Doruk Erkan, MD

Catastrophic APS (CAPS) is the most severe form of antiphospholipid syndrome, in which thromboses develop rapidly in multiple organs, usually associated with microthrombosis. Because defining appropriate treatment is urgent, while multiple other conditions such as sepsis and hemolytic-uremic syndrome (HUS) may show similar clinical features, early suspicion is crucial.

Clinically significant antiphospholipid  antibodiy positivity is an important diagnostic step; however, multiple factors can impede the timely diagnosis.

(For a detailed discussion of CAPS diagnosis, including algorithms, see 

Catastrophic antiphospholipid syndrome: how to diagnose a rare but highly fatal disease.

Which of the following are true regarding “clinically significant aPL profile”? (You may choose more than one.)

1.   Because transient aPL positivity is common during infections, it is important to demonstrate two successive positive aPL results within one month.
2.   A positive lupus anticoagulant  (LA) test is a better predictor of aPL-related events compared to aCL and a Î²2 GPI ELISA.
3.   An LA test reading taken from a patient on anticoagulants can be falsely positive.
4.   At higher titers, the specificity of aCL and a Î²2 GPI ELISA tests for aPL-related clinical events decreases.
5.   IgG aCL and a Î²2 GPI ELISA are generally more commonly associated with clinical events compared with IgM isotype.

correct responses about antibody testing for CAPS

 Because transient aPL positivity is common during infections, documentation of two positive aPL tests 

 The specificity of aCL and Î²2 GPI ELISA tests for aPL-related clinical events 

  IgG aCL and a Î²2 GPI ELISA are generally more commonly associated with clinical events compared with IgM isotype.

Which of the following are true regarding CAPS diagnosis? (You may choose more than one.)

1.   CAPS can commonly overlap with other thrombotic microangiopathic conditions, e.g. thrombotic thrombocytopenic purpura (TTP), hemolytic-uremic syndrome (HUS), and HELLP syndrome (hemolysis with elevated liver enzymes and low platelet count).
2.     Previous APS diagnosis and/or history of persistent clinically significant aPL positivity without history of aPL-related clinical events is of great importance for diagnosis.
3.    Two or more organ thromboses developing in less than a week is the cornerstone of Definite CAPS.
4.    Unless the patient fulfills the Definite or Probable CAPS Classification Criteria, there is no reason to suspect CAPS.
5.   Based on the thrombotic storm concept, several comparable disorders (including CAPS) with an extreme prothrombotic presentation may possess a similar underlying pathophysiologic process representing an extreme response to an initial prothrombotic stimulus.

Based on the preliminary classification criteria, “Definite CAPS” is defined as thromboses developing in 

three or more organs in less than a week, microthrombosis in at least one organ, and persistent aPL positivity

 One of the definitions of “Probable CAPS” is thromboses developing in two organs in less than a week, microthrombosis in at least one organ, and persistent aPL positivity.

   aPL-positive patients presenting with severe thrombotic, hemorrhagic, and/or microangiopathic manifestations but who do not fulfill the “Definite” or “Probable” CAPS constitute a “

be monitored closely for the development of CAPS

treatment may need to be just as intensive

Here's that citation again, for further information: 

Articles

In CAPS, the most severe form of antiphospholipid syndrome, thromboses emerge widely and rapidly--clearly an urgent situation. Update your diagnostic skills in this quick two-part quiz.

Author | Doruk Erkan, MD

Articles

Catastrophic APS: Can You Clinch the Diagnosis?