Charcot Foot: A Potential Risk Factor for Diabetic Patients, is a valuable report on an under diagnosed problem written by Jennifer Webb, Doctor of Pharmacy Candidate, FAMU. You may want to print this out and hand it to your patients.
The condition known as Charcot arthropathy or Charcot foot has become an elevated risk factor for the diabetic population. The American College of Foot and Ankle Surgeons say that Charcot foot’s prevalence appears to be growing as more Americans are diagnosed with diabetes. This condition is classified as a pedal neuropathic joint disease that progressively deteriorates weight bearing joints, usually in the in the foot or ankle. The acute phase of the condition is characterized by edema, erythema, and elevated foot temperature. It causes significant trauma and injury to the bony structure of the foot. If gone untreated this complication could lead to foot deformities causing abnormal pressure, foot ulcers, and possibly amputation. Once this condition occurs it can not be reversed, but damage can be stopped if it is detected early.
The exact cause is unknown but there are two theories that attempt to explain the pathogenesis of Charcot foot. The neurotraumatic theory suggests that cumulative mechanical strain on patients with nerve damage leads to progressive fractures. While the neurovascular theory claims that
there is increased blood flow the lower limbs due to sympathetic inervation. The subsequent loss of vasomotor control allows blood vessels to dilate, thus increasing peripheral blood flow. The increased blood flow causes arteriovenous shunting which accounts for hyperemia and bone growth. Most cases often occur in patients suffering from diabetic peripheral neuropathy or other neuropathic conditions. Nerve damage decreases the bodies ability to sense stimuli, especially pain, and decreases muscular reflexes. Repetitive trauma leads to the physical damage of ligaments, cartilage, and bone. In a recent study it was discovered that obesity combined with neuropathy can significantly increase the incidence of developing neuropathic arthropathy.
According to the American Diabetes Association 60-70% of diabetic patients develop nerve damage that could possibly lead to Charcot arthropathy, 0.5% of those patients eventually patients with diabetes alone were approximately 59% more likely to develop Charcot foot. Patients with neuropathy were 14 times more likely, and patients with both diabetes and neuropathy were 21 times more likely to develop the complication. It was also reported that diabetic patients between the ages of 55-65 years old diagnosed for more that 6 years and possessing an A1c greater than 7% are associated with an increased incidence of Charcot arthropathy.
Charcot foot occurs in three stages commonly called Eichenholtz stages. Stage 1 is the acute inflammatory phase characterized by swelling, redness, and increased warmth. If radiographs are performed they will often show fractures and dislocations. The primary concern in this stage is to rule out a possible infection such as cellulitis, a common condition in diabetic patients. Stage 2 is defined as the subacute phase that shows signs of healing, decreased swelling, elevated foot temperature, and radiographic indications of osteoclastic activity. Stage 3 is the chronic or “cool” phase that is marked by the consolidation and resolution of inflammation.
Diagnosis of Charcot foot should be made by a clinical examination. Making a proper diagnosis can be difficult due to the fact that this condition can often mimic cellulitis or deep vein thrombosis (DVT).” It may also be difficult to make a diagnosis due to peripheral neuropathy masking pain stimuli. It is important to remember that pain and tenderness can be diminished or completely absent. A physician should do laboratory tests such as a radiograph and nuclear scan to differentiate from Charcot foot and an infection. Radiographs can potentially reveal bony destruction, fragmentation, and bony remodeling which are all signs of Charcot foot. Swelling of the foot and lower legs are often associated with the presence of DVT’s. According to physicians the foot is predominantly swollen in Charcot arthrophy as compared to cases of DVT where the swelling is located predominantly in the lower legs.
Findings on plain radiographs can be normal during the acute phase of Charcot foot. Radiographic changes take time to develop and may appear absent during initial scans. The potentially false reading also makes diagnosing this condition difficult. If Charcot foot is suspected treatment and a series of radiographs should be preformed.
NICE guidelines suggest that patients strongly suspected of Charcot foot should be referred to a diabetic foot care specialist. Patients should be properly immobilized using a weightbearing total contact cast or an Aircast boot. Immobilization and protection of the foot are the recommended approaches to managing the acute Charcot process. Strict immobilization of the foot and ankle with a weightbearing total contact should be conducted for 3-6 months. A study published in Foot and Ankle International discovered that patients who used total contact casts decreased their risk of developing ulcerations and were able to wear custom footwear in about 9 weeks.
Patients should be educated on Charcot foot complications, protective footwear and routine foot care. Once the casts can be removed a brace is commonly used to protect against foot injury. Braces can remain on the foot for 6 to 24 months. After the braces are no longer needed custom foot wear is then utilized to relieve pressure. Custom orthopedic footwear is considered to be long term management for the prevention of Charcot foot complications. Lastly regularly scheduled foot care by an orthopevdist or podiatrist should be considered as a life long preventative measure.
Proposed treatments of the Charcot porcess have included the use of Bisphosphonates. According to SIGN guidelines there is not sufficient evidence to support the routine use of bisphosphonates for the treatment of Charcot foot. However a recent study indicated that Bisphosphontes could be helpful in stopping the acute phase of arthropathy in some patients. The use of pamidronate resulted in decreased erythema, temperature, and bone growth. Additionl research is need to further evaluated this drugs efficacy.
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