57 yo M with PMHx of uncontrolled DM and HTN who presents with 3 weeks of intermittent visual problems. Patient reports he sees flashes on both left sides of visual fields in both eyes. He is also unable to process 3D spacing and has trouble walking and reading due to vision problems. Episodes of symptoms tend to last 3-4 hours. Additionally patient complaints of mild R parietal headache that usually coincides with visual symptoms. Denies weakness or sensation deficits, dizziness, seizures or fever.
Physical examination in the ED is remarkable for absent vision on both left sides of his visual fields. Detailed eye and neurological exam reveal no additional abnormalities
Labs are only remarkable for hyperglycemia of 600 mg/dl, with no ketones or acidemia.
Management of hyperglycemia did not improve symptoms.
Brain CT and MRI were performed showing no abnormalities that could explain clinical picture.
What is the name of this patient’s deficit and where is anatomically located ?
Answer: left side , homonymous hemianopia and damage is located anywhere along the retrochiasmal visual pathway
Homonymous hemianopia is hemianopic visual field loss on the same side of both eyes occurring with with complete lesions anywhere along the retrochiasmal visual pathway (see picture)
The patient was admitted to neurology service. Given negative neuroimaging, an EEG was perfomed to assess for focal seizure activity.
EEG showed multiple R occipital lobe seizures, that correlated clinically with patient’s intermittent focal visual deficits. Patient was loaded with IV Keppra and then started on 750 mg BID with resolution of symptoms.
Zhang X, Kedar S, Lynn MJ, Newman NJ, Biousse V. Homonymous hemianopias: clinical-anatomic correlations in 904 cases. Neurology. 2006;66(6):906.
Thanks Dr. Schnapp for an interesting case.