Purpose. We report a case of a 60-year-old male who underwent sequential Onyx embolizations of a cerebral arteriovenous malformation (AVM) which we implicate as the most likely etiology of subsequent acute respiratory distress syndrome (ARDS). Methods. Case report and literature review.
Results. Shortly after the second Onyx embolization procedure, the patient declined from respiratory failure
secondary to pulmonary edema. Clinical entities typically responsible for pulmonary edema including cardiac
failure, renal failure, iatrogenic volume overload, negative-pressure pulmonary edema, and infectious etiologies were
evaluated and excluded. The patient required mechanical ventilatory support for several days, delaying operative
resection. The patient met clinical and radiographic criteria for ARDS. After excluding other etiologies of ARDS,
we postulate that ARDS developed as a result of Onyx administration. The Onyx copolymer is dissolved in
dimethyl sulfoxide (DMSO), a solvent excreted through the lungs and has been implicated in transient pulmonary
side effects. Additionally, a direct toxic effect of the Onyx copolymer is postulated. Conclusion. Onyx embolization and DMSO toxicity are implicated as the etiology of ARDS given the lack of other
inciting factors and the close temporal relationship. A strong physiologic rationale provides further support.
Clinicians should consider this uncommon but important complication.