Dr. Castillo presents an unusual case of a carotid-cavernous fistula with Horner syndrome at EUNOS 2017 conference

From September 10^th-13^th the XIII conference of the European Society of Neurophthalmology (EUNOS 2017) was held in Budapest, Hungary.

The congress is a showcase for the latest advances in the fields of neurology and ophthalmology, with a special focus on pathophysiology and therapy. Amongst those attending were international experts in these fields, such as Dr. Lorena Castillo, head of the Neuro-ophthalmology and Teaching Departments at ICR.

Presentation of Dr Castillo’s poster at EUNOS 2017

The conference included a poster presentation dedicated to the afferent visual system and, amongst others, anisocoria and disorders of the superior visual function. It was during this presentation session that Dr. Castillo presented an unusual case of Horner syndrome as the first manifestation of carotid-cavernous fistula. The patient was a 61 year old man who had begun with a sudden ptosis (droopy eyelid) in the left eye, anisocoria (the left pupil was smaller than the right) and eye pain.

Horner Syndrome and carotid-cavernous fistula

Horner syndrome is caused by an interruption in the chain of 3 neurons from the oculosympathethic pathway, which begins in the part of the brain known as the hypothalamus, descends through the head, the neck and the upper part of the thorax and then rises until it reaches the face and eyes, meaning that changes to the pupils or eyelids can have their origins in injuries very far from the eyes.

In the cavernous sinus, the third order neuron is closely linked with the tunica externa of the internal carotid artery. Carotid-cavernous fistulas are irregular communications between the carotid artery system and the cavernous sinus, and their speed of flow can be high or low. Low-flow fistulas normally occur in middle-aged women (our patient was a man) and the orbital symptoms are normally notable (in our case there were none).

The study showed that carotid-cavernous fistulas can show without characteristic orbital signs (red eyes, “bug-eyed”…) and reiterated that Horner syndrome with eye pain on the same side suggests an injury of the third order neuron in the oculosympathetic pathway. These results conclude that, although unusual, an isolated Horner syndrome may represent the first sign of a carotid-cavernous fistula.

Abstracts from the EUNOS 2017 conference have been published in the latest edition of Neuro-ophthalmology magazine