SUBJECT SEMINAR ON APPROACH TO STRIDOR

28.6.2010

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STRUCTURES OF THE UPPER AIRWAY

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DEFINITION

Stridor, a harsh, medium-pitched, inspiratory sound associated with obstruction of the laryngeal area or the extrathoracic trachea, often accompanied by a croupy cough and hoarse voice

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Turbulent air flow through partially obstructed / narrowed airway.

Stridor is a symptom, not a diagnosis or disease, and the underlying cause must be determined.

Stridor may be inspiratory, expiratory, or biphasic

-Inspiratory stridor = extrathoracic lesion (eg, laryngeal, nasal, pharyngeal).

-Expiratory stridor = intrathoracic lesion (eg, tracheal, bronchial).

-Biphasic stridor suggests a subglottic or glottic anomaly

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PATHOPHYSIOLOGY During normal inspiration extrathoracic intraluminal airway

pressure is negative relative to atmospheric pressure, leading to collapse of supraglottic structures.

In contrast, stridor caused by intrathoracic obstructions tends to be more prominent on expiration. On expiration, intrathoracic pressure is positive and tends to collapse the airway.

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DISEASES ASSOCIATED WITH ACUTE STRIDOR Acute laryngotracheitis.

Acute laryngotracheobronchitis.

Acute epiglottitis.

Bacterial tracheitis.

Foreign body.

Uncommon Peritonsillar abscess.

Retropharyngeal abscess.

Diphtheria

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SIGNS OF WORK OF BREATHING

Tachypnoea

Chest retractions (SC / IC / SS )

Stridor / Wheeze / Grunt

Flaring of Ala nasi

Head bobbing

Abdominal breathing

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Respiratory distress – Clinical pearlsRespiratory distress – Clinical pearls

Supra-sternal indrawingSupra-sternal indrawing(Use of accessory muscles, Upper airway (Use of accessory muscles, Upper airway

involvement)involvement)

Intercostal indrawingIntercostal indrawing(Decreased Parenchymal Compliance)(Decreased Parenchymal Compliance)

Subcostal indrawingSubcostal indrawing(Increased work of diaphragm)(Increased work of diaphragm)

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SOUNDS DURING RESPIRATORY CYCLE

Stridor(Extra thoracic airway structures)

Wheeze(Intra thoracic airway structures)

Grunt(Parenchymal lesions)

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RESPIRATORY NOISES

Noises Phase of Respiration Localisation

Snoring Insp. / Exp. Oro-pharynx

Stridor Inspiration Larynx

Wheeze Expiration Small AW

Grunt Expiration Alveoli

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5 DIFFERENCES BETWEEN PEDIATRIC AND ADULT AIRWAY

Relatively larger tongue

Angled vocal cords

More anterior and cephalax larynx

Funneled shaped larynx-narrowest part of pediatric airway is cricoid cartilage

Differently shaped epiglottis

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PHYSIOLOGY: EFFECT OF EDEMA

Poiseuille’s law Poiseuille’s law

R = 8nl/ R = 8nl/ ππrr44

If radius is halved, resistance increases 16 x If radius is halved, resistance increases 16 x Image from: http://www.hadassah.org.il/NR/rdonlyres/59B531BD-EECC-4FOE-9E81-14B9B29D139B1945/AirwayManagement.ppt

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ANATOMIC CLASSIFICATION

BROAD SPECTRUM OF NEONATAL AIRWAY ABNORMALITIES

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VIRAL CROUP

Common respiratory illness in young children.

Anglo-Saxon word Kropan; cry aloud.

Hoarse voice; dry barking cough; inspiratory stridor; and variable amount of respiratory distress that develops over a brief period of time.

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CROUP SYNDROME

Group of diseases that varies in anatomic involvement and etiologic agents.

Laryngotracheitis.

Spasmodic croup.

Bacterial tracheitis.

Laryngotracheobronchitis.

Laryngotracheobronchopneumonitis.

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CROUPACUTE LARYNGOTRACHEITIS

Disease of viral origin causing subglottic & tracheal swelling.

The narrowed airway is responsible for the hallmark of clinical picture.

The cricoid ring in the upper trachea which is subglottic, has a narrow diameter which renders children vulnerable to inflammation.

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VIRAL CROUP( ACUTE LARYNGOTRACHEITIS)

Etiology: Respiratory viruses e.g. parainfluenza viruses

1,2,and 3, RSV, Influenza viruses A & B.

Clinical picture: Age 6mths- 3 years, M>F, Fall & winter. Gradual onset of low grade fever,URTI, barking

cough, inspiratory stridor & respiratory distress.

Hoarseness & aphonia may occur.

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CROUP, DIAGNOSIS & TREATMENT

Clinically Lateral neck X-ray ( steeple sign). Fluid intake Cool mist/ hot steamy bathroom. Aerosolized adrenaline. Steroids( controversial) Endotracheal intubation. Helium-Oxygen Mixture. Antibiotics

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ACUTE EPIGLOTTITIS, ETIOLOGY

Bacterial infection of the supraglottic structures (epiglottis, aryepiglottic folds & arytenoids soft tissues) causing rapid airway obstruction.

Haemophilus Influenza type B in prevaccination era.

Bacteria associated with epiglottitis in the Hib vaccine era include: HiA, Str. Pn, Staph aureus, ß-hemolytic streptococci Gps A,B,C,and F

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ACUTE EPIGLOTTITIS, CLINICAL PICTURE

Age usually 2- 7 years.

Sudden onset.

High fever.

Apprehensive, sitting forward, drooling saliva, hyperextended neck & protruded chin.

Stridor, dysphagia.

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ACUTE EPIGLOTTITIS, DIAGNOSIS & TREATMENT

Direct visualization. Blood cultures. Latex agglutination of serum or urine. Treatment is a medical emergency. Ventilatory support, intubation. IV antibiotics, 2nd or 3rd generation

cephalosporin's or chloramphenicol till cultures & sensitivity are known.

25ASSESSMENT- DOWNE’S

SCORE0 1 2

Stridor None Inspiratory Inspiratory + expiratory

Cough None Hoarse Barking

Retractions None Suprasternal Flaring + max.retractions

Cyanosis None In air In 40% oxygen

Breath sounds

Normal Harsh,wheeze/ rhonchi

+ delayed

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CharacteristCharacteristicic

EpiglottitisEpiglottitis CroupCroup

AgeAge Any ageAny age 6months-6months-12yrs12yrs

OnsetOnset SuddenSudden GradualGradual

LocationLocation SupraglotticSupraglottic SubglotticSubglottic

TemperaturTemperaturee

High feverHigh fever Low-grade Low-grade feverfever

DysphagiaDysphagia SevereSevere Mild or Mild or absentabsent

DyspneaDyspnea PresentPresent PresentPresent

DroolingDrooling PresentPresent PresentPresent

CoughCough UncommonUncommon Characteristic Characteristic coughcough

PositionPosition Leaning forward, Leaning forward, mouth openmouth open

comfortablecomfortable

X-RayX-Ray Thumb signThumb sign Steeple signSteeple sign

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ETIOLOGYLaryngotracheobronchitis (croup) Parainfluenza virus Adenovirus Echovirus Influenza viruses Respiratory Syncytial viruses Mycoplasma Epiglotitis H.influezae

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CLINICAL FEATURES

Epiglotitis- acute onset, fever, sore throat, hoarseness, and noisy breathing. Retraction of the suprasternal & infrasternal chest.

Look for the 4 Ds Dysphagia Dysphonia (Hot potato voice) Drooling Distress

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EPIGLOTITIS

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EPIGLOTITIS

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CLINICAL FEATURES

LARYNGITIS

Barking cough , fever

Tachypnea, dyspnea,subglottic obstruction, inspiratory stridor

Retraction of the suprasternal notch and supraclavicular retractions

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CLINICAL FEATURES

Laryngotracheobronchitis

Also called viral croup or just croup

Fever is higher, restlessness & air hunger

Demonstrate substernal & intercostal retractions in addition to suprasternal notch & supraclavicular retraction.

A barky cough, bronchitic inspiratory rales & expiratory wheezes are heard

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CROUPUSUALLY INVOLVES LARYNX TRACHEA, AND VARIABLE PART OF

BRONCHI.

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DIAGNOSIS

Etiology should be determined

Look for hoarseness, barking cough, inspiratory stridor and retractions

Throat swabs & smears are cultured and examined

Other airway obstructions should be considered

Serological tests

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X-RAY

A positive thumb sign on lateral X-ray of neck is diagnostic of epiglottitis.

The "steeple sign" in an anteroposterior neck X-ray is characteristic of viral croup (acute laryngotracheobronchitis).

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X-RAYCROUP

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Croup

This radiograph shows a long area of narrowing extending below the Normally narrowed area at the level of the vocal cords.

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EPIGLOTTITIS

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THERAPY

Two fold Maintenance of an adequate airway Control of infection

H. influenzae - ampicillin or chloramphenicol.

C. diphtheriae - antitoxin & erythromycin or penicillin G.

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DRUGS IN MANAGEMENT

GLUCOCORTICOIDS

Dexamethasone - most potent, long acting & can be given orally or parenterally.

Budesonide - lower systemic bioavailability, provides greater benefit as it is deposited in upper airway

Epinephrine - short term benefit by reducing secretions & mucosal edema. effective in severe cases.

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MIST THERAPY

Blow-by or nebulisation method

Humidified air

Benefits- soothes inflamed airway, decreases airway obstruction by reducing viscosity of secretions, improves respiratory flow pattern.

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MANAGEMENT - MILD CROUP

Minimal interference

Continue oral feeds

Steroids-budesonide 2mg in 4ml NS

Improvement discharge

No improvement treat as moderate croup

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MANAGEMENT - MODERATE CROUP

Oxygen if spo2<95%

Nebulised adrenaline1:1000.1st dose 1ml in 3ml NS.2nd dose 0.5ml/kg(max 4 dose)

NPO. IV Fluids.

Steroids - Dexamethasone 1mg/kg IV stat,then q 8hr for 2-3 days.

Budesonide nebulisation 2 mg in 4 ml NS single dose.

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MANAGEMENT - SEVERE CROUP

Oxygen. Iv fluids. Nebulised adrenaline. Steroids -IV dexamethasone + budesonide neb. Artificial airway .

ET tube – one size smaller than recommended

Quickly by experienced person

preferably under halothane anesthesia.

LARYNGOMALACIALARYNGEAL CONDITIONS

Inspiratory collapse of arytenoids, aryepiglottic folds and epiglottis

Anatomic, neurologic and inflammatory factors

Symptoms:

stridor, respiratory distress

possible feeding difficulties

weak cry

vary with position and activity

Onset usually delayed several weeks

LARYNGOMALACIALARYNGEAL CONDITIONS

Treatment

Supportive

Monitor symptoms, weight and feeding

Role of antireflux medications (PPI, H2RA)

Aryepiglottiplasty division of the short aryepiglottic

folds

VOCAL CORD PARALYSIS

LARYNGEAL CONDITIONS

2nd most common neonatal laryngeal anomaly Causes about 10% of congenital airway

obstruction Etiology

increased ICP injury to vagus nerve injury to left recurrent laryngeal nerve 20% result from traumatic birth

VOCAL CORD PARALYSIS LARYNGEAL CONDITIONS

Clinical Findings

Inspiratory stridor

Cyanosis, apneas (bilateral)

Weak/hoarse cry, aphonia (unilateral)

Feeding difficulties (unilateral)

Diagnosis

direct laryngoscopy

Treatment

expectant

reduce ICP (if present)

Tracheostomy (bilateral)

LARYNGEAL WEBLARYNGEAL CONDITIONS

Etiology- failure of laryngeal recanalization complete occlusion by mucosal and submucosal tissue

partial occlusion by a thin membranous web

Incidence- 1/10,000 births Clinical findings

stridor

weak or absent cry

not positional

Treatment Perforation, excision, dilation,

Cryotherapy, CO2 laser

SUBGLOTTIC HEMANGIOMA

Relatively rare 50% are associated

with cutaneous hemangiomas

Symptomatic within first 2 months, and present before 6 months

Present with inspiratory stridor

SUBGLOTTIC STENOSISLARYNGEAL CONDITIONS

Narrowing of the subglottic airway

housed in the cricoid cartilage

narrowest area of airway

Congenital and acquired

Most common abnormality requiring trach in children <1yr

ACQUIRED SUBGLOTTIC

STENOSISFACTORS IMPLICATED IN ITS

DEVELOPMENT

ETT size relative to child’s larynx

Duration of intubation

Motion of the tube

Repeated intubations

Factors affecting wound healing

Laryngotracheal reflux

Infection (historically tuberculosis and diphtheria)

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DO`S & DON`TS IN SEVERE CROUP

DO`S Treat on priority basis Relieve anxiety Humidified oxygen Portable x-ray neck If pus-antibiotics & send

investigation Consult ENT surgeon or

anaesthetist

DONT’S Do not panic. Don`t disturb sleep. comfort the child,Avoid crying. Don`t send to x-ray room. Don’t neglect child till x-ray. No IVF or venepuncture until

airway is secured Do not wait for culture for

antibiotics

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IMPORTANT POINTS

Symptomatic child with increased work of breathing should be treated with glucocorticoids

Rx may be with dexamethasone or nebulised budesonide

Use L/ Epinephrine for moderate or severe croup

Glucocorticoids reduce hospitalisation

Injectable dexamethasone provides more benefit than nebulised budesonide

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EPIGLOTTITIS

Stabilize airway under controlled situation.

Antibiotics – ampicillin and chloramphenicol or 3rd generation cephalosporins.

Bacterial tracheitis - Use appropriate antibiotics.

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PROGNOSIS

Depends on severity of illness

Complications -obstruction of the airway, atelectasis, pneumothorax, obstructive mediastinal emphysema, and bronchopneumonia

morbidity and mortality of epiglottitis can be very high with bacteremia often resulting in meningitis, septic arthritis or osteomyelitis .

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RECURRENT

Allergic (spasmodic) croup

Respiratory infections in a child with otherwise asymptomatic anatomic narrowing of the large airways

Laryngomalacia

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PERSISTENT STRIDOR - CAUSES

Laryngeal obstruction

Laryngomalacia

Papillomas, other tumors

Cysts and laryngoceles

Laryngeal webs

Bilateral abductor paralysis of the cords

Foreign body

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TRACHEOBRONCHIAL DISEASE

Tracheomalacia

Subglottic tracheal webs

Endotracheal, endobronchial tumors

Subglottic tracheal stenosis

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EXTRINSIC MASSES

Mediastinal masses

Vascular ring

Lobar emphysema

Bronchogenic cysts

Thyroid enlargement

Esophageal foreign body

Tracheoesophageal fistulas

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OTHER

Gastroesophageal reflux

Macroglossia, Pierre Robin syndrome

Cri-du-chat syndrome

Hysterical stridor

Hypocalcemia

Vocal cord paralysis

Chiari crisis

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SYMPTOMS OF LARYNGOMALACIA

Onset typically days to weeks after birth

Most commonly within the first 2 weeks of life

Inspiratory stridor

Low pitch with a fluttering quality secondary to circumferential rimming of the supraglottic airway and

aryepiglottic folds

More prominent when child is

Supine

Agitated

Louder quality with more forceable inspiration

Often associated with general noisy respiration

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DIAGNOSIS OF LARYNGOMALACIA

Clinical assessment

Suspect laryngomalacia in a neonate with auscultation of inspiratory stridor

Confirm suspicion with flexible laryngoscopy

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FLEXIBLE LARYNGOSCOPY FINDINGS WITH

LARYNGOMALACIA Cyclical collapse of supraglottic larynx with inspiration

Short aryepiglottic folds

Draw the cuneiform and corniculate cartilages forward over the laryngeal inlet resulting in prolapse during inspiration

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LARYNGOMALACIA SEEN BY FLEXIBLE

LARYNGOSCOPY

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