Bronchiolitis

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Bronchiolitis

BASICS

DESCRIPTION:

Inflammation of the bronchioles, usually seen in young children, occasionally in high-risk adults. May be seasonal (winter and spring) and often occurs in epidemics. Usual course: insidious; acute; progressive.Read more...

System(s) affected: Pulmonary
Genetics: N/A
Incidence/Prevalence in USA: Medical care provided to 1000-1500/100,000 annually. Estimated incidence is higher.
Predominant age: newborn-2 years (peak age 2-6 months)
Predominant sex: Male > Female

SIGNS AND SYMPTOMS:

  •Anorexia
  •Cough
  •Cyanosis
  •Expiratory wheezing
  •Apnea
  •Fever
  •Grunting
  •Inspiratory crackles
  •Intercostal retractions
  •Irritability
  •Noisy breathing
  •Otitis media
  •Pharyngitis
  •Tachycardia
  •Tachypnea
  •Vomiting

CAUSES:

  •Respiratory syncytial virus
  •Parainfluenza
  •Adenovirus
  •Rhinovirus
  •Influenza virus
  •Chlamydia
  •Eye, nose, mouth inoculation
  •Exposure to adult with URI
  •Day care exposure (significant)
  •Idiopathic (many adult cases)

RISK FACTORS:

  •Contact with infected person
  •Children in day care environment
  •Heart-lung transplantation patient
  •Adults - exposure to toxic fumes, connective tissue disease

DIAGNOSIS

DIFFERENTIAL DIAGNOSIS:

  •Asthma
  •Vascular ring
  •Lobar emphysema
  •Foreign body
  •Heart disease
  •Pneumonia
  •Reflux
  •Aspiration
  •Cystic fibrosis

LABORATORY:

  •Arterial blood gas - hypoxemia, hypercarbia, acidemia
  •Respiratory viral culture - positive
  •Respiratory viral antigens - positive

Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS:

  •Abundant mucous exudate
  •Mucosal - hyperemia, edema
  •Submucosal lymphocytic infiltrate, monocytic infiltrate, plasmacytic infiltrate
  •Small airway debris, fibrin, inflammatory exudate, fibrosis
  •Peribronchiolar mononuclear infiltrate

SPECIAL TESTS:

Infant pulmonary function studies - bronchodilator response

IMAGING:

  •Chest x-ray
      •Focal atelectasis
      •Air trapping
      •Flattened diaphragm
      •Increased anteroposterior diameter
      •Peribronchial cuffing

DIAGNOSTIC PROCEDURES:

N/A

TREATMENT

APPROPRIATE HEALTH CARE:

  •Most patients can be treated at home
  •Inpatient indicated for patient with increased respiratory distress, cyanosis, and dehydration

GENERAL MEASURES:

  •Most critical phase is first 48-72 hours after onset. Treatment is usually symptomatic.
  •Fluid at maintenance
  •Mechanical ventilation in respiratory failure
  •Isolation: contact; handwashing most important
  •Antiviral agents for selected high-risk patients
  •Cardio-respiratory monitoring
  •Inhaled bronchodilators are commonly used, although efficacy has been hard to demonstrate in controlled studies
  •Steroids may not change course - except in patients with reactive airway disease

SURGICAL MEASURES:

N/A

ACTIVITY:

  •Avoid exposure to crowds, viral illness for 2 months
  •Avoid smoke

DIET:

  •Frequent small feedings of clear liquids
  •If hospitalized, may require intravenous fluids

PATIENT EDUCATION:

Griffith: Instructions for Patients; Philadelphia, W.B. Saunders Co.

MEDICATIONS

DRUG(S) OF CHOICE:

  •Oxygen
  •Albuterol: may be effective for acute symptoms.
  •Epinephrine aerosols may be of benefit
  •Ribavirin: For infants and children, an inhaled antiviral agent active against RSV, may be indicated in patients with underlying cardio-pulmonary disease, young age (< 6 weeks), or with severe RSV (elevated pCO2; require mechanical ventilation - use with caution via ventilator). Nebulize via small particle aerosol generator (SPAG). Use of ribavirin has decreased in recent years, secondary to lack of significant clinical efficacy.

Contraindications: Refer to manufacturer's literature
Precautions: None
Significant possible interactions: None

ALTERNATIVE DRUGS:

  •Antibiotics only if secondary bacterial infection present (rare)
  •Corticosteroids do not change course, unless infant has reactive airway disease. In adults corticosteroids may be helpful.

FOLLOW UP

PATIENT MONITORING:

  •If patient is receiving home care, follow daily by telephone for 2-4 days
  •For hospitalized patient, monitor as needed depending on severity of infection. Bronchiolitis can be associated with apnea.

PREVENTION/AVOIDANCE:

  •Hand washing
  •Contact isolation of infected babies
  •Persons with colds should keep contacts with infants to a minimum
  •´Palivizumab´ (Synagis), a monoclonal product, can be used for prevention in high-risk patients (28-32 weeks gestation and less than 6 months old; less than 28 weeks gestation and less than 12 months old; moderately severe BRD and up to two years old). Administer monthly (November thru March) 15 mg/kg IM. Single use vial of 100 mg and 50 mg.
  •´RSV immune globulin´, a human blood product, can also be used in at-risk patients. Monthly infusions of 750 mg/kg, November thru March, in a controlled setting. Avoid fluid overload. Vial is 50 mg/mL; infuse at 1.5-6 mL/kg/hr; monitor oximeter and vital signs.
  •Both of these medications are quite expensive.

POSSIBLE COMPLICATIONS:

  •Bacterial superinfection
  •Bronchiolitis obliterans
  •Apnea
  •Respiratory failure
  •Death
  •Increased incidence of RAD

EXPECTED COURSE AND PROGNOSIS:

  •In most cases, recovery is complete within 7-10 days
  •Mortality statistics differ, but probably under 1%
  •High-risk infants (BPD, CHD) may have prolonged course

MISCELLANEOUS

ASSOCIATED CONDITIONS:

  •Common cold
  •Conjunctivitis
  •Pharyngitis
  •Otitis media
  •Diarrhea

AGE-RELATED FACTORS:

Pediatric: Most common in infants
Geriatric: N/A
Others: N/A

PREGNANCY:

N/A

SYNONYMS:

N/A

SEE ALSO:

N/A

OTHER NOTES:

N/A

ABBREVIATIONS:

BPD = bronchopulmonary dysplasia
CHD = congenital heart disease
RAD = reactive airway disease
SPAG = small particle aerosol generator

REFERENCES

  •Mandell GL, ed: Principles and Practice of Infectious Diseases. 4th Ed. New York, Churchill Livingstone, 1995
  •Fields BN, et al, eds: Virology. 2nd Ed. New York, Raven Press, 1990