PATHOPHYSIOLOGY The viral pathogen is inhaled and infects the cells of the respiratory epithelium. Consequently leading to localized inflammatory response including Inflammation of the subglottic area Mucosal oedema Increased mucous production Swelling of the involved airway particularly involving the lateral walls of the trachea just below the vocal cords The combination of swelling, oedema and excess mucous production leads to narrowing of the internal airway lumen- this is aggravated by inspiration where further inflammation can results from walls of the subglottic space are drawn in during inspiration
DIFFERENTIAL DIAGNOISIS Peritonsillar or retropharengeal abcessSigns and symptomsMuffled voice, fever, ill appearance, stiff neck, dysphagia Foreign body aspirationSigns and symptomsSudden onset of stridor in a previously well child- can be associatedwith coughing or choking. Child playing with small objects AnaphylaxisSigns and symptomsHistory of allergy. Itching, facial swelling, Urticaria, wheeze, flushing and shock(Hammer, 2004) ( Dykes, 2005)
SIGNS AND SYMPTOMS• Runny nose• Sore throat• Mild fever• Barking cough• Hoarseness• Stridor- due to narrowing of the upper airway• Increase heart and respiratory rate• Subcostal, intercostal, suprasternal and sternal recession• Pallor• Fatigue• Restlessness(Hammer, 2004 & Dykes, 2005)
NURSING ASSESSMENT Children with croup need minimal handling . This includes limiting examination, nursing with parents. Supplemental oxygen is not usually required. If needed consider severe airways obstruction. Do not forcibly change a childs posture - they will adopt the posture that minimises airways obstruction. Avoid distressing the child further. Auscultation not require if stridor heard at rest Assess childs ability to demonstrate a cough to hear ‘barking’ Visualise trachi, chest wall and abdo for signs of increase work of breathing. SaO2 above 92% on room air, O2 not normally required Other investigations not normally required
TREATMENT Mild-moderate croup Can be managed using Dexametasone This systematic review has shown that treatment with glucocorticoids is effective in improving symptoms of croup in children as early as six hours and for up to at least 12 hours after treatment. (Russell et al, 2004)• A single dose of oral Dexametasone can shorten the duration and severity of Croup as early as 6 hours after treatment (Hammer, 2004)• Recommend dose of oral Dexametasone between 0.15-0.6 mg/kg. Fremantle hospital currently uses . 15mg/kg
Adrenaline (nebulised) is used for those children with severe upper airway obstruction For severe croup not effectively controlled with corticosteroid treatment, nebulised adrenaline solution 1 in 1000 (1 mg/mL) can be given with close clinical monitoring in a dose of 400 micrograms/kg (max. 5 mg) repeated after 30 minutes if necessary The effect last for appropriately 2 hours- staff need to be aware of potential `rebound`- where symptoms can reoccur once the Adrenaline has worn off. Taussig & Landau (1999) recommend that children who have received nebulised Adrenaline should be observed for 6 hours after dose
SIDE EFFECTS Upset stomach Muscle atrophy, negative protein balance Cushing syndrome resembling hyperactive adrenal cortex with increase in adiposity, hypertension, bone demineralization Hypertension, fluid and sodium retention, oedema, worsening of heart insufficiency (due to mineral corticoid activity) Allergic reactions
MECHANISIM OF ACTION Action- Dexamethasone is a glucocorticoid agonist. Unbound dexamethasone crosses cell membranes and binds with high affinity to specific cytoplasmic glucocorticoid receptors. This complex binds to DNA elements (glucocorticoid response elements) which results in a modification of transcription and, hence, protein synthesis in order to achieve inhibition of leukocyte infiltration at the site of inflammation, interference in the function of mediators of inflammatory response, suppression of humoral immune responses, and reduction in oedema or scar tissue.
NURSE MANAGEMENT PRIOR TO DISCHARGE Oxygen saturations > 95 % in air No sternal recession No audible stridor Observations within age appropriate ranges Good colour Parents happy to discharge
EVIDENCE BASED PRACTISE How fast does oral dexamethasone work in mild to moderately severe croup? A randomized double- blinded clinical trial. For children with croup an oral dose of 0.15 mg/kg dexamethasone offers benefit by 30 min, much earlier than the 4 hrs suggested by the Cochrane Collaboration. This result might encourage doctors to treat more children with all severities of croup being less worried about potential side-effects and delayed benefit. 2012 Feb;24(1):79-85. doi: 10.1111/j.1742-6723.2011.01475.x. Epub 2011 Sep 4. Dobrovoljac M, Geelhoed GC Emergency Department, Princess Margaret Hospital for Children, Perth, Western Australia, Australia.
REFERENCES Deny, FW. Murphy, TF. Cylde, WA Jnr. Collier, AM& Henderson, FW.Croup: an 11 year study in pediatric practice.Pediatrcs, 1983, vol 71, p.871-876. Dykes, J (2005) Managing children with Croup inemergency departments.Emergency Nurse, vol.13, no. 6, p. 14-19 Hammer, J (2004) Acquired upper airway obstructionPaediatric Respiratory Reviews, vol. 5, p. 25-33. Klassen, TP. Croup: a current perspective. Emergencymedicine. Paediatric Clinics of North America, 1999, vol. 14, no. 6, p.1167-1178• Moore M, Little P. Humidified air inhalation for treating croup. Cochrane Database of Systematic Reviews 2006, Issue 3. Art. No.: CD002870. DOI: 10.1002/14651858.CD002870.pub2• Russell K, Wiebe N, Saenz A, Ausejo Segura M, Johnson D, Hartling L, Klassen TP. Glucocorticoids for croup. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD001955. DOI: 10.1002/14651858.CD001955.pub2• Taussig, L & Landau, L (1999) Paediatric Respiratory Medicine. Mosby. St Louis MO