A case of peripheral neuropathy due to pyridoxine toxicity in association with NOS energy drink consumption (P4.043)

Objective: Peripheral neuropathy is a commonly encountered condition. We describe a case of peripheral neuropathy due to an excess of vitamin B6 from NOS energy drinks.

Background: Pyridoxine, or vitamin B6, is a water soluble vitamin that serves as a coenzyme in biological reactions. The NIH recommends 1.7 mg per day for a man 51 years of age and up. At high daily intakes, pyridoxine has been shown experimentally to cause damage to peripheral neurons. The mechanism of pyridoxine induced peripheral neuropathy is necrosis of the dorsal root ganglion and is duration and dose dependent.

Design/Methods: A 65 year old male presented with recent imbalance, specifically with positional changes. He reported generalized progressive weakness and difficulty with certain tasks such as climbing stairs, getting out of the car, riding his motorcycle, and holding small items. Exam revealed normal mentation, orientation, cranial nerves, motor strength and tone. He had decreased bulk of biceps and decreased sensation to multiple modalities. He had decreased pinprick in bilateral lower extremities in a gradient to the level of the lower shin and in bilateral hands. His vibratory sensation was absent in great toes, medial malleoli, and hands bilaterally. Deep tendon reflexes were 1+ in the biceps and brachioradialis bilaterally, 2+ in the left patella, 0 in the right patella (status post total knee replacement), and 0 in the Achilles bilaterally. Romberg was positive. He was unable to toe walk, heel walk, or tandem walk. Lab values of vitamin B6 were noted to be 62.3ng/mL.

Results: Cause was identified as 6 daily NOS energy drinks, each containing 300% DV B6. Upon cessation and physical therapy, symptoms have improved.

Conclusions: There is a high risk of irreversible nerve damage with continuous ingestion of any causative agent. The cause of peripheral neuropathy is important to identify to decrease the risk for permanent damage.

Disclosure: Dr. Blackburn has nothing to disclose. Dr. Warren has nothing to disclose.