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1.  A report of disseminated adenocarcinoma presenting as thrombotic thrombocytopenic purpura 
Hematology Reports  2011;3(2):e14.
Thrombotic microangiopathies (TMAs) represent a heterogeneous group of diseases characterized by a microangiopathic hemolytic anemia, peripheral thrombocytopenia, and organ failure of variable severity. TMAs encompass thrombotic thrombocytopenic purpura (TTP), typically characterized by fever, central nervous system manifestations and hemolytic uremic syndrome (HUS), in which renal failure is the prominent abnormality. In patients with cancer TMAs may be related to various antineoplastic drugs or to the malignant disease itself. The reported series of patients with TMAs directly related to cancer are usually heterogeneous, retrospective, and encompass patients with hematologic malignancies with solid tumors or receiving chemotherapy, each of which may have distinct presentations and pathophysiological mechanisms. Patients with disseminated malignancy who present with microangiopathic hemolytic anemia and thrombocytopenia may be misdiagnosed as thrombotic thrombocytopenic purpura (TTP) Only a few cases of TTP secondary to metastatic adenocarcinoma are known in the literature. We present a case of a 34-year-old man with TTP syndrome secondary to metastatic small-bowel adenocarcinoma. Patients with disseminated malignancy had a longer duration of symptoms, more frequent presence of respiratory symptoms, higher lactate dehydrogenase levels, and more often failed to respond to plasma exchange treatment. A search for systemic malignancy, including a bone marrow biopsy, is appropriate when patients with TTP have atypical clinical features or fail to respond to plasma exchange.
PMCID: PMC3238485  PMID: 22184535
metastatic cancer; microangiopathic hemolysis; thrombocytopenia; thrombotic thrombocytopenic purpura; ADAMTS13.
2.  ADAMTS-13 in the Diagnosis and Management of Thrombotic Microangiopathies 
Thrombotic microangiopathies (TMAs) comprise a group of distinct disorders characterized by microangiopathic hemolytic anemia, thrombocytopenia, and microvascular thrombosis. For many years distinction between these TMAs, especially between thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS), remained purely clinical and hard to make. Recent discoveries shed light on different pathogenesis of TTP and HUS. Ultra-large von Willebrand factor (UL-VWF) platelet thrombi, resulting from the deficiency of cleavage protease which is now known as ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), were found to cause TTP pathology, while Shiga toxins or abnormalities in regulation of the complement system cause microangiopathy and thrombosis in HUS. TMAs may appear in various conditions such as pregnancy, inflammation, malignancy, or exposure to drugs. These conditions might cause acquired TTP, HUS, or other TMAs, or might be a trigger in individuals with genetic predisposition to ADAMTS-13 or complement factor H deficiency. Differentiation between these TMAs is highly important for urgent initiation of appropriate therapy. Measurement of ADAMTS-13 activity and anti-ADAMTS-13 antibody levels may advance this differentiation resulting in accurate diagnosis. Additionally, assessment of ADAMTS-13 levels can be a tool for monitoring treatment efficacy and relapse risk, allowing consideration of therapy addition or change. In the past few years, great improvements in ADAMTS-13 assays have been made, and tests with increased sensitivity, specificity, reproducibility, and shorter turnaround time are now available. These new assays enable ADAMTS-13 measurement in routine clinical diagnostic laboratories, which may ultimately result in improvement of TMA management.
PMCID: PMC4222415  PMID: 25386342
ADAMTS-13; aHUS; HUS; thrombotic microangiopathies; TTP; UL-VWF; Von Willebrand factor
3.  A Case of Thrombotic Thrombocytopenia Purpura Associated with Systemic Lupus Erythematosus: Diagnostic Utility of ADAMTS-13 Activity 
Autoimmune Diseases  2011;2011:483642.
Thrombotic thrombocytopenia purpura (TTP) caused by a deficiency in ADAMTS-13 activity is considered to involve a subset of thrombotic microangiopathy (TMA). Although concept of TTP is included under the umbrella of TMA, discrimination of TTP from TMA is occasionally difficult in an autoimmune disorder. Herein, we report a case with TTP associated with systemic lupus erythematosus (SLE). In this case, it was difficult to discriminate TTP from TMA and the measurement of ADAMTS-13 activity was useful for obtaining an accurate diagnosis. SLE patients having thrombocytopenia in complication with anemia should be considered a monitoring of ADAMTS-13 activity even though the patients lacked symptoms of TTP related to the microvascular coagulation.
PMCID: PMC3138087  PMID: 21776377
4.  Thrombotic Microangiopathy with Targeted Cancer Agents 
Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are clinically similar disorders characterized by microvascular thrombosis, hemolysis, thrombocytopenia, and end organ damage. Although they may present with overlapping symptoms, multiple etiologies have been proposed for these thrombotic microangiopathies (TMAs). Chemotherapy-induced TMA has been described with the use of mitomycin, gemcitabine, and others and has a poor prognosis. Recently, reports of TMA associated with targeted cancer agents have surfaced in the literature. We discuss the clinical presentation, outcome, and etiology of TMA reported with the use of immunotoxins, monoclonal antibodies, and tyrosine kinase inhibitors. A search of PubMed and meeting abstracts was conducted for cases of TMA with the use of targeted cancer agents. The defining symptoms, laboratory values, time to onset, and patient outcomes were compiled. Consistent definitions of TMA and grading of severity in these cases are lacking. However, presentation of TMA in these cases revealed the importance of monitoring for renal toxicity, hemolysis, and thrombocytopenia. Patient outcomes appear to differ from those seen in cases of chemotherapy-induced TMA and may reflect a different underlying etiology. Little is known about the pathogenesis of TMA with targeted cancer agents. In contrast to chemotherapy-induced TMA, partial to full reversibility may be a common outcome. However, further research is warranted into optimal management of patients diagnosed with TMA following treatment with targeted agents.
PMCID: PMC3176977  PMID: 21813634
Hemolytic Uremic Syndrome; Thrombotic Thrombocytopenic Purpura; Thrombotic Microangiopathy; Immunotoxin
5.  Renal thrombotic microangiopathy in a patient with septic disseminated intravascular coagulation 
BMC Nephrology  2013;14:260.
The mechanism for the development of thrombotic microangiopathy (TMA) during sepsis has only been partially elucidated. TMA is recognized as a disease caused by various factors, and may be involved in the emergence of organ damage in severe sepsis. Here we report a case of TMA that followed disseminated intravascular coagulation (DIC) due to severe infection in a patient with a reduced ADAMTS-13 activity level.
Case presentation
An 86-year-old Japanese woman was admitted to our hospital because of low back pain and fever. A careful evaluation led to a diagnosis of acute obstructive pyelonephritis due to a ureteral stone. Proteus mirabilis was isolated from both blood and urine cultures. The patient developed systemic inflammatory response syndrome and DIC, and was treated with antibiotics and daily continuous hemodiafiltration. Although infection and the coagulation abnormalities due to DIC were successfully controlled, renal failure persisted and her consciousness level deteriorated progressively in association with severe thrombocytopenia and microangiopathic hemolytic anemia. We therefore suspected the presence of TMA and started plasma exchange, which resulted in an impressive improvement in consciousness as well as the laboratory abnormalities. The ADAMTS-13 activity was 44% and the patient tested negative for the ADAMTS-13 inhibitor prior to the initiation of plasma exchange. A renal biopsy was performed to determine the etiology of acute renal injury, which revealed findings that were interpreted to be compatible with the sequelae of TMA. The follow-up studies performed after the successful treatment of TMA showed that her plasma ADAMTS-13 activity level remained persistently low. It is surmised that septic DIC occurring in the presence of preexisting reduced ADAMTS-13 activity have led to the development of secondary TMA in the present case.
The present case suggests that TMA can be superimposed on sepsis-induced DIC, and plasma exchange is expected to be beneficial in such situations. Clinicians should consider the possibility of secondary TMA that follows sepsis-induced DIC in certain indicative clinical settings.
PMCID: PMC4222681  PMID: 24279773
Thrombotic microangiopathy; Cortical necrosis; DIC; Sepsis; Renal biopsy; TTP; HUS; Plasma exchange; ADAMTS-13
6.  Pathogenesis of Thrombotic Microangiopathies 
Annual review of pathology  2008;3:249-277.
Profound thrombocytopenia and microangiopathic hemolytic anemia characterize thrombotic microangiopathy, which includes two major disorders: thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). TTP has at least three types: congenital or familial, idiopathic, and nonidiopathic. The congenital and idiopathic TTP syndromes are caused primarily by deficiency of ADAMTS13, owing to mutations in the ADAMTS13 gene or autoantibodies that inhibit ADAMTS13 activity. HUS is similar to TTP, but is associated with acute renal failure. Diarrhea-associated HUS accounts for more than 90% of cases and is usually caused by infection with Shiga-toxin-producing Escherichia coli (O157:H7). Diarrhea-negative HUS is associated with complement dysregulation in up to 50% of cases, caused by mutations in complement factor H, membrane cofactor protein, factor I or factor B, or by autoanti-bodies against factor H. The incomplete penetrance of mutations in either ADAMTS13 or complement regulatory genes suggests that precipitating events or triggers may be required to cause thrombotic microangiopathy in many patients.
PMCID: PMC2582586  PMID: 18215115
thrombotic thrombocytopenic purpura; hemolytic uremic syndrome; von Willebrand factor-cleaving metalloprotease; ADAMTS13; complement dysregulation
7.  ADAMTS13-binding IgG are present in patients with thrombotic thrombocytopenic purpura 
Thrombosis and haemostasis  2006;95(5):886-892.
Functional assays are commonly used to measure the antibodies of ADAMTS13 found in patients of thrombotic thrombocytopenic purpura (TTP). In this study we used an enzyme-linked immunoassay to analyze the ADAMTS13-binding IgG levels in six groups of individuals: normal, random hospitalized patients, acute TTP,TTP after receiving plasma therapy, TTP in remission, and other types of thrombotic microangiopathy (TMA). The results showed thatADAMTS13-binding IgG levels were elevated in 100% of the acute TTP group, 75% of the TTP group after receiving plasma therapy, and 40% of the remission group. Overall, the ADAMTS13-binding IgG levels correlated with the inhibitory activity levels against ADAMTS13 (r=−0.69,P<0.0001). The assay also detected elevated IgG binding levels in 5% – 15% of the normal, random, and other TMA control groups. Addition of purified ADAMTS13 protein to the plasma samples suppressed the IgG binding in each of the acute TTP patients, but in none of the non-TTP groups. Serial measurement in a patient that had two exacerbations of TTP within the first three weeks revealed that the ADAMTS13 activity levels remained < 0.1 U/ml during this period, and the ADAMTS13-binding IgG remained elevated, suggesting thatADAMTS13 analysis may provide valuable insight to the disease status during the course of therapy. Analysis of ADAMTS13-binding IgG is helpful for the diagnosis and management of TTP.
PMCID: PMC2603189  PMID: 16676082
ADAMTS13; thrombotic thrombocytopenic purpura; antibody
8.  The Molecular Biology of Thrombotic Microangiopathy 
Kidney international  2006;70(1):16-23.
Thrombotic microangiopathy, which includes thrombotic thrombocytopenic purpura (TTP), shiga-toxin associated hemolytic uremic syndrome (Stx-HUS) and atypical HUS, is characterized pathologically by the development of hyaline thrombi in the microvasculature and clinically by the manifestations of thrombocytopenia, microangiopathic hemolysis, and organ dysfunction. Renal failure is a predominant complication of both Stx-HUS and atypical HUS, while neurological complications are more prominent in TTP. Other disorders such as lupus or bone marrow transplantations may occasionally present with features of thrombotic microangiopathy. Recent studies have found autoimmune inhibitors or genetic mutations of a von Willebrand factor cleaving metalloprotease ADAMTS13 in patients with TTP. In approximately 30% – 50% of patients with atypical HUS, mutations have been detected complement factor H, membrane cofactor protein (CD46), or factor I. All three proteins are involved in the regulation of complement activation. Additionally autoantibodies of factor H have been described in patients without genetic mutations. These advances illustrate that dysregulation of VWF homeostasis or complement activation due to genetic or autoimmune mechanisms may lead to syndrome of thrombotic microangiopathy.
PMCID: PMC2497001  PMID: 16760911
ADAMTS13; Hemolytic uremic syndrome; Shear stress; Thrombotic microangiopathy; Thrombotic thrombocytopenic purpura; Regulators of complement activation; von Willebrand factor
American journal of hematology  2011;86(9):743-751.
The absence of specific diagnostic criteria, the urgency to begin plasma exchange treatment, and the risk for complications from plasma exchange make the initial evaluation of patients with suspected thrombotic thrombocytopenic purpura (TTP) difficult. Systemic infections may mimic the presenting clinical features of TTP. In the Oklahoma TTP-HUS (hemolytic-uremic syndrome) Registry, 1989–2010, 415 consecutive patients have been clinically diagnosed with their first episode of TTP; in 31 (7%) the presenting clinical features were subsequently attributed to a systemic infection. All 31 patients had diagnostic criteria for TTP; 16 (52%) had the complete “pentad” of microangiopathic hemolytic anemia, thrombocytopenia, neurologic abnormalities, renal failure and fever. Four (16%) of 25 patients who had ADAMTS13 measurements had <10% activity; three patients had a demonstrable ADAMTS13 inhibitor. Compared to 62 patients with severe ADAMTS13 deficiency (<10%) who had no recognized alternative disorders, patients with systemic infections had more frequent fever, coma, renal failure, and the complete “pentad” of clinical features. Seventeen different infectious etiologies were documented. A systematic literature review identified 67 additional patients with a diagnosis of TTP or HUS and also a systemic infection. Among all 98 patients, infections with 41 different bacteria, viruses, and fungi were documented, suggesting that many different systemic infections may mimic the presenting clinical features of TTP. Initial plasma exchange treatment is appropriate in critically ill patients with diagnostic features of TTP, even if a systemic infection is suspected. Continuing evaluation to document a systemic infection is essential to determine the appropriateness of continued plasma exchange.
PMCID: PMC3420338  PMID: 21850657
infection; thrombotic thrombocytopenic purpura; TTP; hemolytic uremic syndrome; HUS; ADAMTS13
10.  Atypical Hemolytic Uremic Syndrome: Differential Diagnosis from TTP/HUS and Management 
Turkish Journal of Hematology  2014;31(3):216-225.
Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy (TMA). It has an unfavorable outcome with death rates as high as 25% during the acute phase and up to 50% of cases progressing to end-stage renal failure. Uncontrolled complement activation through the alternative pathway is thought to be the main underlying pathopysiology of aHUS and corresponds to all the deleterious findings of the disease. Thrombotic thrombocytopenic purpura (TTP) and Shiga toxin-associated HUS are the 2 other important TMA diseases. Although differentiating HUS from TTP is relatively easy in children with a preceding diarrheal illness or invasive S. pneumoniae, differentiating aHUS from TTP or other microangiopathic disorders can present a major diagnostic challenge in adults. ADAMTS13 analysis is currently the most informative diagnostic test for differentiating TTP, congenital TTP, and aHUS. Today empiric plasma therapy still is recommended by expert opinion to be used as early as possible in any patient with symptoms of aHUS. The overall treatment goal remains restoration of a physiological balance between activation and control of the alternative complement pathway. So it is a reasonable approach to block the terminal complement complex with eculizumab in order to prevent further organ injury and increase the likelihood organ recovery. Persistence of hemolysis or lack of improvement of renal function after 3-5 daily plasmaphereses have to be regarded as the major criteria for uncontrolled TMA even if platelet count has normalized and as an indication to switch the treatment to eculizumab. Eculizumab has changed the future perspectives of patients with aHUS and both the FDA and the EMA have approved it as life-long treatment. However, there are still some unresolved issues about the follow-up such as the optimal duration of eculizumab treatment and whether it can be stopped or how to stop the therapy.
PMCID: PMC4287021  PMID: 25319590
Atypical hemolytic uremic syndrome (aHUS); Thrombotic thrombocytopenic purpura (TTP); eculizumab; TTP/HUS; Thrombotic microangiopathy (TMA); ADAMTS13
11.  Thrombotic microangiopathy and associated renal disorders* 
Nephrology Dialysis Transplantation  2012;27(7):2673-2685.
Thrombotic microangiopathy (TMA) is a pathological process involving thrombocytopenia, microangiopathic haemolytic anaemia and microvascular occlusion. TMA is common to haemolytic uraemic syndrome (HUS) associated with shiga toxin or invasive pneumococcal infection, atypical HUS (aHUS), thrombotic thrombocytopenic purpura (TTP) and other disorders including malignant hypertension. HUS complicating infection with shiga toxin-producing Escherichia coli (STEC) is a significant cause of acute renal failure in children worldwide, occurring sporadically or in epidemics. Studies in aHUS have revealed genetic and acquired factors leading to dysregulation of the alternative complement pathway. TTP has been linked to reduced activity of the ADAMTS13 cleaving protease (typically with an autoantibody to ADAMTS13) with consequent disruption of von Willebrand factor multimer processing. However, the convergence of pathogenic pathways and clinical overlap create diagnostic uncertainty, especially at initial presentation. Furthermore, recent developments are challenging established management protocols. This review addresses the current understanding of molecular mechanisms underlying TMA, relating these to clinical presentation with an emphasis on renal manifestations. A diagnostic and therapeutic approach is presented, based on international guidelines, disease registries and published trials. Early treatment remains largely empirical, consisting of plasma replacement/exchange with the exception of childhood STEC-HUS or pneumococcal sepsis. Emerging therapies such as the complement C5 inhibitor eculizumab for aHUS and rituximab for TTP are discussed, as is renal transplantation for those patients who become dialysis-dependent as a result of aHUS.
PMCID: PMC3398067  PMID: 22802583
HUS; TTP; complement; kidney; eculizumab
12.  The spectrum of renal thrombotic microangiopathy in lupus nephritis 
Among various lupus renal vascular changes, thrombotic microangiopathy (TMA) presented with the most severe clinical manifestations and high mortality. The pathogenesis of TMA in systemic lupus erythematosus (SLE) was complicated. The aim of this study was to assess clinical manifestations, laboratory characteristics, pathological features and risk factors for clinical outcomes of lupus nephritis patients co-existing with renal TMA in a large cohort in China.
Clinical and renal histopathological data of 148 patients with biopsy-proven lupus nephritis were retrospectively analyzed. Serum complement factor H, A Disintegrin and Metalloprotease with Thrombospondin type I repeats 13 (ADAMTS-13) activity, antiphospholipid antibodies and C4d deposition on renal vessels were further detected and analyzed.
In the 148 patients with lupus nephritis, 36 patients were diagnosed as co-existing with renal TMA based on pathological diagnosis. Among the 36 TMA patients, their clinical diagnoses of renal TMA were as followings: 2 patients combining with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome, 2 patients combining with anti-phospholipid syndrome, 2 patients with malignant hypertension, 1 patient with scleroderma and the other 29 patients presenting with isolated renal TMA. Compared with the non-renal TMA group, patients with renal TMA had significantly higher urine protein (7.09 ± 4.64 vs. 4.75 ± 3.13 g/24h, P = 0.007) and serum creatinine (159, 86 to 215 vs. 81, 68 to 112 μmol/l, P <0.001), higher scores of total activity indices (AI) (P <0.001), endocapillary hypercellularity (P <0.001), subendothelial hyaline deposits (P = 0.003), interstitial inflammation (P = 0.005), glomerular leukocyte infiltration (P = 0.006), total chronicity indices (CI) (P = 0.033), tubular atrophy (P = 0.004) and interstitial fibrosis (P = 0.018). Patients with renal TMA presented with poorer renal outcome (P = 0.005) compared with the non-TMA group. Renal TMA (hazard ratio (HR): 2.772, 95% confidence interval: 1.009 to 7.617, P = 0.048) was an independent risk factor for renal outcome in patients with lupus nephritis. The renal outcome was poorer for those with both C4d deposition and decreased serum complement factor H in the TMA group (P = 0.007).
There were various causes of renal TMA in lupus nephritis. Complement over-activation via both classical and alternative pathways might play an important role in the pathogenesis of renal TMA in lupus nephritis.
PMCID: PMC3672792  PMID: 23320601
13.  Clinical features and prognostic factors of thrombotic thrombocytopenic purpura associated with systemic lupus erythematosus: a literature review of 105 cases from 1999 to 2011 
Clinical Rheumatology  2013;33(3):419-427.
This study aims to review clinical features, treatments, and prognostic factors of thrombotic thrombocytopenic purpura (TTP) associated with systemic lupus erythematosus patients (sTTP). The case reports of sTTP published in world literature from 1999 to 2011 were collected, and 105 cases were divided into death group and survival group. The epidemiologic characteristics, clinical manifestations, laboratory examinations, treatments, and prognostic factors were analyzed. We found that coexistence of renal and neurological impairments were significantly frequent in the death group (100 %) than in the survival group (56.5 %) (P = 0.002). Type IV was predominant in 57.7 % of renal pathological damage, followed by type V (11.5 %), type II (5.8 %), and thrombotic microangiopathy (TMA) (5.8 %). TMA appeared more frequently (50 %) in the death group than in the survival group (6.25 %) (P = 0.042). End-stage renal disease occurred in nine cases with type IV in five (55.6 %), type TMA in one (11.1 %), and unspecified in three cases (33.3 %). Of 32 cases, 40.6 % showed severe ADAMTS13 deficiency and returned to normal or mildly deficient after remission. The total mortality rate of sTTP was 12.4 % and the mortality rate of patients with infection (27.3 %) was significantly higher than those without infection (8.4 %) (P = 0.028). Plasma exchange and glucocorticoids were administrated in over 80 % of cases with 65.7 % remission rate, while additional cytotoxics or rituximab was mostly used in refractory sTTP and achieved over 90 % of remission rate. Above all, coexistence of renal and neurological impairments, infection, and renal damage with type IV or TMA might denote a poor prognosis of sTTP.
PMCID: PMC3937538  PMID: 23954922
ADAMTS13; Infection; Prognostic factors; Systemic lupus erythematosus; Thrombotic thrombocytopenic purpura
14.  Thrombotic Thrombocytopenic Purpura and Gemcitabine 
Case Reports in Oncology  2011;4(1):143-148.
Thrombotic thrombocytopenic purpura (TTP) is a rare and life-threatening complication of gemcitabine treatment. Since the approval of this nucleoside analog for the treatment of pancreatic cancer by the FDA in 1996, reported incidence varies from 0.015 to 1.4%. The classic ‘pentad’ describing the disease process (fever, hemolytic anemia, thrombocytopenia, neurological complications and renal impairment) is not always present to the same extent in every patient. Here, we present a rare case of TTP associated specifically with gemcitabine treatment, and further, we briefly discuss the manifestations, treatment options and outcomes related to the complication. In our opinion, it is important to realize that as the indications for the use of gemcitabine increase and its use becomes more widespread, TTP and other disorders on the spectrum of thrombotic microangiopathies are important considerations to remember in patients with worsening anemia and thrombocytopenia. New onset or exacerbation of underlying hypertension may provide a clue to diagnose the disease entity earlier in this subgroup of patients.
PMCID: PMC3114619  PMID: 21691573
Thrombotic thrombocytopenic purpura; Gemcitabine Non-small cell lung cancer
15.  Differentiating malignant hypertension-induced thrombotic microangiopathy from thrombotic thrombocytopenic purpura 
Malignant hypertension can cause thrombotic microangiopathy (TMA) and the overall presentation may mimic thrombotic thrombocytopenic purpura (TTP). This presents a dilemma of whether or not to initiate plasma exchange. The objective of the study was to determine the clinical and laboratory manifestations of malignant hypertension-induced TMA, and its outcomes.
Using several search terms, we reviewed English language articles on malignant hypertension-induced TMA, indexed in MEDLINE by 31 December 2013. We also report a new case. All these cases were analyzed using descriptive statistics.
A total of 19 patients, with 10 males, had a median age of 38 years at diagnosis; 58% had a history of hypertension. Mean arterial pressure at presentation was 159 mmHg (range 123–190 mmHg). All had prominent renal dysfunction (mean creatinine of 5.2 mg/dl, range 1.7–13 mg/dl) but relatively modest thrombocytopenia (mean platelet count of 60 × 103/µl, range 12–131 × 103/µl). Reported cases (n = 9) mostly had preserved ADAMTS-13 activity (mean 64%, range 18–96%). Following blood pressure control, the majority had improvement in presenting symptoms (100%) and platelet counts (84%); however, only 58% had significant improvement in creatinine. More than half (53%) needed hemodialysis. One patient died of cardiac arrest during pacemaker insertion.
Prior history of hypertension, high mean arterial pressure, significant renal impairment but relatively modest thrombocytopenia and lack of severe ADAMTS-13 deficiency (activity <10%) at diagnosis are clues to diagnose malignant hypertension-induced TMA. Patients with malignant hypertension respond well to antihypertensive agents and have favorable nonrenal outcomes.
PMCID: PMC4480518  PMID: 26137201
ADAMTS-13 deficiency; malignant hypertension; plasma exchange; renal failure; thrombocytopenia; thrombotic microangiopathy; thrombotic thrombocytopenic purpura
16.  Re-Examination of 30-Day Survival and Relapse Rates in Patients with Thrombotic Thrombocytopenic Purpura-Hemolytic Uremic Syndrome 
PLoS ONE  2015;10(5):e0127744.
Background and Objectives
Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are characterized by microangiopathic hemolytic anemia and thrombocytopenia. Interestingly, markedly different survival rates have been reported despite increases in survivability. We studied TTP-HUS 30-day mortality and relapse rates of patients who received TPE at our institution and compared them to published data.
Patients and Methods
Retrospective study analyzed 30-day mortality and relapse rates attributed to TTP-HUS from 01/01/2008 to 12/31/2012 and compared them to comparable literature reporting mortality and survival. Studies describing other etiologies for TPE and different mortality time interval were excluded.
Fifty-nine patients were analyzed and all were initially treated with TPE and corticosteroids. Eleven patients were classified as not having TTP-HUS due to testing or clinical reassessment which ruled in other etiologies, and 18/59 patients had ADAMTS13 activity <10%. Of remaining patients, 36/48 (75%) were diagnosed as idiopathic and 12/48 (25%) as secondary TTP-HUS. Patients received a mean of 12 TPEs (range 1-42); 42/48 (87.5%) patients had ADAMTS13 activity measured; complete response obtained in 39/48 (81.2%) patients (platelet count >100 x 109/L); partial response in 4/48 (8%); and 5/48 (10.4%) did not have increases in platelet counts (2/5 of these patients died within the study period). Forty percent of patients obtained platelet counts >150 x 109/L. Overall 30-day mortality for our patient cohort was 6.7% (4/59). Comparison of our mortality rate to combined data of five published studies of 16% (92/571) showed a significant difference, p = 0.04. Our relapse rate was 18.6% (11/59) similar to previous reports.
Wide differences in mortality may be due to grouping of two distinct pathologic entities under TTP-HUS; and presence of confounding factors in the patient populations under study such as co-morbidities, promptness of TPE initiation, delay in diagnosis and therapeutic practice.
PMCID: PMC4441419  PMID: 26000799
17.  Thrombotic Thrombocytopenic Purpura: Three Peripartum Cases and Diagnostic Challenges 
Thrombotic thrombocytopenic purpura (TTP) is a medical emergency characterized by occlusive microangiopathy due to intravascular platelet aggregation. This event results in damage to the red blood cells (RBCs) known as microangiopathic hemolytic anemia (MAHA). Schistocytes are circulating fragments of damaged RBCs that have different morphological features including keratocytes, helmet cells, and spherocytes. It is critical to report even a small number of these abnormal RBCs in the peripheral blood and to be alert for the possible diagnosis of TTP, especially in unexplained anemia and thrombocytopenia. The application of pentad criteria in the diagnosis has been reviewed, and the challenges still remained on the hematologic evidence of this disorder. In the 3 cases discussed here, the red cell morphological diagnosis gave an impact on TTP diagnosis, but overdiagnosis might be encountered in obstetrical patients due to nonspecific diagnostic criteria.
PMCID: PMC3782395  PMID: 24093001
thrombotic thrombocytopenic purpura; schistocytes; spherocytes; LDH
18.  Acquired Idiopathic ADAMTS13 Activity Deficient Thrombotic Thrombocytopenic Purpura in a Population from Japan 
PLoS ONE  2012;7(3):e33029.
Thrombotic thrombocytopenic purpura (TTP) is a type of thrombotic microangiopathy (TMA). Studies report that the majority of TTP patients present with a deficiency of ADAMTS13 activity. In a database of TMA patients in Japan identified between 1998 and 2008, 186 patients with first onset of acquired idiopathic (ai) ADAMTS13-deficient TTP (ADAMTS13 activity <5%) were diagnosed. The median age of onset of TTP in this group of patients was 54 years, 54.8% were female, 75.8% had renal involvement, 79.0% had neurologic symptoms, and 97.8% had detectable inhibitors to ADAMTS13 activity. Younger patients were less likely to present with renal or neurologic dysfunction (p<0.01), while older patients were more likely to die during the TTP hospitalization (p<0.05). Findings from this cohort in Japan differ from those reported previously from the United States, Europe, and Korea with respect to age at onset (two decades younger in the other cohort) and gender composition (60% to 100% female in the other cohort). We conclude that in one of the largest cohorts of ai-TTP with severe deficiency of ADAMTS13 activity reported to date, demographic characteristics differ in Japanese patients relative to those reported from a large Caucasian registry from Western societies. Additional studies exploring these findings are needed.
PMCID: PMC3299727  PMID: 22427934
19.  Cumulative Review of Thrombotic Microangiopathy, Thrombotic Thrombocytopenic Purpura, and Hemolytic Uremic Syndrome Reports with Subcutaneous Interferon β-1a 
Advances in Therapy  2015;32(5):445-454.
Rare cases of thrombotic microangiopathy (TMA), manifested as thrombotic thrombocytopenic purpura (TTP) or hemolytic uremic syndrome (HUS), have been reported with interferon β products. We performed a cumulative review of TMA cases recorded in a Global Safety Database for patients with multiple sclerosis who received subcutaneous interferon β-1a treatment.
Search criteria were: all reported cases, serious and non-serious, from all sources (including non-health care professionals and clinical trial reports), regardless of event ranking and causality assessment by reporter or company. Data lock was May 3, 2014, with additional analysis of cases reported between August 1, 2014–November 30, 2014.
Ninety-one patient cases (76.9% female) with 105 events were retrieved. Time to onset varied from 2 months to 14 years, and in 31.9% of patients the event occurred within 2 years of treatment initiation. Seven patients had a fatal outcome (five were secondary to other causes and two reported insufficient information). Forty-four patients recovered, 32 patients had not recovered at the time of the report, and in eight cases outcome was either not reported or unknown. Treatment was discontinued in 84.6% (77/91) of patients. In 67% (61/91) of patients, the reporter suspected a causal association between treatment and TMA/TTP-HUS. Risk factors and/or confounding factors were present in 45.1% (41/91) of patients. Early prodromal syndrome or specific patterns were not detected, although 54.9% (50/91) of cases contained insufficient information. Overall reporting rate of TMA/TTP-HUS was estimated as 7.2 per 100,000 patient-years. Reporting rates for human serum album (HSA)-containing and HSA-free formulations were 5.72 and 7.68 per 100,000 patient-years, respectively.
No new signal relating specifically to increased frequency of TMA/TTP-HUS with HSA-free subcutaneous interferon β-1a was detected and no additional risk mitigation measures are required regarding the different formulations. The benefit–risk balance of subcutaneous interferon β-1a remains positive, and routine pharmacovigilance monitoring is appropriate.
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PMCID: PMC4449386  PMID: 25991578
Hemolytic uremic syndrome; Interferon β-1a; Thrombotic microangiopathy; Thrombotic thrombocytopenic purpura
20.  Relevance of ADAMTS13 to liver transplantation and surgery 
World Journal of Hepatology  2015;7(13):1772-1781.
A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS13) specifically cleaves unusually-large von Willebrand factor (VWF) multimers under high shear stress, and down-regulates VWF function to form platelet thrombi. Deficiency of plasma ADAMTS13 activity induces a life-threatening systemic disease, termed thrombotic microangiopathy (TMA) including thrombotic thrombocytopenic purpura (TTP). Children with advanced biliary cirrhosis due to congenital biliary atresia sometimes showed pathological features of TMA, with a concomitant decrease of plasma ADAMTS13 activity. Disappearance of their clinical findings of TTP after successful liver transplantation suggested that the liver is a major organ producing plasma ADAMTS13. In situ hybridization analysis showed that ADAMTS13 was produced by hepatic stellate cells. Subsequently, it was found that ADADTS13 was not merely responsible to development of TMA and TTP, but also related to some kinds of liver dysfunction after liver transplantation. Ischemia-reperfusion injury and acute rejection in liver transplant recipients were often associated with marked decrease of ADAMTS13 and concomitant formation of unusually large VWF multimers without findings of TMA/TTP. The similar phenomenon was observed also in patients who underwent hepatectomy for liver tumors. Imbalance between ADAMTS13 and VWF in the hepatic sinusoid might cause liver damage due to microcirculatory disturbance. It can be called as “local TTP like mechanism” which plays a crucial role in liver dysfunction after liver transplantation and surgery.
PMCID: PMC4491906  PMID: 26167250
A disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13; Thrombocytopenia; Microcirculation; Liver dysfunction; von Willebrand factor; Liver transplantation; Acute rejection; Ischemia-reperfusion injury; Hepatectomy; Liver surgery; Local thrombotic thrombocytopenic purpura like mechanism
21.  Thrombotic Thrombocytopenic Purpura Associated with Mixed Connective Tissue Disease: A Case Report 
Case Reports in Medicine  2011;2011:953890.
Thrombotic thrombocytopenic purpura (TTP) is a multisystemic disorder characterized by microangiopathic hemolytic anemia and thrombocytopenia, which may be accompanied by fever, renal, or neurologic abnormalities. Cases are divided into acute idiopathic TTP and secondary TTP. Autoimmune diseases, especially systemic lupus erythematosus, in association with TTP have been described so far in many patients. In contrast, TTP occurring in a patient with mixed connected tissue disease (MCTD) is extremely rare and has only been described in nine patients. We describe the case of a 42-year-old female with MCTD who developed thrombocytopenia, microangiopathic hemolytic anemia, fever, and neurological symptoms. The patient had a good clinical evolution with infusion of high volume of fresh frozen plasma, steroid therapy, and support in an intensive care unit. Although the occurrence of TTP is rare in MCTD patients, it is important to recognize TTP as a cause of thrombocytopenia and hemolytic anemia in any patient with autoimmune diseases. Prompt institution of treatment remains the cornerstone of treatment of TTP even if plasma exchange is not available like what frequently happens in developing countries.
PMCID: PMC3170900  PMID: 21915182
22.  Pseudo-thrombotic thrombocytopenic purpura: A rare presentation of pernicious anemia 
Schistocytes are fragmented red blood cells due to the flow of blood through damaged capillaries and indicate endothelial injury. They are typical of microangiopathic hemolytic anemia seen in life threatening conditions like disseminated intravascular coagulation or thrombotic thrombocytopenic purpura/hemolytic uremic syndrome .We report a rare sub-acute presentation of pernicious anemia with hemolysis, thrombocytopenia and numerous schistocytes that was initially diagnosed as a more serious thrombotic thrombocytopenic purpura.
Case Report:
A 31-year-old Caucasian woman presented with fatigue and paresthesia of both feet for 1 week. Past medical history included hypertension and gastro-esophageal reflux disease. Examination revealed scleral icterus and pallor. Examination of the abdomen did not show hepatosplenomegaly. Initial laboratory tests showed severe anemia, and low platelets. Indirect bilirubin and serum Lactate De Hydrogenase were elevated. Prothrombin time, partial thromboplastin time, serum fibrinogen, and serum fibrin degradation product levels were normal. Peripheral smear revealed numerous schistocytes, anisocytosis and macro-ovalocytes. Thrombotic thrombocytopenic purpura (TTP) was suspected due to the constellation of sub-acute onset of fatigue and paresthesia along with thrombocytopenia, schistocytes and an elevated LDH. Plasmapheresis was initiated for possible TTP. However, platelet count worsened despite plasmapheresis for 4 days. On re-evaluation, vitamin B12 was found to be low. Treatment with intra-muscular vitamin B12 led to symptomatic and hematologic improvement. Pernicious anemia was confirmed by the presence of anti-intrinsic factor antibodies, elevated serum gastrin level and atrophic gastritis.
Clinicians must be aware of unusual clinical presentation of vitamin B12 deficiency with schistocytes as the management is simple and effective.
PMCID: PMC3271428  PMID: 22363087
Anemia; pernicious anemia; schistocytes
23.  Elevated Procalcitonin and C-Reactive Protein as Potential Biomarkers of Sepsis in a Subpopulation of Thrombotic Microangiopathy Patients 
Journal of clinical apheresis  2009;24(4):150-154.
Thrombotic microangiopathy (TMA) comprises a group of microvascular thrombosis syndromes associated with multiple pathogenic factors. Deficient activity of ADAMTS13 is a pathogenic factor in a subset of TMA patients that provides strong rationale for plasma exchange treatment. However, the subset of TMA patients with normal ADAMTS13 activity remains a heterogeneous group of patients in which the appropriate treatment is not well understood. In addition to the common forms of TMA thrombotic thrombocytopenic purpura and the hemolytic uremic syndrome, the differential diagnosis of TMA may include sepsis, autoimmune disorders, and disseminated intravascular coagulation. Optimal treatment of TMA depends on timely recognition of treatable pathogenic factors. We hypothesized that sepsis is a rapidly identifiable pathogenic factor in a subset of TMA patients. To test this hypothesis, we retrospectively measured the rapid biomarkers of sepsis C-reactive protein (CRP) and procalcitonin (PCT), in a repository of pre-treatment plasma samples from 61 TMA patients treated with plasma exchange. Levels were analyzed in 31 severely ADAMTS13-deficient and 30 ADAMTS13-normal patients. None of the 31 patients with severe deficiency of ADAMTS13 had elevated PCT. However, 11 of 30 (37%) non-ADAMTS13-deficient patient samples were strongly positive for PCT. These patient samples also had a >10-fold higher median CRP level than patients with normal PCT. We conclude that rapid assays may help identify sepsis in a subset of TMA patients.
PMCID: PMC2750870  PMID: 19591197
Thrombotic microangiopathy (TMA); sepsis; C-reactive protein (CRP); procalcitonin (PCT); ADAMTS13
American journal of hematology  2010;85(11):844-847.
Thrombotic thrombocytopenic purpura (TTP) and hemolytic-uremic syndrome (HUS) represent multiple disorders with diverse etiologies. We compared the gender and race of 335 patients enrolled in the Oklahoma TTP-HUS Registry across 21 years for their first episode of TTP or HUS to appropriate control groups. The relative frequency of women and white race among patients with TTP-HUS associated with a bloody diarrhea prodrome and the relative frequency of women with quinine-associated TTP-HUS were significantly greater than their control populations. The relative frequency of women and black race among patients with idiopathic TTP and TTP associated with severe ADAMTS13 deficiency was significantly greater than their control populations. The relative frequency of black race among patients who had systemic lupus erythematosus (SLE) preceding TTP was significantly greater than among a population of patients with SLE, and the relative frequency of black race among patients with other autoimmune disorders preceding TTP was significantly greater than their control population. No significant gender or race disparities were present among patients with hematopoietic stem cell transplantation-associated thrombotic microangiopathy, TTP associated with pregnancy, or TTP associated with drugs other than quinine. The validity of these observations is supported by the enrollment of all consecutive patients across 21 years from a defined geographic region, without selection or referral bias. These observations of different gender and race disparities among the TTP-HUS syndromes suggest the presence of different risk factors and may serve as starting points for novel investigations of pathogenesis.
PMCID: PMC3420337  PMID: 20799358
Thrombotic thrombocytopenic purpura; hemolytic uremic syndrome; ADAMTS13; quinine; race disparities; gender disparities
25.  Hemorrhagic Stroke in an Adolescent Female with HIV-Associated Thrombotic Thrombocytopenic Purpura 
HIV-1 infection can trigger acute episodes of Idiopathic Thrombocytoponic Purpura (ITP), and Thrombotic Thrombocytopenic Purpura (TTP), particularly in populations with advanced disease and poor adherence to antiretroviral therapy (ART). These diseases should be distinguished because they respond to different treatments. Previous studies done in adults with HIV-TTP have recommended the prompt initiation or re-initiation of ART in parallel with plasma exchange therapy to improve the clinical outcome of these patients. Here, we describe a case of HIV-TTP resulting in an acute hemorrhagic stroke in a 16 year old female with perinatally acquired HIV infection and non-adherence to ART, who presented with severe thrombocytopenia, microangiopathic hemolytic anemia, and a past medical history of HIV-ITP. Both differential diagnosis and treatments for HIV-ITP and HIV-TTP were considered simultaneously. A decrease in plasma ADAMTS13 activity (<5%) without detectable inhibitory antibodies confirmed the diagnosis of HIV-TTP. Re-initiation of ART and plasma exchange resulted in a marked decrease in the HIV-RNA viral load, recovery of the platelet count, and complete recovery was achieved with sustained virologic suppression.
PMCID: PMC4241775  PMID: 25429351
HIV-TTP; Hemorrhagic stroke; HIV-ITP; HIV-HUS; Microangiopathic hemolytic anemia; Immune thrombocytopenic purpura; Antiretroviral therapy; Plasma exchange

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