Hemolytic uremic syndrome is characterized by non-immune hemolytic anemia, thrombocytopenia, and renal failure caused by platelet thrombi in the microcirculation of the kidney and other organs . The disease is not uncommon in children, where approximately 80% of the cases are associated with E. coli O157:H7 infection and 80-90% of cases resolve without squelae . HUS is rare in adults, and the overall prognosis in adults is poor with a reported mortality of up to 90% if not treated, and a rate of chronic renal failure of 40-60% [2, 3].
The etiology of HUS following pancreatitis is not clearly understood, as there are only about 20 cases reported in the literature . Our case and previously reported cases suggest that the acute inflammatory response to pancreatitis may trigger the onset of HUS . Silva  hypothesized that the release of inflammatory mediators such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 during an acute episode of pancreatitis may induce widespread vascular endothelial injury. It has also been suggested that modification of circulating von Willebrand factor (VWF) by pancreatic proteases leads to platelet aggregation [4, 5]. The release of ultralarge VWF multimers from endothelial cells during inflammation, and the inhibition of the VWF cleaving protease ADAMTS-13 by cytokines have also been suggested as a contributory mechanism of HUS .
The treatment of HUS following acute pancreatitis is primarily supportive. Fresh frozen plasma infusion may improve the renal outcome in adult HUS , and exchange plasmapheresis has been reported to be an effective treatment with a response rate of 79% . However, in patients with relapsing or refractory HUS with or without ADAMTS-13 deficiency, plasma exchange is often unsuccessful . Rituximab, a chimeric monoclonal antibody directed against CD20 antigen expressed by B lymphocytes, has shown promise as a treatment option [8, 9]. At the time the patient was seen and treated plasmapheresis was not available (treatment was carried out before dawn and CRRT was performed in the emergency department), and because CRRT therapy was very effective performing plasmapheresis was not considered necessary.
In renal replacement therapy (RRT) performed via hemofiltration, solute movement is governed by convection and unlike in dialysis a dialysate is not used . Positive hydrostatic pressure causes water and solutes to migrate across a filter membrane from the blood to the filtrate compartment, where it is drained. An isotonic replacement fluid is added to the blood to replace fluid volume and electrolytes. Treatments can be given intermittently, or continuously. CRRT has proven to be particularly useful in the treatment of renal failure as it can help in restoration of acid–base imbalances and electrolyte abnormalities, maintain hemodynamic stability, and allows the adjustment drug dosages to prevent drug accumulation and overdose . In addition, it can remove metabolic waste products and clear inflammatory mediators such as IL-1, IL-6, IL-8. It is possible that removal of inflammatory mediators by the rapid initiation of CRRT contributed to the recovery of our patient, though we have no clear evidence to support this hypothesis.
In summary, we have presented a case of adult HUS secondary to acute pancreatitis successfully managed by prompt diagnosis and rapid initiation of CRRT via hemofiltration before severe kidney injury or renal failure had occurred. Prior case reports and our case should remind clinicians that HUS is a possible complication of acute pancreatitis. Early institution of CRRT may be an effective treatment to prevent mortality and improve outcomes.