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Hematology-Oncology Section, Department of Medicine, College of Medicine (KKS, JTD, JNG); Department of Biostatistics and Epidemiology, College of Public Health, The University of Oklahoma Health Science Center Oklahoma City, OK, USA (SKV, JNG); Division of Hematology/Oncology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA (HCK, BK); Department of Hematology and Central Hematology Laboratory, University Hospital, Berne, Switzerland (BL, JAKH)
Correspondence: James N. George, M.D., The University of Oklahoma Health Sciences Center, Hematology-Oncology Section, P.O. Box 26901, Oklahoma City, OK 73190 USA. E-mail: james-george{at}ouhsc.edu
| ABSTRACT |
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Design and Methods: We report on three patients from the Oklahoma Registry and two patients from Northwestern University who had an acute episode of TTP-HUS following pancreatitis. A systematic review of published case reports was performed to identify additional patients who had TTP-HUS following pancreatitis.
Results: In each of our five patients there was an apparent etiology of alcoholism or common bile duct obstruction for the pancreatitis and no evidence of TTP-HUS when the pancreatitis was diagnosed. Two patients had severe ADAMTS13 deficiency with an inhibitor; in one of these patients TTP-HUS recurred following a subsequent recurrent episode of pancreatitis. The systematic review identified 16 additional patients who had TTP-HUS following pancreatitis; recurrent TTP-HUS occurred in three of these patients following a subsequent episode of recurrent pancreatitis. In all 21 patients, the interval between the diagnosis of pancreatitis and TTP-HUS was short (1–13 days; median, 3 days). The three Oklahoma patients represent approximately 1% of the 356 patients in the Registry.
Interpretation and Conclusions: These observations suggest that in some patients pancreatitis, a disorder that results in an intense systemic inflammatory response, may be a triggering event for acute episodes of TTP-HUS.
Key words: pancreatitis, thrombotic thrombocytopenic purpura, TTP, hemolytic uremic syndrome, HUS.
The thrombotic thrombocytopenic purpura-hemolytic uremic syndromes (TTP-HUS) have multiple diverse recognized etiologies, clinical manifestations, associated conditions, and risk factors.1 Although the pathogenesis in many patients may involve deficiency of ADAMTS132–4 or disorders of complement regulation,5;6 the events that actually trigger acute episodes of TTP-HUS are often unclear. Patients may have undetectable ADAMTS13 activity or disorders of complement regulation, on either a congenital or acquired basis, without evidence of TTP-HUS until a precipitating condition, such as pregnancy, infection, or surgery, occurs.5;7–12 These clinical observations are similar to experimental observations on transgenic mice.13;14 In some strains of mice complete ADAMTS13 deficiency was well tolerated, demonstrating that although ADAMTS13 deficiency caused a prothrombotic state, other genetic modifying factors or environmental triggers were necessary to induce abnormalities similar to TTP-HUS syndromes.13,14 In the conditions that have been reported to trigger acute episodes of TTP-HUS,5,7–12 inflammatory cytokines may stimulate endothelial cell release of ultralarge and hyperreactive von Willebrand factor multimers and inhibit the cleavage of these multimers by ADAMTS13.15
The pancreas is an organ frequently and severely involved in patients with TTP-HUS,16,17 and pancreatic ischemia caused by TTP-HUS may contribute to the common symptom of abdominal pain.16 Our clinical experience suggests that the reverse of this sequence may also occur, that pancreatitis may immediately precede an acute episode of TTP-HUS. We report on five patients who were diagnosed with acute pancreatitis and then subsequently, 1–13 days after the diagnosis of pancreatitis, developed an acute episode of TTP-HUS. In these patients there was evidence that the pancreatitis preceded the acute episode of TTP-HUS and was not caused by TTP-HUS. (i) Each patient had a documented etiology for her/his pancreatitis, either alcoholism or common bile duct obstruction. (ii) When the pancreatitis was diagnosed, there was no microangiopathic hemolysis or thrombocytopenia. (iii) In three of the patients the pancreatitis was resolving when the signs of TTP-HUS first appeared. To supplement our experience we conducted a systematic literature review to identify all previously reported patients in whom acute pancreatitis preceded TTP-HUS.
| Design and Methods |
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Northwestern University patients
Following a presentation of the Oklahoma data at Northwestern University in 2005 describing pancreatitis preceding TTP-HUS, two additional patients from the Northwestern University were identified.
ADAMTS13 activity and inhibitor
ADAMTS13 activity and inhibitors in serum samples (Oklahoma patients) or plasma samples (Northwestern University patients) obtained immediately before beginning the first plasma exchange treatment were measured in Berne, Switzerland, using an immunoblotting method.20,21 Previously published data documented that there is no significant difference in ADAMTS13 activity measured in either citrated platelet-poor plasma or serum obtained from unanticoagulated blood20 and that the activity of ADAMTS13 is stable in both serum and plasma.22 In the two patients with ADAMTS13 deficiency and an inhibitor, IgG antibodies to ADAMTS13 were also measured by the Technozym® ADAMTS13-INH ELISA assay (Technoclone GmbH, Vienna, Austria). Results are given in arbitrary antibody units/mL (AU/mL) and titers <15.1 AU/mL were considered to be negative, according to the manufacturers instructions.
Systematic review
Ovid software was used to search the Medline database of published reports to identify additional patients who had TTP-HUS following pancreatitis. Key words and MeSH terms searched for TTP-HUS were: thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, thrombotic thrombocytopenic purpura-hemolytic uremic syndrome, TTP-HUS, thrombotic microangiopathy, microangiopathic hemolytic anemia, thrombocytopenia, renal failure, kidney failure, hemolysis, hemolytic anemia, and thrombosis. Keywords and MeSH terms searched for pancreatitis were: pancreatitis, pancreatitis-acute necrotizing, pancreatitis-alcoholic, pancreatitis-severe, and pancreatitis-gallstone. All articles identified by both one of the TTP-HUS terms and by one of the pancreatitis terms were reviewed and their bibliographies searched for additional articles. All reviewed articles were searched to identify patients who had TTP-HUS diagnosed following the onset of pancreatitis.
Levels of evidence
Levels of evidence for pancreatitis as a potential triggering event for an acute episode of TTP-HUS were assessed according to criteria presented in Table 1. Pancreatitis preceding TTP-HUS was the criterion for identifying all patients. The presence of a recognized etiology for the pancreatitis and evidence that the pancreatitis was resolving when the TTP-HUS was diagnosed supported the interpretation that pancreatitis preceded the TTP-HUS and was not caused by TTP-HUS. Recurrent TTP-HUS following a subsequent episode of recurrent pancreatitis also supported the interpretation that pancreatitis may be a triggering event for TTP-HUS. The levels of evidence derived from these criteria describe pancreatitis as a possible or probable precipitating event.
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| Design and Methods |
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Patient #2
A 48-year old white woman had a previous episode of pancreatitis related to gallstones and was treated by cholecystectomy in 2002. In early 2003 she was diagnosed with recurrent pancreatitis attributed to excessive alcohol. During the first 3 days in hospital she developed anemia, thrombocytopenia, acute renal failure requiring dialysis, and became confused while her serum amylase was improving. Coagulation tests were normal. On day 5 schistocytes were noted and TTP-HUS was diagnosed. Serum amylase was normal; ADAMTS13 activity was 90%. She had a grand mal seizure on day 7 requiring intubation. She recovered with plasma exchange treatment and hemodialysis and has had no further illness during the following 4 years.
Patient #3
A 43-year old white alcoholic man was admitted to the hospital in late 2005 with severe epigastric pain and was diagnosed with pancreatitis. The following day he developed delirium tremens. On day 3, TTP-HUS was diagnosed when he became more anemic and thrombocytopenic, schistocytes were noted, and his creatinine increased. Coagulation tests were normal. ADAMTS13 was <3% with a strong inhibitor (defined as >2 Bethesda Units). The anti-ADAMTS13 IgG antibody titer by immunoassay was 18 AU/mL. He recovered with plasma exchange and prednisone treatment and has had no further illness over the following 15 months.
Patient #4
A 37-year old black woman presented in late 2005 with the onset of severe epigastric pain, nausea and vomiting. The previous day, she had undergone a mediastinoscopy and lymph node biopsy resulting in the diagnosis of sarcoidosis. Computed tomography scans were consistent with pancreatitis and also demonstrated large peri-pancreatic and porta-hepatis lymph nodes. The diagnosis was pancreatitis due to bile duct obstruction by sarcoid lymphadenopathy23 or granulomatous infiltration of the pancreas.24 On day 2, the woman was confused and developed anemia with schistocytes and thrombocytopenia. Coagulation tests were normal except for a slightly prolonged prothrombin time. TTP-HUS was diagnosed; ADAMTS13 activity was 80%. She recovered with plasma exchange and prednisone and has had no further illness over the following 12 months.
Patient #5
A 35-year old white woman was first diagnosed with TTP-HUS in 1999. Following recovery she had enterobacter sepsis related to her central venous catheter that was complicated by acute pancreatitis with pseudocyst and abscess formation requiring surgical drainage. Later in 1999 she had an elective splenectomy, described as definitive therapy for her TTP-HUS. In 2003 TTP-HUS recurred following surgery to repair an incisional hernia at the splenectomy site. In 2006 she was admitted to the hospital for acute pancreatitis. Ultrasound demonstrated bile sludge. Computed tomography scan documented multiple pancreatic abscesses that required surgical drainage on day 13. TTP-HUS was diagnosed and plasma exchange begun on day 14 because of hemolytic anemia with schistocytes, thrombocytopenia, and renal failure. ADAMTS13 activity was <3% with a strong inhibitor. The immunoassay for anti-ADAMTS13 IgG antibody was also positive (>88.3 AU/mL). Coagulation tests were normal. On day 32 she had ventricular fibrillation and cardiac arrest that was attributed to an acute exacerbation of TTP-HUS. Again she responded promptly to plasma exchange. The pancreatitis apparently resolved and she was discharged on day 83. Pancreatitis recurred on day 101 with no signs of TTP-HUS. Four days later she became septic and required another laparotomy for pancreatic necrosis and multiple abscesses. Three days after her laparotomy TTP-HUS was diagnosed because of thrombocytopenia and the appearance of schistocytes on her blood smear. ADAMTS13 activity was again <3%. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) were slightly prolonged; fibrinogen was increased. She recovered with plasma exchange, her pancreatitis resolved, and she has had no further illness for the following 6 months. She did not receive glucocorti-coids or other immunosuppressives agenst because of her recurrent pancreatic abscesses.
| Results |
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The demographics of these patients are characteristic of patients with TTP-HUS:18,25 four were women; three of the women (patients 1, 4, and 5) were obese (body mass index 30.1–62.1); the one man was not obese. ADAMTS13 activity was measured in patients 2–5; patients 2 and 4 had normal activity; patients 3 and 5 had severe deficiency and strong inhibitors of ADAMTS13 activity were demonstrated. Patient 5 had had two previous episodes of TTP-HUS; her first episode had no apparent triggering event; her second followed abdominal surgery. It was considered that spuriously low levels of ADAMTS13 activity could have resulted from circulating pancreatic proteases, since ADAMTS13 can be proteolytically inactivated.26 However the normal ADAMTS13 activity in two of the four patients supports the validity of the measurements demonstrating absent ADAMTS13 activity in the other two patients. The identification of the ADAMTS13 inhibitor in patients 3 and 5 as an IgG immunoglobulin further supports the clinical relevance of the ADAMTS13 deficiency No tests for disorders of complement regulation5,6 were performed in these patients.
Previously reported patients
The literature review identified 16 articles, each describing one patient in whom pancreatitis preceded TTP-HUS (Table 3).27–42 Among these 16 patients, 13 were men, opposite to the gender disparity of TTP-HUS25 but consistent with the greater frequency of acute pancreatitis among men.43 The etiologies of the pancreatitis in these 16 patients were typical for acute pancreatitis among adults:43,44 seven cases were related to chronic severe alcohol use, five to gallbladder disease, and four were idiopathic. The diagnosis of acute pancreatitis was made by clinical signs and elevated serum amylase and/or lipase levels in all patients. The diagnosis was supported by computed tomography scan or ultrasound demonstrating pancreatic abnormalities in eight patients; two patients required laparotomy for pancreatic necrosis and abscess formation.29,36
TTP-HUS was diagnosed 2–15 days (median, 3 days) after the diagnosis of pancreatitis. In only two patients was the onset of TTP-HUS accompanied by neurologic abnormalities: patient 1 had slurred speech and patient 10 had right hemiparesis. Coagulation test results were reported in 12 patients and all were normal. Eight patients had acute renal failure and seven required dialysis. ADAMTS13 activity was reported only for patient 15; her activity was slightly low (53%, normal range 67–177%) without a demonstrable inhibitor.41 Ten patients were treated with plasma exchange, four with plasma infusion, one with splenectomy,27 and one with only supportive care including hemodialysis.32 Using the criteria in Table 1, there was a possible relation between the pancreatitis and the subsequent development of TTP-HUS in eight patients (Table 3). In these patients, either there was no apparent etiology for their pancreatitis or it was not reported that the pancreatitis was resolving at the time TTP-HUS was diagnosed. In the other eight patients, pancreatitis probably triggered the acute episode of TTP-HUS. Recurrent TTP-HUS occurred in three of these patients following a subsequent episode of recurrent pancreatitis. The recurrent episodes of TTP-HUS of patient 11 are not presented in Table 3 because the case report only describes that the patient had several episodes of acute pancreatitis over the following 3 years and that following each of these episodes he developed clinical and laboratory evidence of TTP-HUS within 48 hours.
| Discussion |
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The possibility of coincidental occurrence of pancreatitis and TTP-HUS can be estimated from the annual incidence of TTP-HUS (5 per 106 population, the mean value of four estimates determined in the US)25,45–47 and the annual incidence of new and recurrent episodes of pancreatitis in the US population (750 per 106 population).48 Based on these data, the expected incidence of coincidental occurrence of both disorders within the same year is 3.75 per 109 population), indicating that the percentage of patients with TTP-HUS who would also have pancreatitis would be 0.000000375%, 2.24x106-fold less than our observed percent.
Since this assessment is based on annual incidence rates for TTP-HUS and pancreatitis, it would be much less likely for TTP-HUS to occur by chance just a few days after pancreatitis. Therefore, our observed cases of pancreatitis preceding acute episodes of TTP-HUS are unlikely to be the result of coincidence.
The hypothesis that pancreatitis may trigger an acute episode of TTP-HUS is consistent with observations that multiple factors may be involved in the onset of TTP-HUS. In Upshaws initial patient with congenital TTP-HUS, infections and pancreatitis were noted to trigger her acute episodes.7 Women with congenital ADAMTS13 deficiency may have no signs of TTP-HUS until near the end of their first pregnancy.8,9 Pregnancy, infections, and surgery may also trigger acute episodes of acquired TTP-HUS associated with ADAMTS13 deficiency.8–10;12,18
The former conditions may result in an inflammatory response that could augment the risk of ADAMTS13 deficiency by enhancing the release of ultralarge von Willebrand factor (VWF) multimers from endothelial cells and inhibiting their cleavage by ADAMTS13.15 This has been demonstrated in in vitro studies in which the inflammatory cytokines, interleukin (IL)-8 and tumor necrosis factor (TNF)-
, stimulated endothelial cell release of ultralarge VWF multimers in a dose-dependent manner and IL-6 inhibited the cleavage of ultralarge VWF by ADAMTS13.15 Similar conditions may trigger acute episodes of TTP-HUS not associated with ADAMTS13 deficiency18 and acute episodes in patients with congenital HUS due to abnormal complement regulation.5
The systemic inflammatory response of pancreatitis, mediated by IL-6, IL-8, TNF-
, and other cytokines,49 may also contribute to the onset of an acute episode of TTP-HUS.15 Furthermore, pancreatitis is associated with endothelial cell damage, which may contribute to the development of TTP-HUS as well as lead to disseminated intravascular coagulation.50 Since TTP-HUS is a rare complication of pancreatitis, patients who develop TTP-HUS following pancreatitis may have a predisposing risk. Acquired ADAMTS13 deficiency was the apparent risk factor present in two of the four patients in whom ADAMTS13 activity was measured.
| Footnotes |
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KKS, JTD, SKV, HCK, BK, BL, JAKH, JNG: substantial contributions to conception and design of the study revising the article critically for important intellectual content; final approval of the version to be published.
The authors reported no potential conflicts of interest.
Funding: supported by grants from the Swiss National Foundation for Scientific Research (3200B0-108261) and the Mach-Gaensslen Foundation, Switzerland.
Received for publication October 24, 2006. Accepted for publication May 7, 2007.
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