INTERPRETATION OF POSITIVE EDROPHONIUM (TENSILON) TEST IN PATIENTS WITH END-STAGE RENAL-DISEASE

Many patients with end-stage renal disease (ESRD) have signs and sympt oms of easy fatigability, fluctuating weakness, apathy, dry mouth, and blurring of vision. These symptoms can be confused with disorders of neuromuscular transmission. When present, the physician may want to de termine whether the patient has myasthenia gravis-the commonest of all neuromuscular disorders-and administer the edrophonium (Tensilon) tes t. An unequivocally positive response to the test must be interpreted with caution in ESRD. However, the exact mechanism of a positive respo nse is unclear but may be explained by metabolic abnormalities related to end-stage renal disease, i.e., uremic toxins, disordered calcium m etabolism, abnormal neuromuscular mechanism, associated neurological d isorders, or myopathic processes in uremia, all of which can affect ne uromuscular transmission.