Computed tomographic finding of bilateral optic nerve head drusen in a dog – a case report

Optic nerve head drusen are acellular calcified deposits in the optic nerve head reported in humans. A six year old, male, Rottweiler dog with a history of respiratory distress and epistaxis for the previous two months was anaesthetised and a computed tomographic scan of the head was performed. The axial view of the computed tomography scan with a slice thickness of 1mm was viewed in a soft tissue window (380x40 HU). There was an incidental discovery of a characteristic discrete round hyper dense area in the optic nerve head region in both eyes during the routine computed tomographic scan. The Hounsfield Unit of the optic nerve head drusen in the right eye measured 91 HU, of 2 mm2 and in the left eye 131 HU of 1 mm2 confirming the diagnosis of optic nerve head drusen. To the authors’ knowledge, this is the first report of optic nerve head drusen in a dog.