Abstract
Purpose :
We present a case of severe biltaral visual loss caused by taking overdose of Praziquantel and Triclabendazole.
Methods :
We observed the development and recovery of toxic retinopathy by swept-source optical coherence tomography (SS-OCT).
Results :
This patient presented to our clinics with acute onset of severe bilateral visual loss for one month after ingesting 1g praziquantel and 2g triclabendazole daily for 4 days. His visual acuity was light perception bilateral. Anterior chamber examination was unremarkable. Cancer-associated retinopathy and melanoma-associated retinopathy were already excluded. SS-OCT showed outer plexiform layer thinning, outer nuclear layer disrupted, external limiting membrane, myoid zone, ellipsoid zone and interdigitation zone disappeared, and increased reflex of the RPE/Bruch’s complex in macular region. It also showed increased diameter of choroidal vessels (Figure 1). Ganglion cell layer-inner plexiform layer (GCL-IPL) in the macular region revealed significant loss. He was diagnosed bilateral toxic retinopathy and prescribed mecobalamin 0.5mg three times daily. One month later, the visual acuity increased to 0.1 bilateral. On SS-OCT, retinal thinning progressed, in which outer nuclear layer most significant. Diameter of choroidal vessels decreased. GCL-IPL in the macular region presented progressive loss. It was interesting that ellipsoid zone reappearance was observed in foveal, which could explain the improvement of patient’s central visual acuity (Figure 2).
Conclusions :
Praziquantel (PZQ) and triclabendazole (TCBZ) are common anthelmintics applied worldwide. The known adverse effects of PZQ and TCBZ include abdominal discomfort or pain, vomiting, diarrhea and headache. The recommended total dosage of PZQ is 40-60mg/kg, and TCBZ 10-30mg/kg. To the best of our knowledge, this is the first case of toxic retinopathy related to overdosage of praziquantel and triclabendazole. Further animal toxicity research would be necessary for approving this phenomenon.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.