Leg Pain (cont.)
What Are Other Causes of Nontraumatic Leg Pain?
- Joint pain: Joint pain may occur because of a local injury but may also be due to medical conditions that can cause inflammation and swelling. Joint pain associated with swelling is called arthritis (arth=joint+ it is=inflammation) while pain without swelling is called arthralgia (arthr=joint + algia= pain). Some examples include the following:
- Patients with progressive osteoarthritis may have days in which affected joints may hurt.
- Similarly, patients with rheumatoid arthritis may have episodes of joint inflammation when their disease flares.
- Exacerbations of gout can cause joints to become inflamed if uric acid crystals start to deposit within the joint. It is often the joints that are under significant workload that are affected. The joints in the great toe are commonly involved, but the ankle, knee, wrist, and fingers are also common sites of uric acid crystal deposition.
- Pseudogout can also cause joint inflammation. Instead of uric acid, calcium pyrophosphate crystals deposited in joints are the cause of this condition. The knee is often affected by pseudogout, and the diagnosis is sometimes made when calcification of the cartilage is seen on plain X-rays of the knee joint (chondrocalcinosis).
- Systemic illnesses (there are too many to discuss in this article) may also cause joint inflammation. Some common conditions that may cause joint pain include systemic lupus erythematosus (SLE), psoriasis, hepatitis, inflammatory bowel disease, and Lyme disease.
- Joints may become inflamed as part of the body's generalized reaction to an infection. Infections may cause synovitis, or inflammation of the synovium (the lining tissue of a joint). Most often it is due to a virus, but in children, there is always a concern that a bacterial infection may be the cause.
- People who take warfarin (Coumadin), prasugrel (Effient), enoxaparin (Lovenox), dabigatran (Pradaxa), rivaroxaban (Xarelto) or apixaban (Eliquis) for anticoagulation to thin their blood may spontaneously bleed into a joint or muscle, causing pain.
- Muscle pain: Muscle pain or myalgia (myo=muscle +algia=pain) is a common complaint and may be due to overuse (mild trauma) or associated with the generalized aches and pain of an infection. Muscles may also become inflamed for a variety of reasons (myositis: myo= muscle + itis=inflammation).
- Muscle cramps: Muscles may cramp, causing significant pain. This may be due to a lack of stretching or an imbalance of electrolytes in the bloodstream. The body needs to have the right amount of calcium, sodium, and potassium for muscles to function well. Calf and foot muscles are particularly prone to cramping, especially at night.
- Muscles will also go into spasm to help protect an injured site. For example, when a hip bone is broken, the muscles that move the hip will go into spasm to help minimize movement of the injury.
- Heat cramps occur as part of the spectrum of heat-related illness due to dehydration and electrolyte imbalances. They may occur immediately after exercising or working in a hot environment or their onset may be delayed for a few hours. Often it is the large muscles of the legs that are involved because of the amount of work they are asked to do.
- Muscle injuries: The muscles in the leg tend to be in balance with each other to promote joint stability and act as shock absorbers for the forces that are generated by walking and running. The quadriceps muscles on the front of the thigh extend or straighten the knee and are balanced by the hamstring muscles in the back of the thigh responsible for flexing or bending the knee. If this balance is lost, the muscle fibers may become overstretched and tear. This is called a strain.
- Hamstring injury: The hamstring (posterior thigh muscle group) is made up of a group of individual muscles known as the semitendinosus, the semimembranosus, and the biceps femoris. While the tendons can be felt at the back of the knee, the muscle originates and is anchored in the pelvis bone. When the muscle contracts, the knee bends and the leg is able to generate power to push the foot away from the ground so that the body can walk. Walking also requires the quadriceps muscles to fully extend the knee so that the heel of the foot can strike the ground and begin the footstep.
If the hamstring muscle tendon fibers are not flexible or if there is too much stretch placed on the structure, these fibers may be damaged if the knee extends too much or too quickly. Muscle or tendon fibers may be stretched or even torn, causing pain and swelling. To protect itself, the muscle may go into spasm, which may cause even more pain.
- Skin abnormalities: Skin abnormalities may cause pain. Lacerations and skin tears, ranging from trauma to ulcers caused by poor blood flow, are among the causes of pain from skin conditions. The skin has numerous nerve fibers that can sense pain, and anything that damages the skin can cause pain. Skin infections may be painful, again because of inflammation and swelling.
- Leg pain in children: Leg pain in children is a special situation. While most leg pain in children is not serious, there are times when the pain has a significant cause. These may include a joint infection causing hip pain, trauma causing damage to growth plates, and pain due to systemic illnesses like Henoch-Schönlein purpura, juvenile rheumatoid arthritis, or rheumatic fever.
"Growing pains" are most likely due to muscle overuse, although they may be associated with a mild stretching as the muscles grow along with bone.
- Children with leg pain who limp or who will not bear weight on the leg should be seen urgently by a health-care provider.
- Diabetes: Diabetes may cause leg pain in a variety of ways. If blood sugar levels are not well controlled over a period of many years, nerves and blood vessels deteriorate and lose their function. Often the damage occurs in the feet and progresses up the leg. With loss of sensation, skin infections and foot injuries may occur without the affected person feeling much discomfort. Alternatively, the nerves may be so inflamed that the patient feels intractable pain. Diabetes also causes blood vessels to narrow and cause symptoms of PAD (peripheral artery disease) or claudication.
People with diabetes are also more prone to infection because of an impaired immune system. Along with poor blood supply to the legs, the ability to heal skin damage is decreased and increases the risk of foot and leg infections.
Medically Reviewed by a Doctor on 12/15/2015
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