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
How can Q-fever be prevented?
Vaccine
What are the symptoms of pneumonia?
Typical symptoms:
Fever, chills/rigors
Cough
Shortness of breath
Chest pain
Atypical symptoms:
In 20%
myalgia
Arthralgia
headache
gastrointestinal symptoms
What kind of cough do people with pneumonia get?
Productive (producing sputum) or non-productive
Haemoptysis
What kind of pain do people with pneumonia get?
Pleuritic pain
What clinical signs can be seen in people with pneumonia when examined?
Tachycardia and low blood pressure
Elevated respiratory rate
Reduced Oxygen saturation
Stethoscope sounds (Reduced air entry over affected lung, sounds like crepitations (crackling) or crackles can appear as well as bronchial breathing)
How can pneumonia be diagnosed?
Blood tests (FBC, inflammatory markers (C-reactive protein), blood culture)
Radiology (chest x-ray with presence of consolidation in multiple lobes, or CT scan)
Microbiological (culture of sputum and gram stain)
Serological tests (antibodies, 4-fold rise in IgM)
Molecular tests (throat swab PCR)
What kind of bacteria is strep pneumoniae?
Gram positive diplocci
What procedure is used fore treating pneumonia?
Guideline based (Pneumonia Severity Index is used):
If it isn’t severe in a young person (outpatient treatment)
If admitted is there a risk of death or ICU?
What guidelines are used for treatment of pneumonia?
PSI (designed to identify low-risk patients who can stay at home)
CURB-65 (designed to identify those at risk of death)
CORB and SMARTCOP (Australian designed, use predictors of requirement for intensive care therapy and mortality, CORB is much simpler)
How is mild CAP treated?
Pneumonia that doens’t warrant admission is treated via oral amoxycillin or clarithromycin (clarithromycin is used if atypical organism is suspected)
How is moderate CAP treated?
IV antibiotics are used with narrow spectrum or penicillins.
Oral doxycyclin or clarithromycin is given in case of atypical pneumonia.
How is severe CAP treated?
IV ceftrioxone or penicillin + IV azithromycin (IV macrolides generally) to cover aypical organisms
How is aspiration pneumonia treated?
A more broad spectrum antibiotic which also covers gut bacteria is used as well as gram negatives in alcoholics.
Tazocin covers all (too broad spectrum)
IV Metronidazole or clindamycin/lincomycin
What are the important additional treatments that must be done for people with pneumonia?
Supplemental oxygen
IV fluids and electrolytes
Analgesia (chest pain)
Bronchodilators
Physiotherapy
What are the potential complications of CAP?
Respiratory failure
Multi-organ failure
DIC
If fever and inflammatory markers don’t improve within 2 - 4 days potential complications include:
Abscess
Complicated effusion/empema
Metastatic infection
Can CAP pathogens also cause healthcare associated pneumonia?
Yes.
What kind of problematic feature is associated with pathogens that are present in hospitals?
Multi-drug resistant pathogens
What kind of drug resistant bacteria are commonly seen in hospital associated bacteria?
ESBLs (extended spectrum beta lactamase containing bacteria)
Acinetobacter species
pseudomonas aeruginosa
MRSA
What kind of antibiotics are used for multi-drug resistant bacteria?
Carbapenems
True or False:
The causes for both ventilator and hospital acquired pneumonia are the same
True
When are people most at risk of VAP?
During the first 5 days.
What are the 3 main risk factors for VAP?
Oropharynx colonizations replaced by pathogens
Aspiration (endotracheal tube bypasses)
Compromised defences
How can HAP/VAP be diagnosed?
Same investigations as CAP but sputum collection is difficult.
In special circumstances a lung biopsy may be used.
How is HAP/VAP treated?
In high risk patients:
IV pipericillin-tazobactam
IV cefepime
in addition to:
IV gentamicin and IV vancomycin (If MRSA is suspected)
What causes chronic pneumonia?
Mycobacterium (TB and non-TB)
Nocardia
Fungi (Pneumacystis jiraveci (PCP), cryptococcus neoformans, Aspergillus)
What are the clinical features of TB?
Chronic cough
Fever
Night sweats
Loss of appetite
Weight loss
This disease is present for months
What bacteria cause MAC?
Mycobacterium avium and M. intracellulare.
Where does MAC pneumonia come from?
It is Environmental (found in soil and water)
What kind of disease does MAC cause?
Chronic pneumonia in patients with existing lung disease or elderly women with no previous lung disease.
How is MAC pneumonia treated?
Prolonged antibiotics (>18 months of treatment)
Antibiotics are clarithromycin and ethambutol.
Which part of the lung does MAC pneumonia infect?
Right middle lobe or left lingula lobe.
What is pleurisy?
Inflammation of the pleura. It causes fever and pleuritic chest pain.
What causes pleurisy?
Infection (bacterial, viral, TB)
Can pleurisy be caused by a primary bacterial infection?
Yes, but it is often secondary to pneumonia
What does the image of a thoracoscope show in the case of pleurisy?
Tubercles lining the pleura.
What is pleural effusion?
Abnormal collection of fluid in the pleural space caused by excess fluid production or decreased absorption (or both).
Pleural effusion is a manifestation of what disease?
Pleural disease, cardiopulmonary, inflammatory, or malignant disease.
What is a transudate?
Result from imbalance in oncotic and hydrostatic pressures resulting in cardiac failure, cirrhosis, and hypoalbuminaemia.
What is an exudate?
Result of inflammation of the pleura and/or decreased lymphatic drainage.
What is the difference between exudate and transudate?
High protein = exudate
Low protein = transudate
What is an uncomplicated parapneumonic effusion?
Exudative neutrophilic effusion. The inflammation (pneumonia) causes an increase in passage of interstitial fluid.
Can organisms be seen on a gram-stain or a culture from uncomplicated parapneumonic effusions?
No
What happens to uncomplicated parapneumonic pleural effusions if the underlying pneumonia is treated?
It completely resolves.
What causes complicated parapneumonic pleural effusion?
Invasion of bacteria into the pleural space.
What is required for resolution of complicated parapneumonic pleural effusion?
Drainage
What is emPYema?
Frank pus in pleural space
What are the stages of empyema?
Bacterial invasion
Fibrinopurulent stage
Organisation with locules and septation.
What does empyema require to form?
Pleural fluid
How is empyema treated?
Drainage and antibiotics.
What is bronchiectasis?
A common inflammatory condition of the lung which creates a cycle of inflammation then destruction then more inflammation etc.
What causes bronchiectasis?
Infection
Autoimmune disease
Cystic fibrosis
Unknown in up to 50% of cases
What kind of infections are associated with bronchiectasis?
Pneumonia
Partially treated necrotising bacteria
Tuberculosis and MAC
pertussis
Viral infection (adenovirus and influenza)
What are the symptoms of bronchiectasis?
Chronic cough, haemoptysis
Acute exacerbations
What do lung abscesses most commonly follow?
Aspiration or pneumonia/blood stream infection.
Necrotising infections
What are lung abscesses?
Pus filled cavities
What bacteria most commonly cause lung abscesses?
Anaerobes
Gram negatives
Staph aureus
Nocardia species
How are lung abscesses treated?
Radiological or surgical drainage is required followed by:
Prolonged intravenous then oral antibiotics
Which antibiotics are used for lung abscesses?
IV penicillin
IV clindomycin
How are lung abscesses diagnosed?
Gram stain and culture
Who most often gets tropical pneumonia in Australia?
It is endemic to NT, Northern Queensland and parts of N WA.
What bacteria is commonly associated with tropical pneumonia?
Burkholderia pseudomallei
What is the condition caused by burkholderia pseudomallei called?
Malleoid
Where does the bateria enter the body of people to cause melioidosis?
Percutaneous innoculation, ingestion, or inhalation caused by contact with soil and water.
How long is the incubation period for melioidosis?
9 days but can be very long (up to 62 years has been seen)
How does melioidosis present?
Acute fulminant septic illness or as chronic infection which mimics cancer or TB.
How is melioidosis diagnosed?
Culture of clinical sample
PCR
Serology
How is melioidosis treated?
IV meropenem for 10 - 14 days then 3 - 6 months of oral trimoxazole
What does aspergillus infection cause in infected immunocompromised people’s x-ray?
A halo formation
What is the most common cause of aspergillus infection in immunocompromised patients?
A. fumigatus
What is allergic bronchopulmonary aspergillus?
An allergic or hypersensitivity response to aspergillus spores.
What is aspergilloma?
A fungal ball which grows inside pre-existing lung cavity.
What is invasive aspergillosis?
Infection caused by aspergillus which is fatal without treatment and is spread via invasion of blood vessels.
What are the 4 main clinical prediction tools for pneumonia?
Pneumonia severity score
CURB-65
CORB
SMART-COP
How is moderate CAP treated?
IV antibiotics are used with narrow spectrum or penicillins.
Oral doxycyclin or clarithromycin is given in case of atypical pneumonia.
