Bronchiolitis

Bronchiolitis

OVERVIEW:

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.

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

ICD-9-CM:

466.1 acute bronchiolitis

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Medical Diagnosis » B » Bronchiolitis