Preanesthetic severe postural hypotension following 5-aminolevulinic acid pretreatment in patients for photodynamic diagnosis-assisted urological surgery.

BACKGROUND: 5-Aminolevulinic acid (5-ALA) is utilized for photodynamic diagnosis-assisted (PDD) surgery. However, it has been associated with vasodilation, hence, occasional hypotension. CASE PRESENTATION: We encountered two patients who had severe postural hypotension following 5-ALA pretreatment prior to an operation. They were scheduled for urological PDD surgery, but upon standing to walk to the operation room, they felt sick because of severe hypotension. One of them underwent the surgery after recovery, but the other surgery was canceled due to a prolonged hypotension that lasted for more than a day. CONCLUSIONS: Severe postural hypotension may develop as a result of the high concentration of porphyrin precursors, which may affect the nervous system. Severe postural hypotension may be due to 5-ALA-induced autonomic dysfunction as well as vasodilative action of 5-ALA. These observations suggest that in addition to the careful monitoring of patients' vital signs, standing should be avoided following 5-ALA pretreatment.