After discussing potential sources of exposure, our patient decided to move out of the house he shared with his ex-wife. He started to recover soon after moving out. Two weeks after his clinic visit, he no longer needed a cane to walk, and his blood arsenic level had dropped to 6 µg/L. Two months after his clinic visit, the patient’s blood arsenic level was undetectable. The patient’s peripheral neuropathy symptoms continued to improve.
The source of this patient’s arsenic exposure was never confirmed. The exposure could have occurred in Puerto Rico or in Louisiana. Even though no one else in the Louisiana home became ill, the patient was instructed to contact the local health department and water department to have the water tested. However, when he returned to the clinic for follow-up, he had not followed through.
THE TAKEAWAY
When evaluating causes of peripheral neuropathy, consider the possibility of heavy metal toxicity, which can be easily overlooked by the busy clinician. In this case, the patient initially experienced asymmetric paresthesia that gradually increased to burning pain and weakness, with reduced motor control bilaterally. This was significant because mechanical low back pain and the associated discogenic radiculopathy would be unilateral, manifesting with asymmetric paresthesias and pain.
Our patient’s leg symptoms, the constellation of forgetfulness, confusion, and agitation, and his sleep issues prompted us to look outside our normal differential. Fortunately, once arsenic exposure ceases, patients will gradually improve because arsenic is rapidly cleared from the bloodstream.3,6
CORRESPONDENCE
Charles W. Webb, DO, CAQSM, FAMSSM, FAAFP, Department of Family Medicine, 1501 Kings Highway, PO Box 33932, Shreveport, LA 71130-3932; charles.webb@lsuhs.edu