["Seronegative" catastrophic antiphospholipid syndrome in pediatrics: Clinical case]

The antiphospholipid syndrome is an acquired autoimmune thrombophilia, characterized by arterial and/or venous thrombosis. Rarely, this condition can have a catastrophic presenta tion, with high mortality, and presence of microangiopathy and involvement of three or more organs.

To describe the clinical presentation and evolution of a pediatric patient with catastrophic antiphospholipid syndrome, with a seronegative onset form, whose response to aggressive therapy was favorable.

Adolescent female, with a one-week history of pain, increased abdo minal volume and edema in the lower extremities. Generalized lupus erythematosus was diagnosed and the neoplastic process was ruled out. During its evolution, she presented various thrombotic events, initially with the presence of negative antiphospholipid antibodies, which were subsequently positive. The patient presented multisystemic failure secondary to multiorgan thrombosis, required hemodynamic and ventilatory support. It was managed with low molecular weight heparin, plas mapheresis, anticoagulation, immunosuppression and boluses of rituximab with excellent response.

We consider this case interesting because it is an infrequent diagnosis in the pediatric age and whose suspicion, timely and aggressive intensive management, can change the poor progno sis and high mortality of these patients.