EP21: Catastrophic APS: The Rapid Descent into Multiorgan Failure

Our 21st issue focuses on Catastrophic Antiphospholipid Syndrome, a very rare but devastating form of APS marked by the rapid development of extensive thrombosis across multiple organs. Let’s increase awareness and help drive better outcomes for patients!

Werfen is dedicated to Powering Patient Care by advancing knowledge and awareness of thrombotic disorders, with the ultimate goal of improving outcomes. This episode is dedicated to Catastrophic Antiphospholipid Syndrome (CAPS), an extremely rare yet lethal variant of Antiphospholipid Syndrome (APS), characterized by the sudden onset of widespread thrombosis affecting multiple organs.

Introduction

CAPS, also known as Asherson’s Syndrome, represents less than 1% of all APS cases but is widely recognized as its most severe clinical manifestation, with a mortality rate of 30–50% despite treatment. Unlike classical APS, which usually involves isolated thrombosis or pregnancy morbidity, this form is characterized by rapidly progressive, simultaneous or sequential thromboses, frequently leading to multiorgan failure.

Predisposing Factors and Patient Profiles

CAPS most often occurs in patients with a previous history of Antiphospholipid Syndrome, but it may also develop during pregnancy or in the postpartum period. Notably, CAPS may sometimes represent the initial clinical presentation of APS, arising in patients without a previous diagnosis or documented antiphospholipid antibodies.

Pathophysiology

CAPS is typically precipitated by identifiable triggers such as infection, surgery, trauma, malignancy, or sudden withdrawal of anticoagulation in APS patients. Its pathophysiology reflects a complex interplay between antiphospholipid antibodies, endothelial activation, platelet aggregation, and dysregulated complement pathways, creating a severe prothrombotic and proinflammatory state leading to diffuse microvascular thrombosis and tissue injury.

Clinical Presentation and Complications

Symptoms are highly variable and depend on the organs involved. The kidneys, lungs, central nervous system, and heart are most frequently affected, although virtually any organ can be involved. Patients commonly present with acute renal failure, respiratory distress, neurological dysfunction, cardiac ischemia, and skin manifestations. Clinical deterioration is often rapid, evolving within days into severe, life‑threatening multiorgan failure.

Diagnosis

Diagnosis of CAPS relies on integrated clinical, laboratory, and histopathological criteria. Laboratory findings commonly include thrombocytopenia, elevated D‑dimer levels, microangiopathic hemolytic anemia, and persistently positive antiphospholipid antibodies. Given its fulminant nature, treatment must not be delayed while awaiting confirmatory results.

Classification Criteria

CAPS Classification Criteria, proposed by Asherson in 2003, include rapid onset, involvement of three or more organs, antiphospholipid antibodies fulfilling APS criteria, and histological evidence of microvascular ischemia. Complete fulfillment defines definite CAPS, while partial fulfillment suggests probable CAPS. The recent 2023 ACR/EULAR APS Criteria may support recognition in critical care, but misuse for diagnosis could increase risk in currently non‑APS patients.

Management

Treatment demands rapid, aggressive, and multidisciplinary intervention, since mortality remains high despite optimal care. The cornerstone is “triple therapy,” including life‑long anticoagulation with heparin, high‑dose systemic corticosteroids, and plasma exchange and/or intravenous immunoglobulin. In refractory cases, targeted therapies such as rituximab or eculizumab may be considered.

Conclusion and Outlook

CAPS remains a rare but devastating manifestation of APS, marked by rapid progression to widespread multiorgan thrombosis. Early recognition, swift diagnosis, and prompt initiation of aggressive therapy are critical to improving survival. Continued research, increased awareness, and multidisciplinary care are essential to advancing outcomes for patients affected by this grave condition.