Case Presentation: A 33-year-old G2P1011 woman who was 6 days postpartum from an uncomplicated vaginal delivery presented to the emergency department with acute right flank pain, hypotension (BP 88/60), tachycardia (HR 125) and new onset anemia with hemoglobin 9g/dL. CT abdomen/pelvis (CT AP) revealed a 21.5cm right renal angiomyolipoma (AML) with an associated bleeding pseudoaneurysm and retroperitoneal hemorrhage. She underwent catheter-directed embolization with interventional radiology (IR) on hospital day #1 (HD#1); this procedure involved ethanol and coil placement to the feeder branch of the renal artery and pseudoaneurysm.On HD#2 she had persistent flank pain and tachycardia (HR 150s). On HD#4, she developed fever (39.9 C). Exam was notable for stable right upper quadrant pain, but otherwise normal abdominal and pelvic exams. Broad spectrum antibiotics were started for presumed sepsis of unknown source. Repeat CT AP confirmed stable AML, no continued hemorrhage, or infectious complications. Additional work up including blood and urine cultures, CTPE, respiratory viral panel, and echocardiogram was negative. Fever and tachycardia persisted despite antibiotics. In discussion with urology and IR, her presentation was most consistent with post-embolization syndrome (PES). Antibiotics were discontinued at 72 hours given no infectious source was identified. Her fever and tachycardia gradually improved, and all infectious cultures were negative at 7 days.
Discussion: PES is the most common complication of AML embolization and occurs in approximately 54% of cases, though with a wide range of variability in the literature (12-100% of cases based on reports) [1,2]. The syndrome includes fever, flank pain, leukocytosis, nausea, vomiting and occasionally, paralytic ileus. [3]. Infarcted tissue leads to a systemic inflammatory response similar to a sepsis presentation. PES risk is increased with a larger mass, so it is not surprising this patient developed PES given her large AML. Treatment involves supportive care. Small studies have demonstrated that prophylactic steroids may reduce the incidence of PES, however, larger randomized trials are needed to validate these results [4].Since fever and leukocytosis are the most common presenting signs of PES [2], clinicians will also have concern for sepsis when caring for these patients. PES can present 1 to 7 days after the embolization, which may further cloud the picture, as was this case for our patient. However, studies examining outcomes after embolization for AML have determined that sepsis and infection are much less common than PES [1].
Conclusions: AMLs are being increasingly detected, and those that are large, symptomatic or have high risk features such as bleeding warrant intervention. Catheter directed embolization is increasingly used for management of these tumors, given roughly equivalent major complication risk and improved sparing of kidney function relative to surgical partial or complete nephrectomy [1-3]. As such, hospitalists should be prepared to encounter patients presenting with PES, including those presenting with fever and leukocytosis up to 7 days after their procedure. This case highlights that PES must be considered in the differential diagnosis in a patient presenting with systemic inflammatory response syndrome after IR directed embolization treatment, and it may be prudent to observe off antibiotics if patients are hemodynamically stable with no suspected sources of infection.