eMedicine Specialties > Neurology > Neuro-vascular Diseases

Foix-Alajouanine Syndrome

Author: Cheryl Ann Palmer, MD, Professor, Departments of Pathology and Neurology, University of Alabama at Birmingham School of Medicine; Consulting Staff, Departments of Pathology and Neurology, University of Alabama at Birmingham Hospital; Consulting Staff, Departments of Pathology and Neurology, Veteran Affairs Medical Center; Consulting Staff, Department of Pathology, Children's Hospital of Alabama
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Updated: Dec 10, 2008

Introduction

Background

Foix and Alajouanine first described Foix-Alajouanine syndrome in 2 young men (aged 31 and 37 y) in 1926.¹ The patients presented with subacute myelopathy, and autopsy revealed spinal cord necrosis and abnormally dilated and tortuous vessels situated primarily on the spinal cord surface. The underlying pathology was believed to be a dural arteriovenous (AV) fistula. Krause first attempted surgical treatment in 1911² , performing a laminectomy to expose the abnormal segments of the spinal cord.

Historically eponymic, the syndrome now has many other names in the literature — angiodysgenetic necrotizing myelopathy, subacute necrotizing myelopathy, and venous congestive myelopathy.³

Pathophysiology

Foix-Alajouanine syndrome is an arteriovenous malformation of the spinal cord predominantly affecting the lower thoracic and/or lumbosacral levels; cervical cord involvement is rare. Findings include necrosis of the affected cord regions. Grey matter (as compared to white matter) structures are more severely involved. Masses of enlarged, tortuous, and thick-walled subarachnoid veins are observed overlying the surface of the cord (primarily on the posterior aspect). Smaller blood vessels with thickened fibrotic walls also are present within the affected spinal cord segments.

The enlarged, abnormal veins are associated with dural arteriovenous (AV) shunt or fistulas, usually intradurally but rarely extradurally. These AV shunts are associated with reflux of arterial blood into the venous drainage of the cord. This results in increased venous pressure in the affected regions of the spinal cord, often leading to ischemic injury.⁴

Frequency

United States

Foix-Alajouanine syndrome is a rare entity. No specific statistics are available, but the condition is likely underdiagnosed.

International

Foix-Alajouanine syndrome also is rare internationally.

Mortality/Morbidity

• Foix-Alajouanine syndrome is a subacute disorder that gradually evolves over 1-5 years.⁴
• Affected patients initially are spastic but eventually develop flaccid paralysis of the limbs and may become wheelchair bound.
• Death can occur with terminal sepsis or other sequelae.

Race

No racial predilection has been observed.

Sex

Male-to-female ratio is nearly 5:1.⁵

Age

Foix-Alajouanine usually occurs in older patients (>50 y).⁴ Patients younger than 30 years are rarely reported.

Clinical

History

• Patients present with increasing unilateral and/or bilateral weakness, dysesthesias, and numbness or tingling in the lower extremities, which may be symmetric or asymmetric.
• Early problems with bowel, bladder, and sexual function are common.
• Symptoms begin after brief exertion as a heavy feeling in the legs that generally improves with rest.
• Symptoms gradually worsen over months, and the patient may have difficulty standing for long periods.
• Frequent falls can be a problem.
• Urinary and fecal incontinence eventually appear.
• Complaints of nonradiating lower back pain in the lumbosacral or coccygeal regions are common. This may be initially interpreted as sciatica.
• Weakness or numbness eventually can progress to the upper extremities.
• An acute onset of symptoms is reported in a minority of patients; a protracted course over a few years is more common in most patients before a diagnosis is made.⁵

Physical

• Neurologic examination reveals an alert patient with normal mentation.
• Normal mental status, speech, and language and cranial nerve function are generally present.
• Unsteadiness of gait, which also may be halting in nature but on a narrow base, is common.
• Spastic or flaccid paraparesis and a sensory level below the lesion can be observed.
• Deep tendon reflexes may be normal or increased.
• Bilateral Babinski signs may be present, as may clonus. Upper motor neuron and lower motor neuron signs may be seen simultaneously.⁵
• Vibration and joint position senses usually are preserved.
• Rectal sphincter tone frequently is diminished.

Causes

• The etiology of this syndrome is not well understood.
  • Most patients have an arteriovenous (AV) fistula in the lower thoracic dura.
  • One hypothesis is that the higher arterial pressure within the dura is transmitted to the spinal venous plexus via the intradural venous system, compromising perfusion and leading to infarction of the spinal cord parenchyma. Arterial blood originating from the dural fistula enters the venous system, increasing pressure and impairing normal drainage from the cord parenchyma.³
  • Thrombosis may occur but not until late in the course of the disease.
  • Venous stasis, not thrombosis, may be the primary cause of infarction. The preferential involvement of the distal cord is presumably due to orthostasis.
• The onset in middle age suggests that the syndrome is acquired, in contrast to other arteriovenous malformations, which are assumed to be congenital abnormalities, although the specificity for the spinal cord is not easily explained.

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