Examination of the Diabetic Foot:

- neurological exam for the neuropathic charcot foot:
      - in exam of the diabetic foot note the neurologic findings are usually distal, symmetrical, and sensory; 
      - absent or diminished tendon reflexes are characteristic findings; 
      - ankle jerk is mainly affected and is absent 4 times > knee jerk; 
      - diminution or loss of vibratory sense in the area of the foot and ankle is also common; 
      - development of claw toes occurs as a result of peripheral neuropathy w/ loss of foot instrinsics
      - clawing of toes may result in anterior displacement of the forefoot fat pad leading to metatarsalgia; 
      - in trying to distinguish between a neuropathic foot and an infection, consider observing the foot after it has been elevated for 5 min;
                   - peristence of erythemia is more consisent with infection (and vice versa, disappearance of erythema is consistent with a Charcot foot); 

- neurological exam for pressure ulceration:
     - mal perforant is typical manifestation of diabetic neuropathy and is characterized by chronic painless ulcer on plantar surface of foot over a pressure point;
     - typically are rimmed by callus, and typically are less necrotic than vascular ulcers;
     - in early stages, ulcer appears over 1st, 3rd, or 5th metatarasal head, but w/ concomitant osseous neuropathic changes, midfoot collapse may occur which may lead to excessive pressure in this region and ulceration;
     - w/ neuropathic ulceration, progression to mixed fiber neuropathy results in loss of light touch & vibration sense & in motor neuropathy;
     - when feet are neglected, necrosis under callus results in ulcer w/ overlying hanging edges, which is painless;
               - infection spreads into underlying joint & proximally into plantar space; 

- sensory testing:
     - EMG nerve conduction testing
       - 10-g (5.07) nylon Semmes-Weinstein monofilament test;
     - vibration testing with a 128-Hz tuning fork (more sensitive predictor of early neuropathy)
      - references:
           - The prediction of diabetic neuropathic foot ulceration using vibration perception thresholds. A prospective study
           - The North-West Diabetes Foot Care Study: incidence of, and risk factors for, new diabetic foot ulceration in a community-based patient cohort. 
           - Clinical examination for the detection of protective sensation in the feet of diabetic patients. International Cooperative Group for Clinical Examination Research.

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Wednesday, January 9, 2013 8:23 pm