Digital Gangrene in a Teenager: Catastrophic Antiphospholipid Syndrome or Lupus Vasculitis

Abstract

BACKGROUNDCatastrophic antiphospholipid syndrome (APS) is a severe acquired thrombophilia characterized by rapid development of thromboses in several organs, in presence of antiphospholipid antibodies. For histopathologic confirmation, thrombosis should be present without significant evidence of vessel wall inflammation. APS is a known association of systemic lupus erythematosus (SLE) and, when present with lupus, has the worst outcome. Peripheral vascular disease leading to digital gangrene is a well-recognized complication of APS, particularly in patients with SLE. Digital gangrene in SLE is a rare form of vascular injury and generally leads to digital amputation. CASE REPORTA previously healthy 12-year-old girl is brought to the emergency department because of a 3-day history of purpuric lesions in the lower limbs and digital gangrene in all right toes and in the second, third and fourth fingers on the left hand. She had rapid progression to gangrene in all the aforementioned digits and ulceration and gangrene of purpuric lesions. Arterial Doppler ultrasound of the four limbs showed no changes. Brain magnetic resonance imaging (MRI) showed lacunar infarcts of probable microembolic etiology. Laboratory findings included triple positivity in high titers of antiphospholipid antibodies, ANA and anti-DNA and hypocomplementemia, suggesting SLE and probable catastrophic APS diagnosis. Biopsy of skin lesions showed nonleukocytoclastic cutaneous small vessel vasculitis, leading to the hypothesis of lupus vasculitis. Methylprednisolone pulse therapy, human immunoglobulin, vasodilators and anticoagulation were performed. Due to the presence of lupus vasculitis, it was chosen to use cyclophosphamide. There was a halt in the progression of the vascular condition, but the patient evolved with self-amputation of some of the affected distal phalanges of the right toes and the left hand. After six doses of cyclophosphamide in a biweekly schedule, azathioprine was started, and the patient is currently asymptomatic with a SLEDAI-2K score of zero. CONCLUSIONDigital gangrene may be secondary to thrombosis or small vessel vasculitis. This distinction can be difficult, especially in patients with lupus-associated antiphospholipid syndrome. Only 0.2% of patients with SLE presented initially as digital necrosis and less than 10% of pediatric APS patients present with small-vessel thrombosis. Despite the rarity of presentation and the difficulty in distinguishing the diagnosis, early recognition and treatment of both diseases are essential to prevent progression and reduce their morbidity and mortality.