Bronchiolitis

Lecture MBBS

1. WELCOME ALL

2. Bronchiole: A tiny continuation of the bronchi & connects to the alveoli. Resp. bronchioles the final branches

3. A clinical scenario Age: 5mo, formula fed , with UR catarrh ( rhinitis, -/+ cough, LGF x3d). Then suddenly developed fast br., tachycardia, chest indrawing, wheezing. Still playful, ~normal feeding What is the Dx?

4. BRONCHIOLITIS

5. At the end of this session you will learn Bronchiolitis is a very common viral (RSV) ARI Commonest LRTI & pneumonia in infants  (3-9mo) Mostly mild: LGF & cold; s elf-limited Prognosis is excellent Needs only supportive Rx: mostly no ABT It is uncommon in breastfed babies Can cause hyperactive airways ABT: antibiotic therapy LRT: lower resp. tract

6. INTRODUCTION Bronchiolitis: inflammation of bronchioles with excessive mucus & bronchospasm Common c/of hospitalization May be associated with significant MM Can cause Hyperactive/Reactive Airway: Bronchospasm from allergy/infection Mostly temporary Not BA; but asthma-like syn. May later become BA (child is old enough for bronchial challenge test)

7. MICROBIOLOGY Typically viral: RSV: 80% Influenza, parainfluenza A B C Rhinovirus Metapneumovirus Coronavirus (SARS. MERS) Bocavirus Occasionally M pneumoniae

8. RSV Ubiquitous Seasonal Temperate Southern H: May-Sep, peak May-July ,, Northern H: Nov.- April, peak Jan-Feb Tropical: rainy season 90% by 2y age have exposure METAPNEUMOVIRUS Paramyxovirus; m ay co-infect with other viruses May cause pneumonia PARAINFLUENZA: Usually type 3

9. Electron micrograph of respiratory syncytial virus (RSV)

10. INFLUENZA VIRUS Very similar to RSV or parainfluenza v. in CF Similar in distribution to RSV BOCAVIRUS: May cause pertussis-like illness RHINOVIRUS >160 serotypes! Mainly ‘common cold’ Affects LRT in children with chr. LD Often co-infects with other viruses CORONAVIRUS 2 nd commonest c/of common cold Non-SARS types cause bronchiolitis SARS, MERS

11. EPIDEMIOLOGY Typically 3-9 mo 60% <6 mo; 80% <1y. Not beyond 5y 60% of all LRTI in infants. 3% admission Incidence : 31/1,000 infants RSV in admitted pts. 40% of all LRTI in 1 st y of life 20% of all LRTI in  5 y ..

12. PATHOGENESIS IP: 2-8 days Inflammation, cell necrosis, ciliary damage Edema, mucus, sloughed epithelium: block Peribronchial lymphocytic infiltration (cuffing)

13. FACTORS FOR SEVERE B. Preterm, LBW, age: <6w Cystic fibrosis BA, Chr. LD or anatomical defects of airways Cardiac disease, kidney disease Immunodeficiency ENVIRONMENTAL: active/passive smoking, overcrowding, child care centre, high altitude

14. CLASSICAL PRESENTATION Starts as URT catarrh : rhinitis, -/+ cough, LGF: 1-3d then : fast br., tachycardia, chest indrawing, wheezing Mostly mild Full recovery: 2-8w No recurrence in RSV. If any, look for HD, BA, CF, etc.

15. PHYSICAL SIGNS Tachypnea : cut-offs <60d 60 bpm ( Preterm 70) 2mo-12mo 50 ,, 1y- 5y 40 ,, Vesicular br. with prolonged expiration, diffuse wheezes and crackles ~Dehydration ~conjunctivitis or AOM ~cyanosis or apnea in young infants

16. S/of SEVERE DISEASE Indication of admission: average stay: 3 d Age <3 mo. Toxic look, dehydrated, apneic spells RR: >70 O2 <90% on room air; CO2 trapping Nasal flare (pneumonia) Atelectasis Poor feeding S/o HF 2y infx. Parent unable to home care

17. Apnea in bronchiolitis 20% of admitted RSV Bronchiolitis in < 2-3 mo, prematurity May be the presenting symptom Recurrence rate 50% Mortality <2%

18. Dehydration in ARI Fever Fast br. Poor intake Vomiting Runny nose Parenteral diarrhea

19. DIAGNOSIS: Clinical Based on: h/o & PE Supported by CXR hyperinflation, flat diaphragm, air bronchograms, peribronchial cuffing , patchy infiltrates, atelectasis

20. Air trapping. Peribronchial cuffing due to wall thickening. Minimal focal atelectasis. Tubular heart. Flat low-set D

21. Peribronchial cuffing

22. DX: VIRAL ISOLATION Generally not warranted . It rarely affects Rx/outcomes it may decrease AB use; may stop spread may help guide antiviral Rx Nasal aspirate: Ag detection; EM; FAB tests; culture & PCR OTHER TESTS Mostly in complications CBC: 2y infx. CRP: … ABG to evaluate respiratory failure CXR for pneumonia, heart disease

23. DD BA Bronchitis/pneumonia Chr. lung D FB, GERD or aspiration Cong. HD or HF Vascular rings, bronchomalacia, complete tracheal rings or other anomalies COURSE Depends on co-morbidities. Usually self-limited wheezing may continue >1w Anorexia & disturbed sleep may persist for 2-4w

24. DD: Bronchiolitis & Bronchitis Anatomical: bronchioles are very small & delicate airways that lead to alveoli ("cul de sacs“ for gas exchange). Bronchi are much larger "pipes" immediately after the trachea Bronchiolitis is an infant to early childhood illness Bronchitis is more seen in teens & adults Cigarette smoke is a predisposing factor for both d. Both  are viral inf. & do not require ABT Bronchitis has more productive cough

25. TREATMENT: SUPPORTIVE CARE Clean airway with saline, correct dehydration Antipyretics SOS Humidified O2 Mechanical ventilation for pCO2 >55 or apnea Monitor: apnea, hypoxia hydration, respiratory failure, HF

26. CHEST PHYSIOTHERAPY Not recommended : no cl. improvement, nor reduces O2 need or shorten hospital stay May increase distress & irritability FLUID ADMINISTRATION O ral & IVF in dehydration Monitor for fluid overload as SIADH may occur BRONCHODILATORS: Not recommended Consider in severe wheezing Albuterol/racemic epinephrine may work; but SE common: tachycardia, hypoxemia, tremor, constipation, insomnia, etc. Anticholinergics: No benefit

27. CORTICOSTERIODS Not recommended May help in chr. LD or recurrent wheezing Prednisone, dexamethasone Inhaler: not helpful RIBAVIRIN Not routinely recommended Very costly. May be useful in severe RSV Must be used early ANTIBIOTICS: No routine ABT. Used in 2y bacterial infx. ( positive culture, AOM, Consolidation on CXR)

28. NON-STANDARD THERAPIES Heliox helium & O2 decreases breathing work only small benefit in limited patients RSV-IG or Palivizumab no improvement in routine cases Surfactant may decrease duration of mechanical ventilation or ICU stay

29. DISCHARGE CRITERIA Normal RR Adequate feeding No supplemental O2 Caretaker educated & confident; capable of bulb suctioning PROGNOSIS: Excellent MR <1% in admitted children 80% deaths in infants

30. COMPLICATIONS Highest in high-risks Apnea: in young infants Respiratory failure: 15% 2y bacterial inf.: 1% Collapse, consolidation Otitis media Prognosis Excellent Death: <2% (2y bacterial pn. & interstitial pn.)

31. CXR: hyperinflation with flattened diaphragm & bilateral atelectasis in the R apical & L basal regions in a 16d-old with severe bronchiolitis

32. PREVENTION Hand washing; avoid viral contact, smoking New vaccine under trials Hyperimmune Ig MAB: palivizumab 55% less admission for preterm/chr. LD & 45% for cong. HD. Given monthly through RSV season Influenza vaccine

33. BRONCHIOLITIS & B.A. RSV is a risk for recurrent wheeze (40%) & reduced FEV1 up to age 11y Association of RSV with later BA may be a predisposition factor

34. Bronchiolitis obliterans (BO) Or obliterative/constrictive B. usually adenovirus . Rare but fatal (irreversible): fibrosis +/or inflammation: block B. obliterans organizing pn. ( BOOP ) o r cryptogenic organizing pn. ( COP ) Non-infx.; often in Rh A, or with amiodarone CF & CXR show pn. But no response to ABT

35. Some interesting CX-Rays

36. DH: Asymmetry of L hemidiaphragm. Gas-filled organs or a NGT within the chest confirm DX. confused in diaphragmatic paralysis or after lung reduction surgery

37. CDH: Morgagni defect

38. Pneumoperitoneum: mostly perforation. Erect XR: air crescent under D. Sometimes, a double-wall, or Rigler's , sign can be seen which refers to internal & external air outlining the intestinal wall

39. A tension PT: air under pressure: one-way valve. tracheal shift, hyperresonance & no BS, distended neck veins, hypoxia. affected lung collapses; widened IC spaces

40. Pneumomediastinum. Most commonly follows injury to esophagus/adjacent alveoli. CXR: free air may outline anatomic structures. Common findings are a thin line of radiolucency that outlines the cardiac outline, vertically oriented streaks of air in the mediastinum, a double bronchial wall sign, or lucency around the right pulmonary artery, the "ring around the artery" sign. Air is most easily detected retrosternally on lateral CXR. Air is fixed in a pneumomediastinum & does not rise to the highest point

41. Airway FB, most often in children; the commonest site is R main B due to its being posterior, straighter, & wider. Indirect s/of ingestion include focal overinflation with partial obstruction or collapse in complete obstruction. See a radiopaque object lodged in the R main bronchus of a child

42. Aspiration pn.: aspirated flora or gastric contents. A. pneumonitis: from chemical insult. CXR: bilateral opacities in the middle or lower zones. Acute: infiltrates or lobar consolidation. Chr.: solidified mass

43. Rt. middle lobe collapse with obliteration of R heart border

44. A hydropneumothorax: esophageal rupture, trauma, gas-forming MO, bronchopleural fistula, surgery. See horizontal AF level

45. MCQs RSV is the commonest c/of bronchiolitis ABT is usually required in B Most B are later associated with BA In EBF babies B is rare Anticholingergic nebulization is beneficial in B B is usually a killer D SARS/MERS is caused by RSV Antiviral Rx is beneficial in all B cases

46. T H A N K Y O U