Acute Bronchitis Flashcards
What is acute bronchitis
- self limiting lower respiratory tract infection
- bronchitis = infections causing inflammation in the bronchial airways, whereas pneumonia denotes infection in the lung parenchyma resulting in consolidation of the affected segment/lobe
-cough that is worse at night or with exercise; lasts >2 weeks in 50% and 4 weeks in 25% of pts
Diagnosis of acute bronchitis
- clinical
- rule out pneumonia, asthma, postnasal drip
- dyspnoea
- sore throat
- low-grade fever
- presence of RFs
- acute illness <21 days
- cough
- at least 1 other lower respiratory tract symptom: sputum, wheezing (on forced expiration), chest pain
- rhonchi = large airway sounds
- no alternative explanation
- no history of chronic respiratory illness
- > 30 day cough suspect chronic pulmonary inflammatory disorder (sarcoidosis, Goodpasture’s syndrome), malignancy especially if haemoptysis, weight loss
-rales = small clicking, bubbling sounds = investigation for pneumonia or congestive heart failure CHF
Risk factors of acute bronchitis
- viral/atypical bacterial infection exposure
- cigarette smoking
- household pollution
Risk factors of acute bronchitis
- viral/atypical bacterial infection exposure
- cigarette smoking (tho more linked to chronic bronchitis)
Aetiology of acute bronchitis
-most are viral infections
-most common viruses implicate din AB are the same as those that cause upper respiratory infections; coronavirus, rhinovirus, respiratory syncytial virus, adenovirus
(-sometimes Chlamydia pneumoniae and Mycoplasma pneumoniae in minority
-
Aetiology of acute bronchitis
-most are viral infections
-most common viruses implicate din AB are the same as those that cause upper respiratory infections; coronavirus, rhinovirus, respiratory syncytial virus, adenovirus
(-sometimes Chlamydia pneumoniae and Mycoplasma pneumoniae in minority)
-ACE inhibitors (non-productive cough)
-occupational exposures (cough with no systemic symptoms)
-
-
Pathophysiology of acute bronchitis
-symptoms due to acute inflammation of the bronchial wall = increased mucus production together with oedema of the bronchus
= hallmark productive cough
- infection may clear in several days, but repair of the bronchial walls may take several weeks (continued cough)
- bronchial obstruction similar to that in asthma
Differentials other than acute bronchitis
- Coronavirus - RT-PCR (real time reverse transcription polymerase): + SARS-2 RNA
- Pneumonia - pleuritic chest pain, higher fever, rigours, malaise, haemoptysis, rales sounds, CXR
- Allergic rhinitis - postnasal drip causing a cough, evident on nasal examination & posterior pharyngeal drainage
- Asthma - bilateral wheezing, bronchospasm is recurrent and progressive- PFTs
- Pertusis infection - characteristic whoop in children with pertussis but not in adults with infection- cultures, PCR, antibody testing
- CHF - cough, dyspnoea on exertion, orthopnoea, rales, peripheral oedema, raised JVP, Hx of cardiac problems- CXR, cardiomegaly in CHF
- Reflux oesophagitis - aspiration may cause non-productive cough that is usually chronic, burning chest pain, wheezing only on right - Upper GI endoscopy (inflammation), pH monitoring
- Upper respiratory infection/common cold - viral URI and AB may be indistinguishable, common cold
- Upper airway cough syndrome - cough (dry) >8weeks, unpleasant throat sensation, trial postnasal drip, antihistamine and decongestant for 2 weeks
- Medication/environmental exposures - ACE inhibitors (non-productive cough), occupational dusts/chemicals, no systemic symptoms
- Lung cancer- >30 days, haemoptysis, weight loss, poor appetite- chest CT to detect lesion, bronchoscopy
Investigations for acute bronchitis
- PFT - Pulmonary function tests NOT recommended; if done because underlying asthma suspected, be aware that patients with AB will show mild/moderate bronchial obstruction that clears after infection and should not be confused with asthma
- if underlying asthma suspected, PFT should be delayed until after the infection has gone
- PFT improves over time with AB
-examination of the sputum by Gram stain or culture is NOT helpful - only if pneumoniae suspected
-CRP ordered if after clinical assessment a diagnosis of pneumonia not made, and antibiotic therapy is being considered to help guide therapy
= <20 mg/L (no antibiotics); 20-100 mg/L (delayed antibiotics); >100 mg/L (immediate antibiotics)
- imaging not indicated for AB
- CXR may be helpful to rule out pneumonia as cause of cough/fever
Emerging Ix:
-Procalcitonin promising biomarker for bacterial infection diagnosis as it’s higher in severe bacterial infection and low in viral infections
Management of acute bronchitis
- minimising symptoms until illness resolves
- cough suppressants, bronchodilators
- mucolytics, corticosteroids (wheezing), antibiotics are of limited effectiveness in AB
- antipyretics for fever
- patient education about AB being a self-limited illness that’ll resolve in up to 4 weeks
- consider potential adverse effects e.g bet-agonists may produce tremors
- cough > 4 weeks - short acting beta-agonist bronchodilator
Treatment of acute bronchitis
Acute <4 weeks cough:
- observation
- antipyretic- paracetamol 500-1000mg 4-6hrs
- adjunct- short acting beta agonist bronchodilator- salbutamol 100-200 micrograms 4-6hrs/ 2.5mg nebulised
-antitussive- dextromethorphan: 20mg 4hrs or codeine phosphate 15-30mg 6-8hrs
=often combined with guaifenesin (expectorant), antihistamines
-consider immediate or delayed antibiotics (not well evidenced tho)
Ongoing cough >4weeks:
- evaluate for other causes
- short-acting beta-agonist bronchodilator
- consider immediate or delayed antibiotics
Emerging treatment for acute bronchitis
Alternative/herbal medicines
- Pelargonium sidoides reduced AB symptoms
- Gankeshuangqing may decrease symptoms
- Ivy extract
- Eucalyptol/cineole increases mucociliary beat rates and has bronchodilating effects
- Spicae aetheroleum
- no adverse effects
Prevention of acute bronchitis
Primary:
- counselling for smoking
- vitamin A and D sufficiency
Complications with acute bronchitis
- Chronic cough
- Pneumonia
Prognosis of acute bronchitis
- nearly all recover within 6 weeks
- recurrence with subsequent viral infection, especially in smokers
