Background: Incomplete KD, as well as a higher incidence of CAA, has been reported to occur more commonly in infants ≤ 6 months (mos), but only small case series have been published. We characterized the KD course in infants ≤6 mos and compared to outcomes in KD pts >6 mos.
Methods: We retrospectively reviewed the course of 88 subjects ≤ 6 mos diagnosed with KD between January 2004 and December 2013 at Children’s Orange County (CHOC) and Rady Children’s Hospital San Diego (RCHSD) and compared to 632 subjects >6 mos at RCHSD. Complete and incomplete KD cases were defined based on the 2004 AHA guidelines. Subjects were classified by coronary artery (CA) status (normal, dilated, or aneurysmal CA based on RCA and LAD measurements) and by Z-score (RCHSD only). IVIG resistance was defined as fever ≥38C at least 36 hours after completion of IVIG. Fisher’s Exact test was used for comparisons.
Results: Of the 88 infants, 62 (70.4%) were male and 76 (86.3%) were treated at ≤ 10 days of illness. Treatments in the 88 pts were as follows: IVIG responder: 55(62.5%); IVIG resistant: 13(14.7%); infliximab for cardiac indications: 16 (18.2%); late treatment >10days: 2 (2.3%); not treated: 2 (2.3%). Infliximab was administered to a total of 27 pts (30.7%) and was well-tolerated with rash as the only adverse event in 1 pt. Worst CA status was “normal” in 37 (42.1%), dilated in 29 (32.9%), aneurysm in 15 (17.1%) and giant aneurysm in 7 (7.9%) pts. Of the 48 pts at RCHSD who presented within the first 10 days of illness, only 26 (54.2%) had a Z-score <2.5. Of these 26 pts, 7(26.9%) went on to have a subsequent Z score ≥ 2.5. Comparing the ≤6 mos vs. > 6 mos RCHSD cohorts, there were no significant differences in number of pts treated within the first 10 days of illness (48/53, 90.5% vs. 545/632, 86.2%) or pts having incomplete presentations (12/53, 22.6% vs. 106/632, 16.8%).
Conclusions: There were no significant differences in the rate of incomplete KD or rate of diagnosis within the first 10 days of illness in children ≤6 mos vs. >6 mos. Infliximab use in 30.7% of the ≤6 mos old pts was safe. Infants ≤6 mos had a high rate of aneurysms (22/88, 25%) despite timely diagnosis and treatment. Better treatments are needed for this high risk group of KD pts.