Chiasmal syndrome caused by arteriovenous malformations

Area of Science:

• Ophthalmology
• Neurology
• Radiology

Background:

• Chiasmal syndromes, affecting vision, are infrequently caused by arteriovenous malformations (AVMs).
• Only four cases of AVM-induced chiasmal syndrome have been previously documented in medical literature.

Purpose of the Study:

• To report and analyze two additional cases of chiasmal dysfunction attributed to AVMs.
• To identify potential diagnostic indicators and clinical presentations associated with AVMs affecting the optic chiasm.

Main Methods:

• Clinical case study of two patients presenting with visual disturbances.
• Diagnostic workup included neurological examination and angiography.
• Review of presenting symptoms, including seizures, proptosis, and transient visual loss.

Main Results:

• One patient's AVM was diagnosed via angiography, with a potential early sign being a lip angioma.
• The second patient's AVM was diagnosed pre-angiography, prompted by seizures and pulsating proptosis.
• This second patient experienced transient bilateral blindness, possibly linked to postictal states or 'chiasmal steal' ischemia.

Conclusions:

• AVMs represent a rare but significant cause of chiasmal syndrome.
• Clinical features such as lip angiomas, seizures, and proptosis can suggest AVM diagnosis.
• Transient visual disturbances may occur due to ischemic events related to AVMs at the optic chiasm.