EFFECT OF DEXAMETHASONE IN ACUTE LARYNGOTRACHEITIS

*Al Khaldi O., *Raggad M. and **Aldhanhani M.S.
Departments of *Pediatrics and **ENT, United Arab Emirates Hospital United Arab Emirates

Abstract:

Fifty eight patients between the ages of six months and five years were studied in a randomized double-blind trial to determine whether dexamethasone has a role in the outpatient management of patients with acute viral croup of moderate severity. For various reasons, twelve were excluded from the final results. In the 46 patients who completed the study (32 males, 14 females) the only significant differences detected between the treatment groups were that the duration of rhinorrhea was longer in the dexamethasone group compared with placebo (median 2,5 days vs 1,5 day) and the pre-discharge croup score was higher in the dexamethasone group compared with placebo (2 vs 0).

Conclusion: The use of dexamethasone in the outpatient management of viral croup is associated with a reduction in the severity of illness within 24 hours of treatment. Patients with viral croup of moderate severity should be considered candidates for the use of dexamethasone before discharge from the paediatric emergency clinic.

Abbrevations: IM, intramuscular U.A.E United Arab Emirates

Introduction:

Acute inflammation of the upper airway is of greater importance in infants and small children than older children because the airway is smaller and the inflammation predisposes young children to a relatively greater narrowing. Inflammation involving the vocal cords and structures inferior to the cords is called laryngitis, laryngotracheitis, and laryngo-tracheo-bronchitis. Inflammation superior to the cords is called supraglottitis. Croup is a generic term encompassing a heterogeneous group of relatively acute conditions (mostly infectious) characterized by a peculiarly brassy or “croupy” cough, which may or may not be accompanied by inspiratory stridor, hoarseness and signs of respiratory distress due to various degrees of laryngeal obstruction(1).

The use of steroids in patients hospitalized with acute laryngotracheitis (viral croup) has been debated for more than 30 years. Earlier studies were plagued with methodological flaws making it difficult to interpret the results(2)! Recent studies have been more rigorously designed. Super(3), in a double blind randomized placebo-controlled trial, found that hospitalized patients treated with a single injection of intramuscular dexamethasone showed significant improvement in croup scores at 12 and 24 hours and required less co-interventions with racemic epinephrine and cool mist therapy.

Barkin(4) recommends that dexamethasone 0,6mg / kg i.m. or i.v. be given in the emergency department to a patient with viral croup requiring hospitalization. Steroids are now more commonly used in the initial management of patients requiring hospitalization for croup. Our study was undertaken to determine whether a single intramuscular injection of dexamethasone has a role in the outpatient management of acute viral croup.

Materials and Methods:

From October 1999 until 1st April 2000 a double-blind placebo-controlled randomized trial was conducted on patients who came to the paediatric emergency clinic, UAE hospital of Kosova, with a clinical diagnosis of acute laryngotracheitis or viral croup. Croup was defined by: 1) a history of viral prodrome followed by hoarseness, barking cough; and 2) clinical evidence of hoarseness, barking cough, or stridor. Eligible patients were between six months and five years of age with a croup score of at least two (based on the modified Westley croup scoring system(3). (Table 1)

We excluded from the study patients who had any anatomic airway abnormalities, a history of hospitalization or prior intubation, who required more than one racemic epinephrine treatment, or who had received B-agonist therapy or steroids taken 24 hours previously. Initial administration of cool mist or racemic epinephrine was left to the discretion of the attending of of pediatric physician. Patients receiving racemic epinephrine were observed in the paediatric emergency clinic for three to four hours and were then discharged if they remained clinically stable without evidence of retraction or respiratory distress.

Patients were followed up by phone for 24 hours and seven to ten days after discharge. Primary outcome was whether the patient sought additional medical attention for lack of improvement or worsening of symptoms. There were two secondary outcome measures. At 24 hours after discharge parents were asked how the patient was doing in terms of respiratory symptoms and the degree of improvement was scored on a four-point ordinal scale (see Table 3) (worse = 1, same = 2, improved = 3, symptoms resolved = 4). Parents were then asked at seven to ten days how many days it took for the patient to recover completely.

Results:

Of the fifty-eight patients enrolled initially, forty-six (32 males, 14 females) completed the study after twelve patients were excluded; five because they needed hospitalization and seven lost to follow up. The only significant difference between the treatment groups was that the duration of rhinorrhea was longer in the dexamethasone group compared to the placebo group (median 2,5 days vs 1,5 day). The duration of other symptoms (Table 2) was similar in the two treatment groups. The pre-discharge croup score was also higher in the dexamethasone group compared to the placebo group (2 vs 0). All children were available for both the 24 hours and the 7 to 10 days follow up. After discharge from the paediatric emergency clinic, twelve patients sought additional medical attention within 48 hours; nine returned to the paediatric emergency clinic and three called the primary investigator within 18 hours of discharge because of concern that the patient was not improving.

Of the twelve children seeking additional medical attention, eight had received placebo (35% of the placebo groups) and four had received dexamethasone (17% of the dexamethasone group). None of the children who returned to the paediatric emergency clinic required subsequent hospitalization. The three patients who tried to call the primary investigator at the hospital were unable to reach the investigator.

At the 24-hour telephone follow-up 88% patients in the dexamethasone group had improved with a score consistent with improvement compared to 40% of the placebo group (median score 3 vs 2 based on the four-point ordinal scale). At the seven to ten day follow-up there was no difference in the number of the days for all symptoms to completely resolve (mean 3 days).

Discussion:

The most common cause of acute upper airway obstruction in children aged three months to six years is a viral croup. Using a single injection of intramuscular dexamethasone has been shown recently to decrease the severity and duration of illness when given to hospitalized patients(2, 3). Racemic epinephrine aerosols have significantly lessened the severity of illness but the effects are generally limited to two hours with a frequent return to baseline respiratory distress(5). Using a questionnaire Gould(6) found that 91% of 75 emergency medicine physicians use corticosteroids for croup in outpatients. The rationale for injecting dexamethasone is that it is quickly absorbed when given intramuscularly, achieving high plasma levels within 15 minutes(7). Clinical effects may be delayed for three to four hours but, as dexamethasone has a long half–life of 36 to 54 hours, a single dose may be all that is required to get the patient past the initial severity of the illness. It is felt that a single dose of steroids, no matter how massive, is well tolerated without adverse effects(8).

Although we did not look at the combination specifically, ideally dexamethasone should follow the use of racemic epinephrine to prevent a relapse after the effects of the racemic epinephrine have diminished. A larger study would have been more convincing but our study had to be concluded early because of the opening of an inpatient 24–hour observation unit for “border line patients” with more moderate disease.

Despite the relative mild disease in our study population we were still able to detect a statistical as well as clinical improvement at 24 hours in the dexamethasone group. Another possible limitation of our study is that we did not attempt to distinguish spasmodic from viral croup. It has been suggested, however, that spasmodic and viral croup are actually presentations of the same disease process(5) and, a management standpoint, making the distinction is impractical given the frequent overlap of symptoms. In addition the incidence of fever and cough was similar in both dexamethasone and placebo groups; so we feel that spasmodic croup was not a confounding factor.

A final possible confounding factor is that the duration of rhinorrhea was longer in the dexamethasone group was already improving by the time they were enrolled into the study. We feel that this was not the case for several reasons. First: the duration of fever, cough and stridor was similar between the treatment groups and because most viral croup starts with fever and cough, rhinorrhea alone is not an indicator that the duration of disease was longer in the dexamethasone group. Second the predischarge croup score was higher in the dexamethasone group compared with placebo (median score 2 vs 0) and although not statistically significant, the clinical significance suggests that the dexamethasone group may actually have been more sick than the placebo group at time of discharge. Thus the improvement at 24 hours in the dexamethasone group compared with placebo is even more significant.

Conclusion:

We conclude that using dexamethasone in the outpatient management of viral croup is associated with a reduction in the severity of the illness 24 hours after treatment. Patients with viral croup of moderate severity should be considered candidates for the use of a single intramuscular injection of dexamethasone, 0,6 mg/kg before discharge from the paediatric emergency clinic.

References:

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