Pain may affect all or part of a leg or arm. Pain in the joints is discussed elsewhere.
Limb pain may be constant or occur irregularly. Pain may be precipitated by motion or have no relation to movement. Other symptoms, such as warmth, redness, numbness, or tingling, may also be present, depending on the cause of the limb pain.
Causes of Limb Pain
Injuries and overuse are the most common causes of pain in a limb, but people usually know when these events are the cause of their pain. This discussion covers limb pain unrelated to injury or strain. Among the disorders that cause such limb pain, most affect the legs more than the arms. There are many causes.
The most common causes are the following:
Blood clot in a deep-lying vein (deep vein thrombosis)
Bacterial infection of the skin (cellulitis)
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Uncommon but serious causes that require immediate evaluation and treatment include
Sudden blockage of an artery in the limb (acute arterial occlusion)
Deep soft-tissue infection
Heart attack (arm pain only)
Other less common causes include bone tumors, bone infections (osteomyelitis), and nerve problems such as pressure on nerves or degeneration of nerves (such as caused by diabetes or long-term alcohol abuse).
Evaluation of Limb Pain
It is particularly important to make sure the person does not have a sudden blockage of an artery because the limb can develop gangrene if there is no blood flow for more than a few hours. The following information can help people decide when a doctor's evaluation is needed and help them know what to expect during the evaluation.
Warning signs
In people with limb pain, certain symptoms and characteristics are cause for concern. They include
Sudden, severe pain
Limb that is cold to the touch or pale
Chest pain, sweating, shortness of breath, or palpitations
Signs of severe illness (for example, confusion, fever, or collapse)
Limb that is suddenly swollen, blistered, or has black spots
Risk factors for deep vein thrombosis, such as recent surgery, bed rest, or a cast on a leg
New nerve deficits, such as weakness or numbness of the affected limb
When to see a doctor
People who have warning signs should see a doctor right away. People without warning signs should call a doctor. The doctor will decide how quickly the person needs to be seen based on the symptoms, age, and presence of other medical disorders.
What the doctor does
Doctors first ask questions about the person's symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause of the limb pain and the tests that may need to be done.
Doctors ask
How long limb pain has been present
Whether pain occurs at certain times or during specific activities
How intense the pain is
Whether the pain is sharp or throbbing
Where the pain is located
What activities trigger or worsen pain
What the person does to relieve pain
What other symptoms (such as numbness or tingling) occur along with the pain
Doctors look for symptoms that may indicate a cause of the pain. Some obvious findings may be very helpful in diagnosing the cause of limb pain. For example, back or neck pain suggests that a nerve root may be affected and fever suggests that the person has an infection. Shortness of breath and a rapid heart rate suggest blockage of an artery by a blood clot that has traveled from a leg to the lungs (pulmonary embolism). An irregular pulse suggests that the person may have a certain abnormal heart rhythm (atrial fibrillation) that has caused a blood clot to travel from the heart to block an artery in the leg.
The painful limb is inspected for color, swelling, and any skin or hair changes. The doctor also checks for pulses, temperature, tenderness, and crepitation (a subtle crackling sensation indicating gas in the soft tissue caused by a serious infection). Strength, sensation, and reflexes are compared between affected and unaffected sides. Blood pressure is sometimes measured in the ankle or wrist of the affected limb and compared with the blood pressure in an unaffected arm or leg. If blood pressure is much lower in the painful limb, it is likely that the arteries in the limb are blocked.
Testing
Testing is not needed for all people with limb pain. Doctors can often diagnose some causes of limb pain based on the people's symptoms and the physical examination findings. However, testing is needed in some cases to confirm the diagnosis. For example, doctors may check the ankle-brachial index to diagnose peripheral arterial disease.The blood pressure is measured in both arms and both legs. If blood pressure in the ankle is lower than that in the arms by a certain amount (less than 90% of arm pressure), blood flow to the leg is inadequate.
Treatment of Limb Pain
Key Points
In people with sudden, severe pain, blood flow to the limb has often been stopped or reduced and testing must be done quickly.
Symptoms and characteristics found during the doctor's examination usually provide clues to the cause of limb pain.
