Med Note [1]: Airway

Chapter 1 – Respiratory Syncytial Virus (RSV)

v History & Physic’ Exam

o ~ present w/: fever (typic’ low grade); cough; tachypn’; cyanos’; retracti’; wheezi’; rales; & sepsislike presentati’ or apneic episodes (in very young infants).

o In infant, RSV can cause variety of ill’, presenti’ w/ cold-like ill’, sometimes (+) fever (can also (+) bronchit’, croup, & LRTI s.as (25-40% cases) (+) bronchiolit’ & pneumon').

o Infant w/ LRTI typic’ (+) runny nose, ↓ed appetite before (+) other sympt’, cough usu’ (+) at 1-3 days later, then ~ (+) sneezi’, fever, & wheezi’. In very young infant, ~ only (+) irritabil’, ↓ed activi’, & apnea.

o Phys’ exam’ of infant w/ RSV Lower Respiratory Tract Infection (LRTI) (+) evidence of diffus’ small airway ill’. 40% cases in child’, + related otitis media (~ viral & or bacterial). Hydrati’ status assessm’ (eg: via skin turgor, capillary refill, & mucous membran’) is importa’ at infant w/ bronchiolit’.

o In adults (particular’ (+) at healthcare workers & caretakers of small child’), usu’ lasts < 5 days usu’ w/ Upper RTI (URTI)-consistent sympt’ (can include rhinorrhea, pharyngit’, cough, headache, fatig’, & fever), but at high-risk Px (immunosupressed or (+) certain chronic ill’) ~ (+) more +++ sympt’ (LRTI-consistent) s.as pneumon’.

v Complicati’

o InPx RSV LRTI infant has higher risk (~ lasts > 10 years) for subseq’ wheezi’ & abnorm’ pulmon’ funct’.

v DDx

o High risk of for +++ RSV infec’, in:

o Prematu’ infant in 1st year of life (younger child at RSV season, the higher risk).

o Infant w/ chronic lung ill’ (eg: bronchopulmon’ dysplas’, or cystic fibrosis) during 1st 2 years of life.

o Child w/ hemodynamical’ signific’ congeni’ ♥ ill’, espec’ w/ ↑ed pulmon’ blood flow.

o Immunodefici’ Px.

o Child’ w/ metabol’ disord’, structur’ airway abnorm’, & neuromuscul’ disord’.

o Children of multiple births ( ≥ triplets).

o Adenoviruses

o Asthma

o Bronchiolitis

o Croup

o Human Metapneumovirus

o Influenza

o Neonatal Sepsis

o Other respiratory viruses

o Parainfluenza Virus

o Pediatric Bronchitis

o Pediatric Pneumonia

v Workup

o Lab studies

§ General’ Ø indicated @ in infant w/ bronchiolit’ who is comfortab’ in room air, well-hydrated, & feeding adequate’.

§ Øspecific lab studies: CBC (~ (+) normal or mild’ ↑ed WBC count & ↑ed % of band forms); blood culture (frequent’ obtained, rare’ (+) pathogen’ bacter’); Arterial Blood Gas (~ indicated if (+) concerni’ CO₂ retenti’); serum electrolyte concentrati’; urinalysis; O₂ saturati’ measurem’.

§ Specific lab studies (~ indicated for deciding of Tx (eg: withdrawi’ unnecessary antibiot’) needs of Px isolation, education for parents & staff) to confirm RSV infec’ are readi’ availab’ & performab’ on sample of secretion ((for virus) culture, antigen-reveali’ technic, or PCR) taken by washi’, suctioni’, or swabbi’ the nasopharynx (molecular probes to detect RSV at clinic’ specimen ~ more sensitive).

§ General’, Antigen-detecti’ & culture technic’re reliab’ in young child, less useful in older child & adults.

§ RT-PCR should be considered, espec’ toward older children & adult Pxs because their respirat’ specimens ~’ve low viral loads.

§ Antigen-detecti’ technic ~ (+) Dx w/in hours & obtained reliably w/o sophisticated virolo’ Lab. (Critical) Test performa’ monitoring to maintain appropriate sensitivity & specificity.

o Chest Radiography

§ Frequent’ obtained at child +++ RSV infec’. Typic’ (+) hyperinflated lung fields w/ diffuse ↑ in interstiti’ markings. 20-25% cases, (+) areas of atelectasis or pulmon’ infiltrates. General’, not specific & not course-predictive except if infant w/ addition’ find’ of atelectasis or pneumon’ (~ (+) +++ course).

o Histolo’ Find’

§ (In infant whose died of RSV bronchiolit’) (+) MN cell & neutrophil infiltrati’ of peribronchiol’ areas, necrosis of small airway epitheli’, plugging of lumens w/ exudat’ & edema, & atelectasis & hyperinflati’.

Reference:

1. http://emedicine.medscape.com/article/971488-workup

2. http://emedicine.medscape.com/article/971488-clinical

3. http://emedicine.medscape.com/article/971488-workup

4. www.cdc.gov/rsv
5. http://www.cdc.gov/rsv/clinical/index.html

Chapter 1 – Croup

v History

o Usu’ starts w/ Øspecific respirat’ sympt’: rhinorrhea, sore throat, cough. General’ fever is low grade (38-39^OC), can > 40^OC. W/in 1-2 days, (oft’ sudden’) (+) characteris’ hoarseness, barking cough, & inspirat’ stridor, along w/ variab’ degree of respirat’ distress. Perception: sympt’ worsen at night. Sympt’ typic’ resolve w/in 3-7 days, but can last for 2 weeks.

o Spasmod’ (recurr’) croup typic’ presents @ night w/ sudden onset of barking cough & stridor. Child ~’ve had mild upper resiprat’ complaints prior to this, but more oft’ has presented well prior to sympt’ onset. Allergic factors ~ cause recurr’ croup due to respirat’ epithel’ changes from viral infec’.

o Recurr’ croup child’ report’ sympt’ relief when treated for gastroesophag’ reflux (GER).

v Physic’ Exam’

o Wide varia’ of physic’ present’. Most child’ only (+) barki’ cough & hoarse cry. Some ~ (+) stridor only @ activi’ or agitation, others’ve audib’ stridor at rest & clinical’ evident respirat’ distress. +++ly affected child’ ~ (+) quiet stridor due to bigger degree of airway obstruction. @ Child’, typic’ Ø appear toxic.

o Child’s sympt can range from minim’ inspirat’ stridor to +++ respirat’ fail’ due to airway obstruction. If mild, resti’ respirat’ sound is normal; mild expirat’ wheezi’ ~ heard. If more +++, (+) inspirat’ & expirat’ stridor at rest w/ visib’ suprastern’, inter- & sub-cost’ retract’. Air entry ~ poor. Lethargy & agitat’ due to marked respirat’ diffcul’ à hypoxem’ & ↑ed hypercarbia. During episode of +++ cough, ~ (+) sudden respirat’ arrest.

o Other respirat’ distress’s warni’ signs: tachypn’, tachy♥, out of proportion to fever, & hypotonia. If child’ w/o adequate oral intake, (+) dehydration. Cyanosis, late, ominous sign.

o Scori’ syst’

· Westley Score (wide use @ research & Tx protocol’s evaluati’, its clinic’ value Ø yet extensive’ studied): Inspirat’ stridor: (-) – 0, at agitat’ – 1, at rest – 2; Retracti’: (-) – 0, mild – 1, moderate – 2, +++ - 3; Air entry: normal – 0, mild ↓ - 1, heavy ↓ - 2; Cyanosis: (-) – 0, at agitat’ – 4, at rest – 5, Conscious’: normal, includi’ sleep – 0, depressed – 5.

< 3: mild ill’. 3-6: moderate ill’. > 6: +++ ill’.

· Mild: (+) occasional barki’ cough, no stridor at rest, mild or no suprastern’ or subcost’ retracti’. Moderate: frequent cough, audib’ stridor at rest, visib’ retracti, little distress or agitat’. +++: frequent cough, +++ inspirat’ (occasional’ + expirat’) stridor, conspicu’ retracti’, ↓ed air entry on auscult’, +++ distress & agitat’. Lethargy, cyanos’, & ↓ing retracti’ presage respirat’ fail’.

· Alberta Clinical Practice Guideline Working Group classifi’:

o Mild: occasion’ barki’ cough, no audib’ stridor at rest, & no or mild suprastern’ & or intercost’ retracti’.

o Moderate: frequent barki’ cough, easi’ audib’ stridor at rest, suprastern’ & stern’ wall retracti’ at rest, & no or minim’ agitat’.

o +++: frequent barki’ cough, +++ inspirat’ (occasion’ + expirat’) stridor, +++ stern’ wall retracti’, & +++ agitat’ & distress.

o Impendi’ respirat’ fail’: barki’ cough (oft’ Ø +++), audib’ stridor @ rest, stern’ wall retracti’ ~ Ø +++, lethargy & ↓ed conscious’, & oft’ dusky appear’ w/o supplemental O₂ support.

· Tx based on algorithm based on Px’s initial symptoms’s severity.

v DDx

o Spasmodic croup (recurrent croup)

o Retropharyngeal abscess

o Subglottic stenosis

o Angioedema

o Allergic reaction

o Tracheomalacia

o Laryngeal web

o Laryngeal papillomatosis

o Laryngeal hemangioma

o Subglottic hemangioma

o Vocal cord paralysis

o Uvulitis

o Innominate artery compression

o Right aortic arch vascular ring

o Double aortic arch

o Aberrant subclavian artery

o Pulmonary artery sling

o Rarer etiologies in the pediatric population - Laryngeal tuberculosis, neoplasm (compressing trachea), sarcoidosis, Wegener granulomatosis

o Gastroesophageal reflux (diagnostic consideration for recurrent croup)

o Bacterial Tracheitis

o Inhalation Injury

o Laryngeal Fractures

o Laryngomalacia

o Measles

o Pediatric Airway Foreign Body

o Pediatric Diphtheria

o Pediatric Epiglottitis

o Pediatric Mononucleosis and Epstein-Barr Virus Infection

o Pediatric Peritonsillar Abscess

v Workup

o Prmari’ a clinic’ Dx. CBC usu’ Øspecific, WBC ~ suggest viral etio’ w/ lymphocytosis. Specific viral etio’ identification (eg: parainfluenza virus serotype, respiratory syncytial virus (RSV)) via nasal washi’ ~ for determini’ isolation needs in hospital setting, or (in influenza A) antiviral Tx initiati’.

o Pulse O₂metry, most’ normal, used to monitor need for supplement’ O₂ support or worsen’ respirat’ comprom’ as evident w/ tachypn’ & poor mainten’ of O₂ saturation. ABG is standard’ unnecessary & Ø reveal hypoO₂ or hypercarbia unless respirat’ fatig’ ensues.

o If Px presentat’ w/ fever, tachypn’, & history of ↓ed fluid intake à evaluate Px’s hydration status! Compromised oral intake & inabili’ to mainta’ needed fluid volume ~ need IV fluid support to sustain Px’s fluid needs.

o Laryngoscopy: indicated only in unusu’ setting (eg: atypic’ course of ill’, child (+) sympt’ suggesti’ underly’ congeni’ or anatomi’ disord’, child (+) bacterial tracheit’ (to get culture to guide antibiot’ Tx)); if throat (+) tongue depression, no epiglottit’ (which (+) erythem’ enlarg’ epiglottis (cherry red epiglott’). Thought that vigor’ exam’ of child’s throat cause laryngospasm & respirat’, but never has been documented.

o ~ be indicated: direct laryngoscopy if child Ø at acute distress; fiberoptic laryngoscopy; bronchoscopy (for recurr’ croup to rule out airway ill’).

o (+) High risk of moderate to +++ find’ in laryngo & bronchoscopy & need of further surgic’ interventi’ @ child w/: (1) w/o history of intubati’ but (+) inPx consulta’, or (2) w/ history of intubati’ & age < 36 months.

o Radiography

§ Plain film can verify presump’ Dx or exclude other stridor-causing ill’. Lateral neck radiog’ can help detect clinical Dx s.as aspirated or esophage’ foreign bodi’, congeni’ subglott’ stenos’, epiglottit’, retropharyng’ absce’, or bacterial tracheit’ (thicken’ trach’). Ø needed @ uncomplica’.

§ ~ (-) at 50% cases @ child.

Anteroposterior (AP) radiog’ of neck’s soft tissues classic’ (+) steeple sign (pencil-point sign), signifies subglott’ narrowi’; lateral neck view ~ (+) distended hypopharynx (ballooni’) at inspirati’.

§ Steeple sign ~ also (+) w/o croup @ epiglottit’, therm’ injury, angioedema, or bacterial tracheit’. Monitor during imaging because progress’ of airway obstruction ~ rapid.

(Figure right below) Croup at child. Steeple sign at proximal trachea evident. AP view.