Renal Venous Thrombosis
- Thrombus formation in renal veins (stellate veins, interlobular veins, ascending vasa recta, arcuate veins, hilar veins, or renal vein)
- Most common non–catheter-related thromboembolism in the neonatal period
- May also be associated with nephrotic syndrome, hypercoagulable states, and oral contraceptive use
- May present with a clinical triad of flank mass, gross hematuria, and thrombocytopenia
- Most commonly seen in the newborn period
- Slight male predominance
- In neonates, most cases are unilateral (70%), with the left kidney more frequently affected. The left side predominance may be due to the anatomical course of the left renal vein underneath the aorta.
- Not well-defined due to lack of data
- Ranges from 0.5 to 2.3 per 100,000 live births
Accounts for 16–20% of thromboembolic events in newborns
- Maternal diabetes mellitus
- Birth asphyxia
- Dehydration/blood loss
- Cyanotic heart disease
- Hypercoagulable states
- Nephrotic syndrome
- Venous catheter
- Oral contraceptive use
- Renal transplant recipient
- ~50% of affected neonates have at least one hereditary prothrombotic risk factor.
- Factor V Leiden, protein C/S, and MTHFR mutations and lupus anticoagulant
- Maintaining a high index of suspicion in patients at risk (i.e., infant of diabetic mother, child with nephrotic syndrome)
- Counseling regarding the importance of adequate fluid intake and avoidance of dehydration, especially in newborn infants
- Prophylactic anticoagulation may be indicated in certain populations, although conclusive data is lacking.
- Thrombus formation is initiated by endothelial cell injury from hypoxia or other insults.
- In neonates, non–catheter-related renal vein thrombosis (RVT) is believed to originate in the arcuate or interlobular veins, as evidenced by early ultrasound findings.
- Thrombosis may extend to the inferior vena cava (IVC) in 50–60% of cases.
- Neonates also have decreased levels of protein C, protein S, antithrombin, and plasminogen, which may make them more susceptible to thrombosis.
- Lower renal blood flow may also predispose neonates to venous thrombosis.
- In older children, thrombosis may be associated with nephrotic syndrome, hypercoagulable states, or cyanotic heart disease.
- Renal venous thrombosis can result in renal enlargement, decreased renal venous flow, and increased arterial resistive indices.
- Adrenal hemorrhage and left varicocele may also result from renal venous thrombosis.
There's more to see -- the rest of this topic is available only to subscribers.