Artery of Percheron Syndrome

Artery of Percheron syndrome is a rare neurological condition caused by occlusion of an anatomical variant of the cerebral circulation known as the artery of Percheron. When this small artery becomes occluded, it can result in an infarction involving both thalami simultaneously and, in some cases, the midbrain.

Due to the wide range of clinical manifestations it may produce, this syndrome represents a significant diagnostic challenge and may initially be mistaken for other neurological disorders or conditions associated with an altered level of consciousness.

What is artery of Percheron syndrome?

The artery of Percheron is a rare anatomical variant in which a single perforating artery, arising from one of the posterior cerebral arteries, supplies both medial thalami.

In most individuals, each thalamus receives its blood supply from separate arterial branches. However, when this anatomical variant is present, occlusion of a single artery can affect both structures simultaneously.

This vascular pattern explains the occurrence of bilateral neurological symptoms, which are uncommon in other types of stroke.

What causes artery of Percheron syndrome?

The most common cause is an ischemic infarction resulting from occlusion of the artery of Percheron.

Associated risk factors include:

• Small vessel disease.
• Cardioembolism.
• Atherosclerosis.
• Arterial hypertension.
• Diabetes mellitus.
• Coagulation disorders.

Less commonly, other vascular conditions may produce a similar clinical presentation.

Main symptoms

Bilateral involvement of the thalamus can produce a highly variable combination of neurological manifestations.

The most common include:

• Decreased level of consciousness.
• Profound drowsiness.
• Confusion.
• Memory impairment.
• Disorientation.
• Difficulty with eye movements, particularly vertical gaze.
• Diplopia (double vision).
• Behavioral disturbances.
• Limb weakness in some cases.

When the midbrain is also involved, additional oculomotor abnormalities and other neurological deficits may occur.

Why does the thalamus produce so many different symptoms?

El tálamo actúa como una de las principales estaciones de relevo del cerebro.

Participa en funciones esenciales como:

• Regulación del estado de alerta.
• Procesamiento de la información sensitiva.
• Integración del movimiento.
• Memoria.
• Atención.
• Funciones cognitivas.

Por este motivo, una lesión bilateral puede provocar síntomas muy diversos que afectan tanto a la conciencia como a la función cognitiva y motora.

Diagnosis

Diagnosis can be challenging during the first few hours because symptoms are variable and the initial computed tomography (CT) scan may appear normal.

The most commonly used diagnostic tests include:

• Brain magnetic resonance imaging (MRI).
• Diffusion-weighted magnetic resonance imaging (DWI).
• Magnetic resonance angiography (MRA) or computed tomography angiography (CTA).
• Comprehensive neurological examination.

MRI is generally the most useful imaging technique for confirming bilateral thalamic infarction.

Treatment

Treatment depends on the underlying cause of the arterial occlusion.

When the syndrome is caused by an ischemic stroke, management follows established treatment protocols for this type of cerebrovascular event.

In addition, many patients require rehabilitation to recover cognitive, motor, and oculomotor functions affected by the lesion.

Differences from other thalamic infarctions

Artery of Percheron syndrome has distinct characteristics that differentiate it from other thalamic infarctions.

These include:

• Simultaneous involvement of both thalami.
• Early impairment of consciousness.
• Memory and behavioral disturbances.
• Frequent involvement of eye movements.
• Possible extension into the midbrain.

These features can help raise suspicion of this rare stroke variant when the clinical presentation is compatible.

Conclusion

Artery of Percheron syndrome is a rare form of cerebral infarction caused by occlusion of an anatomical variant that supplies both thalami. Its clinical presentation may include altered consciousness, cognitive impairment, and abnormalities of eye movements, making diagnosis challenging. Recognizing this pattern is essential for localizing the lesion and guiding the evaluation of the underlying cerebrovascular disease.

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