Intermittent Claudication, is a predictable pattern of lower leg pain caused by inadequate blood flow to exercising muscle.
Intermittent claudication is caused by arterial insufficiency (inadequate blood supply), primarily due to atherosclerosis. Atherosclerosis is a condition that involves fatty build-up and narrowing of the arteries, which thus occludes or limits blood flow through them; the narrowed areas may be localized or extensive. Cigarette smoking is the most important risk factor for vascular disease bar none. Others include high blood pressure, high cholesterol, diabetes mellitus and a family history of atherosclerosis.
The muscle pain of intermittent claudication may be dull and aching, or sharp and crampy; or it may feel like plain old muscle fatigue. Blockages may cause pain in the thighs or buttocks. The location of the pain depends on the location of the clogged or narrowed artery: if the blockage is lower in the legs, pain may affect the calves or feet. Triggered by activity, just like angina, such pain is the warning cry of oxygen-starved muscles during exertion. If you find that the distance you can walk without pain is growing shorter, it's probable that the condition is getting worse.
The pain of intermittent claudication has three characteristics:
Pain in the lower legs can also be caused by arthritis of the spine, herniated vertebral disk, and other diseases of the spine which can pinch the nerves that supply the legs. Muscle cramps can also cause leg pain, but do not exhibit the same three characteristics listed above.
Inadequate blood flow to the lower extremities may result in deformed toenails, hair loss, skin thinning, and ulcers or infections on the feet or ankles.
Pain brought on by walking is less serious than pain occurring during sleep or while at rest; these are indications of disease progression, and warrant more aggressive therapy. Patients with these symptoms are classified as "pre-gangrenous", meaning that deterioration could lead to gangrene, a condition where so little blood reaches the affected tissue that damage is irreversible and tissue death results, requiring amputation. This occurs in 5% of untreated atherosclerotic patients within 5 years.
In more advanced cases, the pain may also come on at rest, especially during the night. It may be relieved by sitting up or dangling the feet over the side of the bed so gravity can bolster the blood supply. In other cases, narrowed leg arteries produce no pain. For example, a person who doesn't walk far enough or fast enough to bring on discomfort may remain unaware of a problem. Someone who suffers decreased sensation in the legs or feet from a condition such as diabetes may also feel no pain.
Conventional medicine uses doppler studies (a specialized ultrasound test) and transcutaneous oxygen pressure measurements to evaluate blood flow. Angiography may be performed to determine the best treatment; this is a method used to visualize the blood vessels using dye injection and X-ray. This test shows the extent of vessel narrowing.
Conservative treatment is indicated in patients who experience symptoms only upon exertion. In these cases, stopping smoking is critical. Blood pressure, lipids and blood sugar (in diabetics) should be lowered and monitored closely. "Blood thinning" drugs (anti-platelet drugs) have not proven helpful in this group of patients, but exercise has.
Small cuts and wounds on the lower legs may heal very slowly; thus foot care is an important part of treatment.
Initial symptoms of intermittent claudication are pain, aching, cramping, or fatigue of the muscles in the lower limbs that develop during walking and are quickly relieved by rest. Symptoms typically occur in the calf but may also be located in the foot, thigh, hip, or buttocks. In more advanced stages, the painful symptoms are present even at rest and are worsened by elevating the legs.
Cigarette smoking is the most important risk factor for vascular disease bar none.
In double-blind trials, supplementation with either L-carnitine and propionyl-L-carnitine (a form of L-carnitine) has increased walking distance in people with intermittent claudication. Walking distance was 75% greater after three weeks of L-carnitine supplementation (2 grams taken twice per day), than after supplementation with a placebo, a statistically significant difference. [Brevetti G, Chiariello M, Ferulano G, et al. Increases in walking distance in patients with peripheral vascular disease treated with L-carnitine: a double-blind, cross-over study. Circulation 1988;77: pp.767-73.]
In a double-blind German study, ginkgo biloba was significantly superior to a placebo in improving symptoms of intermittent claudication [Peters, 1998]. After six months of treatment, pain-free walking distance in the ginkgo group improved by almost 50% compared to baseline measurements.
A standardized extract of garlic has been tested as a treatment for intermittent claudication. In a double-blind trial, the increase in walking distance was significantly greater in people receiving garlic powder extract (400mg twice per day for 12 weeks) than in those given a placebo. [Kiesewetter H, Jung F, Jung EM, et al. Effects of garlic-coated tablets in peripheral arterial occlusive disease. Clin Investig 1993;71: pp.383-6]
In a double-blind trial, people with intermittent claudication received 760mg twice daily of the Tibetan herbal formula Padma 28 or a placebo for 16 weeks. The average walking distance increased by 115% among people receiving Padma 28, compared with a 17% increase in the placebo group (a statistically significant difference). No side effects were reported. [Smulski HS, Wojcicki J. Placebo-controlled, double-blind trial to determine the efficacy of the Tibetan plant preparation Padma 28 for intermittent claudication. Altern Ther 1995;1(3): pp.44-9]
Padma 28 was also found to increase walking distance in a second study. [Drabaek H, Mehlsen J, Himmelstrup H, Winther K. A botanical compound, Padma 28, increases walking distance in stable intermittent claudication. Angiology 1993;44: pp.863-7]
In a preliminary trial, supplementing with evening primrose oil (approximately 1,600mg per day) led to a 10% increase in exercise tolerance in people with intermittent claudication. [Christie SB, Conway N, Pearson HE. Observations on the performance of a standard exercise test by claudicants taking gamma-linolenic acid. J Atheroscler Res 1968;8: pp.83-90]
The benefit of chelation therapy in cases of intermittent claudication is controversial. The controversy has been fueled by two studies showing no benefit. Proponents of chelation therapy have pointed out how these studies were flawed.
Weight loss is often recommended.
Important dietary changes for preventing atherosclerosis (and, consequently, intermittent claudication) include avoiding meat and dairy fat, increasing fiber, and possibly avoiding foods containing trans fatty acids.
Smoking is the chief cause of intermittent claudication.
A systematic review of randomized trials suggests that exercise rehabilitation therapy improves symptoms of intermittent claudication. [Physical Therapy 1998 78: pp.278-88]
Magnesium may increase blood flow by helping to dilate blood vessels. A preliminary trial found that magnesium supplementation may increase walking distance in people with intermittent claudication. [Neglen P, Overfordt P, Eklof B. Peroral magnesium hydroxide therapy and intermittent claudication. Vasa 1985;14: pp.285-8]
Many doctors suggest that people with atherosclerosis, including those with intermittent claudication, take approximately 250 to 400mg of magnesium per day.
One study showed a slightly increased risk of vascular surgery among people with intermittent claudication who took beta-carotene supplements. [Törnwall ME, Virtamo J, Haukka JK, et al. The effect of alpha-tocopherol and beta-carotene supplementation on symptoms and progression of intermittent claudication in a controlled trial. Atherosclerosis 1999;147: pp.193-7]
Until more is known, people with intermittent claudication wishing to use beta-carotene supplements should first consult with their doctor.
If artery-clearing procedures are recommended for your leg pain, it's wise to seek a second opinion: up to 90% of people with intermittent claudication will find that their symptoms stabilize or improve with nothing more than the passage of time and simple lifestyle changes. That means only one in 10 will need "intervention" in the form of angioplasty or surgery. The most likely candidates are folks who face serious tissue damage or risk of amputation from impaired blood flow and those whose pain is so severe that it interferes with the activities of daily living.
Aside from angioplasty, another non-surgical approach coming into wider use is atherectomy. In this procedure, the doctor uses a catheter tipped with a rotating cutter to ream out the blockage. Also in use are catheters tipped with lasers that burn off the plaque.
Surgical options to restore blood supply, called "revascularization" procedures, are usually reserved for those with progressive or disabling symptoms.
Inositol hexaniacinate, a special form of vitamin B3, has been used successfully to treat intermittent claudication. A double-blind trial explored the effect of 2gm bid for 3 months. In non-smokers and in people with unchanged smoking habits, the increase in walking distance was significantly greater than in the placebo group. [Br J Clin Pract 1988;42: pp.141-5, 377-83]
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