|
||||||
|
|
|
|
|||||||||||
|
|||||||||||||
| ||||||||||||||||||||||||||||||||||||||
Days after crafting a dollhouse for his granddaughter, a 57-year-old man heard a strange tap on the linoleum floor. The patient, who has type 2 diabetes, visited David G. Armstrong, DPM, PhD, with a roofing nail that was stuck in his foot and making the noise.
"It's the kind of wound that gets infected and ultimately leads to amputation," says Armstrong, professor of surgery, chair of research, and assistant dean at the Dr. William M. Scholl College of Podiatric Medicine at Rosalind Franklin University of Medicine and Science in North Chicago. "We often will have people come to the emergency room with the shoe nailed to the foot."
Peripheral neuropathy inhibits some patients with diabetes from feeling what Armstrong calls the "gift of pain," which alerts them to problems. Damage occurs in silence, unless care providers remain vigilant in the absence of symptoms.
Nothing can beat the basic prevention of diabetic foot problems with good glucose control, regular foot exams by a clinician, and daily self-exams by patients (DOC News, September 2005). For the high-risk foot, or patients who already have ulcers or other problems, there are some additional steps clinicians can take to maintain the health of their patients' feet.
The majority of foot ulcers occur in patients who have had diabetes for a long time and who have sustained "hits" in terms of their sensation, circulation, and joint flexibility. The primary care physician should be searching for these patients with his or her foot examinations. As the "hits" are detected, the patient should be educated about care for the high-risk foot and referred as needed for special shoes.
|
When ulcers arise, the patient should be referred to specialists for definitive vascular evaluation and possibly revascularization procedures, and for unweighting of the affected limb and appropriate wound care.
PROPER FOOTWEAR
Diabetic shoes almost always are recommended for patients with poor circulation, inadequate glucose control, or existing foot problems, says Michael Maier, DPM, CWS, director of the Lower Extremity Wound Clinic in the cardiovascular medicine department at the Cleveland Clinic. Accommodative orthotics eliminate excessive pressure points.
|
"The shoe is the medication for the foot, just like the tablet is for diabetes," says Javier La Fontaine, DPM, CWS, medical director of the podiatry clinic at the Texas Diabetes Institute and assistant professor at the University of Texas Health Science Center in San Antonio. "As long as you have your shoe on, your foot is going to be protected from any complications."
New types of extra-depth shoes, also referred to as diabetic shoes, and insoles are being developed with different kinds of materials to prevent ulcerations.1,2 Patients who are more prone to foot problems should wear diabetic shoes religiously, even on special occasions, experts say, although some patients with diabetes may be able to stick with regular footwear. For them, an athletic shoe with good arch support and a flexible sole is best. At home, custom-molded slippers are a wise choice.3
"We tell [patients] to avoid narrow pointy shoes or hard dress shoes," Maier says. Shoes with hard ridges and seams fall into this category because they can rub the skin and create sores.
IDENTIFY ULCER RISK
La Fontaine says gait analysis systems have been developed that help clinicians identify areas of the foot at risk for ulcerations. Among these technologies, the EMED-SF plantar pressure analyzer enables physicians to detect areas under maximum pressure.4
He also notes the utility of new devices to measure skin temperatures. One
of these, a handheld, battery-operated device, features an infrared sensor at
the tip of a rubber neck. After the clinician obtains a baseline reading,
patients should monitor for temperature changes two to four times a day,
depending on how active they are, by pointing the sensor to areas on the
bottom of their feet. A surge of 
4°F above the baseline indicates that
a specific area is at risk for
ulcerations.5
Research shows at-home patient self-monitoring of daily foot temperatures may be an effective tool to prevent foot complications in patients at high risk for lower-extremity ulceration and amputation.6
WHEN TO REFER: PULSES, ABI OFFER GUIDANCE
Any ulcer, blister, or foot sore should be evaluated by a specialist, according to Frank LoGerfo, MD, chief of vascular surgery at Beth Israel Deaconess Medical Center in Boston. When primary care providers can't feel the pulses, that's reason enough to refer to a vascular surgeon for a baseline circulation assessment.
The primary care clinician may consider measuring ankle brachial index (ABI), which is more reliable than examining pulses to diagnose peripheral arterial disease (PAD), says endocrinologist Peter Sheehan, MD, director of the Diabetes Foot and Ankle Center at the Hospital for Joint Diseases Orthopaedic Institute in New York.
"The ABI is performed with the patient supine, using a blood pressure cuff and a handheld Doppler," Sheehan says. "It is calculated by dividing the highest pressure in each ankle by the highest brachial pressure."
An ABI ratio <0.9 confirms PAD. "Patients with diabetes often have medial arterial calcification, making the ankle pressure noncompressible," Sheehan says. "This will give an ABI >1.3, in which case other tests, such as a toe systolic pressure, should be done" by a vascular specialist.
Even before problems arise, "don't try to take care of people's feet
without the assistance of a local podiatrist," cautions James McGuire,
DPM, PT, CPED, CWS, director of the Leonard S. Abrams Center for Advanced
Wound Healing at Temple University School of Podiatric Medicine in
Philadelphia. "Always examine diabetics' feet on every visit. And look
at the footwear that they choose to wear, because it may be very
dangerous." 
Sizing Up Hyperbaric Oxygen
Adjunctive therapy not for every patient
Nestled in a glass tank under atmospheric pressure, a patient breathes 100%
oxygen—much more than he or she usually gets breathing normal air. This
hyberbaric oxygen chamber treatment is an adjunctive therapy for ulcers and
amputations.
"It will force your red blood cells to bind to the oxygen that you're breathing," says Javier La Fontaine, DPM, CWS, medical director of the podiatry clinic at the Texas Diabetes Institute. "Eventually, your vascular system delivers oxygen to the wound to increase the chances of healing. It doesn't mean that every ulcer will heal with this."
About 60 treatments may be necessary, depending on the wound's size, he estimates. Medicare covers the therapy, but insurance companies have been reluctant to pay for it, with costs about $400–$600 per session. Sometimes patients can watch a movie during the 90-minute procedure. "Most of the time, the patient is claustrophobic," La Fontaine says.
While an important modality, hyperbaric oxygen is not a fi rst-line treatment in most cases, says Michael Maier, DPM, CWS, of the Cleveland Clinic, where it is not offered as a therapeutic option. "It's usually reserved for patients who have poor circulation to a wound but are not good candidates for vascular intervention or revascularization procedures."
Signs of Charcot: Be Alert to Foot Irregularities
Both patient and provider should notice if one foot looks different from the other, says Michael Maier, DPM, CWS, of the Cleveland Clinic. Other elements of concern include breaks in the skin or a change in the shape of the foot, especially in the arch height. These may be signs of Charcot foot or Charcot arthropathy, a degenerative joint condition. In the setting of peripheral neuropathy, painless and progressive bone and joint damage can occur without patient awareness. Over time, this can lead to profound foot deformity.1,2
An estimated 60–70% of people with diabetes develop nerve damage that can lead to Charcot disease. About 0.5% of this group develop Charcot foot, according to the American Diabetes Association. In most instances, it strikes after age 50, and after patients have had diabetes for 15–20 years. While neuropathy develops over decades, Charcot foot may develop over weeks to months.
"Charcot is a very aggressive bone and joint destructive process," Maier says. "Some authors will refer to it as degenerative arthritis with a vengeance."
The foot's bony architecture is altered, which may impair normal foot function. An injury to the foot or ankle can initiate a cascade of events, possibly resulting in limb loss. The key to halting this cascade is early detection and appropriate treatment. Clinicians should be aware of signs of acute Charcot disease, including redness, warmth, swelling, and pain. X-rays are used to confirm the diagnosis.
The message to patients with diabetes is to seek prompt medical attention for foot injuries and see a podiatrist regularly for routine foot exams.
"[Charcot] is a smaller fraction of the foot ulcers we see," says Frank LoGerfo, MD, of Beth Israel Deaconess Medical Center in Boston. These patients "have perfectly normal circulation" despite severe neuropathy, he says.
|
Footnotes
Clinical Care of the Diabetic Foot is an affordable handbook that suggests strategies for providing state-of-the-art foot care and is beneficial for the clinician and the motivated patient with diabetes. It is available online at the American Diabetes Association bookstore, http://store.diabetes.org.
References
2. Praet SF, Louwerens JW: The influence of shoe design on plantar
pressures in neuropathic feet. Diabetes Care 26: 441–445, 2003.
3. Singh N, Armstrong DG, Lipsky BA: Preventing foot ulcers in
patients with diabetes. JAMA 293: 217–228, 2005.
4. Stess RM, Jensen SR, Mirmiran R: The role of dynamic plantar pressures in diabetic foot ulcers. Diabetes Care 20: 855–858, 1997.[Abstract]
5. Armstrong DG, Lavery LA, Liswood PJ, et al.: Infrared dermal
thermometry for the high-risk diabetic foot. Phys Ther 77: 169–175, 1997.
6. Lavery LA, Higgins KR, Lanctot DR, et al.: Home monitoring of foot
skin temperatures to prevent ulceration. Diabetes Care 27: 2642–2647, 2004.
2. Armstrong DG, Todd WF, Lavery LA, et al.: The natural history of acute Charcot's arthropathy in a diabetic foot specialty clinic. J Am Podiatr Med Assoc 87:272–278, 1997.[Abstract]
CiteULike 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
| ||||||||||||||||||||||||||||||||||||||
|
||||||
|
| DOC News | Diabetes | Diabetes Care | Clinical Diabetes | Diabetes Spectrum |
