Atlas of pathophysiology, 2 Edition

Part II - Disorders

Cardiovascular disorders

Raynaud's Disease

Raynaud's disease is one of several primary disorders characterized by episodic spasms of the small peripheral arteries and arterioles, precipitated by exposure to cold or stress. This condition occurs bilaterally and usually affects the hands or, less often, the feet. It's benign, requires no specific treatment, and has no serious sequelae. Raynaud's phenomenon, however, is secondary to any of several connective disorders—such as scleroderma, systemic lupus erythematosus, or polymyositis—and progresses to ischemia, gangrene, and amputation. Distinguishing between the two disorders is difficult because some patients experience mild symptoms of Raynaud's disease for several years and then develop overt connective tissue disease, especially scleroderma.

Age Alert

Raynaud's disease is most prevalent in females, particularly between puberty and age 40.

Causes

Raynaud's disease

·         Unknown; family history is a risk factor

Raynaud's phenomenon

·         Connective tissue disorders, such as scleroderma, rheumatoid arthritis, systemic lupus erythematosus, or polymyositis

·         Pulmonary hypertension

·         Thoracic outlet syndrome

·         Arterio-occlusive disease

·         Myxedema

·         Trauma

·         Serum sickness

·         Exposure to heavy metals

·         Long-term exposure to cold, vibrating machinery (such as operating a jackhammer), or pressure to the fingertips (as in typists and pianists)

Pathophysiology

Raynaud's disease is a syndrome of episodic constriction of the arterioles and arteries of the extremities, resulting in pallor and cyanosis of the fingers and toes. Several mechanisms may account for the reduced digital blood flow, including:

·         intrinsic vascular wall hyperactivity to cold

·         increased vasomotor tone due to sympathetic stimulation

·         antigen-antibody immune response (most likely because abnormal immunologic test results accompany Raynaud's phenomenon).

Signs and symptoms

·         Bilateral blanching (pallor) of the fingers after exposure to cold or stress:

§  Vasoconstriction or vasospasm reduces blood flow

§  Cyanosis caused by increased oxygen extraction resulting from sluggish blood flow

§  Spasm resolves, and fingers turn red (rubor) as blood rushes back into the arterioles

·         Cold and numbness

·         Throbbing, aching pain, swelling, and tingling

·         Trophic changes (as a result of ischemia), such as sclerodactyly, ulcerations, or chronic paronychia

Diagnostic test results

·         Antinuclear antibody (ANA) titer identifies autoimmune disease as an underlying cause of Raynaud's phenomenon; further tests must be performed if the ANA titer is positive.

·         Doppler ultrasonography shows reduced blood flow if the symptoms result from arterial occlusive disease.

Treatment

·         Avoiding triggers, such as cold, and mechanical or chemical injury

·         Smoking cessation and avoidance of decongestants and caffeine to reduce vasoconstriction

·         Calcium channel blockers, such as nifedipine, diltiazem, and nicardipine

·         Alpha-adrenergic blockers, such as phenoxybenzamine or reserpine

·         Biofeedback and relaxation exercises to reduce stress and improve circulation

·         Sympathectomy or amputation

P.69

PROGRESSIVE VASCULAR CHANGES

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