Bonnet–Dechaume–Blanc syndrome

A rare congenital disorder affecting the eyes and brain

Bonnet–Dechaume–Blanc syndrome (BDBS), also known as Wyburn-Mason syndrome, is a rare congenital disorder characterized by arteriovenous malformations (AVMs) that primarily affect the retina and the brain. This condition is part of the phakomatoses group of disorders, which are neurocutaneous syndromes involving the central nervous system and the skin.

Presentation

BDBS is typically identified by the presence of AVMs in the retina and the cerebral vasculature. These malformations can lead to a variety of symptoms depending on their size and location.

Ocular Manifestations

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Ocular manifestations of BDBS

The ocular manifestations of BDBS include retinal AVMs, which can be detected through ophthalmoscopy or fluorescein angiography. These AVMs may cause visual disturbances such as decreased visual acuity, visual field defects, or even retinal detachment.

Neurological Manifestations

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Intracerebral hemorrhage in BDBS

Neurologically, patients may present with symptoms due to cerebral AVMs, such as headaches, seizures, or intracerebral hemorrhage. The location of the AVMs in the brain can lead to specific neurological deficits, including hemiparesis or aphasia.

Visual Field Defects

Visual field defect in BDBS

Patients with BDBS may experience visual field defects such as homonymous hemianopia, which is a loss of half of the field of view on the same side in both eyes. This occurs due to the involvement of the visual pathways in the brain.

Pathophysiology

The exact cause of BDBS is not well understood, but it is believed to result from developmental anomalies in the embryonic vasculature. The AVMs are thought to arise from a failure of the normal regression of embryonic vascular connections, leading to direct arterial-to-venous shunts without intervening capillaries.

Diagnosis

Diagnosis of BDBS is primarily clinical, supported by imaging studies. Magnetic resonance imaging (MRI) and computed tomography (CT) scans can reveal cerebral AVMs, while fluorescein angiography is used to visualize retinal AVMs.

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Fluorescein angiography showing retinal AVMs

Management

There is no cure for BDBS, and management is primarily symptomatic and supportive. Treatment options may include:

• Laser photocoagulation or cryotherapy for retinal AVMs to prevent complications such as retinal detachment.
• Surgical intervention or endovascular therapy for cerebral AVMs to reduce the risk of hemorrhage.
• Anticonvulsants for seizure management.

Prognosis

The prognosis of BDBS varies depending on the severity and location of the AVMs. Early detection and management of complications can improve outcomes, but the condition can lead to significant morbidity due to visual and neurological impairments.

Related pages

• Arteriovenous malformation
• Phakomatoses
• Retinal detachment
• Intracerebral hemorrhage