Section 3. Heart and Blood Vessel Disorders

Chapter 34. Peripheral Arterial Disease

Topics: Introduction | Occlusive Peripheral Arterial Disease | Functional Peripheral Arterial Disease

Functional Peripheral Arterial Disease

Functional peripheral arterial disease is much less common than occlusive peripheral arterial disease. Normally, the arteries of the arms and legs widen (dilate) and narrow (constrict) in response to changes in the environment, such as a change in temperature. Functional peripheral arterial disease usually occurs when the normal mechanisms that dilate and constrict these arteries are exaggerated. The affected arteries constrict more tightly and more often. These changes in constriction can be caused by an inherited defect in the blood vessels, by disturbances of the nerves that control the dilation and constriction of arteries (sympathetic nervous system), by injuries, or by drugs.

Raynaud's Disease and Raynaud's Phenomenon

Raynaud's disease and Raynaud's phenomenon are conditions in which small arteries (arterioles), usually in the fingers or toes, constrict more tightly in response to exposure to cold.

Doctors use the term Raynaud's disease when no cause is apparent. They use the term Raynaud's phenomenon when a cause is known. Raynaud's disease is much more common than Raynaud's phenomenon. Between 60% and 90% of cases of Raynaud's disease occur in young women aged 15 to 40.

Anything that stimulates the sympathetic nervous system, particularly exposure to cold but also strong emotion, can cause arteries to constrict and thus trigger Raynaud's disease.

Raynaud's phenomenon may be caused by scleroderma, rheumatoid arthritis, atherosclerosis, cryoglobulinemia, an underactive thyroid gland (hypothyroidism), injury, or reactions to certain drugs, such as beta-blockers, clonidine, and the antimigraine drugs ergotamine and methysergide. Use of such drugs, which constrict blood vessels, can also make Raynaud's phenomenon worse. Some people with Raynaud's phenomenon also have other disorders that occur when arteries are prone to constrict. These disorders include migraine headaches, variant angina, and high blood pressure in the lungs (pulmonary hypertension). The association of Raynaud's phenomenon with these disorders suggests that the cause of arterial constriction may be the same in all of them.

Symptoms and Diagnosis

Constriction of small arteries in the fingers and toes begins quickly, most often triggered by exposure to cold. It may last minutes or hours. The fingers and toes become pale or bluish, usually in patches. Only one finger or toe or parts of one or more may be affected. The fingers or toes usually do not hurt, but numbness, tingling, a pins-and-needles sensation, and a burning sensation are common. As the episode ends, the affected areas may be redder than usual or bluish. Rewarming the hands or feet restores normal color and sensation. However, if episodes of Raynaud's phenomenon recur and are prolonged (especially in people with scleroderma), the skin of the fingers or toes may become smooth, shiny, and tight. Small painful sores may appear on the tips of the fingers or toes.

Often, no procedures are needed to make the diagnosis. If doctors suspect an artery is blocked, color Doppler ultrasonography (see Section 3, Chapter 21) may be performed before and after the person is exposed to cold. Doctors may also order blood tests to check for conditions that can cause Raynaud's phenomenon.

Treatment

People can control mild Raynaud's disease by protecting their head, trunk, arms, and legs from cold. For those who experience symptoms when they get excited, mild sedatives or biofeedback may help. People who have the disorder must stop smoking because nicotine constricts blood vessels.

Raynaud's disease is commonly treated with a calcium channel blocker (see Section 3, Chapter 22), such as nifedipine, amlodipine, diltiazem, or verapamil. Other antihypertensives, such as doxazosin, phenoxybenzamine, prazosin, reserpine, and terazosin, may be effective. They may be used alone or in combination.

If the disorder becomes progressively disabling and other treatments do not work, certain sympathetic nerves may be temporarily blocked or even cut to relieve the symptoms in a procedure called sympathectomy. However, even when this procedure is effective, relief may last only 1 to 2 years. This procedure is usually more effective for people with Raynaud's disease than for those with Raynaud's phenomenon. For people with Raynaud's phenomenon, the disorder causing it is treated.

Acrocyanosis

Acrocyanosis is a persistent, painless bluish discoloration of both hands and, less commonly, of both feet, caused by unexplained spasm of the small blood vessels within the skin.

The disorder usually occurs in women. The fingers and hands or toes and feet tend to feel cold and to be bluish. They sometimes sweat profusely and may swell. Exposure to cold usually intensifies the bluish discoloration, and warming reduces it. The disorder is not painful and does not damage the skin.

Doctors diagnose the disorder based on symptoms that are limited to the person's hands or feet and that persist even though pulses are normal. Treatment is usually unnecessary. Doctors may prescribe drugs that dilate the arteries (such as calcium channel blockers (see Section 3, Chapter 22)), but these drugs usually do not help. Very rarely, an operation to cut certain sympathetic nerves (sympathectomy) is performed to relieve symptoms. Usually, reassurance that the bluish skin discoloration does not indicate a serious disorder is all that is necessary.

Erythromelalgia

Erythromelalgia (erythermalgia) is a rare syndrome in which arterioles of the skin dilate periodically, causing a burning pain, making the skin feel hot, and making the feet and, less often, the hands turn red.

Usually, the cause of erythromelalgia is unknown. In such cases, the disorder tends to start when people are in their 20s or older. A rare hereditary form of erythromelalgia starts at birth or during childhood. Less commonly, the disorder is related to the use of some drugs, such as nifedipine (an antihypertensive) or bromocriptine (a drug used to treat Parkinson's disease). It also occurs in people who have certain blood disorders (myeloproliferative disorders), high blood pressure, venous insufficiency, diabetes mellitus, rheumatoid arthritis, lichen sclerosis, gout, spinal cord disorders, or multiple sclerosis. Erythromelalgia usually develops 2 to 3 years before the underlying disorder is diagnosed.

Symptoms include burning pain in the feet or hands, which feel hot and appear red. Attacks are usually triggered by environmental temperatures of over 84° F (over about 29° C). Symptoms may remain mild for years or may progress and become completely incapacitating.

Diagnosis is based on the symptoms and the increase in skin temperature. Tests, such as blood cell counts, are usually performed to help identify a cause.

Treatment includes resting, elevating the legs or arms, and applying cold packs to the legs or arms or immersing them in cold water. These measures sometimes relieve symptoms or prevent attacks. If no underlying disorder is identified, aspirin may relieve symptoms, and drugs that constrict blood vessels (such as ephedrine, methysergide, and propranolol) may help. However, aspirin does not relieve symptoms for the form that starts at birth or during childhood. If an underlying disorder is identified, treating that disorder may relieve symptoms.