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.
Who is at higher risk of CA-MRSA?
Indigenous people, alcoholics, gay people, and people in prison
What happens to people with bronchopneumonia?
Microbes access lower respiratory tract and proliferate within the alveoli.
How do microbes access lower respiratory tract?
Aspiration from oropharynx (can be caused by vomiting)
Inhalation of contaminated droplets
Blood stream
What are the 4 phases of bronchopneumonia?
Oedema (lungs swell up with fluid)
Red hepatization (lungs look swollen and red)
Grey hepatization (lungs look swollen and grey)
Resolution
What is consolidation?
A confluent opacity visible on x-ray
What is pneumonitis?
Presence of opacities all over the lung.
Where is pneumonitis commonly seen?
In viral pneumonia
Which microorganisms cause community acqured pneumonia?
Bacteria:
Strep pneumoniae
Haemophilus influenzae
moraxella catarrhalis
Klebsiella pneumoniae
Enteric pathogens
Oral anaerobic bacteria
Staph aureus
Mycoplasma pneumoniae
clamydophila pneumoniae
Legionella pneumophila
Viruses:
Influenza, parainfluenza, RSV
Chickenpox
Fungi:
Cryptococcus neoformans (dust inhalation)
Aspergillus
Pneumocystis
Where do pneumococci come from originally?
They are present in airways of 1/10 people but are asymptomatic
How is pneumococcal pneumonia prevented?
Vaccination
What is the most common cause of pneumonia?
Pneumococcal pneumonia
What is the most common cause of severe illness and death from pneumonia?
Streptococcus pneumoniae (Pneumococcus)
What causes staphylococcal pneumonia?
It is a common condition that complicates the flu.
However, it is being increasingly reported as a primary cause of illness.
Can MRSA cause staphylococcal pneumonia?
Yes
What is PVL?
Pantonvalentine Lecukocydin toxin which is commonly caused by strains of MRSA resulting in necrotizing pneumonia.
What is the most severe atypical pneumonia?
Legionnella pneumophila infection
What kind of environments do legionnella prefer to live in?
Water environments due to symbiotic relationship with water born amoebae. (hot water tanks, air condtioning, and cooling towers)
Inhalation of aerosols
What strain of legionella causes more cases of pneumonia in WA than legionella pneumophila?
Legionella longbeachae which is found in potting mix and gardening equipment.
What is chlamydophila psittaci?
An intracellular bacteria that is found in feral birds and domesticated poultry that can cause pneumonia.
How is chlamydophila psittaci transmitted?
Inhlation, contact, or ingestion
What is the most predominant symptom of chlamydophila psittaci?
Headache and it can cause severe pneumonia in addition
What other animals can carry chlamydophila psittaci?
Cattle, pigs, sheep, and horses.
What bacteria causes Query/Q-fever?
Coxiella burnetii
Who most commonly gets Q-fever?
Vets, farmers, shearers