Lower RTI Flashcards
What are the barriers of entry into the lower respiratory tract?
Mechanical factors (Nose hairs, branching of respiratory tract, mucociliary clearance, local antibacterial factors.)
Normal flora
Alveolar macrophages
What do the normal flora do to protect the lungs from infection?
They prevent pathogens from binding to surface of respiratory epithelium.
What is bronchitis/bronchiolitis?
Inflammation of the bronchi. (aka chest infection)
How does bronchitis/bronchiolitis develop?
Usually during an upper respiratory tract infection.
What causes bronchitis?
Respiratory viruses cause >90% of these.
What causes pertussis?
A gram negative bacillus (Bordatella pertusis)
How can pertussis be prevented?
Vaccine (antivaccination is leading to this disease coming back to WA)
How does pertussis spread?
Respiratory droplet spread
What are the phases of pertussis?
Catarrhal phase (fever, coryzal, and mild cough)
Paroxysmal phase (frequent and repetitive bursts of coughing then single expiratory “whoop”
Convalescent phase (diminishing cough)
What is characteristic of the catarrhal phase?
It causes fever, coryzal symptoms, and mild cough
What are coryzal symptoms?
acute inflammation of the mucous membrane of the nasal cavities; cold in the head.
How long does the paroxysmal phase of pertussis take to develop?
1 - 2 weeks
How long does the convalescent phase take to develop?
2 - 4 weeks and can last for months.
What happens during convalescent phase?
Cough is reducing until it is gone.
What complications can arise from pertussis?
Subconjunctival haemorrhage (bleeding in the eyes due to bursting of blood vessels in the eyes)
Pneumothorax
Rib fractures
Hernias
How can pertussis be diagnosed?
PCR of throat swab or NP aspirate.
Culture (special media)
Serology (IgA)
What antibody is tested for in pertussis serology?
IgA
How is pertussis treated?
Clarithromycin (macrolides)
What is bronchopneumonia?
Infection of the lung parenchyma
What percentage of people get bronchopneumonia?
1% of adults per year
How many cases of bronchopneumonia per year?
50k admissions per year
What is the rate of fatality of bronchopneumonia?
5% (>65 year olds that probability increases to 10%)
If there are 2 or more comorbidities the percentage rises to 20%
What are the general risk factors for bronchopneumonia?
Chronic chest disease (COPD, asthma)
Smoking
Alcoholism
Institutionalisation
> 70 years of age
Who is at higher risk of pneumonia caused by gram-negatives?
People with dementia, cerebrovascular disease, and alcoholism.