Catastrophic antiphospholipid syndrome

Overview

Catastrophic Antiphospholipid Syndrome (CAPS), also known as Asherson’s syndrome, is a rare and life-threatening variant of antiphospholipid syndrome (APS), an autoimmune disorder in which the body produces antibodies that increase the risk of blood clots. CAPS is characterized by the rapid development of multiple blood clots in small blood vessels across various organs, leading to multi-organ failure. This condition requires immediate medical attention and aggressive treatment due to its high mortality rate if not treated promptly.

Causes

CAPS occurs in individuals who have antiphospholipid antibodies, such as lupus anticoagulant, anticardiolipin antibodies, or anti-beta-2 glycoprotein I antibodies. These antibodies cause abnormal blood clotting. In CAPS, a triggering event sets off a rapid and widespread clotting response. Common triggers include:

• Infections: Particularly bacterial or viral infections

• Surgery or trauma

• Discontinuation of anticoagulant therapy

• Pregnancy or childbirth

• Malignancies or certain medications

CAPS may occur in patients with known antiphospholipid syndrome, systemic lupus erythematosus (SLE), or as the first presentation of APS.

Symptoms

The symptoms of catastrophic antiphospholipid syndrome develop rapidly and involve multiple organ systems. Common clinical manifestations include:

• Respiratory distress: Due to pulmonary embolism or acute respiratory failure

• Neurological symptoms: Such as seizures, confusion, strokes, or coma

• Renal failure: From blood clots in the kidneys

• Skin findings: Livedo reticularis (mottled skin), purpura, or digital gangrene

• Cardiovascular complications: Such as heart valve disease or myocardial infarction

• Gastrointestinal involvement: Including abdominal pain, bowel infarction, or liver dysfunction

• Fever and systemic inflammation

Diagnosis

Diagnosing CAPS requires a high index of suspicion, especially in critically ill patients with multi-organ failure. Diagnostic criteria include:

• Evidence of involvement of three or more organs, systems, or tissues

• Development of manifestations within a week

• Confirmation of small vessel thrombosis in at least one organ or tissue by histopathology

• Presence of antiphospholipid antibodies (lupus anticoagulant, anticardiolipin, or anti-beta-2 glycoprotein I)

Laboratory tests and imaging studies used to support the diagnosis may include:

• Coagulation panels and antiphospholipid antibody testing

• Blood tests showing signs of organ failure (e.g., elevated creatinine or liver enzymes)

• CT, MRI, or ultrasound to detect clots in various organs

• Biopsy to confirm microvascular thrombosis when feasible

Treatment

CAPS is a medical emergency that requires immediate, aggressive treatment. Management typically involves a combination of the following therapies:

• Anticoagulation: Intravenous heparin is used to prevent further clot formation

• Corticosteroids: High-dose steroids help control the severe inflammatory response

• Plasma exchange (plasmapheresis): To remove antiphospholipid antibodies from the blood

• Intravenous immunoglobulin (IVIG): To modulate the immune response

• Treatment of underlying trigger: Such as antibiotics for infections or discontinuation of triggering medications

• Immunosuppressive agents: In refractory or recurrent cases, agents like cyclophosphamide may be used, especially if underlying lupus is present

Supportive care in an intensive care unit (ICU) setting is often necessary to manage organ dysfunction and stabilize the patient.

Prognosis

Despite advances in treatment, the prognosis of catastrophic antiphospholipid syndrome remains guarded. Mortality rates can be as high as 30–50% without prompt and effective treatment. However, outcomes have improved with early recognition and aggressive management. Survivors may require long-term anticoagulation and follow-up to prevent recurrence. Patients with underlying autoimmune disorders or recurrent CAPS may have a more complicated clinical course, necessitating continued immunosuppressive therapy and regular monitoring.