APS 101 takes you through the ins and outs of APS, providing facts and key information to help you better understand the disease.
APS 101 is written by Jacqueline Madison, MD, Assistant Professor in the Division of Rheumatology and member of the APS Research Labs. In this month’s edition, Dr. Madison discusses catastrophic antiphospholipid syndrome (CAPS), how it affects the body, diagnosis, and treatment.
What is CAPS and How Does It Affect the Body?
Everyone with APS should be aware of a rare version of APS aptly named CAPS: Catastrophic Antiphospholipid Syndrome. It is not an entirely different disease, but one way APS shows up in the body in a scary way.
We know that APS affects people differently. In some people, it causes blood clots in their veins or arteries. In others, it causes difficulty with pregnancy. And in yet others, it damages the teeny, tiny blood vessels in the body, sometimes called the “microvasculature.” Or, more simply, small vessels. These small vessels are found in basically every organ and tissue of our bodies.
Small-vessel clots are most easily recognizable in certain parts of the body. For example, a skin pattern called “livedo racemosa” may represent clots in the small vessels of the skin (but most people with livedo don’t have CAPS). Another area where we sometimes detect clots in small vessels is in the kidneys, typically after a biopsy is performed to further evaluate abnormalities in the blood or urine. The only way to know for sure if an area of the body has clots in its small vessels is by doing a biopsy and looking at the tissue under a microscope, whether that biopsy is of the skin, kidney, or other area.
CAPS is truly catastrophic because it causes clots and small vessel changes in many parts of the body to quickly occur all at once, which can lead to multiple organ failure and sometimes death. This life-threatening process is sometimes called a thrombotic storm and we don’t know exactly why it happens. Sometimes, there is a trigger for CAPS to occur, such as an infection, surgery, or some other stress on the body [1]. Other times, we don’t know what sets it off.
How Is It Diagnosed?
To diagnose CAPS, we look for several factors:
- Are there three or more organs or tissues involved?
- Did this all happen very quickly (within a week)?
- Are there definite small-vessel clots (ideally confirmed with a biopsy)?
- Are there antiphospholipid antibodies present in the blood?
The identification of antiphospholipid antibodies is especially important if the patient doesn’t already have a diagnosis of APS. Of people with CAPS, only about half were diagnosed with APS before it happens [2]. Fortunately, this is a pretty rare form of APS (it occurs in about 1% of patients with APS) [3,4], but it is incredibly serious and dangerous when it happens.
How Is It Treated?
CAPS is usually treated with a combination of therapies including blood thinners (anticoagulation), steroids (such as prednisone or a similar medicine given intravenously), and plasma exchange (replacing the liquid part of the blood with that taken from healthy people). Sometimes intravenous immunoglobulin (IVIG), which is a pool of antibodies from blood donors that may work to neutralize the misbehaving antibodies, can be used instead of plasma exchange. Other biologic medications, such as rituximab, are also used to treat CAPS in an attempt to work on the dysregulated immune system.
CAPS is not common, even among patients with APS, but it is very dangerous. If a patient with APS is getting very sick very quickly, we always consider and look for signs of CAPS. We want patients to know about this APS complication so that they have a full understanding of the different ways APS can affect people. One way you may be able to prevent this problem is by staying regular with anticoagulation and other prescribed medications and by trying to prevent triggers, like serious infections, whenever possible. The seriousness of CAPS highlights the importance of research into APS to try to better understand, treat, and prevent this and all forms of APS.
References:
- Asherson RA, Cervera R, de Groot PG, et al. Catastrophic antiphospholipid syndrome: international consensus statement on classification criteria and treatment guidelines. Lupus 2003;12(7):530-4. doi: 10.1191/0961203303lu394oa [published Online First: 2003/08/02]
- Cervera R, Piette JC, Font J, et al. Antiphospholipid syndrome: clinical and immunologic manifestations and patterns of disease expression in a cohort of 1,000 patients. Arthritis Rheum 2002;46(4):1019-27. doi: 10.1002/art.10187 [published Online First: 2002/04/16]
- Sevim E, Zisa D, Andrade D, et al. Characteristics of Patients With Antiphospholipid Antibody Positivity in the APS ACTION International Clinical Database and Repository. Arthritis Care Res (Hoboken) 2022;74(2):324-35. doi: 10.1002/acr.24468 [published Online First: 2020/09/29]
- Cervera R, Serrano R, Pons-Estel GJ, et al. Morbidity and mortality in the antiphospholipid syndrome during a 10-year period: a multicentre prospective study of 1000 patients. Ann Rheum Dis 2015;74(6):1011-8. doi: 10.1136/annrheumdis-2013-204838 [published Online First: 2014/01/28]
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