RAYNAUD'S PHENOMENON

 RAYNAUD'S PHENOMENON

Raynaud's phenomenon , the most frequent extracutaneous complication of SSc (Systemic Sclerosis), is characterized by episodic vasoconstriction in the fingers and toes, sometimes also affecting the tip of the nose and earlobes. Attacks are reversible, and can be triggered by a decrease in temperature, as well as emotional stress and vibration. Attacks typically start with pallor of the fingers, followed by cyanosis of variable duration. Hyperemia ensues spontaneously or with rewarming of the digit. The progression of the three color phases reflects the underlying vasoconstriction, ischemia, and reperfusion. It is important to note that up to 5% of the general population has Raynaud's phenomenon. In the absence of signs or symptoms of an underlying condition, Raynaud's phenomenon is classified as primary (Raynaud's disease), which represents an exaggerated physiologic vasomotor response to cold. Secondary Raynaud's phenomenon occurs in SSc and other connective tissue diseases, hematologic and endocrine conditions, and occupational disorders, and can complicate treatment with beta blockers and anticancer drugs such as cisplatin and bleomycin. Distinguishing primary Raynaud's disease from secondary Raynaud's phenomenon can present a diagnostic challenge. Raynaud's disease is supported by the following: absence of an underlying cause; a family history of Raynaud's phenomenon; absence of digital tissue necrosis or ulceration; and a negative ANA test. Secondary Raynaud's phenomenon tends to occur at an older age, is more severe (episodes are more frequent, prolonged, and painful), and is frequently complicated by ischemic digital ulcers and loss of digits

Figure: Digital necrosis. Sharply demarcated necrosis of the fingertip secondary to ischemia in a patient with limited cutaneous systemic sclerosis (SSc) associated with severe Raynaud's phenomenon.

Nailfold capillaroscopy using a low-power stereoscopic microscope or ophthalmoscope permits visualization of nailbed cutaneous capillaries under immersion oil. Raynaud's disease is associated with evenly spaced parallel vascular loops, whereas in secondary Raynaud's phenomenon, nailfold capillaries are distorted with widened and irregular loops, dilated lumen, microhemorrhages, and areas of vascular "dropout". Thus, nailfold capillaroscopy can be helpful for both differentiating primary from secondary Raynaud's phenomenon and for establishing the early diagnosis of SSc.

Figure: Systemic sclerosis-associated nailfold capillaries alterations. In healthy subjects, note regularly arrayed and uniform-size "hairpin" microvessels. In early pattern, note dilations of microvessels and symmetrically increased microvessels (giant capillaries). In active pattern, note giant capillaries, collapse with microhemorrhages, and loss of capillaries. In late pattern, note massive loss of capillaries, fibrosis, and neoangiogenesis with secondary dilations (nailfold videocapillaroscopy; magnification 220x).