Unilateral Foot Neuropathy Workup

Critical Initial Assessment

The American Diabetes Association recommends suspecting Charcot neuro-osteoarthropathy (CNO) in diabetic patients with unilateral foot neuropathy, redness, warmth, and swelling, and initiating knee-high immobilization immediately while performing diagnostic studies 1, 2
The American Diabetes Association suggests excluding other acute diagnoses such as infection, gout, and deep venous thrombosis in patients with suspected CNO 1, 2
Pain may be absent or mild due to sensory neuropathy in patients with CNO, so lack of pain does not rule out the condition 1, 2
Infrared thermometry can be used to measure skin temperature, comparing the affected foot to the contralateral foot, with a temperature difference ≥2°C suggesting active CNO 1, 2

The American Academy of Neurology recommends characterizing symptoms such as numbness, tingling, burning, and pain distribution in patients with unilateral foot neuropathy 3
The American Diabetes Association suggests assessing for diabetes mellitus, alcohol use, toxin exposure, medication history, and vitamin deficiencies in patients with unilateral foot neuropathy 3
The American Academy of Neurology recommends using the 10-g monofilament test to diagnose loss of protective sensation (LOPS) in patients with unilateral foot neuropathy 4, 5, 6
The American Diabetes Association suggests evaluating vibration perception using a 128-Hz tuning fork to assess large fiber function in patients with unilateral foot neuropathy 4, 5, 6

The American Diabetes Association recommends screening for diabetes mellitus using fasting blood glucose and HbA1c tests in patients with unilateral foot neuropathy 3
The American Academy of Neurology suggests checking vitamin B12 levels to rule out deficiency as a cause of neuropathy in patients with unilateral foot neuropathy 3

The American College of Radiology recommends plain radiographs of the affected foot and ankle in patients with suspected Charcot neuro-osteoarthropathy 1, 2
The American College of Radiology suggests considering MRI or bone scan if radiographs are inconclusive but clinical suspicion remains high 1, 2

The American Heart Association recommends using the ankle-brachial index (ABI) to assess for peripheral arterial disease in patients with unilateral foot neuropathy 4, 5
The American Heart Association suggests urgent vascular imaging if ABI <0.5, toe pressure <30 mmHg, or transcutaneous oxygen pressure <25 mmHg 4, 5

The American Diabetes Association warns against failing to immobilize immediately when CNO is suspected, as waiting for imaging confirmation can allow irreversible bone destruction 1, 2
The American Academy of Neurology cautions against assuming unilateral presentation rules out diabetic neuropathy, as CNO and compressive neuropathies can present unilaterally in diabetics 1, 2
The American Heart Association emphasizes the importance of excluding peripheral arterial disease, which requires urgent revascularization if severe, in patients with unilateral foot neuropathy 4, 5