A case series of 72 neonates with renal vein thrombosis: data from 1 to 800-No-Clots registry

Abstract number: OC419

Kuhle^* S., Massicotte^* M. P., Chan A. K. C., Andrew† M., Mitchell^* L.

†Canada The Hospital for Sick Children, Canada; ^*The Hospital for Sick Children, Canada;

Background  

Renal vein thrombosis (RVT) is a distinct entity of neonatal thromboembolism (TE). Clinical presentation and risk factors appear to differ from the more commonly encountered catheter-related TE. We present data on patient demographics, clinical presentation, location and risk factors of neonatal RVT from a case series of 72 neonates.

Methods  

Data were retrieved from the 1–800-NO-CLOTS registry. 1–800-NO-CLOTS is a free consultative service on pediatric TE for physicians world wide. Between 9/1996 and 8/2001, the service has registered the data on 2379 children with TE. Age, gender, associated conditions, prothrombotic disorders, family history, location of the clot, diagnostic techniques, and treatment were prospectively recorded using a standardized form.

Results  

Twenty-five percent (n = 602) of all children reported during the study period were neonates with RVT accounting for 12% of TE. RVT affected males (65%, CI 52–76%) significantly more often than females (35%, CI 24–48%). The median age at presentation was 2 days (0–21 days). Two cases of RVT were diagnosed antenatally, 43% on the first day of life, and 77% within the first week of life. RVT was unilateral in 72% (left side: 67%, CI 49–81%; right side: 33%, CI 19–51%), and bilateral in 28%. The majority (83%) had at least one associated condition: Prematurity (54%) (median gestational age: 34 weeks, range 25–36 weeks), central venous lines (17%), a diabetic mother (13%), asphyxia (6%), infections (6%). Prothrombotic testing was performed in 21 neonates. APC resistance and/or heterozygous Factor V Leiden mutation was found in 8 children (38%), homozygous FII G20210A mutation in one, combined defects in two.

Conclusion  

This is the largest prospective case series of neonatal RVT to date. Data from the study show for the first time that (i) male infants are affected twice as often as females and (ii) there appears to be a left-sided predominance of neonatal RVT. The majority of cases are diagnosed on the first day of life, and it may be speculated that RVT is of intrauterine origin in some cases. RVT in the newborn is only infrequently (17%) associated with the presence of a catheter as compared to thrombosis at other sites (89% [Schmidt and Andrew 1995]). In the majority of cases, affected infants have associated conditions with prematurity being most frequent. A small subset of neonates were screened for prothrombotic abnormalities and 50% of the children screened were positive.