A 65-year-old woman presented to the office for evaluation of burning parathesias, “painful numbness,” and intermittent lancinating pains of the left and right foot of 9 months duration. She related the occurrence of her pain to be primarily at night and during periods of non-weight bearing rest, such as while sitting in a chair. She related a significant inability to obtain a restful sleep for the previous 3 months. Prior treatment with amitriptyline 50 mg failed to resolve her symptoms. She evaluated her discomfort at its worst as 7/10 and on average 5/10.
The patient had a 3-year history of type 2 diabetes mellitus for which she took metformin and glipizide. She was also under management for hypertension with hydrochlorothiazide.
Examination revealed bilateral 3/4 posterior tibial pulses and 2/4 dorsalis pedis pulses. The patient related no history of claudication. Capillary filling time was less than 3 seconds to her toes. Skin color, temperature, and turgor appeared normal on evaluation. There was no clubbing, cyanosis, or subungual infarctions noted on examination of her toes.
Neurologic evaluation revealed no muscle wasting. Muscle tone and power were normal to testing. No ataxia, nystagmus, or cerebellar signs were noted. Her Achilles reflexes were 1/3 bilaterally. She demonstrated no loss of 10 g filament perception. Vibratory sensation was diminished in the left and right forefeet. Temperature and pain perception was normal to testing. She demonstrated no findings to suggest radiculopathy. Cranial nerve function was grossly intact. Provocative testing of the posterior tibial nerves at the ankle elicited tingling parathesias into the plantar arches and forefeet, suggestive of a tarsal tunnel syndrome. The plantar skin of both feet was somewhat erythematous and anhidrotic, suggestive of sudomotor deficit.
Musculoskeletal evaluation revealed no significant deformities.
Radiographic evaluation of the left and right feet and ankles revealed mild vascular calcification and osteopoenic changes of the bones of the feet.
Initial clinical impression was that of symptomatic large fiber neuropathy associated with diabetes mellitus. The possibility of a tarsal tunnel compression neuropathy was also entertained.
Nerve conduction studies were obtained and interpreted as consistent with a peripheral neuropathy and indeterminate for entrapment of the posterior tibial nerve bilaterally.
Laboratory data revealed a normal complete blood count with differential and normal electrolytes. Hemoglobin A1c was 6.2. Renal function studies revealed a blood urea nitrogen of 24 and a serum creatinine of 1.1. Serum homocysteine level was 13.4.
The patient was placed on Metanx 1 daily and was asked to return for follow-up examination in 4 months.
At the time of her re-evaluation, the patient reported subtotal resolution of her parathesias. She was able to sleep without awakening due to pain in her feet with the onset of relief initially noted 21 days into therapy. She reported complete resolution of her “painful numbness” and a reduced frequency of her lancinating type pain. She regarded her pain at the time of her re-evaluation as 3/10 at its worst and 1/10 on average.
The patient was continued on therapy for an additional 90 days and again re-evaluated. She reported no additional change in her status and continued to enjoy a substantial diminution in the frequency and intensity of the parathesias and dysthesias for which she sought evaluation and management.
Commentary
David E. Allie, MD
This patient had exhibited severe pain at night for 3 months prior to treatment and exhibited an excellent response. The patient likewise should have a thorough cardiovascular evaluation, as she has multiple risk factors. The concept of diabetes as a cardiovascular disease is becoming well accepted. In my practice, it is not unusual for the wound care specialist or podiatrist to refer a patient for his or her first cardiovascular evaluation. This is especially important in the patient with diabetes who has a high incidence of silent asymptomatic coronary and carotid artery disease.
|
