Restless Legs Syndrome and Related Disorders - Diagnosis

If the patient's diet suggests low iron intake and other causes cannot be established using inexpensive or noninvasive techniques, then the patient may simply be given a monthly trial of iron supplements. If the patient fails to respond, further evaluation is needed.

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Other Laboratory Tests

Certainly laboratory tests may be helpful in determining causes of RLS or conditions that rule it out. They include the following:

Blood glucose tests for diabetes.
Tests for kidney problems.
Possibly tests for thyroid hormone and magnesium and folate levels.

Ruling Out Other Leg Disorders

In addition to other sleep-related leg disorders, a number of other medical conditions may have features that resemble restless leg syndrome.The doctor will need to consider these disorders in making a diagnosis.

Peripheral Neuropathies. Peripheral neuropathies are nerve disorders in the legs or feet. They can be caused by a wide variety of conditions and can produce pain, burning, tingling, or shooting sensations in the extremities. Diabetes is a very common cause of painful peripheral neuropathies. Other causes include alcoholism, rheumatoid arthritis, systemic lupus erythematosus, amyloidosis, HIV infection, kidney failure, and certain vitamin deficiencies. Symptoms of peripheral neuropathies may mimic RLS. However, unlike RLS they are not usually associated with restlessness, nor are they relieved by movement, and they do not worsen at bedtime.

Deep Vein Thrombosis. Deep vein thrombosis is caused by a blood clot deep in the leg, usually in the thigh or calf. It may cause pain, swelling and aching in the leg where the clot has developed. It can occur in people with heart disease, with varicose veins, during pregnancy, in women from hormonal treatments, from injury to the leg, or from inactivity (such as after surgery or during long flights). Left untreated, this can be a very serious and even life-threatening condition.

This picture shows a red and swollen thigh and leg caused by a blood clot (thrombus) in the deep veins in the groin (ileofemoral veins), which prevents normal return of blood from the leg to the heart.

Intermittent Claudication and Peripheral Artery Disease. Peripheral artery disease (PAD) occurs when atherosclerosis (commonly called hardening of the arteries) affects the feet and legs. In such cases, the arteries become blocked, obstructing oxygen-rich blood flow. Intermittent claudication is an important symptom of peripheral artery disease (PAD) and occurs in between a third and half of these patients. Claudication is taken from the Latin word "to limp". The name is used to describe the pain that occurs in PAD patients when they exercise, particularly during walking. In intermittent claudication, blood flow is sufficient to meet the needs of the person at rest. The result is leg pain during exercise, which is relieved by rest.