Nearly all causes of foot pain can be categorized under one or more of the following conditions.
Shoes. The causes of most foot pain are poorly fitting shoes. High-heeled shoes concentrate pressure on the toes and are major culprits for aggravating, if not causing, problems with the toes. Of interest, however, was a British study, in which 83% of older women experienced some foot pain. In the study, 92% of them had worn 2-inch heels at some point in their lives. Foot problems, however, were significant even in women who regularly wore lower heels.
Temporary Changes in Foot Size and Shape. Temperature, and therefore weather, affects the feet: they contract with cold and expand with heat. Feet can change in shape and increase in size by as much as 5% depending on whether a person is walking, sitting, or standing.
Poor Posture. Improper walking due to poor posture can cause foot pain.
Medical Conditions. Any medical condition that causes imbalance or poor circulation can contribute to foot pain.
Inherited Conditions. Inherited abnormalities in the back, legs, or feet can cause pain. For example, one leg may be shorter than the other, causing an imbalance.
High-Impact Exercising. High-impact exercising, such as jogging or strenuous aerobics, can injure the feet. Common injuries include corns, calluses, blisters, muscle cramps, acute knee and ankle injuries, plantar fasciitis, and metatarsalgia.
Industrial Cumulative Stress. Because of the effects of work-related repetitive stress on the hand, there has been considerable interest in the effect of work-stress on foot pain. According to one 2000 analysis, there is very little evidence for any significant impact of work on various foot disorders, including hallux valgus, neuroma, tarsal tunnel syndrome, toe deformity, heel pain, adult acquired flatfoot, or foot and ankle osteoarthritis. In general, the foot is designed for repetitive stress and few jobs pose the same stress on the feet as many do on the hands. Nevertheless, certain professions, such as police work, are associated with significant foot pain. More research is needed.
Medical Conditions Causing Foot Pain
Arthritic Conditions. Arthritic conditions, particularly osteoarthritis and gout, can cause foot pain. Although rheumatoid arthritis almost always develops in the hand, the ball of the foot can also be affected.
Diabetes. Diabetes is an important cause of serious foot disorders. It is discussed in a separate section.
Diseases That Affect Muscle and Motor Control. Diseases that affect muscle and motor control, such as Parkinsons disease, can cause foot problems.
High Blood Pressure. High blood pressure can cause fluid buildup and swollen feet. The effects of high blood pressure on the nervous and circulatory systems can cause pain, loss of sensation, and tingling in the feet, and can increase the susceptibility for infection and foot ulcers.
|Blood pressure is the force applied against the walls of the arteries as the heart pumps blood through the body. The pressure is determined by the force and amount of blood pumped and the size and flexibility of the arteries.
Osteoporosis. Osteoporosis, in which bone loss occurs, can cause foot pain.
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Pregnancy. Pregnancy can cause fluid buildup and swollen feet. The increased weight and imbalance of pregnancy contributes to foot stress.
Other Diseases. Diseases that affect the nervous and circulatory systems, such as anorexia, can cause pain, loss of sensation, and tingling in the feet, as well as increase the susceptibility for infection and foot ulcers. A number of conditions, including heart failure, kidney disease, and hypothyroidism, can cause fluid buildup and swollen feet.
Medications. Some medications, such as calcitonin and drugs used for high blood pressure, can cause foot swelling.
Diabetes and Foot Problems
An estimated 15% of people with diabetes experience serious foot problems. They are the leading cause of hospitalizations for these patients. Foot problem develop from problems in the blood vessels and in the peripheral nervous system (the nerves that reach the limbs). Diabetes can also cause changes in the bone structure and soft tissue of the feet.
Infections and Ulcers. People with diabetes are at particularly high risk for infections, such as those resulting from blood vessel injury, which may be severe enough to cause ulcers in the legs and feet. Numbness from nerve damage, which is common in diabetes, compounds the danger since the patient may not be aware of injuries. Being overweight also increases the risk. Even minor infections can develop into severe complications. About one-third of foot ulcers occur on the big toe. Some research suggests that early risk factors for ulcers here may be problems with movement in the toe or ankle.
Charcot Foot. Charcot foot or Charcot joint (medically referred to as neuropathic arthropathy) is of particular note. Between 1% and 2.5% of people with diabetes suffer from this condition. It is caused by abnormalities in the nerves in the feet, which can numb the feet so that the sufferer does not feel pain at first and is not aware of injury. Instead of resting an injured foot or seeking medical help, the patient often continues to walk, causing further damage. Early changes appear like an infection, with the foot becoming swollen, red, and warm. A seriously affected foot can become deformed. The bones may crack, splinter, and erode, and the joints may shift, change shape, and become unstable.
Risk for Amputations. Extensive surgery may be required, and, in extreme cases, amputation may be necessary. Diabetes is responsible for more than half of all the lower limb amputations performed in the US each year and every year there are more than 86,000 foot amputations due to this disease. According to a 2002 study, 25% of these amputations are performed on the toe, 6% mid-foot, 38% below the knee, and 21% above the knee. The remaining 10% of amputations are performed on the hip, pelvis, knee, and other sites.
Prevention of Foot Disorders in Diabetes
Preventive foot care could reduce the risk of amputation in people with diabetes by 44% to 85%. Some tips for preventing problems include the following:
- Patients should inspect their feet daily and watch for changes in color or texture, odor, and firm or hardened areas, which may indicate infection and potential ulcers.
- When patients wash their feet, the water should be warm (not hot) and the feet and areas between the toes should be thoroughly dried afterward. Check water temperature with the hand or a thermometer before stepping in.
- Moisturizers should be applied, but not between the toes.
- Corns and calluses should be gently pumiced and toenails trimmed short and the edges filed to avoid cutting adjacent toes.
- Patients should not use medicated pads or try to shave the corns or calluses themselves.
- Well-fitting footwear is very important. In a 2001 study, 30% of diabetes patients wore shoes that were too narrow. Patients should also avoid high heels, sandals, thongs, and going barefoot. Specific therapeutic shoes, boots, and insoles do not appear to add advantage over careful attention and monitoring of the feet. However, people who are not attentive might do better with such footwear. For example, custom-molded boots (e.g., Conformer Diabetic Boot) are designed to increase the surface area over which foot pressure is distributed. This reduces stress on the ulcers and allows them to heal. Special insoles (e.g., the Rocker insole) have also been designed to reduce pressure on the front of the foot.
- Shoes should be changed often during the day.
- Wear socks, particularly with extra padding (which can be purchased).
- Patients should avoid tight stockings or any clothing that constricts the legs and feet.
- Foot pain, numbness, or tingling is worse at night; diphenhydramine (Benadryl) may help.
A specialist in foot care should be consulted for any problems.
Treating Foot Disorders in Diabetes
About one-third of foot ulcers will heal within 20 weeks with good wound care treatments. Some treatments are as follows:
- In virtually all cases, wound care requires debridement, which is the removal of injured tissue until only healthy tissue remains. Debridement may be accomplished using chemical (enzymes), surgical, or mechanical (e.g. irrigation) means. Hospitalization and intravenous antibiotics for up to 28 days may be needed for severe foot ulcers.
- Hydrogels (Nu-Gel, Intrasite Gel, Scherisorb, Clearsite, Duoderm, Geliperm) are proving to be effective in healing ulcers and are noninvasive and soothing. They should be applied and covered with a dressing.
- Charcot foot is initially treated with strict immobilization of the foot and ankle; some centers use a cast that allows the patient to move and still protects the foot. A 2001 study in the UK concluded that a single dose of pamidronate, a bisphosphonate, reduces bone turnover, symptoms, and disease activity. When the acute phase has passed, patients usually need lifelong protection of the foot using a brace initially and custom footwear.
A number of recent investigative measures include the following:
- A number of treatments that use human skin equivalent or HSE (Dermagraft, Apligraf, Regranex) are now available that stimulate new cell growth and help heal skin ulcers or use cultures of human skin cells. Studies are showing that HSE promotes healing and the risk for rejection of such grafts is low. Adverse effects include infections at other sites.
- Silver-containing wound dressings (Acticoat, Silverlon) have shown promise for wound care in some studies due to their anti-microbial properties, and may provide new avenues for managing diabetic ulcers. However, one study study suggested that silver may be toxic to some cell types.
- Administering hyperbaric oxygen (oxygen given at high pressure) is showing promise in promoting healing and preventing amputation.
- Granulocyte-colony stimulating factor, or G-CSF (filgrastim, Neupogen, Amgen) is showing promise as an effective alternative to antibiotics. Studies are reporting that G-CSF accelerates healing and significantly reduces the need for surgery.
- Total-contact casting (TCC). This approach uses a cast that is designed to contact the exact contour of the foot and distribute weight along the entire length of the foot. It is usually changed weekly. In one trial, it healed ulcers in nearly 90% of selected patients. It is also useful for Charcot foot.
- A device that compresses the foot (NuPulse) appears to increase the circulation, reduces edema (swelling) and improves wound healing.
- Light therapy called monochromatic near-infrared photo energy (MIRE) may help reduce pain, improve balance, and improve sensation in the feet of patients with peripheral neuropathy.
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