Eye Movement Abnormalities After Thalamo-Mesencephalic Junction Infarction

Area of Science:

• Neuroscience
• Neurology
• Ophthalmology

Background:

• Bilateral thalamic and left paramedian midbrain infarcts can lead to severe neurological deficits.
• Paradoxical embolism is a rare but critical cause of stroke, often originating from intrapulmonary shunts.
• Ocular motor abnormalities can be subtle yet indicative of complex neurological damage.

Purpose of the Study:

• To report a rare case of stroke secondary to paradoxical embolism.
• To describe the emergence of complex eye movement abnormalities following thalamo-mesencephalic infarcts.
• To emphasize the importance of the thalamo-mesencephalic junction in ocular motor control.

Main Methods:

• Case report of a 54-year-old male patient.
• Clinical presentation including coma and left mydriasis.
• Diagnostic workup including identification of an intrapulmonary shunt and paradoxical embolism.
• Observation of evolving ocular motor abnormalities during recovery.

Main Results:

• The patient presented with coma and left mydriasis due to bilateral thalamic and left paramedian midbrain infarcts.
• Paradoxical embolism from an intrapulmonary shunt was diagnosed as the underlying cause.
• As the patient's mental status improved, complex eye movement abnormalities manifested, including vertical ophthalmoplegia, bilateral ptosis, and right pseudo-abducens palsy.

Conclusions:

• This case underscores the critical role of the thalamo-mesencephalic junction in coordinating eye movements.
• Paradoxical embolism should be considered in stroke patients with unexplained neurological and ocular findings.
• Understanding the complex ocular motor neural circuitry is essential for diagnosing and managing such cases.