Bronchiolitis

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Bronchiolitis

• Dr Rajesh
• 07/11/07

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Introduction

• Bronchiolitis is the most common lower
  respiratory tract infection in infants.
• Virtually all children have been exposed to
  respiratory syncytial virus (RSV), the cause of
  most bronchiolitis cases, by their second
  birthday.
• Clinically identical disease can occur with
  infections from parainfluenza virus, adenovirus,
  rhinovirus, influenza or mycoplasma pneumonia
• Up to 3 of all children are hospitalized with
  bronchiolitis in their first year of life.
• Despite the high prevalence of bronchiolitis,
  little consensus exists on the optimal management
  of the disease.

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Pathology

• Direct viral invasion, an increase in goblet cell
  mucous production, and subsequent necrosis and
  desquamation of the ciliated respiratory
  epithelium, particularly in bronchioles
• Cellular debris and fibrin form plugs in the
  bronchioles resulting in air flow obstruction
• As the respiratory epithelium regenerates, the
  new, non-ciliated cells are poorly equipped to
  clear the products of inflammation.
• Thus, airway oedema, necrosis and mucous plugging
  are the predominant pathological features in
  bronchiolitis

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Bronchiolitis
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Definition

• Bronchiolitis is an acute, highly communicable
  lower respiratory tract infection characterized
  by
• cough, coryza (runny nose),
• fever,
• expiratory wheezing,
• grunting,
• tachypnea (fast breathing),
• retractions
• air trapping

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(No Transcript)
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Complications

• Acute respiratory distress syndrome (ARDS)
• Bronchiolitis obliterans
• Congestive heart failure
• Secondary infection
• Myocarditis
• Arrhythmias
• Chronic lung disease

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Indications for admission

• Oxygen saturation monitored by pulse oximetry
  below 92 in room air
• Younger than 6 months and unable to maintain oral
  hydration
• Markedly elevated respiratory rate
• History of chronic cardiorespiratory disease
• Extra pulmonary symptoms

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Utility of CXR

• large numbers of infants with bronchiolitis have
  abnormalities on chest x-ray films.
• However, chest x-ray films do not discriminate
  well between bronchiolitis and other forms of
  LRTI
• In mild disease, chest x-ray films offer no
  information that is likely to affect treatment
  and should not be routinely performed.
• Chest x-ray films may lead to the use of
  antibiotics.
• It could be argued that chest x-ray films are
  more likely to lead to inappropriate antibiotic
  use than to improved clinical outcomes

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Bronchodilators

• Bronchodilators have been commonly used in the
  management of bronchiolitis.
• A Canadian study (Law 1993) found that 78 of
  those hospitalized with bronchiolitis received
  bronchodilators. A survey of pediatric allergists
  and pulmonologists in the United States (Newcomb
  1989) found that 86 recommended a trial of
  bronchodilators for this condition. Similarly, in
  a survey of pediatric infectious disease
  specialists in Europe, the majority used
  bronchodilators for treatment of bronchiolitis
  (Kimpen 1997)
• Three prior meta-analyses (Flores 1997 Hartling
  2003 Kellner 1996) and a systematic review (King
  2004) have shown that bronchodilators may improve
  clinical symptom scores but they do not affect
  disease resolution, need for hospitalization or
  length of stay.

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Bronchodilators

• Bronchodilators are very effective in the
  treatment of asthma, where airway obstruction is
  caused by inflammation, bronchospasm and
  bronchial hyperreactivity
• The pathophysiology of bronchiolitis consists of
  terminal bronchiolar and alveolar inflammation
  with airway swelling and luminal debris, which
  lead to airway obstruction
• In addition, mediators of bronchospasm have been
  shown to be present in variable amounts in
  children with bronchiolitis
• Not all children with bronchiolitis are likely to
  have the same propensity to have bronchospasm and
  bronchial hyperreactivity.

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Bronchodilator Cochrane

• No improvement in clinical score for 43 of those
  treated with bronchodilators compared to 57 of
  those treated with placebo (odds ratio (OR) for
  no improvement 0.45, 95 confidence interval (CI)
  0.15 to 1.29).
• There was a statistically significant but
  clinically modest improvement in the overall
  average clinical score.
• No statistically significant improvement in
  oxygenation overall (weighted mean difference
  (WMD) -0.57, 95 CI -1.17 to 0.03).

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• Subgroup analyses showed a slightly greater
  effect size in outpatient studies

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Bronchodilator Cochrane

• Authors' conclusions
• Bronchodilators produce small short-term
  improvements in clinical scores. This small
  benefit must be weighed against the costs and
  adverse effects of these agents

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Bronchodilators

• Two groups of patients
• Responds to bronchodilator ( ? HRAD)
• Do not respond to bronchodilator

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Role of Salbutamol

• Although evidence about the efficacy of
  bronchodilators in bronchiolitis is conflicting,
  administering a beta-agonist, such as albuterol
  (0.15 mg/kg/dose), on a trial basis to patients
  with bronchiolitis and assessing the clinical
  response in 10-15 minutes is reasonable.
• If improvement in retractions, respiratory rate,
  and wheezing is noted, scheduled aerosol
  treatments may be continued, with additional
  treatments administered as needed.

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Epinephrine
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Epinephrine versus Placebo Cochrane

• There were five inpatient studies that compared
  epinephrine and placebo.
• Only one out of ten inpatient outcomes
  demonstrated a significant difference between
  treatment groups change in clinical score at 60
  minutes showed a SMD of -0.52 favouring
  epinephrine (95 CI -1.00,-0.03).

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Epinephrine versus Placebo

• Three studies compared epinephrine and placebo
  among outpatients.
• Five of 10 outcomes were significant. Change in
  clinical score at 60 minutes, change in oxygen
  saturation at 30 minutes , respiratory rate at 30
  minutes , and "improvement" (OR 25.06 95 CI
  4.95,126.91).
• Admission rates, change in clinical score at 30
  minutes, change in oxygen saturation at 60
  minutes, and heart rate at 30 minutes
  post-treatment were not significantly different
  between the treatment arms.

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Epinephrine versus Salbutamol

• Four studies compared epinephrine to salbutamol
  among inpatients.
• Only one of the seven outcomes evaluated was
  statistically significant respiratory rate at 30
  minutes favoured epinephrine over salbutamol (WMD
  -5.12 95 CI -6.83,-3.41).
• Changes in clinical score, oxygen saturation,
  heart rate, and length of stay were not
  significantly different between the treatment
  groups

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Epinephrine versus Salbutamol

• Four studies compared epinephrine to salbutamol
  among outpatients.
• Four out of sixteen outcomes favoured epinephrine
  over salbutamol change in oxygen saturation at
  60 minutes post-treatment ,heart rate at 90
  minutes post-treatment respiratory rate at 60
  minutes post-treatment "improvement" (OR 4.51
  95 CI 1.93,10.53).
• Sensitivity analyses using fixed-effects models
  found significant differences favouring
  epinephrine for an additional two outcomes
  change in clinical score at 60 minutes and
  admissions.

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Epinephrine versus Salbutamol

• Epinephrine appears to be a better choice than
  salbutamol

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Nebulisation Dose

• Epinephrine 0.03mg/kg/dose
• Salbutamol
• Ipratropium

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Epinephrine

• Constriction of capillary arterioles
• For croup
• Racemic Epinephrine11 mixture of the d- and
  l-isomers of epinephrine (2.25), dose
  0.25ml-0.75 ml in saline
• L-isomer (0.1) 4mg, 4-5 ml 2ml saline
• Racemic for bronchiolitis 0.05 mL/kg diluted in
  3 mL NS given via nebulizer over 15 min q1-2h

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L-Epinephrine

• Dose of L-epinephrine
• 2-3 ml diluted to 5 ml with NS

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Inhaled corticosteroid for post bronchiolitic
wheezing Cochrane

• It has been shown that RSV is an independent risk
  factor for post-bronchiolitic wheezing (Stein
  1999). The vast majority of patients included in
  the studies of this review suffered from RSV
  bronchiolitis. In a post-hoc analysis we were
  unable to show a beneficial effect of inhaled
  steroids on hospital re-admissions in patients
  who suffered from bronchiolitis caused by RSV.

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Systemic Steroid

• Theoretically steroid should have effect in
  bronchiolits, especially in the early phase of
  diseasae
• Evidence ?

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Systemic Corticosteroid Cochrane

• Limited current evidence is unable to show any
  benefit of corticosteroid use in infants and
  young children with bronchiolitis.
• Widespread use is not recommended until the
  benefits and harms can be clarified further.
• The expected benefits appear to be limited to a
  shorter length of hospital stay in admitted
  patients of up to, but less than, one day.
• There is no supporting evidence to show
  improvements in clinical score, respiratory rate
  or haemoglobin oxygen saturation in treated
  infants and young children compared to those
  receiving placebo.

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Systemic Corticosteroid Cochrane
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Steroids Hospital stay pediatrics
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Systemic Corticosteroid Cochrane
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Additive effects of dexamethasone in nebulized
salbutamol or L-epinephrine treated infants with
acute bronchiolitis.Pediatr Int. 2004
Oct46(5)539-44

• either nebulized L-epinephrine (3 mg) or
  salbutamol (0.15 mg/kg) and 15 min later, either
  dexamethasone 0.6 mg/kg or placebo (PLA),
  intramuscularly
• CONCLUSIONS A single dose of intramuscular
  dexamethasone added to nebulized L-epinephrine,
  or salbutamol therapies resulted in better
  outcome measures than bronchodilators alone in
  the late phase (fifth day) of mild to moderate
  degree bronchiolitis attack. However, effects of
  EPI DEX combination was not different from SAL
  DEX combination.

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RIBAVARIN

• The current recommendations of the Academy of
  Pediatrics are that ribavirin aerosol therapy may
  be considered selected infants and young children
  at high risk for serious RSV disease.
• This includes patients with complicated
  congenital heart disease, including pulmonary
  hypertension patients with bronchopulmonary
  dysplasia, cystic fibrosis, and other chronic
  lung disease patients with underlying
  immunosuppressive disease patients who are
  severely ill with or without mechanical
  ventilation and hospitalized patients who are
  younger than 6 weeks or who have underlying
  conditions such as multiple congenital anomalies
  or certain neurological and metabolic diseases.

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RIBAVARIN

• 20 mg/mL as starting solution using continuous
  aerosol administration for 12-18 h/d for 3-7 d

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Prevention Palivizumab

• Intramuscular injection, of 15 mg/kg every 30
  days from October through February or according
  to the local RSV season.
• In a multi-institutional, randomized,
  placebo-controlled study of 1502 high-risk,
  preterm infants in 139 centers in the US and
  Canada during the 1996-1997 RSV season,
  hospitalizations were decreased by 55. Hospital
  length of stay, days on oxygen, and intensive
  care unit admissions all were reduced. Adverse
  effects were uncommon. Unfortunately, while cost
  effective, per-patient cost is approximately
  3000, thus restricting availability to only
  high-risk patients.

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Conclusion

• OPD treatment Steroid ?
• Borderline cases Epinephrine nebulisation
  Dexona (?)
• Admitted cases Epinephrine nebulisation
  Steroid (?)

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RSV and Parainfluenza virus
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RSV immunity
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Bronchiolitis Obliterans