Platelet count and prothrombin time help distinguish thrombotic thrombocytopenic purpura-hemolytic uremic syndrome from disseminated intravascular coagulation in adults

ADAMTS13 testing update: Focus on laboratory aspects of difficult thrombotic thrombocytopenic purpura diagnoses and effects of new therapies

TTP is a life-threatening disorder diagnosed using a combination of clinical information and laboratory results. ADAMTS13 activity and antibody testing represent a major advance in the field, but results can sometimes be difficult to interpret due to technical aspects of the tests and characteristics of the causative antibodies in acquired TTP. Genetic testing for ADAMTS13 mutations is also now available to assist with the diagnosis of inherited TTP. This review will focus on ADAMTS13 testing and will highlight patient and laboratory aspects that can lead to diagnostic difficulty. The effects of TTP therapies on test results will also be discussed.

Platelet enhancement by Carica papaya L. leaf fractions in cyclophosphamide induced thrombocytopenic rats is due to elevated expression of CD110 receptor on megakaryocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Carica papaya leaf juice/decoction has been in use in folk medicine in Srilanka, Malaysia and in few parts of India for enhancing the platelet counts in dengue. In Siddha medicine, a traditional form of medicine in India, papaya leaf juice has been used for increasing the platelet counts. Papaya leaf has been reported to enhance blood volume in ancient Ayurveda books in India. Carica papaya leaf is well known for its platelet enhancement activity. Although many preclinical and clinical studies have demonstrated the ability of papaya leaf juice for platelet enhancement, but the underlying mechanisms are still unclear.

AIM OF THE STUDY

The study is aimed at identifying the key ingredients of papaya leaf extract and elucidate the mechanism (s) of action of the identified potent component in mitigating thrombocytopenia (Thp).

MATERIALS AND METHODS

C. papaya leaf juice was subjected for sequential fractionation to identify the anti-thrombocytopenic phytochemicals. In vivo, stable thrombocytopenia was induced by subcutaneous injection of 70 mg/kg cyclophosphamide (Cyp). After induction, rats were treated with 200 and 400 mg/kg body weight papaya leaf juice and with identified fractions for 14 days. Serum thrombopoietin level was estimated using ELISA. CD110/cMpl, a receptor for thrombopoietin on platelets was measured by western blotting.

RESULTS

Administration of cyclophosphamide for 6 days induced thrombocytopenia (210.4 ± 14.2 × 103 cells/μL) in rats. Treating thrombocytopenic rats with papaya leaf juice and butanol fraction for 14 days significantly increased the platelet count to 1073.50 ± 29.6 and 1189.80 ± 36.5 × 103 cells/μL, respectively. C.papaya extracts normalized the elevated bleeding and clotting time and decreased oxidative markers by increasing endogenous antioxidants. A marginal increase in the serum thrombopoietin (TPO) level was observed in Cyp treated group compared to normal and treatment groups. Low expression of CD110/cMpl receptor found in Cyp treated group was enhanced by C. papaya extracts (CPJ) and CPJ-BT. Furthermore, examination of the morphology of bone marrow megakaryocytes, histopathology of liver and kidneys revealed the ability of CPJ and fractions in mitigating Cyp-induced thrombocytopenia in rats.

CONCLUSION

C. papaya leaf juice enhances the platelet count in chemotherapy-induced thrombocytopenia by increasing the expression of CD110 receptor on the megakaryocytes. Hence, activating CD110 receptor might be a viable strategy to increase the platelet production in individuals suffering from thrombocytopenia.

Disseminated intravascular coagulation: new identity as endotheliopathy-associated vascular microthrombotic disease based on in vivo hemostasis and endothelial molecular pathogenesis

Disseminated intravascular coagulation (DIC) can be correctly redefined as disseminated intravascular microthrombosis based on "two-path unifying theory" of in vivo hemostasis. "DIC" is a form of vascular microthrombotic disease characterized by "microthrombi" composed of platelets and unusually large von Willebrand factor multimers (ULVWF). Microthrombotic disease includes not only "DIC", but also microthrombosis occurring in thrombotic thrombocytopenic purpura (TTP), TTP-like syndrome, and focal, multifocal and localized microthrombosis. Being a hemostatic disease, microthrombotic disease occurs as a result of lone activation of ULVWF path via partial in vivo hemostasis. In endothelial injury associated with critical illnesses such as sepsis, the vascular damage is limited to the endothelial cell and activates ULVWF path. In contrast, in intravascular traumatic injury, the local damage may extend from the endothelial cell to subendothelial tissue and sometimes beyond, and activates both ULVWF and tissue factor (TF) paths. When endotheliopathy triggers exocytosis of ULVWF and recruits platelets, ULVWF path is activated and promotes microthrombogenesis to produce microthrombi composed of microthrombi strings, but when localized vascular damage causes endothelial and subendothelial tissue damage, both ULVWF and TF paths are activated and promote macrothrombogenesis to produce macrothrombus made of complete "blood clots". Currently, "DIC" concept is ascribed to activated TF path leading to fibrin clots. Instead, it should be correctly redefined as microthrombosis caused by activation of ULVWF path, leading to endotheliopathy-associated microthrombosis. The correct term for acute "DIC" is disseminated microthrombosis-associated hepatic coagulopathy, and that for chronic "DIC" is disseminated microthrombosis without hepatic coagulopathy. TTP-like syndrome is hematologic phenotype of endotheliopathy-associated microthrombosis. This correct concept of "DIC" is identified from novel theory of "in vivo hemostasis", which now can solve every mystery associated with "DIC" and other associated thrombotic disorders. Thus, sepsis-associated coagulopathy is not "DIC", but is endotheliopathy-associated vascular microthrombotic disease.

Quetiapine-induced thrombotic microangiopathy in a patient on maintenance dialysis

Quetiapine has been reported to cause immune-mediated thrombotic microangiopathy (TMA), although few cases have been reported thus far. A 71-year-old man with autosomal dominant polycystic kidney disease on maintenance dialysis was hospitalized with a hemorrhagic basal ganglia stroke, and was treated with 25 mg quetiapine for delirium from day 4 of admission. There was no worsening of consciousness, fever, diarrhea, or elevated blood pressure during the hospitalization. Gingival bleeding appeared on day 35, and the platelet count on day 38 was 0.5 × 10⁴/μL (13.2 × 10⁴/μL on day 16). The presence of 1% schistocytes, high LDH level, inability to measure haptoglobin, negative direct Coombs test, and normal prothrombin time and activated partial thromboplastin time indicated TMA. We considered an exclusionary diagnosis of drug-induced TMA, because of normal ADAMTS13 activity, no evidence of complement activation and the absence of Shiga toxin or symptoms of collagen disease or cancer. Quetiapine was the most likely causative factor; however, all drugs, including heparin, were discontinued or changed. Due to persistent microbleeding, platelet transfusions were performed several times. After only quetiapine was discontinued, the platelet count recovered smoothly to 3.1 and 7.2 × 10⁴/μL on days 45 and 72, respectively; LDH and fibrinogen levels normalized on day 47. All medications, except quetiapine, were restarted sequentially after day 47, without subsequent thrombocytopenia. Platelet activation predominantly by a drug-dependent antibody might be the etiology of quetiapine-induced TMA. Plasmapheresis may not be necessary for quetiapine, because of its unproven efficacy in drug-induced TMA.

Acute Respiratory Distress Syndrome as an Organ Phenotype of Vascular Microthrombotic Disease: Based on Hemostatic Theory and Endothelial Molecular Pathogenesis

Acute respiratory distress syndrome (ARDS) is a life-threatening noncardiogenic circulatory disorder of the lungs associated with critical illnesses such as sepsis, trauma, and immune and collagen vascular disease. Its mortality rate is marginally improved with the best supportive care. The demise occurs due to progressive pulmonary hypoxia and multi-organ dysfunction syndrome (MODS) with severe inflammation. Complement activation is a part of immune response against pathogen or insult in which membrane attack complex (MAC) is formed and eliminates microbes. If complement regulatory protein such as endothelial CD59 is underexpressed, MAC may also cause pulmonary vascular injury to the innocent bystander endothelial cell of host and provokes endotheliopathy that causes inflammation and pulmonary vascular microthrombosis, leading to ARDS. Its pathogenesis is based on a novel "two-path unifying theory" of hemostasis and "two-activation theory of the endothelium" promoting molecular pathogenesis. Endotheliopathy activates two independent molecular pathways: inflammatory and microthrombotic. The former triggers the release inflammatory cytokines and the latter promotes exocytosis of unusually large von Willebrand factor multimers (ULVWF) and platelet activation. Inflammatory pathway initiates inflammation, but microthrombotic pathway more seriously produces "microthrombi strings" composed of platelet-ULVWF complexes, which become anchored on the injured endothelial cells, and causes disseminated intravascular microthrombosis (DIT). DIT is a hemostatic disease due to lone activation of ULVWF path without activated tissue factor path. It leads to endotheliopathy-associated vascular microthrombotic disease (EA-VMTD), which orchestrates consumptive thrombocytopenia, microangiopathic hemolytic anemia, and MODS. Thrombotic thrombocytopenic purpura (TTP)-like syndrome is the hematologic phenotype of EA-VMTD. ARDS is one of organ phenotypes among MODS associated with TTP-like syndrome. The most effective treatment of ARDS can be achieved by counteracting the activated microthrombotic pathway based on two novel hemostatic theories.

Gastrointestinal infection-related disseminated intravascular coagulation mimicking Shiga toxin-mediated hemolytic uremic syndrome - implications of classical clinical indexes in making the diagnosis: A case report and literature review

BACKGROUND

Thrombocytopenia associated with acute kidney injury is a challenging disorder. Thrombotic microangiopathy (TMA) is a potentially life- or organ-threatening syndrome that can be induced by several disorders or medical interventions. There is overlap between the clinical presentation and pathophysiology of thrombotic thrombocytopenia purpura and hemolytic uremic syndrome (HUS), and to a lesser extent, disseminated intravascular coagulation (DIC). We describe a case to illustrate the potential diagnostic difficulty, especially at initial presentation.

CASE SUMMARY

We reported a case of a 44-year-old woman that presented with diarrhea, thrombocytopenia, schistocytes, elevated serum lactate dehydrogenase (LDH) level and acute kidney injury. While the clinical presentation resembled that of Shiga toxin–induced HUS, the disease course was more consistent with gastrointestinal infection-related DIC. To aid in the accurate diagnosis of TMA and other associated disorders, we have undertaken a review and provided a clear interpretation of some typical biomarkers including schistocytes, LDH and platelet count, coagulation profile and more specific indexes of ADAMTS13, complement profile, and the isolation of Shiga toxin-producing Escherichia coli (commonly referred to as STEC).

CONCLUSION

The use and correct interpretation of classical indexes of schistocyte, LDH, and platelet count is vital in diagnosing TMA and associated disorders. Understanding the characteristics of these biomarkers in the context of thrombocytopenia purpura, HUS and DIC will facilitate the accurate diagnosis and early initiation of appropriate treatment.

Hemolytic Uremic Syndrome: An Increasingly Recognized Public Health Problem

A 28-year-old man was referred and admitted to our hospital due to Escherichia coli O157-mediated hemorrhagic colitis with severe thrombocytopenia. A systemic workup concluded that the patient had acute pancreatitis as well as hemolytic uremic syndrome. The patient was ultimately discharged, with his platelet count having recovered. Our case serves an illustrative example of potentially serious complications of an increasingly recognized public health problem. Systemic studies on this topic are insufficient, and we strongly recommend the further accumulation of more experiences like ours. Several diagnostic and management concerns that emerged in this case are also discussed.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Syndromes of Thrombotic Microangiopathy

Thrombotic thrombocytopenia purpura (TTP) and the hemolytic uremic syndrome (HUS) are rare thrombotic microangiopathies that can be rapidly fatal. Although the acquired versions of TTP and HUS are generally highest on this broad differential, multiple rarer entities can produce a clinical picture similar to TTP/HUS, including microangiopathic hemolysis, renal failure, and neurologic compromise. More recent analysis has discovered a host of genetic factors that can produce microangiopathic hemolytic syndromes. This article discusses the current understanding of thrombotic microangiopathy and outlines the pathophysiology and causative agents associated with each distinct syndrome as well as the most accepted treatments.

[Clinical course and differential diagnosis of thrombotic microangiopathy]

BACKGROUND

Thrombotic microangiopathies are complex diseases, requiring early differential diagnosis and targeted intervention.

OBJECTIVES

Presentation of clinical phenotype and diagnostic algorithm, discussion of underlying pathophysiology, clinical management and therapy.

METHODS

Summary of current knowledge from literature and expert opinion.

RESULTS

Our understanding of pathophysiology and therapeutic options have changed substantially in recent years. Early differential diagnosis and targeted therapy are of prognostic relevance.

CONCLUSIONS

A better understanding of underlying pathophysiology, increased clinical awareness and novel therapeutic options allow for a better prognosis of patients with thrombotic microangiopathy.

Pathology Consultation on the Diagnosis and Treatment of Thrombotic Microangiopathies (TMAs)

OBJECTIVES

Pathologists specializing in transfusion medicine, apheresis medicine, and/or coagulation are often consulted by clinicians to reach a diagnosis for patients with thrombotic microangiopathy (TMA), so that disease-specific, often life-saving therapy can be initiated as promptly as possible.

METHODS

This article describes how to proceed when treating a patient with TMA. The differential diagnosis is broad and potentially very challenging. Thrombotic thrombocytopenic purpura (TTP), atypical hemolytic uremic syndrome (aHUS), and typical hemolytic uremic syndrome (HUS) are three such TMAs that require timely diagnosis and treatment.

RESULTS

TTP is treated with daily therapeutic plasma exchange (TPE) and commonly with adjunctive immunosuppressive therapy, while aHUS may initially be managed with TPE but is best controlled with eculizumab once a presumptive diagnosis is made. TPE has no proven role in typical HUS, which is most commonly treated with supportive measures only.

CONCLUSIONS

Prompt and accurate diagnosis of TMA subtypes optimizes treatment and improves patient outcomes.

A non-invasive laboratory panel as a diagnostic and prognostic biomarker for thrombotic microangiopathy: development and application in a Chinese cohort study

Background

Thrombotic microangiopathy (TMA) in the kidney is a histopathologic lesion that occurs in a number of clinical settings and is often associated with poor renal prognosis. The standard test for the diagnosis of TMA is the renal biopsy; noninvasive parameters such as potential biomarkers have not been developed.

Methods

We analyzed routine parameters in a cohort of 220 patients with suspected TMA and developed a diagnostic laboratory panel by logistic regression. The levels of candidate markers were validated using an independent cohort (n = 46), a cohort of systemic lupus erythematosus (SLE) (n = 157) and an expanded cohort (n = 113), as well as 9 patients with repeat biopsies.

Results

Of the 220 patients in the derivation cohort, 51 patients with biopsy-proven TMA presented with a worse renal prognosis than those with no TMA (P = 0.002). Platelet and L-lactate dehydrogenase (LDH) levels showed an acceptable diagnostic value of TMA (AUC = 0.739 and 0.756, respectively). A panel of 4 variables - creatinine, platelets, ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 repeats 13) activity and LDH - can effectively discriminate patients with TMA (AUC = 0.800). In the validation cohort, the platelet and LDH levels and the 4-variable panel signature robustly distinguished patients with TMA. The discrimination effects of these three markers were confirmed in patients with SLE. Moreover, LDH levels and the 4-variable panel signature also showed discrimination values in an expanded set. Among patients undergoing repeat biopsy, increased LDH levels and panel signatures were associated with TMA status when paired evaluations were performed. Importantly, only the 4-variable panel was an independent prognostic marker for renal outcome (hazard ratio = 3.549; P<0.001).

Conclusions

The noninvasive laboratory diagnostic panel is better for the early detection and prognosis of TMA compared with a single parameter, and may provide a promising biomarker for clinical application.

Renal thrombotic microangiopathy in a patient with septic disseminated intravascular coagulation

Background

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.

Conclusion

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.

Diagnosis of Streptococcus pneumoniae-associated hemolytic uremic syndrome

BACKGROUND

Hemolytic uremic syndrome related to pneumococcal infection (P+HUS) can be difficult to diagnose due to the lack of a specific test and the absence of a consensus for definite diagnostic criteria.

METHODS

A retrospective study was conducted on the cases that have been considered as P+HUS in the participating centers during the past 10 years. Diagnostic strategy and criteria used for the diagnosis of P+HUS were evaluated and compared with a review of literature data.

RESULTS

A total of 17 children were studied. Tests ruling out other causes of HUS were performed in 94% of cases. Direct confirmatory tests for P+HUS were done in a minority of cases as Thomsen-Friedenreich antigen testing using lectin assay were done in only 2 patients (11%). Retrospectively, the diagnosis of P+HUS was confirmed in 28% to 89% of cases depending on the already published criteria used. A literature review focused on the last 15 years confirmed these diagnostic difficulties due to variable definition criteria and bring a new light on the potential usefulness of tests used to reveal T activation in this setting.

CONCLUSION

To date, in a context of suspicion of P+HUS, no precise, practical and consensual strategy exists for T-antigen exposure diagnosis. The T-antigen activation test using peanut lectin might be the most appropriate test for a direct diagnosis of P+HUS. A large prospective study is required to confirm this hypothesis. However, before such data are available, its use could be of help when a suspicion of P+HUS is present given the therapeutic impact of such a diagnosis.

Acute renal failure as the presenting sign of disseminated intravascular coagulation in a patient with metastatic prostate cancer

Disseminated intravascular coagulation (DIC) is the most frequent coagulation disorder in patients with prostate cancer. However, renal involvement in DIC associated with prostate cancer has rarely been documented. Herein, we present a case of metastatic prostate cancer presenting with acute renal failure (RF) triggered by DIC. An 80 year old man with metastatic prostate cancer was treated with antihormone therapy at an outpatient clinic. He was admitted to our hospital because of severe dyspnea and progressive RF. A hemorrhagic tendency was not clinically evident. Laboratory tests exhibited a significant coagulation disorder, suggestive of DIC. Despite treatment, his RF and dyspnea worsened, and he eventually passed away. An autopsy study revealed hypertensive nephrosclerosis superimposed by fibrin rich thrombi formation involving glomerular capillaries and arterioles characteristic of DIC. Additionally, focal segmental glomerulosclerosis was identified, which was presumably secondary to the glomerular endothelial and/or podocyte injury augmented by DIC. Those findings showed that glomerular injury, which was induced and subsequently exacerbated by DIC associated with prostate cancer, highly contributed to the progression of RF in our case. A differential diagnosis of DIC should be considered when a patient with prostate cancer presents with renal dysfunction.

Thrombotic microangiopathy and associated renal disorders

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.

The loss of homeostasis in hemostasis: new approaches in treating and understanding acute disseminated intravascular coagulation in critically ill patients

Disseminated intravascular coagulation (DIC) profoundly increases the morbidity and mortality of patients who have sepsis. Both laboratory and clinical research advanced the understanding of the biology and pathophysiology of DIC. This, in turn, gave rise to improved therapies and patient outcomes. Beginning with a stimulus causing disruption of vascular integrity, cytokines and chemokines cause activation of systemic coagulation and inflammation. Seemingly paradoxically, the interplay between coagulation and inflammation also inhibits endogenous anticoagulants, fibrinolytics, and antiinflammatory pathways. The earliest documented and best-studied microbial cause of DIC is the lipopolysaccharide endotoxin of Gram-negative bacteria. Extensive microvascular thrombi emerge in the systemic vasculature due to dysregulation of coagulation. The result of this unrestrained, widespread small vessel thromboses multiorgan system failure. Consumption of platelets and coagulation factors during this process can lead to an elevated risk of hemorrhage. The management of these patients with simultaneous hemorrhage and thrombosis is complex and challenging. Definitive treatment of DIC, and attenuation of end-organ damage, requires control of the inciting cause. Currently, activated protein C is the only approved therapy in the United States for sepsis complicated by DIC. Further research is needed in this area to improve clinical outcomes for patients with sepsis.

Attending rounds: microangiopathic hemolytic anemia with renal insufficiency

The classification of thrombotic microangiopathy has evolved and expanded due to treatment and advances in understanding of the diseases associated with this clinical presentation. The three clinical forms of thrombotic microangiopathy-thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), and disseminated intravascular coagulation-encompass a wide range of disorders that can be classified as either primary (idiopathic) or secondary to another identifiable disease or clinical context. Identification of an inhibitor to a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) in the idiopathic and acute forms of TTP, recognition of the absence of ADAMTS13 inhibition in diarrheal HUS, identification of complement abnormalities in atypical HUS, and a better understanding of the role of plasma therapy, rituximab, and eculizumab therapy have all had a major effect on current understanding of the thrombotic microangiopathies. In this Attending Rounds, a patient with a thrombotic microangiopathy is presented, along with discussion highlighting the difficulty of differentiating TTP from HUS and disseminated intravascular coagulation, the need for a prompt diagnosis, and the role for plasma therapy in appropriately selected patients. The discussion attempts to provide a simple clinical approach to the diagnosis, treatment options, and future course of adults and children suffering from a thrombotic microangiopathy.