Cholesterol embolism: A pseudovasculitic syndrome☆

El síndrome (o signo) del dedo azul (SDA) es la manifestación cutánea de un gran número de enfermedades que producen un compromiso isquémico agudo o subagudo en uno o más dedos. La causa más frecuente del SDA es la disminución del flujo arterial por el compromiso u oclusión de pequeños vasos periféricos, conservándose los pulsos distales palpables. La disminución del flujo arterial puede producirse por diferentes mecanismos patogénicos incluyendo la trombosis, la embolia, la vasoconstricción severa o la afección inflamatoria o no inflamatoria de la pared vascular. El dedo que sufre la isquemia adquiere un tono azul o violáceo, lo que da nombre al síndrome, y puede llegar a presentar fenómenos de necrosis.

Independientemente de la causa, este cuadro clínico es una urgencia médica que requiere un diagnóstico y tratamiento específico rápido, dado el riesgo de progresión a necrosis irreversible.

Blue digit syndrome (or sign) is a cutaneous manifestation of multiple diseases that produce acute or subacute ischemic compromise in one or more fingers or toes. The most frequent cause of this syndrome is a reduction in arterial blood flow due to compromise or occlusion of small peripheral vessels, with preservation of the distal pulses. The reduction in blood flow may be caused by a variety of pathogenic mechanisms including thrombosis, embolism, severe vasoconstriction, or inflammatory or non-inflammatory lesions of the vascular wall. The finger or toe affected by ischemia turns blue or violet and may develop necrosis.

Independently of the cause, blue digit syndrome is a medical emergency requiring rapid diagnosis and specific treatment, given the risk of progression to irreversible necrosis.

The blue (or purple) toe syndrome consists of the development of blue or violaceous discoloration of one or more toes in the absence of obvious trauma, serious cold-induced injury, or disorders producing generalized cyanosis. The major general categories are: (1) decreased arterial flow, (2) impaired venous outflow, and (3) abnormal circulating blood. Depending on its pathogenesis, the discoloration may be blanching or nonblanching. An accurate diagnosis is critical, because many of the causes threaten life and limb, but the patient's medical history, accompanying nondermatologic findings on physical examination, and a discriminating use of laboratory tests are usually more important than the nature of the cutaneous abnormalities in determining the cause.

After completing this learning activity, participants should be able to define the blue (or purple) toe syndrome, categorize the causes, and recognize the important historical, clinical, and laboratory findings that differentiate the causes and lead to the correct diagnosis.

Heart Lung® 2002;31:452-400.