I. Definition = laryngeo-tracheo-bronchiolitis

II. Causes: parainfluenza, RSV; mostly Spring & Fall

III. Typical clinical presentation:

  1. URI x 2-3d beforehand, then us. 48-72h of:
    1. Fever (typically low-grade)
    2. Hoarseness
    3. Inspiratory stridor
    4. "Seal-like" cough
  2. Neck radiographs may show "steeple" sign (from narrowed subglottic space)

IV. Differential includes anaphylaxis, foreign body, diphtheria, and bacterial tracheitis, as well as epiglottitis

V. Treatment

  1. "Mist" (humidity)
    1. A traditional treatment for croup
    2. However, in a study in 140 children presenting to an ED with moderate-to-severe croup randomized to 30min of (100% O2 via blow by, which was the "placebo", 40% humidity with 40% oxygen via nebulizer, or 100% humidity with 40% oxygen via nebulizer), there were no sig. diffs. among the groups in severity scores, O2 sat, or RR at 30min; also no diff. in incidence of hospitalizations or eventual tx with steroids or epinephrine (JAMA 295:1274, 2006--JW)
  2. O2 if hypoxemic or dyspnea (rare)
  3. Inhaled Beta-agonists
  4. Consider inhaled epinephrine via nebulizer if stridorous
    1. Short duration of action; patients may relapse so observe x 3-4h if epinephrine is used
    2. May reduce risk of intubation in pts with severe croup
  5. Steroids (e.g. Dexamethasone 0.6mg/kg PO x 1 or prednisolone 1-2mg/kd PO x 1) are likely beneficial
  1. Moderate-to-Severe croup
    1. 198 children 3mo-5yo presenting to an ER with croup and a "croup score" from 2-7 after 15min of "mist therapy" randomized to dexamethasone 0.6mg/kg PO and placebo neb, PO placebo and budesonide 2mg neb, or dex PO & budesonide neb. No sig. difference in mean change in croup score during ER visit, time in ER, return visits to ER, hospitalization, or sx at 1 week. Authors conclude that PO dex is best b/c it's cheapest and easies to give. (JAMA 279:1629, 1998; ref. for croup score is AJDC 132:484, 1978)
    2. 100 kids 4mo-10yo with croup not severe enough to admit randomized to usual care + placebo vs. usual care + dexamethasone 0.15mg/kg PO; no diff. in duration of sx but sig. reduction in need for return visits & subsequent need for hospitalization (BMJ 313:140, 1996-JW)
    3. 144 kids with "moderately severe" croup all got racemic epi then randomized to single dose of steroids: budesonide neb 4mg, dexamethasone IM 0.6mg/kd, or placebo. 71% in placebo group required hospitalization c/w 38% in budesonide group and 23% in dex group. Diff. between tx groups and placebo groups were sig. as were diff. between budesonide and dex groups (NEJM 339:553, 1998--JW)
    4. Oral dexamethasone (0.6mg/kg, max 8mg) ass'd with no diff. in sx or return visits to hospital c/w IM dexamethasone (same dose) at 48-72h in a randomized trial of 277 kids 3mo-12yo with moderate croup (Peds 106:1344, 2000--JW)
  2. Mild croup
    1. In a study of 264 children 6mo-6yo with mild croup randomized to dexamethasone 0.6mg/kg PO x 1 (max 10mg), dexamethasone neb 160ug x 1, vs. placebo, tx failure was seen in sig. fewer of the oral dex kids than the dex neb or placebo groups (4% vs. 16% and 14%, respectively).  Tx failure defined as need for additional steroids or racemic epi (Arch. Ped. Adol. Med. 155:1340, 2001--JW)
    2. 708 children with mild croup of < 72h duration randomized to dexamethasone 0.6mg/kg PO vs. placebo; over 7d, incidence of return visits was sig. lower in steroid group (7.3% vs. 15.3%) as were clinical scores on days 1 and 2 of follow-up (NEJM 351:1306, 2004--JW)
  3. A meta-analysis of 24 studyies of steroids in croup showed sig. reduction in sx with steroids c/w placebo at 6 and 12h but not at 24h; also, steroid recipients had no sig. diff. in hosp. rate but did have sig. briefer ER stays and, if admitted, sig. shorter inpatient stays. (BMJ 319:595, 1999--JW)