About 5% to 14% of HSCT recipients also develop bronchiolitis obliterans syndrome which is pulmonary graft vs. host disease and can present several months to years after transplantation. [ncbi.nlm.nih.gov]

Residency at high altitude (over 2500 meters) may also contribute to severe disease and increased risk of hospitalization. [47] When severe bronchiolitis is present, it typically develops soon after disease onset. [emedicine.medscape.com]

Data presented as n/N (%) Figuras y tablas - Table 4. Hospital re‐admissions and return healthcare visits (in‐ and outpatients) Table 5. [cochranelibrary.com]

• Inflammation

  Pathophysiology In response to injury from inhalational toxins or autoimmune responses, there is inflammation of subepithelial structures and dysregulated repair, leading to fibroproliferation and abnormal regeneration of epithelium of the small airways [ncbi.nlm.nih.gov]

  inflammation, is related to the severity of a first infection in infants. [16] The inflammation, edema, and debris result in obstruction of bronchioles, leading to hyperinflation, increased airway resistance, atelectasis, and ventilation-perfusion mismatching [emedicine.medscape.com]

  Inflammation pathways and mediators involved in bronchiolitis seem to be distinct from those in glucocorticoid‐sensitive asthma. [cochranelibrary.com]

• Asymptomatic

  The clinical course of bronchiolitis obliterans syndrome related to transplant is variable with some patients being asymptomatic or stable after diagnosis and some patients with the slow and steady decline and others with an episodic drop in FEV1. [ncbi.nlm.nih.gov]

  […] comparator group Notes GLUCOCORTICOID versus PLACEBO Teeratakulpisarn 2007 Inpatients Days 1 to 30 Time from treatment to being symptom free ‐ mean ± SD 7.0 ± 5.9 9.0 ± 6.4 P = 0.035 Cade 2000 Inpatients Days 1 to 28 Time taken for half of infants to become asymptomatic [cochranelibrary.com]

  Although RSV bronchiolitis is clearly a significant disease of the young child, immunity has been shown to wane over time [69] ; susceptible adults may be asymptomatic or mildly symptomatic and act as carriers. [emedicine.medscape.com]

• Fever

  Therapy is based on supportive care, oxygenation, hydration, and fever control. With early recognition and treatment, prognosis is usually very good. Most children with bronchiolitis, regardless of severity, recover without sequelae. [emedicine.medscape.com]

  Bronchiolitis was defined clinically as a first episode of acute wheezing, respiratory distress and clinical evidence of a viral infection (cough, coryza, fever). [cochranelibrary.com]

• Pallor

  Pallor was observed in 7.5% of participants in the glucocorticoid group, compared to 11.1% in the epinephrine group. [cochranelibrary.com]

• Cough

  In these patients, symptomatic treatment should be provided with cough suppressants, inhaled bronchodilators, and oxygen supplementation if needed. [ncbi.nlm.nih.gov]

  No differences were found in time to normal sleeping and time to no coughing. [cochranelibrary.com]

  Chronic cough due to nonbronchiectatic suppurative airway disease (bronchiolitis): ACCP evidence-based clinical practice guidelines. Chest. 2006 Jan. 129(1 Suppl):132S-137S. [Medline]. [emedicine.medscape.com]

• Respiratory Distress

  Bronchiolitis was defined clinically as a first episode of acute wheezing, respiratory distress and clinical evidence of a viral infection (cough, coryza, fever). [cochranelibrary.com]

  distress with tachypnea, nasal flaring, retractions Irritability Possibly cyanosis See Clinical Presentation for more detail. [emedicine.medscape.com]

• Common Cold

  Image courtesy of Wikipedia Commons. [emedicine.medscape.com]

• Tachypnea

  Diagnosis The diagnosis of bronchiolitis is based on clinical presentation, the patient’s age, seasonal occurrence, and findings from the physical examination, which may reveal the following: Tachypnea Tachycardia Fever (38-39°C) Retractions Fine rales [emedicine.medscape.com]

• Dyspnea

  History and Physical Bronchiolitis obliterans characteristically presents with dyspnea and cough that are persistent and progressive. Some may also have wheezing. Symptoms usually develop over weeks to months and are not episodic, unlike asthma. [ncbi.nlm.nih.gov]

• Vomiting

  There were no significant differences in vomiting, bleeding, hypertension, varicella and tremor between glucocorticoids and epinephrine. No other trial from any of the other comparisons reported adverse events data. [cochranelibrary.com]

See Workup for more detail. [emedicine.medscape.com]

Treatment / Management Treatment of bronchiolitis obliterans syndrome after lung transplant involves augmenting immunosuppression since it is thought to be a form of chronic rejection. [ncbi.nlm.nih.gov]

Dexamethasone and salbutamol in the treatment of acute wheezing in infants. Pediatrics. 1983 Jan. 71(1):13-8. [Medline]. Zwerdling RG, O'Sullivan BP. Treatment of bronchiolitis. N Engl J Med. 2003 Oct 2. 349(14):1384-5; author reply 1384-5. [emedicine.medscape.com]

We did not include any treatment groups twice in the same meta‐analysis. [cochranelibrary.com]

Pearls and Other Issues Prognosis of patients with bronchiolitis obliterans is poor, and some may have a rapid decline in lung function. [ncbi.nlm.nih.gov]

Prognosis According to the WHO 2015 Global Health Observatory data repository, acute lower respiratory infection in children younger than 5 years of age remains a leading cause of childhood mortality in the world. [emedicine.medscape.com]

A first episode of wheezing may be a manifestation of wheezing phenotypes with heterogeneous biological, genetic, viral or environmental determinants, and distinct prognosis (Brand 2008; Martinez 2005; Sly 2008). [cochranelibrary.com]

Etiology Several risk factors can lead to the development of bronchiolitis obliterans. It is one of the most common noninfectious complications after lung transplant and hematopoietic stem cell transplantation. [ncbi.nlm.nih.gov]

Prospective multicenter study of viral etiology and hospital length of stay in children with severe bronchiolitis. Arch Pediatr Adolesc Med. 2012. 166:700-706. [Medline]. van den Hoogen BG, de Jong JC, Groen J, et al. [emedicine.medscape.com]

Epidemiologic data for underdeveloped countries are incomplete. [emedicine.medscape.com]

Epidemiology Bronchiolitis obliterans syndrome is considered a form of chronic allograft rejection after lung transplantation. The majority of lung transplant recipients who are long term survivors develop bronchiolitis obliterans syndrome. [ncbi.nlm.nih.gov]

Epidemiological studies have highlighted the short‐ and long‐term impact of RSV disease in prematurity (Figueras‐Aloy 2008; Simoes 2008), and underlying changes in respiratory pathophysiology may limit the external validity of our results in these populations [cochranelibrary.com]

Pathophysiology In response to injury from inhalational toxins or autoimmune responses, there is inflammation of subepithelial structures and dysregulated repair, leading to fibroproliferation and abnormal regeneration of epithelium of the small airways [ncbi.nlm.nih.gov]

Respiratory syncytial virus puzzle: clinical features, pathophysiology, treatment, and prevention. J Pediatr. 1992 Oct. 121(4):503-10. [Medline]. Shay DK, Holman RC, Newman RD, Liu LL, Stout JW, Anderson LJ. [emedicine.medscape.com]

Epidemiological studies have highlighted the short‐ and long‐term impact of RSV disease in prematurity (Figueras‐Aloy 2008; Simoes 2008), and underlying changes in respiratory pathophysiology may limit the external validity of our results in these populations [cochranelibrary.com]

Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis. Pediatrics. 2014 Oct 27. [Medline]. Liebelt EL, Qi K, Harvey K. [emedicine.medscape.com]

We excluded trials assessing the use of longer courses of glucocorticoids started during the acute phase for the prevention of post‐bronchiolitic wheezing. [cochranelibrary.com]