Identify Type of Thrombotic Microangiopathy

Identify Type of Thrombotic Microangiopathy

Identify Type of Thrombotic Microangiopathy

Identify Type of Thrombotic Microangiopathy

1.Patient has Thrombotic Microangiopathy?
2.ADAMTS13 Activity (drawn prior to start of plasma exchange)?
3.Stool for PCR or culture-based assay for the Shiga-toxin producing E. coli (in the presence of diarrhoea in preceding 14 days)?
Created by on 24/09/2018

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About this Calculator

Atypical hemolytic uremic syndrome (aHUS), a thrombotic microangiopathy (TMA), is a rare, life-threatening, systemic disease.

aHUS can be distinguished from TTP on the basis of ADAMTS13 activity, with a severe decrease (<5%-10% of control) characteristic of TTP1. It is important to order this test in any patient presenting with laboratory and clinical signs of a TMA before plasma therapy is initiated.

STEC-HUS can be ruled out using both culture and PCR-based assays of stool samples or rectal swabs for Shiga toxin-producing E. coli.

aHUS is diagnosed by exclusion, diagnosis should be oriented toward aHUS if disseminated intravascular coagulation is ruled out, STEC test is negative, and plasma activity of ADAMTS13 is > 10%.

Consider a multidisciplinary approach to diagnose and manage aHUS.

Acronyms:

  • TMA: Thrombotic microangiopathy
  • aHUS: atypical Haemolytic Uraemic Syndrome
  • TTP: Thrombotic thrombocytopaenic purpora
  • STEC-HUS: Shiga-Toxin E. coli Haemolytic Uraemic Syndrome

References

Laurence J, et al.

Atypical hemolytic uremic syndrome (aHUS): essential aspects of an accurate diagnosis.

Clinical Advances in Hematology & Oncology: H&O 2016, 14 Suppl 11 (11): 2-15

The Identify Type of Thrombotic Microangiopathy calculator is created by QxMD.

1. Patient has Thrombotic Microangiopathy?

More Information

Ensure the following has been performed:

- Collect blood sample for ADAMTS-13 test (prior to starting any plasma therapy).

- Collect stool sample for Shiga Toxin/EHEC Testing (PCR or culture based essay) if presenting with diarrhoea in preceding 14 days.

- Assessment of medical and family history.

It is critical to draw blood for ADAMTS13 analysis prior to instituting plasma therapy, as interpretation of values obtained after initiation of plasma therapy is difficult.

The benefits of plasma exchange, although not evaluated in prospective studies, include the removal of pathologic substances from the blood and the replacement of deficient plasma components. Although plasma therapy has improved outcomes considerably in TTP, reducing the mortality rate from 90% to 10% to 20%, more than 50% of patients with aHUS proceed to end-stage renal disease or death despite plasma therapy duration.

Biopsies can be useful in difficult diagnostic situations. Sampling of any accessible, highly vascular site may help inform the differential diagnosis of a TMA, based on pathologic distinctions between TTP and aHUS.

Reference:

1. Laurence J. Clin Adv Hematol Oncol. 2016;14(suppl 11):1-15.

2. Azoulay E, et al. CHEST. 2017;152(2):424-434

Created by on 24/09/2018

By using this site you acknowledge that you have read, understand, and agree to be bound by our terms of use and privacy policy. All content and tools are for educational use only, are not meant to be a substitute for professional advice and should not be used for medical diagnosis and/or medical treatment.

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