Definitions for the level of evidence, strength of recommendation, and net benefit follow the "Major Recommendations."
Clinical Classification of Bronchiolitis
Clinical Class |
Specific Examples |
Infections |
Mycoplasma pneumoniae, respiratory syncytial virus |
Inhalational mechanism |
|
Toxins |
Respiratory bronchiolitis (tobacco smoke), sulfur dioxide |
Antigens |
Hypersensitivity pneumonitis |
Systemic diseases |
Collagen vascular disease, inflammatory bowel disease, immunodeficiency |
Drug reactions |
Penicillamine, amiodarone |
Allograft recipients |
Lung and bone marrow transplant |
Idiopathic disorders |
Bronchiolitis obliterans (cryptogenic constrictive bronchiolitis), follicular bronchiolitis, diffuse panbronchiolitis (DPB) |
- In patients with cough and incomplete or irreversible airflow limitation, direct or indirect signs of small airways disease seen on high resolution computed tomography (HRCT) scan, or purulent secretions seen on bronchoscopy, nonbronchiectatic suppurative airways disease (bronchiolitis) should be suspected as the primary cause. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
- In patients with cough in whom more common causes have been excluded, because bacterial suppurative airways disease may be present and clinically unsuspected, bronchoscopy is required before excluding it as a cause. Level of evidence, low; benefit, substantial; grade of recommendation, B
- In patients in whom bronchiolitis is suspected, a surgical lung biopsy should be performed when the combination of the clinical syndrome, physiology, and HRCT findings do not provide a confident diagnosis. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
- In patients with infectious bacterial bronchiolitis, prolonged antibiotic therapy improves cough and is recommended. Level of evidence, low; benefit, substantial; grade of recommendation, B
- In patients with toxic/antigenic exposure or drug-related bronchiolitis, cessation of the exposure or medication plus corticosteroid therapy for those with physiologic impairment is appropriate. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
- In the inflammatory bowel disease (IBD) patient with cough, bronchiolitis should be suspected as a potential cause. Level of evidence, low; benefit, substantial; grade of recommendation, B
- In patients in whom IBD-related bronchiolitis is suspected, both adverse drug reaction and infection should be specifically considered. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
- In patients with IBD, therapy with both oral and inhaled corticosteroids may improve cough, and a trial of therapy is suggested. Level of evidence, low; benefit, substantial; grade of recommendation, B
- In patients with chronic cough who have recently lived in Japan, Korea, or China, diffuse panbronchiolitis (DPB) should be considered as a potential cause. Level of evidence, low; benefit, substantial; grade of recommendation, B
- In patients with suspected DPB, an appropriate clinical setting and characteristic HRCT scan findings may obviate the need for invasive testing and a trial of macrolide therapy (erythromycin or other 14-member ring macrolides such as clarithromycin and roxithromycin) is appropriate. Level of evidence, expert opinion; benefit, substantial; grade of recommendation, E/A
- In patients with DPB, prolonged treatment (> 2 to 6 months) with erythromycin (or other 14-member ring macrolides such as clarithromycin and roxithromycin) is recommended. Level of evidence, low; benefit, substantial; grade of recommendation, B
Definitions:
Quality of the Evidence
Good = evidence is based on good randomized controlled trials (RCTs) or meta-analyses
Fair = evidence is based on other controlled trials or RCTs with minor flaws
Low = evidence is based on nonrandomized, case-control, or other observational studies
Expert opinion = evidence is based on the consensus of the carefully selected panel of experts in the topic field. There are no studies that meet the criteria for inclusion in the literature review.
Strength of Recommendations
A = strong recommendation
B = moderate recommendation
C = weak recommendation
D = negative recommendation
I = no recommendation possible (inconclusive)
E/A = strong recommendation based on expert opinion only
E/B = moderate recommendation based on expert opinion only
E/C = weak recommendation based on expert opinion only
E/D = negative recommendation based on expert opinion only
Net Benefit
Substantial = There is evidence of benefit that clearly exceeds the minimum clinically significant benefit and evidence of little harm
Intermediate = Clear evidence of benefit but with some evidence of harms, with a net benefit between that defined for "substantial" and "small/weak"
Small/weak = There is evidence of a benefit that may not clearly exceed the minimum clinically significant benefit, or there is evidence of harms that substantially reduce (but do not eliminate) the benefit such that it may not clearly exceed the minimum clinically significant benefit
None = Evidence shows that either there is no benefit or the benefits equal the harms
Conflicting = Evidence is inconsistent with regard to benefits and/or harms such that the net benefit is uncertain
Negative = Expected harms exceed the expected benefits to the population
Table: Relationship of Strength of the Recommendations Scale to Quality of Evidence and Net Benefits
|
Net Benefit |
Quality of Evidence |
Substantial |
Intermediate |
Small/Weak |
None |
Conflicting |
Negative |
Good |
A |
A |
B |
D |
I |
D |
Fair |
A |
B |
C |
D |
I |
D |
Low |
B |
B |
C |
I |
I |
D |
Expert Opinion |
E/A |
E/B |
E/C |
I |
I |
E/D |