Asthma & Bronchiolitis in the Hospitalized Pediatric Patient

Asthma & Bronchiolitis in

the Hospitalized Pediatric Patient

October 2008

Brian W. Temple, MDChildhood Health Associates of Salem

Goals for todayGeneral definition of asthma and bronchiolitis

Natural history of both disease processes

What’s happening in the lungs?

Treatment

Asthma vs Viral Bronchiolitis

What is asthma?

•Asthma is a chronic disease characterized by increased responsiveness of the airways to various stimuli and manifested by widespread obstruction, which changes in severity either spontaneously or as a result of therapy.

Chronic disease

When can you diagnose?

When do you treat?

Don’t fear “label” since correct diagnosis leads to correct treatment.

Natural HistoryMedian age of onset is 4 years with 20% developing symptoms in first year of life.Risk factors include family history, presence of other inflammatory diseases (like eczema), and early RSV infection.60% resolve by young adulthood.50% that remit during adolescence will return as adultHistory of RSV without family history of asthma or eczema more likely to improve in first few years.

Pathophysiology • Asthma is an inflammatory

disease!• Asthma is an inflammatory

disease!• Asthma is an inflammatory

disease!

Common TriggersInfections: viral respiratory illness (rhinovirus, influenza, RSV, parainfluenza, human metapneumovirus), sinus infections

Allergens: seasonal allergens, indoor allergens, pets

Irritants: cigarette smoke, wood smoke, other pollutants, weather changes

Airway hyperresponsivenes

sPrimarily smooth muscle mediated. Can occur at any age. Reversible with albuterol. Primarily expiratory wheezes.Results in air trapping / obstruction (can be quantified on PFT’s).Variable throughout lungs. May cause atelectasis on x-ray.Primary process for wheezing due to cold air, exercise, pet allergens.

Airway Inflammation

More often triggered by infections and chronic allergies.

IgE mediated triggering mast cell release.

Causes “fixed” obstruction not responsive to albuterol and more often has an inspiratory component.

Strong genetic contribution.

Needs steroids.

A Closer Look

Symptoms• Coughing and wheezing are the most

common symptoms of childhood Asthma

• Breathlessness, chest tightness or pressure, and chest pain also are reported

• Poor school performance and fatigue may indicate sleep deprivation from nocturnal symptoms

Cough• Nocturnal cough, recurring seasonal

cough, or cough in response to specific exposures

• Although wheezing hallmark of asthma, cough is often sole presenting complaint

• Most common cause of chronic cough in children older than 3 years is asthma

Wheeze• Wheezing is a high-pitched, expiratory

sound produced when air forced through narrow airways

• Asthma wheeze tends to be polyphonic (varied in pitch)

• When airflow obstruction severe, can appreciate wheeze with inspiration and expiration.

Acute Treatment

Albuterol and steroids.Neb vs MDIPO vs IV steroids

Oxygen for hypoxiaFluid support if dehydration

Oxygen• Hypoxia primarily due to ventilation /

perfusion mismatch and air trapping

• Albuterol may actually worsen V/Q mismatch.

• Don’t use oximetry alone in assessing response to therapy.

Asthma Classification

•

Mild intermitten

tdaily symptoms < 2/week

night symptoms < 2/month

Mild persistent

daily sx >2 per week but < dailynight > 2/month

Moderate persistent

daily symptomssx > 2x / week affect activity

night symptoms > 1/week

Severe persistent

continuous symptomslimited activity

Outpatient Chronic Treatment

•

Mild intermitten

talbuterol prn

Mild persistent

low dose inhaled corticosteroid or Singulair©

albuterol prnModeratepersistent

low to medium dose inhaled corticosteroid and long acting beta2-agonist

Severepersistent

high dose inhaled corticosteroid and long acting beta2-agonist

consider daily po corticosteroids

What else can be done?

• Avoid and manage triggers

Treatment of allergies.

Treatment of chronic infections.

Management of household irritants and allergens.

Is it really asthma?Foreign body

Laryngotracheomalacia

Other congenital abnormalities (congenital heart disease, vascular ring, TE fistula)

Gastroesophageal reflux

Cystic fibrosis

Is it really asthma?•Asthma vs CroupInspiratory problem or expiratory

problem?

Course of illness?

Age of patient?

Patient’s and family’s history?

Is it really asthma?•Asthma vs bronchiolitisAge of the patient?

Patient’s history of wheezing?

Family history of asthma or other allergic disorders?

Response to therapy?

Bronchiolitis

• Bronchiolitis, a lower respiratory tract infection that primarily affects small airways (bronchioles), is a common cause of illness and hospitalization in infants and young children

Definition of Bronchiolitis

• First episode of wheezing in a child younger than 12 to 24 months with physical findings of a viral respiratory infection and has no other explanation for wheezing

• Broader definition: an illness in children <2 years of age characterized by wheezing and airways obstruction due to primary infection or re-infection, resulting in inflammation of the bronchioles

Microbiology• Typically caused by viral infection

• Respiratory Syncytial Virus (RSV) is the most common cause

• Less common causes include parainfluenza virus, human metaneumovirus, influenza virus, adenovirus, rhinovirus, coronavirus, and human bocavirus

Respiratory Syncytial Virus

• RSV is most common cause of bronchiolitis

• RSV is ubiquitous throughout world and causes seasonal outbreaks

Epidemiology• RSV is responsible for major of cases of

bronchiolitis

• Bronchiolitis typically affects infants younger than 2 years of age

• Peak incidence is 2 to 6 months of age

• Leading cause of hospitalization in infants and young children

Risk Factors for severe disease

• Prematurity (<37 weeks gestation)

• Low birth weight

• Age less than 6 to 12 weeks

• Chronic pulmonary disease

• Significant congenital heart disease

• Immunodeficiency

Pathogenesis

• Viruses penetrate the terminal bronchiolar epithelial cells, causing direct damage and inflammation in small bronchi and bronchioles

• Edema, excessive mucus, and sloughed epithelial cells lead to obstruction of small airways and atelectasis

The Bronciolitic Lung

Clinical Features• Increased respiratory effort and

wheezing

• Tachypnea and intercostal and subcostal retractions with expiratory wheezing

• Auscultation: expiratory wheeze, prolonged expiratory phase, and both coarse and fine crackles

• Bronchiolitis is diagnosed clinically

Hospital Treatment of Bronchiolitis

• Respiratory support: keep oxygen saturation above 90%

• Fluid administration to ensure adequate hydration and avoid aspiration

• Chest PT does not appear to improve clinical course

• Pharmacologic therapy: a number of therapies of been shown to improve outcome

Pharmacologic Therapy

• Inhaled Bronchodilators (e.g. albuterol, Epinephrine), Do they work?

• No to oral bronchodilators

• Glucocorticoids may be beneficial to infants with chronic lung disease and/or asthma component to illness

• Ribavirin is not routinely recommended

Nonstandard Therapies

• Heliox- mixture of helium (70-80%) and oxygen (20-30%)

• Anti-RSV preparations: Palivizumab

• Surfactant

• Hypertonic saline

Inhaled Bronchodilators

• Trial of bronchodilator medication is an option-varied clinical results

• Albuterol should be tried first with assessment within 1 hour of use, if no improvement,

• Epinephrine should be tried, if no improvement within hour,

• Consider discontinuation of bronchodilators

Discharge Criteria• Respiratory rate <70 breaths/min

• Caretaker can clear infants airway

• Patient is stable without supplemental O2

• Adequate oral intake

• Caretaker confident they can provide care

• Education of family is complete

Education

• Expected clinical course: <24 months is 12 days

• Proper techniques for suctioning the nose

• Indications to contact primary care provider