Lower Resp tract infections Flashcards
Acute bronchitis is caused by which class of pathogens:
a) 90% of time?
b) 10% of time?
Acute bronchitis is caused by which class of pathogens:
a) 90% of time: Viral
b) 10% of time: bacterial
Name 3 viruses that can cause acute bronchitis [3]
Name 2 bacteria that can cause acute bronchitis [2]
Viruses: Adenovirus, coronavirus, parainfluenza, influenza & rhinovirus
Bacteria: Bordetella pertussis & Mycoplasma pneumonia
Whats the difference between bronchitis and bronchiolitis?
Severe bronchiolitis (children less than 2 yr): Respiratory Syncytial Virus
Describe the pathophysiology behind acute bronchitis (e.g. caused by respiratory synctial virus)
Epithelial cells: 1st line of defence
RSV: binds and invades mucosal lining via epithelial cells
Epithelial cells switch on immune response after recognised through Toll-like receptor (TLR)-3 and retinoic acid-inducible gene (RIG)-I-like receptors
Cellular infection triggers the release of early inflammatory mediators (e.g.interferons (IFNs) and tumour necrosis factor (TNF)-α) and chemokines (e.g.CXCL8 and CXCL11).
A) Innate: Macrophages and Neutrophils, e.g. PMN polymorphonuclear leukocytes cells recruited PMNs)
B) Acquired: Dendritic cell, triggering B and T cells: CD4, CD8 and primed T cells
Why is pneumonia a significant disease? [2]
Is responsible for more death in children under 5 than any other infectious disease [1]
Community acquired pneumonia (CAP) is the no. 1 cause of death due to infection in USA and EU [1]
How do you distinguish between community acquired pneumonia (CAP) and hospital acquired pneumonia? [1]
Hospital acquired pneumonia is distinguished between CAP by the fact that hospital acquired pneumonia that occurs >48 h after hospital admission & no incubation at time of admission
What is the definition of pneumonia? [1]
Which populations are most at risk of pneumonia? [1]
Pneumonia: inflammation of the alveoli in either one or both lungs: Alveoli become inflamed & fill up with sputum.
V. young and elderly are most at risk
What is the most frequent causative agent of pneumonia? [1]
What is the second most frequent causative agent of pneumonia? [1]
Streptococcus pneumoniae= 50%
Haemophilus influenzae = 20%
Describe the symptoms of pneumonia [4]
How long do pneumonia symptoms normally last? [1]
How long are daily activities normally impaired for? [1]
- headache
- fever
- weakness
- dry cough
- nasal congestion
- chills
- sweating
- muscle aches
Duration: 3-4 weeks
Impairment: Further 3 weeks
Name the signs of pneumonia [4]
Name a complication that pneuomonia a risk factor for !!
Signs:
- Tachypnoea
- Tachycardia
- Hypoxia
- Hypotension
- Fever
- Confusion
Can lead to sepsis
Explain the pathophysiology of pneumonia xx
How can loss of barrier function in pneumonia lead to sepsis?
- Initially localised immune repsone becomes systemic
- Loss of barrier function between alveoli and capillaries may lead to spread of infection (sepsis) and systemic immune response.
What does pneumonia appear like on CXR? [1]
Pneuomonia indicated by consolidation
What investigations would you undertake to ID if Ptx has pneumonia? 6
- CXR: look for consolidation
- PCR to ID pathogen causing infection
- Urea and electrolytes informs severity
- C reactive protein
- FBC
- Liver functon tests
How does CXR compare between acute bronchtits and pneumonia? [1]
Pneumonia: consolidation of the lung parenchyma
Acute bronchitis: appears normal
How do you diagnose community acquired pneumonia (CAP) in:
- Primary care
- Secondary care
Primary care:
- symptoms & new focal chest signs on exam (new complaint less that 7 days old) & at least one systemic feature &or temp greature 38
Secondary care:
- Clinical symptoms & signs of a lower respiratory tract infection + chest-X-ray (consolidation)
How do you assess severity of pneumonia in:
- community
- hospital
Community:
Use CRB65 severity score:
- Confusion
- Resp. rate greater than 30/min
- Blood pressure (SBP <90 or DBP < 60)
- Age <65
Hospital:
CURB severity score
Use CRB65 severity score:
- Confusion
- Urea
- Resp. rate greater than 30/min
- Blood pressure (SBP <90 or DBP < 60)
- Age <65
Label the CRB severity scores xx
A: 0 = Low severity
B: 1-2 = Moderate severity
C: 3-4 = High severity
Which drugs would you use to manage pneumonia for:
CRB Score 0
CRB Score 1-2
CRB Score 3-4
Always follow yourlocal area guidelines. These are developed by looking at the bacteria in the local area for theirantibiotic resistanceso are specific to that population.
CRB Score 0: Amoxicillin or Doxycycline or Clathromycin
CRB Score 1-2: Amoxicillin AND Clathromycin
OR
Doxycycline
CRB Score 3-4: Benzylpenicillin
Why may doxycycline be preferred to amoxycillin as first line of treatment? [1]
Doxy has greater broad spectrum antibiotic than amoxy
What are different methods for O2 delivery systems? [4]
In order of increasing concentrated oxygen therapy:
- Nasal cannuale
- Simple face mask
- Non-rebreather mask
- Venturi mask
How do you diagnose acute bronchitis?
Diagnosis by exclusion:
- Cough >3 weeks
- If signs of consolidation (on CXR), airway obstruction, fever, increase RR, increase HR: NOT acute bronchitis
- If no: is there currently an outbreak of influenza pertusis (whooping cough)?
- If no: Acute bronchitis
How do you treat acute bronchitis?
Self limiting: establish expectation of cough of 14 days
Encourage fluid intake. Explain lack of antiobiotic evidence
Recommend analgesics like paracetemol
