Porth's Essentials of Pathophysiology, 4e

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Circulatory Function

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The impaired circulation increases sensitivity to cold. The peripheral pulses are diminished or absent, and there are changes in the color of the extremity. In mod- erately advanced cases, the extremity becomes cyanotic when the person assumes a dependent position, and the digits may turn reddish-blue even when in a nondepen- dent position. With lack of blood flow, the skin becomes thin and shiny, hair growth slows, and nail growth is impaired. Chronic ischemia causes thick, malformed nails. If the disease continues to progress, tissues even- tually ulcerate and gangrenous changes arise that may necessitate amputation 2 (Fig. 18-8). Diagnostic methods are similar to those for athero- sclerotic disease of the lower extremities. It is essen- tial that the person stop smoking cigarettes or using tobacco. Even passive smoking and nicotine replace- ment therapy should be eliminated. Other treatment measures are of secondary importance and focus on methods for producing vasodilation and preventing tis- sue injury. Sympathectomy, or excision of a segment of a sympathetic nerve, may be done to alleviate the vaso- spastic manifestations of the disease. As the distal arte- rial tree is occluded, revascularization is not possible. If smoking cessation is not achieved, then the prognosis is generally poor, with amputation of both lower and upper extremities the eventual outcome. Raynaud Phenomenon Raynaud phenomenon is a functional disorder caused by intense vasospasm of the arteries and arterioles in the fingers and, less often, the toes. 1,2,21,22 The disorder is divided into primary and secondary types. Primary Raynaud phenomenon is seen in otherwise healthy young women, and it often is precipitated by exposure to cold or by strong emotions and usually is limited to the fingers. The cause of vasospasm in pri- mary Raynaud phenomenon is unknown or idiopathic.

Hyperreactivity of the sympathetic nervous system has been suggested as a contributing cause. Secondary Raynaud phenomenon is associated with previous vessel injury, such as frostbite, occupational trauma associated with the use of heavy vibrating tools, collagen diseases, neurologic disorders, chronic arterial occlusive disor- ders, and drugs, such as bleomycin. Another occupa- tion-related cause is the exposure to alternating hot and cold temperatures such as that experienced by butchers and food preparers. Raynaud phenomenon often is the first symptom of collagen diseases. It occurs in almost all persons with scleroderma and can precede the diagnosis of scleroderma by many years. 22 The ischemic phase of Raynaud phenomenon is manifested by changes in skin color that progress from pallor to cyanosis, a sensation of cold, and changes in sensory perception, such as numbness and tingling. The color changes usually are first noticed in the tips of the fingers, later moving into one or more of the distal pha- langes (Fig. 18-9). After the ischemic episode, there is a period of hyperemia with intense redness, throbbing, and paresthesias. The period of hyperemia is followed by a return to normal color. Primary Raynaud phenom- enon attacks typically involve all fingers in a symmetric fashion and are associated with minimal pain, whereas asymmetric finger involvement and intense pain suggest secondary Raynaud phenomenon. 21,22 In severe progres- sive cases, trophic skin changes may develop. The nails may become brittle, and the skin over the tips of the affected fingers may thicken. Ulceration and superficial gangrene of the fingers, although infrequent, may occur. The initial diagnosis is based on a history of vaso- spastic attacks supported by other evidence of the disor- der. Immersion of the hand in cold water may be used to initiate an attack as an aid to diagnosis. Laser Doppler flow velocimetry may be used to quantify digital blood flow during changes in temperature. Primary Raynaud phenomenon is differentiated from secondary Raynaud

FIGURE 18-8. Buerger disease. Hand showing necrosis of the tips of the fingers.Temporal arteritis. (From Gotlieb AI, Lui A. Blood vessels. In: Rubin R, Strayer DS, eds. Rubin’s Pathology: Clinicopathologic Foundations of Medicine, 6th ed. Philadelphia, PA: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2012:446.)

FIGURE 18-9. Raynaud phenomenon.The tips of the fingers show marked pallor. (From Gotlieb AI, Lui A. Blood vessels. In: Rubin R, Strayer DS, eds. Rubin’s Pathology: Clinicopathologic Foundations of Medicine, 6th ed. Philadelphia, PA: Wolters Kluwer Health/Lippincott Williams &Wilkins; 2012:463.)