Diagnosis Of Thrombotic Thrombocytopenic Purpura Research Articles

Consensus opinion on diagnosis and management of thrombotic microangiopathy in Australia and New Zealand

Thrombotic microangiopathy (TMA) arises in a variety of clinical circumstances with the potential to cause significant dysfunction of the kidneys, brain, gastrointestinal tract and heart. TMA should be considered in all patients with thrombocytopenia and anaemia, with an immediate request to the haematology laboratory to look for red cell fragments on a blood film. Although TMA of any aetiology generally demands prompt treatment, this is especially so in thrombotic thrombocytopenic purpura (TTP) and atypical haemolytic uraemic syndrome (aHUS), where organ failure may be precipitous, irreversible and fatal. In all adults, urgent, empirical plasma exchange (PE) should be started within 4-8 h of presentation for a possible diagnosis of TTP, pending a result for ADAMTS13 (a disintegrin and metalloprotease thrombospondin, number 13) activity. A sodium citrate plasma sample should be collected for ADAMTS13 testing prior to any plasma therapy. In children, Shiga toxin-associated haemolytic uraemic syndrome due to infection with Escherichia coli (STEC-HUS) is the commonest cause of TMA, and is managed supportively. If TTP and STEC-HUS have been excluded, a diagnosis of aHUS should be considered, for which treatment is with the monoclonal complement C5 inhibitor, eculizumab. Although early confirmation of aHUS is often not possible, except in the minority of patients in whom auto-antibodies against factor H are identified, genetic testing ultimately reveals a complement-related mutation in a significant proportion of aHUS cases. The presence of other TMA-associated conditions (e.g. infection, pregnancy/postpartum and malignant hypertension) does not exclude TTP or aHUS as the underlying cause of TMA.

Anti-ADAMTS13 Antibodies and a Novel Heterozygous p.R1177Q Mutation in a Case of Pregnancy-Onset Immune-Mediated Thrombotic Thrombocytopenic Purpura.

In this study, we investigated a case of pregnancy-onset thrombotic thrombocytopenic purpura (TTP). The patient had severely decreased ADAMTS13 ( a d isintegrin a nd m etalloprotease with t hrombo s pondin type 1 motif, member 13) activity levels during acute phase and the presence of inhibitory anti-ADAMTS13 autoantibodies was demonstrated, which led to the diagnosis of immune-mediated TTP. However, ADAMTS13 activity was only mildly restored during remission, although inhibitory anti-ADAMTS13 antibodies were no longer detected. We hypothesized that genetic abnormalities could account for this discrepancy between ADAMTS13 activity and antigen. Genetic analysis revealed the presence of two heterozygous substitutions on the same allele: a single nucleotide polymorphism (SNP) c.2699C > T (p.A900V), located in the beginning of the T5 domain, and a mutation c.3530G > A (p.R1177Q) located in the third linker region of ADAMTS13. In vitro testing of those substitutions by expression of recombinant proteins revealed a normal secretion but a reduced ADAMTS13 activity by the novel p.R1177Q mutation, which could partially explain the subnormal activity levels found during remission. Although changes in the linker region might induce conformational changes in ADAMTS13, the p.R1177Q mutation in the third linker region of ADAMTS13 did not expose a cryptic epitope in the metalloprotease domain. In conclusion, we report on an immune-mediated pregnancy-onset TTP patient who had inhibitory anti-ADAMTS13 autoantibodies during acute phase, but not during remission. Genetic analysis confirmed the diagnosis of immune-mediated TTP and revealed the novel p.R1177Q mutation which mildly impaired ADAMTS13 activity.

Evaluation of a cost-effective ADAMTS13 antigen assay

Thrombotic thrombocytopenic purpura (TTP) is life-threatening and is characterised by platelet deposition in the microvasculature with thrombus formation in particular organs. This results in thrombocytopenia, microangiopathic haemolytic anaemia, kidney failure and neurological symptoms. It is a rare disorder, but can occur in patients infected with the human immunodeficiency virus (HIV). ADAMTS13 is the 13 th member of a disintegrin and metalloprotease with thrombospondin type motifs. Its deficiency causes TTP. Therefore, the measurement of the ADAMTS13 levels in plasma is vital in the diagnosis of TTP and also important in distinguishing it from other thrombotic microangiopathies (TMA’s). Unfortunately, commercial ADAMTS13 antigen assays are expensive for healthcare service providers in developing countries. However, several antibodies and antibody pairs have been produced against ADAMTS13 and are commercially available. In this study, we evaluated an in-house ADAMTS13 antigen assay using two different commercial antibodies and compared the outcomes to that of a commercial ADAMTS13 antigen kit by using the plasma of 40 patients with possible HIV-associated TTP and 40 healthy subjects. The Intra- and inter-assay coefficients of variation were calculated as 8% and 7% respectively. The assay gave linear results between 0.78 to 12.5% ADAMTS13. The limit of detection was 0.2%, and the limit of quantification was 0.8%. The correlation of our assay compared to the commercial test kit was excellent, with a R 2 value of 0.9. In addition, the cost of our ADAMTS13 antigen assay was lower than that of the commercial ADAMTS13 antigen test kit. Our cost-effective in-house ADAMTS13 antigen test also produced reliable results. We therefore recommend that this assay be used to diagnose HIV-associated TTP.

ADAMTS13 test and/or PLASMIC clinical score in management of acquired thrombotic thrombocytopenic purpura: a cost-effective analysis.

The ADAMTS13 test distinguishes thrombotic thrombocytopenic purpura (TTP) from other thrombotic microangiopathies (TMAs). The PLASMIC score helps determine the pretest probability of ADAMTS13 deficiency. Due to inherent limitations of both tests, and potential adverse effects and cost of unnecessary treatments, we performed a cost-effectiveness analysis (CEA) investigating the benefits of incorporating an in-hospital ADAMTS13 test and/or PLASMIC score into our clinical practice. A CEA model was created to compare four scenarios for patients with TMAs, utilizing either an in-house or a send-out ADAMTS13 assay with or without prior risk stratification using PLASMIC scoring. Model variables, including probabilities and costs, were gathered from the medical literature, except for the ADAMTS13 send-out and in-house tests, which were obtained from our institutional data. If only the cost is considered, in-house ADAMTS13 test for patients with intermediate- to high-risk PLASMIC score is the least expensive option ($4,732/patient). If effectiveness is assessed as measured by the number of averted deaths, send-out ADAMTS13 test is the most effective. Considering the cost/effectiveness ratio, the in-house ADAMTS13 test in patients with intermediate- to high-risk PLASMIC score is the best option, followed by the in-house ADAMTS13 test without the PLASMIC score. In patients with clinical presentations of TMAs, having an in-hospital ADAMTS13 test to promptly establish the diagnosis of TTP appears to be cost-effective. Utilizing the PLASMIC score further increases the cost-effectiveness of the in-house ADAMTS13 test. Our findings indicate the benefit of having a rapid and reliable in-house ADAMTS13 test, especially in the tertiary medical center.

Derivation and external validation of the PLASMIC score for rapid assessment of adults with thrombotic microangiopathies: a cohort study

Among the syndromes characterised by thrombotic microangiopathy, thrombotic thrombocytopenic purpura is distinguished by a severe deficiency in the ADAMTS13 enzyme. Patients with this disorder need urgent treatment with plasma exchange. Because ADAMTS13 activity testing typically requires prolonged turnaround times and might be unavailable in resource-poor settings, a method to rapidly assess the likelihood of severe ADAMTS13 deficiency is needed. All consecutive adult patients presenting to three large academic medical centres in Boston, MA, USA, with thrombotic microangiopathy and a possible diagnosis of thrombotic thrombocytopenic purpura between Jan 8, 2004, and Dec 6, 2015, were included in an ongoing multi-institutional registry (the Harvard TMA Research Collaborative). Univariate analysis was used to identify covariates for a logistic regression model predictive of severe ADAMTS13 deficiency (≤10% activity). A clinical point score was generated, and its diagnostic performance was assessed using internal and external validation cohorts and compared to clinical assessment alone. 214 patients with thrombotic microangiopathy were included in the derivation cohort. A seven-component clinical prediction tool, termed the PLASMIC score, was developed and found to reliably assess the pretest probability of severe ADAMTS13 deficiency (C statistic 0·96, 95% CI 0·92-0·98). Our diagnostic model was reproducibly accurate in both the internal (0·95, 0·91-0·98) and external (0·91, 0·85-0·95) validation cohorts. The scoring system also more consistently diagnosed thrombotic microangiopathy due to severe ADAMTS13 deficiency than did standard clinical assessment, as measured by C statistic (0·96, 95% CI 0·92-0·98 for PLASMIC vs 0·83, 0·77-0·88 for clinical assessment; p<0·0001) and mean Brier score (0·065 for PLASMIC vs 0·111 for clinical assessment; mean paired difference 0·05, 95% CI 0·01-0·08; p<0·0001). When utilised in addition to clinical assessment, the PLASMIC score contributed significant discriminatory power (integrated discrimination improvement 0·24, 95% CI 0·11-0·37). We have developed and validated a clinical prediction tool-the PLASMIC score-to stratify patients with thrombotic microangiopathy according to their risk of having severe ADAMTS13 deficiency. We have shown that this scoring system is superior to standard clinical assessment in addressing the diagnostic challenge presented by thrombotic microangiopathy. Its use, together with clinical judgment, may facilitate treatment decisions in patients for whom timely results of ADAMTS13 activity testing are unavailable. The Luick Family Fund of Massachusetts General Hospital.

Thrombotic thrombocytopenic purpura misdiagnosed as autoimmune cytopenia: Causes of diagnostic errors and consequence on outcome. Experience of the French thrombotic microangiopathies reference centre.

Thrombotic thrombocytopenic purpura (TTP) has a devastating prognosis without adapted management. Sources of misdiagnosis need to be identified to avoid delayed treatment. We studied 84 patients with a final diagnosis of severe (<10%) acquired ADAMTS13 deficiency-associated TTP from our National database that included 423 patients, who had an initial misdiagnosis (20% of all TTP). Main diagnostic errors were attributed to autoimmune thrombocytopenia, associated (51%) or not (37%) with autoimmune hemolytic anemia. At admission, misdiagnosed patients were more frequently females (P = .034) with a history of autoimmune disorder (P = .017) and had organ involvement in 67% of cases; they had more frequently antinuclear antibodies (P = .035), a low/undetectable schistocyte count (P = .001), a less profound anemia (P = .008), and a positive direct antiglobulin test (DAT) (P = .008). In multivariate analysis, female gender (P = .022), hemoglobin level (P = .028), a positive DAT (P = .004), and a low schistocytes count on diagnosis (P < .001) were retained as risk factors of misdiagnosis. Platelet count recovery was significantly longer in the misdiagnosed group (P = .041) without consequence on mortality, exacerbation and relapse. However, patients in the misdiagnosed group had a less severe disease than those in the accurately diagnosed group, as evidenced by less organ involvement at TTP diagnosis (P = .006). TTP is frequently misdiagnosed with autoimmune cytopenias. A low schistocyte count and a positive DAT should not systematically rule out TTP, especially when associated with organ failure.

Diagnosis and treatment of TMA based on Japanese clinical guides.

Patients with thrombotic microangiopathies (TMAs), which include thrombotic thrombocytopenic purpura (TTP), atypical hemolytic uremic syndrome (aHUS), and Shiga toxin-producing Escherichia coli hemolytic uremic syndrome (STEC-HUS), exhibit multiple symptoms. These include thrombocytopenia (platelet count <15×104/µl), microangiopathic hemolytic anemia (hemoglobin <10 g/dl), and organ damage, such as renal dysfunction or neurological abnormalities. Guidelines for the management of TTP, aHUS, and STEC-HUS have been published. Diagnosis of TTP, STEC-HUS, or aHUS requires ADAMTS13 activity <10%, the detection of STEC or Shiga toxins, or a genetic analysis to investigate the complement regulatory system, respectively. In the established management of TMAs, fresh frozen plasma is used for congenital TTP to supplement ADAMTS13. Plasma exchange (PE) is used in acquired TTP (ATTP) to remove inhibitors and replace ADAMTS13. Steroid therapy is administered in ATTP to suppress inhibitor production, and rituximab is administered in ATTP without response to PE or with high titers of ADAMTS13 inhibitors. Eculizumab, a monoclonal antibody for complement protein 5, is used for the treatment of aHUS. Supportive therapy is required for some TMAs, particularly STEC-HUS, but platelet transfusion is generally contraindicated for other TMAs, such as TTP. Treatments should be administered in accordance with these guidelines to improve the outcome of TMAs.

Thrombotic thrombocytopenic purpura in the course of systemic lupus erythematosus in a 15-year-old girl

Systemic lupus erythematosus (SLE) concomitant with thrombotic thrombocytopenic purpura (TTP) in children is rarely diagnosed. We report a case of a 15-year-old girl with butterfly patch, generalized edema, leg pain, anemia (Hb 74 g/l), thrombocytopenia (5 x 109/l), schistocytes in peripheral blood smear, acute kidney injury (eGFR 27 ml/min/1.73 m2), proteinuria, and erythrocyturia. The direct Coombs test was positive, and warm antibodies (IgG) were detected on red blood cells. ANA in titer 1 : 2560, low serum C3 and C4 complement level, ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity < 4% and the presence of ADAMTS13 inhibitor were detected. In renal biopsy class IVA/V lupus nephritis was diagnosed. Her clinical symptoms fulfilled criteria for the diagnosis of SLE and the diagnosis of TTP. She was treated with intravenous methylprednisolone and cyclophosphamide 750 mg/1.73 m2/monthly for six months, followed by oral prednisone with azathioprine, chloroquine, and enalapril. The long-term clinical outcome was good.We report a case rare in adolescents, TTP related to SLE, which may suggest the need to test for ADAMTS13 activity and the presence of ADAMTS13 inhibitor in children with SLE and anemia, thrombocytopenia and rapid deterioration of renal function, to make the right therapeutic decisions.

Thrombotic Thrombocytopenic Purpura Misdiagnosed As Autoimmune Cytopenia: Causes of Diagnostic Errors and Consequence on Outcome. Experience of the French Thrombotic Microangiopathies Reference Centre

Introduction:Thrombotic thrombocytopenic purpura (TTP) is a life threatening disease defined by the association of a hemolytic mechanical anemia, a profound thrombopenia and organ failure with a severe ADAMTS13 deficiency. A rapid diagnosis represents a major goal and sources of misdiagnosis need to be identified to avoid diagnostic wandering and delayed adapted treatment that may translate in increased morbi-mortality. The main objective of this study is to describe the characteristics of TTP initially misdiagnosed and analyse the impact of a late diagnosis on patient's outcomes.Methods:From May 2000 to May 2014, all patients with acquired TTP and severe ADAMTS13 deficiency enrolled prospectively in the French TMA Reference Centre registry were included. A misdiagnosis was retained if initial diagnosis was not TTP and if patients did not receive TPE as initial treatment.Results:Among the 423 studied patients, 84 (20%) were initially misdiagnosed and not received plasma exchange. Main diagnostic errors were attributed to an Evans syndrome and an auto-immune thrombopenic purpura in 51% and 37% of cases respectively. Median time to diagnosis was longer in the misdiagnosed group than in the accurately diagnosed (5 [IQR, 2-8] vs. 1 [IQR, 0-3] days, P=.008). At admission, compared to the accurately diagnosed patients, misdiagnosed patients had a higher rate of low or undetectable schizocytosis (57.5% vs. 32%, P=.001), higher hemoglobin level (8.4 [IQR, 6.7-9.7] g/dl vs. 7.7 [IQR, 6.5-9.1] g/dl, P=.008) and rate of positive DAT (18% vs. 4%, P=.008). Anti-nuclear antibodies (65% vs. 51%, P=.045) and an associated auto-immune disease (24% vs. 13%, P=.017) were also more frequent. In multivariate analysis, a positive DAT and hemoglobin level were retained as risk factor (OR= 8.71, 95% CI [1.759-43.181], P=.008 and OR= 1.27, 95% CI [1.002-1.602], P=.048), respectively. Platelet count recovery over time was significantly longer in the misdiagnosed group (log-rank test: P=.041) without any consequence on overall mortality, exacerbation and relapse. However, specific causes of death probably differed between groups: in the accurately diagnosed group, patients died more frequently on early stage from a fulminant form of TTP within the first week, whereas in the misdiagnosed group patients died later (13 [IQR, 3-20] vs. 6 [IQR, 2-9] days; P=.023), had less organ involvement at early diagnosis (49% vs.64%, P=.019) and received more salvage therapies (80% vs. 35%, P=.009), suggesting that prognosis could have been improved with an earlier treatment.Conclusion:TTP is frequently misdiagnosed with auto-immune cytopenias and usual biological parameters may be initially absent. In a context of hemolysis and thrombocytopenia, a low or undetectable rate of schizocytosis at admission, and a positive DAT should not rule out the diagnosis of TTP, especially when associated with organ failure. A rapid accurate diagnosis of TTP may result in a shorter time to platelet recovery and could improve prognosis. DisclosuresNo relevant conflicts of interest to declare.

Thrombotic Thrombocytopenic Purpura Predominance in the Southern United States; Trends in Regional and Seasonal Variation and Mortality of TTP Utilizing the National Inpatient Sample Database Between 1999 and 2013

Abstract Background: Few studies have been able to determine epidemiological factors associated with Thrombotic Thrombocytopenic Purpura (TTP) and no geographic distribution has been determined. Only one study to date, Giri et al., (Am J Hematol, 2015, 90:E24) has looked at regional differences in TTP and found a higher caseload of TTP in the South between 2009 and 2011. Data thus far on seasonal variations has been mixed. Park et al. (Transfusion, 2012, 52.7: 1530) reported an association between summer and presentation of TTP, and Giri et al. found a significant seasonal variation only in the Midwest with a spike in cases during the month of July, while others like Raval et al. (J Clin Apheresis, 2013, 29.2:113) reported no variation. Furthermore, mortality in TTP has traditionally been looked at in terms of data from a single center within their own regional cohort and no recent studies have analyzed the trends in mortality from TTP. Building on this, our study looked at the regional variation, seasonal variation, and national mortality of TTP using data on admissions from the National Inpatient Sample between 1999 and 2013. Methods: Adult admissions with a primary diagnosis of TTP were extracted from the National Inpatient Sample database using the ICD-9 code for TTP (446.2) during a 15 year period between 1999 and 2013 (N = 6,292, weighted N = 30,011). The sample was weighted to approximate the full inpatient population of the United States over the period of interest. Admission information studied included hospital region, which was differentiated into Northeast, Midwest or North Central, South, and West. The season of admissions over this interval was also analyzed. The Winter months were December to February, Spring: March-May, Summer: June-August, and Fall: September-November. We extrapolated seasons to be equivalent to climate. A Chi square analysis was used to analyze differences in categorical variables. To analyze differences in regional distribution, we assumed a normal distribution of 25% per region and then performed a chi squared analysis. Results: There were more cases of TTP in the South (43.50%) compared to the Midwest or North Central (23.31%), Northeast (18.36%), or West (14.82%) among 30,011 cases (p=0.001). In each year between 1999 and 2013, the admissions for TTP were higher in the South. While certain years individually appeared to have a seasonal variation, taking the years between 1999 and 2013 in summation (n=5,857) showed no statistically significant seasonal variation in presentation of TTP (p=0.694). Additionally, analyzing the seasonal data by region (n=5,857) still did not demonstrate any significant variation in the presentation of TTP (p=0.172). During the period of our analysis, overall mortality decreased from 12.12% in 1999 to its lowest level of 5.90% in 2013. Conclusion: These results not only confirm the findings from Giri et al., who showed a higher number of cases of TTP in the South for the years 2009 to 2011, but we also demonstrated this was true for the extended time period from 1999 to 2013. Our results also agree with Raval et al. who showed no seasonal association with presentation of TTP. Previous authors suggested that climate correlated with TTP admissions; however, our data showed that the climate did not have an effect on regional admissions for TTP. Extrapolating from this, even though the majority of cases of TTP occurred in the South, this is unrelated to the warmer climate seen in the South, as had been suggested by prior authors. From 1999 to 2013, hospital mortality trended downward. Perhaps trends in mortality have decreased due to recognition of effective treatment and earlier recognition of TTP. Further studies are needed to clarify why there is a regional difference in TTP and to determine if mortality will continue to decline over time. Disclosures No relevant conflicts of interest to declare.

Post Traumatic Stress Disorder and Depression in Survivors of Thrombotic Thrombocytopenic Purpura

Background and objective: Recent data suggests that patients with thrombotic thrombocytopenic purpura (TTP) have higher rates of chronic morbidities including neurocognitive complications and depression. There is limited information regarding the psychological consequences of this disorder. TTP is conceivably an emotional trauma with a risk of post-traumatic stress disorder (PTSD). We conducted this cross sectional study to estimate the prevalence of symptoms of PTSD and depression in survivors of TTP.Methods: We developed an online survey tool based on two validated questionnaires: the PTSD checklist for DSM-5 (PCL-5) and Beck Depression Inventory-II (BDI-II). We also collected information regarding patient demographics clinical features and experiences. Surveys were distributed through email in collaboration with AnsweringTTP, a patient support organization. Survey responses were managed in RedCap. Associations of clinical and demographic variables with a positive screen for PTSD were first evaluated by the chi-square test and t-test, and then in a multivariable regression model. Prevalence of PTSD and depression were compared with a general primary care population. A p-value of 0.05 was considered significant for all analyses.Results: Three hundred and sixteen patients responded to the survey (response rate 27.5%). Of these, 290 completed consent to participate in the study, and 236 completed either the PCL-5 (n=231) or BDI-II (209) and were included in the analysis. Median age was 44 years and 206 (87.3%) were female. A pre-existing diagnosis of depression, anxiety disorder and PTSD was present in 97 (41.1%), 81 (34.3%) and 37 (15.7%) respondents, respectively. Median time from initial diagnosis of TTP was 80 months (interquartile range 37 to 132 months).BDI-II scores >13 indicating at least mild depressive symptoms were present in 169 (80.8%) patients. Thirty-three (15.8%), 59 (28.2%) and 77 (36.8%) had mild, moderate and severe depressive symptoms, respectively. Eighty-one (35.1%) individuals had a positive screen for PTSD (PCL-5 score >= 38), and 75 (32.4%) met criteria for a provisional diagnosis of PTSD based on the DSM-5 criteria of presence of cluster B, C, D and E symptoms. Compared to an age and sex adjusted primary care population, TTP survivors had a higher prevalence of PTSD (32.4% versus 3.5%) and depression (80.9% versus 10.5%). On multivariable analysis, a previous diagnosis of depression [odds ratio (OR) 3.65 (95% CI 1.26 - 10.57); p=0.017] and being unemployed due to TTP [OR 5.86 (95% CI 1.26 - 27.09); p = 0.024] were identified as significant predictors of depression. A positive screen for PTSD was associated with younger age (p = 0.017), a pre-existing diagnosis of anxiety disorder [OR 3.57 (95% CI 1.76 - 7.25), p < 0.001], and being unemployed for reasons attributable to TTP [OR 6.42 (95% CI 2.75-415.00), p < 0.001).Conclusion: We found a high prevalence of PTSD (32.4%) and depression (80.8%) in survivors of TTP. While responder bias may lead to overestimation of prevalence in this study, these results are concerning and indicate a need for further investigation. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Higher Incidence of TTP in African Americans and Females: An Analysis of Demographics, Cost and Length of Stay in Teaching and Nonteaching Hospitals for Thrombotic Thrombocytopenic Purpura Between 1999 and 2013

Background: Limited studies compare the differences in care for Thrombotic Thrombocytopenic Purpura (TTP) patients in teaching versus nonteaching hospitals. TTP is a rare, life-threatening disease marked by widespread aggregation of platelets throughout the body, resulting in multi-organ sequelae including neurological dysfunction and renal insufficiency: a timely diagnosis is imperative for successful treatment. Academic centers generally have more individuals involved in each patient's care. This was considered in the evaluation of demographics, cost, length of stay, and disposition at discharge in the different settings.Methods: Adult admissions with a primary diagnosis of TTP for a 15-year period between 1999 and 2013 were extracted from the National Inpatient Sample database using the ICD-9 code 446.2 during a 15 year period between 1999 and 2013 (N=6,292, for a weighted N=30,011). The sample was weighted to approximate the full inpatient population of the U.S. over the time period. Teaching and nonteaching hospitals were compared within the parameters of gender, race, total cost, insurance, length of stay, mortality, and disposition. Chi square analysis was performed to examine differences in the categorical variables. Total cost was adjusted for inflation using data from the U.S. Bureau of Labor Statistics.Results: The total number of admission for TTP was weighted N=28,058, divided between 20,426 for teaching and 8,082 for nonteaching hospitals. 67.6% of TTP admissions were female in both categories but a greater percentage of African Americans with TTP were admitted to teaching (N=6,842; 33.50%) than nonteaching hospitals (N=1,962; 24.28%) (p < 0.0001). More Caucasians with TTP were admitted to non-teaching (N=2,707; 33.50%) than teaching hospitals (N=6,834; 32.46%) (p <0.0001).The overall length of stay for TTP hospitalizations was 12.30 days +/- 0.16, with teaching hospitals being found to have a shorter length of stay at 11.26 +/- 0.28 days compared to nonteaching hospitals with 13.15 +/- 0.20 days (p < 0.0001). There was a slightly higher mortality rate in nonteaching hospitals: 8.92% in teaching hospitals versus 9.32% in nonteaching hospitals (p <0.6232). Overall hospital mortality decreased from 12.1% in 1999 to 6.0% in 2013. At discharge, more patients from nonteaching hospitals were transferred to short term facilities than those from teaching: 1,877 (23.23%) non-teaching patients versus 2,038 (9.98%) teaching patients (p = 0.0001).The overall cost of a TTP hospitalization was $106,184.94 +/- $1,762.57. Nonteaching hospitals had more costly hospitalizations at $113,437.87 +/- $2247.78 than teaching hospitals, which cost $99,481.35 +/- $3093.53 (p <0.0001). Medicare paid 26.23% of TTP hospitalizations in nonteaching hospitals and 22.91% in teaching hospitals (p <0.0006). Medicaid paid for 18.12% of TTP hospitalizations in teaching hospitals and 12.89% in nonteaching hospitals (p <0.0006).An increase in the cost for admissions for TTP was noted from 1999 to 2013. While the total charge of TTP admission was $58,437 in 1999, it was found to be $153,643 in 2013, or $109,878 when adjusted for inflation. This amounted to an adjusted 88% increase despite an essentially unchanged average length of stay, 12.5 days in 1999 and 12.6 days in 2013.Conclusion: In comparing TTP hospitalizations, teaching hospitals had a shorter length of stay, lesser cost of stay, and sent fewer patients to short term facilities upon discharge. However, these factors did not play a statistically significant role in decreasing mortality. Additionally, a trend of increasing total charges was noted from 1999 to 2013 despite an unchanged length of hospitalization and a decrease in mortality. Advanced age is associated with worse outcome in TTP and this is reflected by the higher mortality and higher percentage of Medicare payment in nonteaching hospitals. Medicaid was responsible for a higher percentage of payment in teaching hospitals and correlated with an improved mortality. Both African Americans and females were found to have more admissions regardless of hospital type, with African Americans being admitted more often to teaching than nonteaching hospitals. Further studies are necessary to determine the etiology of this significant rise in the cost of TTP treatment and to investigate the disproportionately higher incidence of TTP in African Americans and females. DisclosuresNo relevant conflicts of interest to declare.

Relapsing Thrombotic Thrombocytopenic Purpura: A Single Center Experience

Thrombotic thrombocytopenic purpura (TTP) is due to a severe deficiency of the von Willebrand factor (vWF) cleaving serine metalloprotease ADAMTS13 and is most commonly diagnosed in adults due to autoantibodies against ADAMTS13. Standard therapy includes plasma exchange (PEX) until platelet counts normalize plus concurrent high dose corticosteroids. In refractory cases, weekly pulse Rituximab for 4 doses is often added. Successful long-term management of relapsing patients beyond these treatments is unclear, in part because the mechanisms for relapsing TTP are unknown. Dysfunctional immunoregulatory systems likely play a role in relapsing disease. Several case series have described disease control following bortezomib therapy (Patriquin 2016). Other immunomodulators including complement pathway and tyrosine kinase inhibitors may prove to offer benefit. Further, supplementing PEX with N-acetylcysteine (Rottenstreich 2016) & Caplacizumab (anti-vWF humanized immunoglobulin) (Peyvandi 2016) has shown promising preliminary clinical results when used to treat an acute episode. Effects on relapse rates with these treatments have not been fully evaluated.Eight cases of relapsing TTP were identified at MedStar Georgetown University Hospital May 2004 to July 2016. Relapsing TTP was defined as recurrent episode(s) of thrombocytopenia, microangiopathic hemolysis, and confirmed ADAMTS13 activity levels <10% following remission from the initial TTP episode. Retrospective chart review was completed to evaluate demographic and clinicopathologic features, laboratories and treatment at relapse(s), and clinical outcomes.In our 8 patient cohort, 75% are female (6/8), 62.5% are African American (AA) (5/8), and the mean age at initial TTP diagnosis is 35.38 (range 16-67). The mean number of relapses is 3.38 (range 2-9) with a mean platelet nadir of 45,000/mcL. All patients remain alive. Two are ANA positive, 1 with known systemic lupus erythematosus (SLE) and 1 with suspected SLE. None are HIV positive, and none endorse a family history of TTP. Four identified infections as triggers for their TTP, 1 patient developed TTP during pregnancy and hormonal fertility treatments, and 3 had no identifiable triggers. All had an increased titer of ADAMTS13 inhibitor (Bethesda titer range 0.7 - >8) at the time of relapse(s). Normalization of ADAMTS13 activity was confirmed in most following treatment (n=6), with a mean ADAMTS13 activity level between relapses of 50.5% (range 32-88%). At the time of each relapse, all patients underwent daily PEX with fresh frozen plasma plus high dose corticosteroids for at least 5 days (range 5-21 days), with some requiring gradual PEX weaning over 1-4 weeks and steroid tapering over months based on lab parameters. Two relapsed quickly after PEX discontinuation, both in the setting of systemic illness (lupus flare, cholecystitis). Sequelae of TTP (neurologic, renal, hematologic anomalies) resolved with treatment. All patients received Rituximab therapy during the 1st or 2nd relapse. For the majority (87.5%, 7/8), this intervention did not lead to long-term remission, although 100% (2/2) who transitioned to prophylactic bolus Rituximab every 6 months post splenectomy achieved long-term disease control. It is difficult to distinguish whether remission resulted from maintenance Rituximab, the splenectomy, or a combination of the two. Patients who underwent splenectomy were vaccinated and have not had difficulty with infections or thrombosis.In conclusion, our cohort of patients with relapsing TTP all had documented ADAMTS13 inhibitors and acutely responded to daily PEX (most requiring PEX wean based on lab parameters) plus high dose corticosteroids. Although Rituximab therapy during initial relapse did not offer a high percentage of long-term remissions, the addition of prophylactic Rituximab every 6 months post splenectomy has achieved long-term control in 2 patients. In our cohort the majority are AA, suggesting genetic susceptibility. HLA/immune transcript levels and ribosomal gene signatures may correlate with TTP disease activity and risk for relapse (Edgar 2015), and could be used to identify high-risk patients in need of more intensive therapy. Given the complexity and severity of this disease, there is an ongoing need for evaluation of relapsing TTP and best strategies for long-term management. [Display omitted] DisclosuresKessler:Octapharma: Consultancy, Research Funding; Novo Nordisk: Consultancy, Research Funding; Grifols: Consultancy; Genentech: Consultancy, Research Funding; Biogen: Consultancy; Pfizer: Consultancy; Bayer: Consultancy, Research Funding; Baxalta: Consultancy, Research Funding; LFB: Other: Member of DSMB. Broome:True North Therapeutics: Honoraria; Alexion Pharmaceuricals: Honoraria.

Diagnosis and management of acquired thrombotic thrombocytopenic purpura in southeast China: a single center experience of 60 cases.

Acquired thrombotic thrombocytopenic purpura (TTP) is a rare life-threatening thrombotic microangiopathy. This study aimed to provide a profile of the diagnosis and management of patients with acquired TTP collected in 10 years in a single center in southeast China. A total of 60 patients diagnosed with acute acquired TTP from March 2005 to August 2015 were enrolled. Among the 60 patients, 52 patients presented with their first episodes, and eight patients had two or more episodes. The median age at presentation was 49 (range, 17 to 78) years with a female predominance (male:female ratio, 1:1.60). ADAMTS 13 activity were analyzed in 43 patients, among whom 33 (76.7%) patients had a baseline level of < 5%. Mortality was 30%. Plasma exchange (PEX) was performed in 62 of 69 (89.9%) episodes. Corticosteroids were administered in 54 of 69 (78.3%) episodes. Other immunosuppressants (e.g., vincristine, cyclosporine, and cyclosporin) were used in 7 of 69 (10.1%) episodes. Rituximab was documented in 4 patients with refractory/relapsed TTP for 5 episodes, showing encouraging results. In conclusion, the diagnosis of TTP depended on a comprehensive analysis of clinical data. Plasma ADAMTS13 activity assay helped confirm a diagnosis. PEX was the mainstay of the therapy, and rituximab can be used in relapsed/refractory disease.

Adenocarcinoma of the Lung Presenting as Thrombotic Thrombocytopenic Purpura

SESSION TITLE: Student/Resident Case Report Poster - Lung Cancer II SESSION TYPE: Student/Resident Case Report Poster PRESENTED ON: Tuesday, October 25, 2016 at 01:30 PM - 02:30 PM INTRODUCTION: Thrombotic microangiopathy may be the first manifestation of solid tumors such as lung cancer. Thrombotic thrombocytopenic purpura (TTP) includes the pentad of thrombocytopenia, hemolytic anemia, fever, neurologic abnormalities, and renal disease. We present a case of acute TTP as the first presentation of lung cancer. Prompt recognition and management resulted in a good outcome. CASE PRESENTATION: A 56-year-old African American male with no significant PMH was transferred to our center with an altered mental status. The patient reports that he did not have recollection of the events surrounding his admission and he was having difficulty answering questions appropriately. Physical examination was normal. CBC showed normal leukocytes count, anemia, and platelets count of 16,000. Peripheral smear showed reticulocytosis and schistocytes. Chemistry revealed a mildly elevated creatinine, indirect bilirubin and AST. LDH was elevated. Routine chest X-ray revealed a 3 cm left upper lobe lung mass, a finding confirmed with a chest CT. Mass biopsy showed a poorly differentiated adenocarcinoma of the lung. He was started on plasmapheresis which resulted in short-lived improvement. He underwent a left upper lobe lobectomy, after which, he went into complete remission. DISCUSSION: Cancer related thrombocytopenia can result either from bone marrow metastasis or as a paraneoplastic process. TTP, commonly affects adults, is a life-threatening disseminated thrombotic microangiopathy. Patients rarely present with the pentad of TTP, and recognition of atypical cases and prompt management (plasmapheresis/treatment of underlying condition) is a key factor in improved survival. The presence of a primary malignancy is an essential concern in the differential diagnosis of TTP, particularly in patients with refractoriness to first-line therapy with plasmaperesis; however, sometimes the malignancy is not clinically obvious (as in our case), leading to an initial diagnosis of idiopathic TTP and subsequent plasmapheresis treatment. The treatment of the underlying malignancy may be the best therapeutic decision in paraneoplastic TTP given its poor response to standard treatments (as in our case). CONCLUSIONS: TTP is a medical emergency that is almost always fatal if exchange plasmapheresis is not initiated early. This case report reminds clinicians that TTP may be an atypical presentation of lung cancer and occult malignancy should always be kept in consideration in patients with thrombocytopenia of uncertain etiology. Reference #1: M. Khasraw, H. Faraj, and A. Sheikha. Thrombocytopenia in solid tumors. European Journal of Clinical and Medical Oncology, vol. 2, no. 2, pp. 89-92, 2010 Reference #2: Sevinc A, Kalender ME, Pehlivan Y, Sari I, Camci C.Thrombotic Thrombocytopenic Purpura and Bone Marrow Necrosis as the Initial Presentation of Lung Cancer. Clin Appl Thromb Hemost. 2007 Oct;13(4):449-52 Reference #3: Gastineau DA, Cancer-related TTP and considerations of plasma exchange. Oncology, 2011 Sep;25(10):924, 926 DISCLOSURE: The following authors have nothing to disclose: Ahmed Dirweesh No Product/Research Disclosure Information

Validation of a panel of ADAMTS13 assays for diagnosis of thrombotic thrombocytopenic purpura: activity, functional inhibitor, and autoantibody test.

Quantitation of ADAMTS13 activity, functional inhibitors, and autoantibodies is crucial in diagnosis and management of thrombotic thrombocytopenic purpura. We compared and optimized commercial assay kits and validated a testing panel. Citrated plasma specimens from healthy volunteers and residual samples submitted for clinical testing were used in the study. Commercially available ADAMTS13 activity assays including ACTIFLUOR(™) ADAMTS13 (Sekisui Diagnostics, Stamford, CT, USA), LIFECODES ATS-13 (Gen-Probe Inc., San Diego, CA, USA), and TECHNOZYM(®) ADAMTS-13 (Technoclone, Vienna, Austria) were evaluated. Functional inhibitor assays were performed using internally developed mixing protocols. Two autoantibody assays were also evaluated: IMUBIND(®) (Sekisui Diagnostics) and TECHNOZYM(®) ADAMTS-13 INH ELISA kits (Technoclone). A laboratory-developed assay using ACTIFLUOR(™) reagents showed best agreement with the reference method, and full validation showed a reportable range of 5% (LLOQ) to 114% with a reference interval of ≥68%. Both intra- and interassay coefficients of variation were <10%. Inhibitor assays performed with the kits showed 95% overall agreement with the reference method. A modification of the TECHNOZYM(®) autoantibody assay showed 85% overall agreement with the reference method with imprecision approximately 20%. ADAMTS13 activity and inhibitor tests using ACTIFLUOR(™) reagents and modified TECHNOZYM(®) autoantibody ELISA showed superior performance compared to the other kits for clinical use in this study.

ZAKRZEPOWA PLAMICA MAŁOPŁYTKOWA U CHOREJ NA TOCZEŃ RUMIENIOWATY UKŁADOWY – POWIKŁANIE UKŁADOWEJ CHOROBY TKANKI ŁĄCZNEJ CZY ZESPÓŁ NAKŁADANIA?

Thrombotic thrombocytopenic purpura (TTP) and systemic lupus erythematosus (SLE) are two separate diseases, whose clinical symptoms maybe similar. The coexistence of these two diseases is very rare. We present the case report of a 29-year-old female patient with simultaneous diagnosis of TTP and SLE. The purpose of this article is to draw attention to the diagnostic difficulties which may result from the co-existence of both diseases.

Correlation between ADAMTS13 activity and neurological impairment in acute thrombotic microangiopathy patients.

Differential diagnosis between thrombotic thrombocytopenic purpura (TTP) and other thrombotic microangiopathies (TMA) is usually difficult because of frequently overlapping clinical presentations. Severely depressed ADAMTS13 activity (<10%) seems distinctive for TTP because of its pathogenetic role. However a long debate exists in the literature about its sensibility and specificity. Our aim was to search for clinical differences between TMA patients referred to our laboratory, comparing them for protease activity<10 versus≥10%. ADAMTS13 activity≥10% patients (n=73) showed a higher prevalence of drug- (p=0.005) and cancer-associated (p<0.001) TMA. Mean platelet count and renal dysfunction prevalence was lower (p<0.001), while neurological impairment was more frequent (p=0.001) in the<10% ADAMTS13 activity group (n=109), confirming previous literature findings. When taken neurological manifestations singularly, epilepsy (p=0.04), focal motor deficit (p<0.001) and cranial nerve palsy (p=0.007) were more frequent in the<10% activity group. In our case series, a<10% ADAMTS13 activity depicts a group of patients with clinical features similar to TTP patients. Focal motor impairment or epileptic manifestations could further address toward a TTP diagnosis. Studies about treatment efficacy and follow-up are advised to determine whether laboratory findings can guide therapeutic decisions.

Atypical presentations of thrombotic thrombocytopenic purpura: a diagnostic role for ADAMTS13.

Thrombotic thrombocytopenic purpura (TTP) is an acute, life threatening disease. Only a minority of patients expresses the complete clinical presentation and unusual manifestations can occur. Demonstration of low activity levels of ADAMTS13 (<5%) is highly specific for the diagnosis of TTP. This study reports a series of five cases of TTP presenting with a thrombotic event and no hematological findings. Detailed chart reviews on these patients were conducted. We identified two patients whose first attack of TTP presented as a thrombotic episode without microangiopathic hemolytic anemia and thrombocytopenia, only to be diagnosed as TTP days later, after the appearance of hematological signs. We also describe three cases of classical TTP relapsing atypically as cerebrovascular accidents without hematological signs. Low levels of ADAMTS13 activity were detected and facilitated the diagnosis. The neurological manifestations disappeared concurrent with normalization of ADAMTS13 activity level after plasma exchange. This study underscores the importance of having a high clinical suspicion of TTP in cases of thrombosis even without hematological abnormalities in patients with previous attacks of TTP. In this clinical scenario, measurement of ADAMTS13 activity is important for diagnosis and early administration of treatment.

Thrombotic microangiopathy without renal involvement: two novel mutations in complement‐regulator genes

ESSENTIALS: The differential diagnosis among thrombotic microangiopathies (TMAs) is challenging. We studied a case of TMA with neurologic symptoms, no renal impairment and normal ADAMTS-13 levels. Two novel mutations in complement factor I and thrombomodulin genes were identified. Complement-regulator genes can be involved in TMAs with normal ADAMTS-13 regardless of renal damage. Thrombotic microangiopathies (TMAs) often represent a challenge for clinicians, because clinical, laboratory, and even genetic features are not always sufficient to distinguish among different TMAs. The aim of this study was to investigate the pathogenetic mechanisms underlying an acute case of TMA with features of both thrombotic thrombocytopenic purpura (TTP) and atypical hemolytic uremic syndrome (aHUS). We report the case of a 49-year-old woman who developed an acute TMA with neurologic involvement and no renal impairment. ADAMTS-13, von Willebrand factor, and complement-system biochemical characterization was performed on acute phase samples. Exome sequencing and direct Sanger sequencing of previously aHUS-associated genes were performed. The functional consequences of the thrombomodulin (THBD) mutation were investigated by in vitro expression studies. Despite a clinical diagnosis of TTP, the patient had normal ADAMTS-13 levels and increased VWF antigen levels with ultra-large von Willebrand factor multimers. C3, C4, and complement factors H and I (CFI) were normal. Molecular analysis confirmed two novel heterozygous mutations in CFI (c.805G>A, p.G269S) and THBD (c.1103C>T, p.P368L), and in vitro expression studies showed a reduction in the generation of activated thrombin-activatable fibrinolysis inhibitor (TAFIa) caused by mutated THBD. This proinflammatory condition, associated with the p.G269S mutation in CFI, probably leads to a complement-mediated endothelial activation, with a relevant prothrombotic potential in case of transient environmental triggers. This study identified the first case of acute TMA without renal involvement but with neurological damage carrying two novel mutations in complement-regulator genes, highlighting the possible role of the complement system as a common pathogenetic mechanism in TMAs.