on that causes inflamma)on and obstruc)on of the bronchioles. It primarily affects infants and young children under 2 years old, making it one of the most common causes of hospitaliza=on in this age group. 1. Most Likely Cause Cause: o Respiratory Syncy)al Virus (RSV) is the most common cause of bronchioli=s【 106:0†source】. o Other viruses that may cause bronchioli=s include: § Adenovirus § Human metapneumovirus § Influenza virus § Parainfluenza virus【106:0†source】. o These viruses infect the respiratory tract, par=cularly targe=ng the bronchioles. 2. Pathophysiology 1. Viral Infec)on: o The RSV virus or other respiratory viruses enter the upper respiratory tract and move to the bronchioles. o The virus infects the epithelial cells lining the bronchioles, causing them to swell and die. 2. Inflammatory Response: o The immune system responds by recrui=ng neutrophils, macrophages, and lymphocytes to the infec=on site【106:0†source】. o These immune cells release inflammatory cytokines, which increase vascular permeability and s=mulate mucus produc=on. 3. Airway Obstruc)on: o Mucus, cellular debris, and sloughed-off epithelial cells accumulate in the small airways, causing par)al or complete obstruc)on of the bronchioles【 106:0†source】. o This obstruc=on increases airway resistance, leading to air trapping, difficulty exhaling, and over-infla=on of the lungs. 4. Impaired Ven)la)on and Gas Exchange: o The accumula=on of inflammatory exudate in the alveoli and bronchioles reduces oxygen exchange. o The resul=ng ven)la)on-perfusion (V/Q) mismatch causes hypoxemia (low oxygen in the blood)【106:0†source】. 3. Disease Transmission Transmission: o Direct contact with respiratory secre=ons (e.g., from coughing, sneezing, or touching contaminated surfaces)【106:0†source】. o The virus is highly contagious and can survive on surfaces for extended periods. o Airborne droplet transmission may occur when an infected person sneezes or coughs. 4. Risk Factors Age: o Infants younger than 2 years old are at the highest risk of developing bronchioli=s, especially those younger than 6 months【106:0†source】. Prematurity: o Premature infants (born before 37 weeks gesta=on) have immature lungs and underdeveloped immune systems, making them more suscep=ble【 106:0†source】. Pre-exis)ng Lung or Heart Condi)ons: o Infants with condi=ons like chronic lung disease (CLD) or congenital heart disease (CHD) are at increased risk for severe bronchioli=s【106:0†source】. Exposure to Smoke: o Secondhand smoke exposure damages the respiratory tract and impairs the ability to clear mucus, increasing the risk of bronchioli=s【106:0†source】. Daycare AZendance: o Close contact with other children increases the likelihood of exposure to RSV and other respiratory viruses【106:0†source】. Crowded Living Condi)ons: o Overcrowded homes increase the chance of contact with infected individuals【 106:0†source】. Lack of Breas[eeding: o BreasTeeding provides maternal an=bodies that protect infants from respiratory infec=ons. Infants who are not breasTed have a higher risk of developing bronchioli=s【106:0†source】. Summary Table Criteria Bronchioli)s Most Likely Respiratory Syncy)al Virus (RSV) (most common), adenovirus, human Cause metapneumovirus, influenza, and parainfluenza【106:0†source】. 1. Viral infec)on → 2. Inflammatory response → 3. Mucus produc)on and Pathophysiology airway obstruc)on → 4. Impaired ven)la)on and V/Q mismatch【 106:0†source】. Direct contact with respiratory secre=ons or surfaces, and airborne droplets Transmission (via sneezing or coughing)【106:0†source】. Criteria Bronchioli)s Age (< 2 years), prematurity, chronic lung disease, congenital heart disease, Risk Factors exposure to smoke, daycare aVendance, overcrowding, and lack of breasTeeding【106:0†source】. If you'd like more details or clarifica=on on any of these aspects, let me know!