acute bronchiolitis

Acute bronchiolitis

dr hisham alrabty - 10-4-2014

Acute bronchiolitisBy: Hisham Alrabty(pediatrics consultant).dr hisham alrabty - 10-4-2014

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What is acute bronchiolitis?Bronchiolitis is an acute inflammatory injury of the bronchioles that is usually caused by a viral infection (most commonly respiratory syncytial virus and human metapneumovirus).dr hisham alrabty - 10-4-2014

EPIDEMIOLOGY:dr hisham alrabty - 10-4-2014Bronchiolitis is a significant cause of respiratory disease worldwide. According to WHO bulletin, an estimated 150 million new cases occur annually. About 75% of cases of bronchiolitis occur in children younger than 1 year and 95% in children younger than 2 years. Incidence peaks in those aged 2-8 months.Bronchiolitis as 1.25 times more common in males than in females.Death is 1.5 times more likely in males.Lower socioeconomic status may increase the likelihood of hospitalization.

What causes bronchiolitis?Typically caused by virusesRSV-most common(64%).Para influenza.Human Metapneumovirus(9-30%).Influenza(6%).Rhinovirus(16%).Adenovirus.Occasionally associated with Mycoplasma pneumonia infection


RSV:RSV causes 20-40% of all cases and 44% of cases that involve children younger than 2 years. Two RSV subtypes, A and B, have been identified on the basis of structural variations in the G protein. Subtype A causes the most severe infections. One subtype or the other usually predominates during a given season; thus, RSV disease has good and bad years. Viral shedding in nasal secretions continues for 6-21 days after symptoms develop. The incubation period is 2-5 days.



RSV


Pathophysiology:Bronchiolar injury and the consequent interplay between inflammatory and mesenchymal cells can lead to diverse pathologic and clinical features:Increased mucus secretion.Bronchial obstruction and constriction.Alveolar cell death, mucus debris, viral invasion.Air trapping.Atelectasis.Reduced ventilation that leads to ventilation-perfusion mismatch.Labored breathing.dr hisham alrabty - 10-4-2014

RISK FACTORS : for the development of bronchiolitis include the following :Low birth weight, particularly premature infants.Lower socioeconomic group.Crowded living conditions, daycare, or both.Parental smoking.Chronic lung disease, particularly bronchopulmonary dysplasia.Severe congenital or acquired neurologic disease.Congenital heart disease (CHD) with pulmonary hypertension.Congenital or acquired immune deficiency diseases.Age less than 3 months.Airway anomalies.


Clinical presentation:Begin with upper respiratory tract symptoms: nasal congestion, rhinorrhea, mild cough, low-grade fever.Progress in 3-6 days to rapid respirations, chest retractions, wheezing.Tachypnea.Prolonged expiratory phase, rhonchi, wheezes and crackles. Possible dehydration.Possible conjunctivitis or otitis media.Possible cyanosis or apnea.


DIAGNOSIS: diagnosis is based on history and physical exam on other words it is clinical diagnosis.CBC could show lymphocytosis.ABG for hypoxia and hypercapnia.CxR shows hyper inflated chest and atelectasis.Rapid antigen detection for RSV, Para influenza, influenza, adenovirus (sensitivity 80-90%).Immunofluorescence for viral detection and viral culture,PCR.



DIFFERENTIAL DIAGNOSIS:Pneumonia viral and bacterial.Asthma.FB aspiration.Pulmonary edema( a cyanotic CHD).Gastroesophygeal reflux.


Admission Criteria:Persistent resting oxygen saturation below 92% in room air.Markedly elevated respiratory rate (>70-80 breaths/min).Dyspnea and intercostal retractions, indicating respiratory distress.cyanosis.Chronic lung disease.Congenital heart disease.Prematurity.Age younger than 3 months, when severe disease is most common.Inability to maintain oral hydration in patients younger than 6 months.Parent unable to care for child at home.dr hisham alrabty - 10-4-2014

Treatment:Among many medications and interventions used to treat bronchiolitis, thus far, only oxygen appreciably improves the condition of young children.Therefore, therapy is directed toward symptomatic relief and maintenance of hydration and oxygenation.dr hisham alrabty - 10-4-2014

Nonpharmacotherapy:Supportive care for patients with bronchiolitis may include the following:Supplemental humidified oxygen.Maintenance of hydration.Mechanical ventilation.Nasal and oral suctioning.Apnea and cardiorespiratory monitoring.Temperature regulation in small infants.dr hisham alrabty - 10-4-2014

Pharmacotherapy:Medications have a limited role in the treatment of bronchiolitis. Healthy children with bronchiolitis usually have limited disease and usually do well with supportive care only.The following medications are used in selected patients with bronchiolitis:Alpha/beta agonists (eg, racemic epinephrine, albuterol).Monoclonal antibodies (eg, palivizumab).Antiviral agents (eg, ribavirin).dr hisham alrabty - 10-4-2014

Guidelines for treatment:In 2006, the AAP, in conjunction with the American Academy of Family Physicians (AAFP), the American College of Chest Physicians (ACCP), and the American Thoracic Society (ATS), published the following recommendations :dr hisham alrabty - 10-4-2014

dr hisham alrabty - 10-4-2014Diagnosis and severity should be based on history and physical findings. Bronchodilators should not be routinely used.Corticosteroids should not routinely be used.Ribavirin should not be used routinely.Antibacterials should be used only upon proven coexistence of bacterial infection.Hydration and the ability to take oral fluids should be assessedSupplemental oxygen should be supplied for saturations below 90% on pulse oximetry.Palivizumab prophylaxis should be administered to selected childrenHand decontamination is indicated to prevent nosocomial spread.Infants should not be exposed to secondary smoking, and breastfeeding is recommended.Clinicians should inquire about use of complementary and alternative medicine therapies.

Alpha/Beta Agonists:studies have reported that their use ranges from approximately 50% of cases to more than 90%. They act by decreasing muscle tone in both small and large airways in the lungs, thus increasing ventilation. Most controlled studies have failed to show a benefit in terms of oxygen saturation, rate of hospitalization, or length of hospital stay.Some studies showed salbutamol better than adrenaline and other studies showed the opposite. dr hisham alrabty - 10-4-2014

Ribavirin: It is a synthetic nucleoside analogue that resembles guanosine and inosine. It is believed to act by interfering with expression of messenger RNA and inhibiting viral protein synthesis. Ribavirin appears safe but is expensive. Its efficiency and effectiveness have not been clearly demonstrated in large, randomized, placebo-controlled trials.At present, routine use of ribavirin cannot be recommended.dr hisham alrabty - 10-4-2014

Chest Physiotherapy:A 2012 Cochrane review, which included 9 studies of children younger than 2 years with acute bronchiolitis, confirmed that chest physiotherapy does not decrease the severity of the disease, improve respiratory parameters, shorten the hospital stay, or reduce oxygen requirements in nonventilated hospitalized patients.dr hisham alrabty - 10-4-2014

Hypertonic saline as treatment:A Randomized Trial of Nebulized 3% Hypertonic Saline With Epinephrine in the Treatment of Acute Bronchiolitis in the Emergency Department. Simran Grewal, MD; Samina Ali, MD; Don W. McConnell, MD; Ben Vandermeer, MSc; Terry P. Klassen, MSc, MD.

Conclusion: in the treatment of acute bronchiolitis, hypertonic saline and epinephrine did not improve clinical outcome any more than normal saline and epinephrine in the emergency setting. This differs from previously published results of outpatient and inpatient populations and merits further evaluation.dr hisham alrabty - 10-4-2014

dr hisham alrabty - 10-4-2014Nebulized hypertonic saline solution for acute bronchiolitis in infants.Zhang L1, Mendoza-Sassi RA, Wainwright C, Klassen TP- 2013 Jul 31.

Conclusion:Current evidence suggests nebulized 3% saline may significantly reduce the length of hospital stay among infants hospitalized with non-severe acute viral bronchiolitis and improve the clinical severity score in both outpatient and inpatient populations.

Prevention:Palivizumab is a humanized monoclonal antibody directed against the F (fusion) protein of RSV. Given monthly through the RSV season 15 mg/kg IM q1Month , it has been demonstrated to decrease chances of RSV hospitalization in premature babies who are at increased risk for severe RSV-related illness.



acute bronchiolitis

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