Lower Respiratory Tract Infections Flashcards
(56 cards)
What are the 5 main infections of the lower respiratory tract?
bronchitis bronchiolitis influenza pertussis pneumonia
What are the natural defenses of the lower respiratory tract?
albeolar macrophages (most important)
complement components
alveolar liing fluid containing surfactant, phospholipids, neutral lipids, immunoglobulin, Factor B and B cells and T cells
What are some of the mechanisms bugs use to avoid phagocytosis?
- capsule production
- toxin production -
- parasits and fungi just too big to engulf
- replication INSIDE cells to hide
- mimicry - parasites use surface proteins similar to host 0 look like self
What are some of the ways bugs can survive within the macropahge?
- inhibit lysosome fusion with the phagosome
- just excape from the phagosome
- resistant to killing and digestion in the phagolysosome
- groth in the phagocytic cell
What is bronchitis an infection of?
Infection and inlammation of the trachea and bronchi but NOT the alveoli
Is bronchitis usually viral or bacterial?
viral
What does bronchitis usually follow?
usually occurs after a viral upper respiratory infection that extends into the trachea, bronchi and bronchioles.
What does bronchitis present with?
cough (dry at first them productive), chest pain and fever, malaise, HA, sore throat
How do you differentiate between a bronchitis and a pneumonia?
You can’t really make the differentiation clinically - need to use a CXR. CXR will be normal in bronchitis but will have infiltrates in pneumonia
What are the common viral causes of bronchitis?
basically the ones that cause rhinitis….
rhinovirus parainfluenza virus respiratory syncytial virus influenza A, B, C Coxsckie A B Adenovirus
Although bronchitis is rarely bacterial, what are the two possibilities?
mycoplasma pneumoniae
chlamydia pneumoniae
On to bronchiolitis…..
What is it inflammation of?
the bronchial tree as low as the bronchioles
NOT the alveoli
Who gets bronchiolitis and why?
babies younger than 1 yr of age because they have narrower airways so it doesn’t take much inflammation to close them down
What’s the most common cause of bronchiolitis?
RSV - by a long shot
What can be given to high risk patients with RSV bronchiolitis?
passive immunization with anti-RSV antibodies
RespiGam (immunoglobulin) or palivizumab (humanized monoclonal antibody)
high risk = premature, cystic fibrosis, congenital heart disease, immune deficienty
Bronchiolitis tends to start like a normal head cold, but what symptoms will it progress to?
tachypnea tachycardia fever diffuse wheezing inspiratory crackles nasal flaring vomiting cyanosis hyperinflation of lungs
What are some risk factors for develping bronchiolitis besides age?
bottle feeding, prematurity, exposure to cigarette smoke, living in crowded situations
What bacteria causes whooping cough?
Pertussis is caused by bordatella pertussis
What are the characteristic symptoms of pertussis?
starts with a normal head cold
then progresses to severe paroxysms of coughing with an inspiratory whoop or post-tussis vomiting
What are some of the possible complications of the whooping cough?
hemoptysis, subconjunctival hemorrhages, hernias, seizures and death
What are the 3 stages of pertussis?
- catarrhal stage - bacteria in respiratory tract cause cold symptoms
- Paroxysmal stage - severe uncontrollable coughing
- convalescent phase - bacteria decreases, no longer cause symptoms but cilia are still trying to recover, so you’re prone to secondary bacterial infection during this stage
What does pertussis use to attach to the ciliated epithelial cells?
filemtneous hemagglutinin
What toxins does pertussis produce and what do they do?
the pertussis AB toxin will enter ciliated epithelial cells and cause an increase in cAMP leading to massive overproduction of mucous
The pertussis tracheal toxin is a cytotoxin which will kill the ciliated endothelial cells
Who common gets pertussis?
adolescents and adults (older patients have better outcomes tha nyounger patients)
but the most severe cases are in children under 1 yr of age
