Approach to stridor in a 6 year old child

1. Approach to stridor in a 6 year old child Jacques le Roux 24/08/2012

2. APPROACH TO STRIDOR IN 6 YEAR OLD CHILD • Anatomy (upper airways) • General reminders • Etiology • Approach • - Imaging options • - Imaging findings

3. ANATOMY • 1. Supraglottic Region– above vocal cords • Epiglottis with • Aryepiglottic folds (runs laterally and convex-INF) • 2. Glottic • Level of true vocal cords (triangular space) • Level of thyroid cartilage • 3. Subglottic • Trachea starts here • Level of cricoid cartilage • Trachea on: • - frontal X-Ray, convex shoulders • - axial imaging, round (if not pathology) • Thoracic inlet: Line through sternal angle / T4 • - Above is upper airway • - Below starts lower airway • Retrophareng. (prevert soft tissue) • - From C1 – C4 : normal ¾ of vertebral body • - Lat must be taken in extension (flexion makes it wider)

4. GENERAL REMINDERS(CAUSES OF AIRWAY OBSTRUCTION IN A CHILD) • CLASSICAL • < 3 years - croup (subglottic laringo-tracheo bronchitis) • - not life-threatenig (self limited disease) • Life-threatening • - Infant – choanal atresia • - 3-6 years – epiglottitis • - Any age - foreign bodies (also in esoph) • - 80% radiolucent • - Angioneurotic edema • ± 6 years - other causes • - think: upper or lower airways and intrinsic or extrinsic causes

5. ETIOLOGY • UPPER AIRWAYS • - Above thoracic inlet • Inspiratory stridor • Usually acute (infective) • ACUTE • 1. Foreign bodies • 2. Retropharengeal • - Cellulitis • - Abscess (gas) • 3. Quinsy (tonsils) • 4. Lymphadenitis • - BACT • - TB (scrofula) • 5. Exudative tracheitis • 6. Angioedema • CHRONIC • 1. Enlarged tonsils • (adenoid, palatine, lingual) • 2. Large tongue • (Down) • LOWER AIRWAYS • - Below thoracic inlet • Inspiratory stridor and expiratory wheeze (some • also call it stridor) • More chronic • Some asymptomatic • Intrinsic/Extrinsic • INTRINSIC • 1. Foreign bodies • 2. Post intubation stricture /granuloma • 3. Hemangioma (most common mass in trachea) • - Subglottic • (Ass with facial hemangiomas)

6. LOWER AIRWAY OBSTRUCTION • EXTRINSIC – think ant. and middle mediastinum • A. ANT– the 4 T’s • Normal thymus - large until 6 years • - never compresses airways / vessels • - ABN one does – look for Ca⁺⁺ • 1. Lymphoma (“terrible”) - most common ant. mass (older child) • - look for other nodes • 2. Thymic masses (cyst – AIDS, thymomas – rare) • 3. Teratoma - Ca⁺ and fat • 4. Thyroid tumors – rare • B. MIDDLE • 1. Nodes (lymphoma, TB, METS) – most common mass • 2. Duplication cysts • (a) bronchogenic, ass with carina • (b) enteric – ass with GIT • 3. Vascular – rings - encircle esoph. and trachea • Pulmon. sling – between trachea and esoph. • 4. ↑ L Atrium • C. POST- Rare cause • Neurogenic tumors • Ganglioneuroblastoma and ganglioneuroma (6 years) • Neuroblastoma (classic < 2 years)

7. IMAGING OPTIONS • A. CHOICE • Frontal and lat. neck and CXR • BACK-UP-Δ various intrins and extrins lesions • 1. CT (better than MRI) • faster, seldom sedation • Risk - radiation, CT (10mSv) • MDCT (20-30mSv) • - contrast reactions • options - multiplanar, 3D volume rendered • - vascular rings, sling • - abscess : cellulitis • - metallic for. bodies • 2. Upper GI series - vascular rings, sling • 3. Sonar : Ant. mediast. - ABN thymus (heterog Ca⁺⁺, fat) • - biopsy + local is choice • - if trachea > 50% narrow and with general – expect problems

8. FOREIGN BODIES and IMAGING • 80% RADIOLUCENT (look for indirect signs) • 1. Fluoroscopy (Dynamic) • Mediast. shifts away from obstruc. with expiration (airtrapping) • 2. Lat. Decubitus • Normal: Dependent side hypo-aerated • with FB stays hyper-aerated • 3. EXP CXR - airtrapping (radiolucent) • - flat diaph. (normal inspiration R 6 rib – L 2cm lower) • 20% RADIO OPAQUEeg coin – lateral XR • In airways - perpendicular (round) to projection • In esoph. - parallel (slim-like, pancake) • Bronchoscopy Δ and treatment

9. IMAGING FINDINGS UPPER AIRWAYS – ACUTE/CHRONIC

10. TWO REMINDERS - < 6 Years Normal – subglottic airway shows rounded shoulders • 1. Croup • Loss of shoulders • Steeple sign Subgottic narrowing Epiglottis normal

11. 2. EPIGLOTTITIS • Thick epiglottis • Thumb sign Thick epiglottis and aryepiglottic fold

12. EXUDATIVE TRACHEITIS - 6 – 10 Years - Staph • Trachea walls irregular • Normal epiglottis

13. RETROPHARENGEAL CELLULITIS • A. • Retrofar. soft tissue swelling • More than vertebral body • B and C : CT with contrast • Low att. Mass • No rim enhancement • Difficult to do ΔΔ from abscess – clue is gas • [ cellulitis no gas ]

14. RETROPHARENGEAL ABSCESS • A. Retrophareng – thick soft tissue • B. CT with contrast • - Low att. mass • - Rim enhancement PSEUDORETROPHARENGEAL SOFT TISSUE THICKENING A. Lat - thick retrophar soft tissue - image in flexion B. Lat - no thickening - image in extension ( is the way)

15. TB (SCROFULA) – TB glands • CT WITH CONTRAST • Bilat. necrotic lymph adenopathy • Usually no pulm TB

16. TONSILS Adenoid and palatine enlarged tonsils • T2 with fat saturation • Enlarged lingual tonsisls • - T2 high • [Normal signal • Tonsils same as muscles of tongue]

17. ADENOID TONSILS A. Enlarged • T₂ Gradient echo (cine) • B.Expiration • Airway open • C.Inspiration • Collapse of airway

18. Adenoid tonsils (T₂ with fat saturation – tonsil ↑ signal) • removed gives a V shaped appearance • absent at birth • Reach max size 2 – 10 years • After removal – commonly grows back • Ass with collapse of laringopharynx (stridor) with • inspiration, because sup. obstruction cause • negative pressure in laringopharynx • Bilat. palatine tonsils enlarged • - kissing tonsils • - obstruction of airway

19. PERITONSILLAR ABSCESS • CT WITH CONTRAST • ↓ Att • Rim enhance

20. ANGIOEDEMA • Diffuse edema around trachea (↓Att) • Pat. was on ACE-inhibitor for high BP

21. GLOSSOPTOSIS – eg Down Obstruction of airway

22. LOWER AIRWAYS EXTRINSIC

23. NORMAL THYMUS Infant – passed away - prominent size Normal “sail” sign • CT • Quadrilat. in shape • Homogeneous att. • No compression of trachea or SVC

24. BRONCHOGENIC CYST - COMPRESSING LEFT MAIN BRONCHUS - 50% of intrathoracic cysts - Most asymptomatic - Location - Carina (most common) - Paratracheal (usually right) - Hila A. LLL - Retrocardiac density - Asim. aeration of lungs B. - Low att. Mass - Adjacent to carina - compressing L main bronchus

25. LYMPHOMA – MOST COMMON ANT. MEDIAST. MASS IN CHILD A - Wide mediast. B and C - Trachea post displaced and compressed C and D - SVC encased and compressed

26. VASCULAR RINGS/SLING • Some not found in 6 years • Some will not compress airways

27. NORMAL ANATOMY Level T₃ 9 : Trachea 10 : Esophagus 6,7 : R, L CCA 5,8 : R, L SCA Innominate art.(Br. ceph. truncus) - from right - passes just in front of trachea just inf. to level of thoracic inlet Level T₄ 4 : SVC 3 : normal L aortic arch.

28. VASCULAR ABNORM.( RINGS AND PULM. SLING) DIAGRAMS COMPARED WITH LAT. CXR / FLUOROSCOPY 1. Double aortic arch • Most common • Δ after birth • Both trachea and esoph. compressed • Both join desc. Aorta • - additional compression in midline 2. Pulm. Sling • Only vasc abn that passes between esoph and • trachea • L PA comes from R PA • Compress both (tracea/esoph) 3. Innominate art compression syndrome • Origin more to left and with large thymus, cause • compression just below thoracic inlet • Highest vasc. abn

29. 4. R Arch with aberrant L SCA • Meg of airway compression • Kommerell diverticulum • - dilation of aorta where L SCA starts • Lig. arteriosum completes ring as well • More midline desc. aorta 5. L Arch with aberrant R SCA

30. DOUBLE AORTIC ARCH • CT • Compress trachea ant. • Ba ⁺⁺ study: (Reverse S-shaped esoph.) • Bilateral extrinsic compressions on the esoph.

31. R AORTIC ARCH WITH ABERRANT L SCA A. CXR (AP) – clue of R arch - no knob L seen - trachea to left B. CXR (Lat) – trachea ant. and compressed C. CT – R aortic arch with aberrant L SCA D. Midline desc. Aorta causes compression Ba⁺⁺ study: post compression of esoph.

32. PULM. SLING • CT • L PA comes from R PA instead of MPA • Only vasc. abn that passes between esoph. and trachea • CXR • Above named cause compression of trachea and R main • Bronchus – reason that aeration is less in R lung

33. INNOMINATE ART. COMPRESSION SYNDROME • Compresses the trachea – if trachea not round there is extrins. compression

34. FOREIGN BODIES More common in R main bronchus than upper airways NON OPAQUE(80%) • INDIRECT SIGNS • CXR PA – expiratory • L lung hyperlucent due to airtrapping • Normal dependent side will hypoaerate • Lat. decubitus • L lung will stay aerated RADIO-OPAQUE(20%) • Button in subglottic area (round) • Bronchoscopy for removal

35. RADIO-OPAQUE FB IN ESOPHAGUS vs TRACHEA • CXR LAT • In esoph. – foreign body present • - appears slim (like a pancake) • In trachea – perpendicular (round)

36. POST INTUBATION STRICTURE AND GRANULOMA

37. SUMMARY ETIOLOGY : STRIDORIN 6 YEAR OLD UPPER AIRWAYS LOWER AIRWAYS ACUTE INTRINSIC Foreign bodies Foreign bodies Infections EXTRINSIC – think ant. and middle mediastinum A. ANT – the T’s Lymphoma (“terrible”) - most common ant. mass (older child) B. MIDDLE Nodes (lymphoma, TB, METS) – most common mass C. POST – Neurogenic tumors Rare cause CHRONIC Enlarged tonsils

38. It has been said that one of the differentiating features between a pediatric and a general radiologist is that a pediatric radiologist remembers to look at the airway. Problems with the airway are much more common in children than in adults.

39. References 1. Yedururi S, Multimodality Imaging Of Tracheo Bronchial Disorders In Children Radiographics May 2008. 2. Berrocal T, Cong. Anomalies Of Tracheobronchal Tree And Mediatinum: Radiology And Pathology Radiographics Nov. 2003. 3. Ludwig B, Diagnostic Imaging In Nontraumatic Pediatric Head And Neck Emergencies, Radiographic 2010; 30: 781-799. 4. Capps E, Emergency Imaging Assessment Of Acute Non Traumatic Conditions Of The Head And Neck Radiographics 2010; 30: 1335-1352. 5. Gooding CA, Essentials Of Pediatric Radiology Cambridge 2010, 40-74.