Intermittent claudication

What is intermittent claudication?

Intermittent claudication (a subcategory of peripheral artery disease) is a condition involving pain in the legs during exercise due to poor circulation in the arteries. The term 'claudication' comes from the Roman Emperor Claudius, who was lame, and the term 'intermittent' refers to the fact that the pain comes and goes. The condition is also known as 'smoker's legs' because it is often seen in smokers.

The pain, cramp or a dull or fatigued sensation in the legs felt when walking go away with rest. If the person starts walking again, the same symptoms return after a similar distance has been covered. When people walk, the muscles require additional oxygen, which has to be transported in the blood through the blood vessels.

Intermittent claudication is caused by the narrowing of the arteries in the legs, which prevents adequate amounts of blood flowing through the legs. The muscles get too little oxygen, causing the unpleasant symptoms. The muscles rest when people stop walking, the oxygen deficiency is replenished and the symptoms disappear.

The narrowing of the vessels can be measured with the ankle-arm index, which is also known as the ankle brachial index (ABI). This is a fairly straightforward method in which blood pressure in the ankle is compared with blood pressure in the arm. ABI values of <0.9 are considered to indicate peripheral artery disease.

The narrowing of the arteries is usually caused by atherosclerosis. Symptoms are seen only when there is severe narrowing of the arteries of the legs. The risk factors for narrowing of the arteries are the same as the risk factors for coronary heart disease: smoking, fatty diet, diabetes, high blood pressure, high cholesterol, overweight and a previous history of heart disease or a high prevalence of cardiovascular disease in the family.

What are the complaints associated with intermittent claudication?

The condition results in pain, cramp or a dull or fatigued sensation in the legs when walking. The symptoms may occur in the foot, calf, thigh or buttock and they subside when the person stops walking, returning after a similar distance has been covered when the person starts walking again. The pain is often felt as cramp. There may also be a feeling of tightness or fatigue. Spasms (muscle contractions) may also occur in the upper leg, calf or buttock.

The pain may occur with less and less exercise, and eventually be present even when the person is resting. Other symptoms of the condition include cold feet or legs, hair loss, shiny skin on the legs and a weak pulse in the arteries of the leg.
Simple wounds on the legs generally heal poorly and can easily become a chronic problem. ²⁴²

People with intellectual disabilities sometimes find it impossible to communicate these symptoms. They may not want to walk or the people around them may notice only a change in behaviour.

How common is intermittent claudication in the general population?

The prevalence of symptomatic chronic obstructive arterial disease in the general population measured using the ankle-arm index (<0.9) is estimated at 7-8% at the age of 55 years and at 56% in people aged over 85. ^{242   531}

Only a small number also have pain in the legs. The prevalence and incidence of chronic obstructive arterial disease are almost the same in men and women but men develop intermittent claudication symptoms earlier. Chronic obstructive arterial disease is more frequent in smokers, in diabetes mellitus patients and in people with a dark skin. Chronic obstructive arterial disease is a manifestation of generalised vascular disease and it is found in combination with atherosclerosis of the coronary and/or cerebral arteries. ²⁴²

How common is intermittent claudication in people with intellectual disabilities?

Dutch research has shown that peripheral artery disease is more common in older people with intellectual disabilities than in the general population. The Dutch GOUD study found that 20.7% of those studied had peripheral artery disease. It had not been diagnosed previously in 97% of this group. ⁵³²

When group that was comparable in terms of age (50 to 80 years) was compared with the Dutch sample in the PANDORA study (a European study of peripheral artery disease), it emerged that the prevalence rate for claudication was significantly higher at 17.4% than the 8.1% found in Dutch general practice. ^{531   532}

Peripheral artery disease is found more often in older people, smokers, people living in centralised accommodation, people who need help to walk and people who are less ADL-independent. ⁵³²

In addition, it has emerged that peripheral artery disease begins younger in people with intellectual disabilities. A Dutch study looking at 407 people in the 40-59 age bracket found that the prevalence of peripheral artery disease in people aged over 40 was as high as in people aged over 50. That study found a prevalence rate of 8.4%. The diagnosis of peripheral artery disease had not been made in any of the subjects prior to the study and one of the 34 people in whom the diagnosis of peripheral artery disease was made actually had the associated symptoms. People in a wheelchair were more likely to have peripheral artery disease. ⁵³³