Acute bronchitis (RESP)

Question 1

Define acute bronchitis.

Answer 1

Self-limiting lower respiratory tract infection (to distinguish it from common colds and other upper respiratory ailments)

Question 2

What is acute bronchitis the result of?

Answer 2

Result of inflammation of the trachea and major bronchi and is therefore associated with oedematous large airways and sputum production

Question 3

What is the difference between (acute) bronchitis and pneumonia?

Answer 3

• bronchitis - infections causing inflammation in bronchial airways
• pneumonia - infection in lung parenchyma –> consolidation of affected segment or lobe

Question 4

What criteria can help diagnose acute bronchitis?

Answer 4

MacFarlane criteria:

a. an acute illness of <21 days (but approx 25% last >30 days)
b. cough as the predominant symptom
c. at least 1 other lower respiratory tract symptom (e.g. sputum production, wheezing, chest pain)
d. no alternative explanation for the symptoms

Question 5

What is the leading cause of acute bronchitis? (1 + 6)

Answer 5

Viral infection e.g:

• influenza A
• influenza B
• parainfluenza
• RSV
• coronavirus
• adenovirus

Question 6

What other condition does acute bronchitis often follow?

Answer 6

Upper RTI

Question 7

Describe the disease course of acute bronchitis.

Answer 7

Chest infection which is usually self-limiting in nature, and usually resolves before 3 weeks

Question 8

What are the key clinical features of acute bronchitis? (7)

Answer 8

• duration of cough <30 days
• productive cough
• no Hx of chronic respiratory illness (e.g. asthma)
• exclusion of other respiratory and cardiac illness (e.g. pneumonia, CHF, postnasal drip)
• initial dry cough over 3-4 days –> productive cough + clear sputum
• fever
• preceding URTI (runny nose, sore throat, headache)

Question 9

What might be seen on examination of a patient with acute bronchitis? (2 + 1)

Answer 9

• wheeze on force expiration
• rhonchi
• (rales on examination suggest pneumonia or CHF)

Question 10

How can we differentiate acute bronchitis from pneumonia from the history?

Answer 10

Sputum, wheeze, breathlessness may be absent in acute bronchitis (at least one tends to be present in pneumonia)

Question 11

How can we differentiate acute bronchitis from pneumonia on examination?

Answer 11

• no other focal chest signs (dullness to percussion, crepitations, bronchial breathing) in acute bronchitis
• rales present in pneumonia
• systemic features (malaise, myalgia, fever) may be absent in acute bronchitis but present in pneumonia

Question 12

What are the risk factors for acute bronchitis? (3)

Answer 12

• viral or bacterial infection exposure
• cigarette smoking’
• household pollution exposure

Question 13

How is acute bronchitis diagnosed?

Answer 13

Clinical diagnosis, though other tests (PFT, CXR, CRP etc) may be needed to rule out other diagnoses e.g. asthma or pneumonia

Question 14

What investigations can be considered for acute bronchitis? (4)

Answer 14

• pulmonary function test - mild/moderate bronchial obstruction, improves over time vs asthma
• chest x-ray - normal, rule out pneumonia
• CRP - may guide whether Abx needed
• procalcitonin - emerging test, may be elevated in bacterial infection

Question 15

What CRP levels are indicative of Abx for acute bronchitis?

Answer 15

• <20mg/L = no antibiotics
• 20-100mg/L = delayed antibiotics
• > 100mg/L = immediate antibiotics

Question 16

What are some differential diagnoses for acute bronchitis?

Answer 16

• COVID-19
• pneumonia (fever, rales, infiltration on CXR)
• allergic rhinitis
• asthma (chronic bronchospasm)
• Pertussis infection (children, whooping cough)
• CHF (vascular congestion on CXR, cardiomegaly)
• reflux oesophagitis
• URTI (undistinguishable)
• upper airway cough syndrome (>8wk)
• medication/environmental exposures (ACEi)
• lung cancer

Question 17

What is the 1st line treatment for acute bronchitis with cough < 4 weeks?

Answer 17

• 1st line: observation
• consider antipyretic if fever (paracetamol)
• consider SABA bronchodilator if wheeze (salbutamol)
• consider antitussive if severe cough (dextromethorphan or codeine phosphate)

Question 18

When should cough and cold medications including opioids (e.g. codeine or hydrocodone) NOT be used?

Answer 18

Patients <18 years as risks (slowed/difficult breathing, misuse, abuse, addiction, overdose, death) outweigh the benefits when used for cough in younger patients

Question 19

What is the 1st line treatment for acute bronchitis with cough > 4 weeks?

Answer 19

• 1st line: evaluate for other causes
  
  • occupational or environmental exposures
  • GORD (empirical trial with H2 antagonist or PPI)
• consider SABA

Question 20

In which groups are immediate/delayed antibiotics considered for acute bronchitis?

Answer 20

• raised CRP (20-100mg/L = delayed, >100mg/L = immediate)
• systemic illness
• pre-existing comorbidity
• young children born prematurely
• patients >80 with 1+/>65 with 2+:
  
  • hospitalisation in past year
  • current oral corticosteroid use
  • T1/T2DM
  • Hx of congestive heart failure (CHF)

Question 21

What is the 1st line antibiotic for acute bronchitis and what are some alternatives?

Answer 21

• oral doxycycline
• alternative e.g. amoxicillin if pregnant woman or child, or clarithromycin/erythromycin

Question 22

What are some complications of acute bronchitis? (2)

Answer 22

• chronic cough (post-bronchitis syndrome if >6 months) - evaluate other causes e.g. asthma, postnasal drip, reflux, upper airways cough syndrome - treat with SABA
• pneumonia (especially in older)

Question 23

Describe the prognosis of acute bronchitis.

Answer 23

• generally self-limiting
• poorer prognosis if: advanced age, immunocompromised, pre-existing lung conditions