Gabby is a 1 year old spayed female Labrador Retriever dog with a recent onset of a seizure disorder. Gabby was previously removed from a seeing eye dog program due to a significant left visual field deficit despite normal ophthalmic exam. An MRI examination of her brain was ordered to explore possible structural etiologies for her seizures. The rather striking MR images revealed an absence of the right cerebral hemisphere with a marked dilation of the lateral ventricle on the right. A diagnosis of congenital hydranencephaly of the right cerebrum was reached. Differentials for congenital hydranencephaly include teratogenic viral infections (Bunyaviruses), inherited conditions, and maternal intoxications.
Because Gabby’s condition is relatively static at this age, she may be expected to live a relatively normal life provided adequate seizure control can be accomplished with medications.