Positive bethanechol supersensitivity test in neurologically normal patients

A positive bethanechol supersensitivity test (BST) usually indicates neuropathic detrusor areflexia and warrants neurologic correlation. Seven females, average age thirty-three years, with straining to void and high residual urines, had detrusor areflexia, with a borderline or positive BST, ranging from 19 cm water to 55 cm H2O change in intravesical pressure after 5 mg of subcutaneous bethanechol. However, all patients had a normal neurologic workup, even though 2 patients had insignificant spina bifida occulta. Two of the patients also had prior pelvic surgery, 1 of whom was azotemic, and 4 of the patients had psychosocial problems; factors reported to be associated with a false positive BST. The positive BST is not diagnostic of neurogenic detrusor areflexia because of the many variables that can influence the test. Therefore, the bethanechol supersensitivity test should be interrupted in light of the complete neurourologic evaluation.