Posterior reversible encephalopathy syndrome presenting as acute blindness

Diffuse large B-cell lymphoma (DLBCL) is the most common histologic subtype of non-Hodgkin lymphoma (NHL) accounting for approximately 25–30% of NHL cases. The treatment is based upon stage and extent of disease. In most cases, NHL is treated with systemic chemotherapy and sometimes also radiation. As it is well known, there are numerous side effects to chemotherapy that includes rituximab. We are here to present one rare side effect of treatment called posterior reversible encephalopathy syndrome (PRES). Case Report: This is a 67-yearold female patient with diffuse large B-cell lymphoma with extensive neoplastic involvement of the lower thorax, abdomen, pelvis, and bilateral hydronephrosis with diffuse tumor infiltration of the left renal hilum. She was started on aggressive chemotherapy with dose adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, rituximab (DAEPOCH- R). She was also being treated with intrathecal chemotherapy with methotrexate (MTX). She presented to the emergency room with generalized weakness, confusion, and fevers. She started complaining of loss of vision in the emergency room. A quick ophthalmic examination showed that her pupils were round, regular, and reactive to light with no gross deficits. Computed tomography (CT) of the head demonstrated bilateral, symmetrical vasogenic edema in the right and left posterior frontoparietal and occipital cortices and cerebellar hemispheres. Magnetic resonance imaging (MRI) of the brain showed vasogenic edema in the cerebellum and parieto-occiptal lobes with no restricted diffusion consistent with PRES. Conclusion: Posterior reversible encephalopathy syndrome can result from various etiologies of which hypertensive encephalopathy, thrombotic thrombocytopenic purpura, and eclampsia are common. This case serves to raise awareness among hospitalists that PRES should be a differential diagnosis in the setting of patients receiving certain chemotherapeutic agents presenting with the aforementioned clinical symptoms.