126 A broken nec: case study of idiopathic superior mesenteric vein thrombosis in a premature neonate

Introduction

Neonates are the pediatric population at highest risk for development of venous thromboembolism.¹ Intravascular catheters are a major risk factor. Other risks include prematurity, neonatal asphyxia and sepsis.² Neonatal superior mesenteric venous thrombosis has not previously been described in medical literature.

Case

A preterm female infant was born by emergency Caesarean section at 28 weeks' gestational age, weighing 760g. The indication was severe symmetrical intrauterine growth restriction and absent end diastolic flow. Her mother was an Irish 23-year-old primigravida, with a background of severe depression and smoking. The neonate required continuous positive airway pressure (CPAP) and artificial surfactant. She required an umbilical venous catheter (UVC), umbilical arterial catheter (UAC) and Peripherally Inserted Central Catheter (PICC). The infant developed recurrent abdominal distension, associated with bilious aspirates and vomits. On examination, the abdomen appeared tense and shiny, with dilated veins. Necrotising enterocolitis (NEC) was suspected and enteral feeds were held repeatedly. Plain film abdominal x-rays revealed bowel distension. However they did not identify other radiological features of NEC or perforation, such as pneumatosis intestinalis or pneumoperitoneum. Coagulation screens were normal. On Day 36, the infant's clinical condition rapidly deteriorated. She developed a grossly distended abdomen, associated with increased oxygen requirement and desaturations. She required ventilation, inotropic support and transfer to a tertiary centre. She continued to deteriorate and further treatment was considered futile. Following discussion with her parents, palliative care was introduced and she passed away shortly afterwards. Subsequent postmortem examination revealed idiopathic superior mesenteric vein thrombosis.

Discussion

A differential diagnosis for neonatal abdominal distension and bilious vomiting includes necrotising enterocolitis (NEC), intestinal malrotation and volvulus.³ Superior mesenteric vein thrombosis causes chronic, recurrent and progressive devitalisation of the small bowel wall. It is associated with pre-terminal neutropaenic sepsis and peritonitis.⁴ It may be caused by an unidentified congenital thrombophilia.⁵ Conclusion In refractory cases of suspected NEC, venous thromboembolism should be considered. Abdominal x-ray findings are non-specific and are unlikely to contribute to a correct diagnosis. More specific investigations include Doppler ultrasound and CT angiography.⁶

References

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