by Rosemary Thomas-Mohtat, Children’s National
with Moh Saidinejad, Children’s National

The Case
5 yr old male transferred from OSH for abd pain found to be mostly left sided, worse on left flank/LLQ.  This case addresses the challenges of different imaging modalities for abdominal pain.

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Denouement
Infectious etiology was high on differential with abd pain/emesis/fever/backpain. Also with + left hydronephrosis, consider UPJ obstruction (as etiology of flank pain), but neg UA for pyelonephritis.

On US: tech had concern for mass in abd, but radiology review thought maybe stool. Given unclear US findings, free fluid, LNs, fever, abd exam- Abd CT with po/iv contrast was ordered to further delineate abd pathology. Did also consider UPJ obstruction from mass effect as etio of pelviectasis.

Abd CT: noted large heterogenous mass most consistent with left retroperitoneal/perinephric hematoma (possibly involving left renal vein).  Also with left hydronephrosis.

Admitted to PICU. Seen by surgery. Managed conservatively- serial H/H. Had an MRI the following day, showing left perinephric lobulated nonenhancing lesion compatible with a hematoma.

Diagnostic considerations included bleeding into a pre-existing arteriovenous malformation or lymphatic malformation. Pt was discharged after pain controlled in 48hrs. Returned to IR outpt 10 days later for drainage and sclerotherapy of possible lymphatic malformation. Outpt doing well. Plan to follow up in 3months with repeat US to see if fluid recollected.