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Patient presents with edematous right foot
Following neuropathy, this is the second most common problem contributing to ulcerations in people with diabetes.
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A 77-year-old Hispanic, predominately Spanish-speaking man is seen in the hospital for consultation of ulceration to the lateral aspect of his right foot. The patient related he sustained a traumatic injury to the area three months earlier with failure to heal. Prior to admission, he was being treated with oral amoxicillin-clavulanate potassium (Augmentin, GlaxoSmithKline) for a foot infection, without response. His past medical history was significant for diabetes, hypertension and dysphagia.
Lower extremity physical examination revealed an edematous and erythematous right foot with associated increased warmth. A 2-cm full-thickness ulceration with exposed underlying fascial tissue was noted about the lateral right foot adjacent to the fifth metatarsophalangeal joint with surrounding tissue necrosis (figures 1 and 2). Trophic skin changes and absence of pedal hair were observed. Pain was elicited upon palpation both laterally as well as to the plantar midfoot extending medially to the sub third metatarsal head, indicating plantar space inspection. The fifth metatarsal head was easily palpable although not visible. Mild malodor was noted. Vascular examination revealed absent palpable pulses to the affected foot as well as to the contralateral limb. Neurologically, the patient was insensate from the right midfoot to proximal foot as well as to the left foot. MRI was suggestive of osteomyelitis about the fifth metatarsal head.
Given the patient presentation, what is the underlying etiology of this patient’s pathology?A. Neuroischemia.
B. Peripheral arterial occlusive disease.
C. Neuropathy.
D. Venous insufficiency.
CASE DISCUSSION
Vascular surgery was consulted. Doppler/ankle-brachial index with waveforms revealed flattened waveforms. Angiogram revealed decreased tibial and peroneal trunk run-off indicating peripheral arterial occlusive disease. Surgical debridement was done immediately following the femoral-tibial bypass surgery. However, minimal bleeding was appreciated. Three weeks later the patient demonstrated healthy bleeding during wound bed preparation for a skin graft substitute (figures 3 and 4).
The answer is B.
 Patris Toney |
Peripheral arterial occlusive disease is the second most common problem contributing to ulcerations in people with diabetes, following neuropathy. In the foot, peripheral arterial disease may lie dormant without the patient noticing. Subtle changes may begin to occur such as rest pains or foot cramps. Patients may even experience uncomfortable pains described as tingling. Neuropathic patients may initially be asymptomatic regarding pain, but eventually as the occlusion progresses the pain increases. This anoxic pain is typically relieved by use of narcotic medications. As for ulcerations, they are seen to occur on the legs, ankles, heels and feet. The medial and lateral foot about the first and fifth metatarsophalangeal joints, respectively, are classic areas where breakdown occurs. Secondary irritation or pressure with difficulty in healing even in the presence of offloading also may occur. Early on, the wound may appear stable and even give the illusion that it is responding to treatment and slowly stabilizing before potentially destabilizing and regressing. Additionally, infections are seen to befall the patient with transient response to oral antibiosis. Furthermore, secondary to the long duration of the ulceration, osteomyelitis ensues.
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| Figures 1 and 2: Appearance of right lateral foot ulceration at time of revascularization and initial debridement. Note dorsal and plantar lines of demarcation (red arrows) outlining the erythema at time of admission with residual mild edema. Also note, the necrotic tissue (black arrows) and involvement of plantar soft tissue probing during surgery (yellow double arrow). | |
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| Figures 3 and 4: Appearance of surgical site at time of secondary surgical debridement prior to skin graft substitute placement three weeks post femoral-tibial bypass. Source: Patris Toney | |
Pathologies with PAD
Both macrovascular and microvascular pathologies are seen in PAD. A major cause attributed to the cause of PAD is atherosclerosis. Other causes may include trauma, thromboembolic events, entrapment or inflammatory processes. Conditions such as diabetes, hypertension, cigarette smoking, hyperhomocysteinemia and dyslipidemia are known to increase the risk for developing atherosclerosis.
In the PAD population, a few patients may experience intermittent claudication, which manifests typically as muscle cramping with ambulation and cessation upon rest. These patients may benefit from antiplatelet therapies, rheological agents, exercise and smoking cessation. Another subset of patients may suffer from more advanced PAD with microvascular involvement that manifests as peripheral arterial occlusive disease. These patients may present with or without ulceration in the presence or absence of focal gangrenous changes. Trophic skin changes may also be noted. These patients often suffer disturbing rest pain relieved with dependent positioning of the affected limb. Such patients are less likely to benefit from pharmaceutical or exercise intervention. Revascularization, as an integral part of limb salvage, is more so the treatment of choice at this point with the urgency of surgical intervention dictated by the patient’s overall presenting condition.
To facilitate vascular assessments, pedal pulses, dorsalis pedis, peroneal and tibial, should be elicited and compared with the contralateral limb. Hand held dopplers may be used in the office or at bedside to obtain supplement vascular evaluation. However, more extensive vascular evaluations should also be ordered such as dopplers with waveforms and toe pressures. Vascular service should also be consulted as soon as possible so further diagnostic tests such as an angiogram can be ordered. In patients with peripheral arterial occlusive disease presenting with poorly healing ulcers or with infected, progressively deteriorating ulcerations, especially about the lower extremity, revascularization is important regarding preventing or minimizing lower limb amputation.
Patris Toney, DPM, MPH, is a Fellow in the Center for Lower Extremity Ambulatory Research, and a Fellow at the National Center for Limb Preservation, Ill.