Foix Alajouanine Syndrome
Foix Alajouanine syndrome is an uncommon cause of lower thoracic and lumbosacral pain. It is caused by an arteriovenous malformation of the lower thoracic and lumbosacral spinal cord, with the grey matter of the spinal cord more severely compromised when compared with the white matter.
Also known as subacute necrotizing myelopathy, angiodysgenetic necrotizing myelopathy, and venous congestive myelopathy. Foix-Alajouanine syndrome is extremely rare with an incidence of four to five occurrences per 1 million patients.
The etiopathology of Foix Alajouanine syndrome is not fully understood, but it has been postulated that intradural arteriovenous fistulas allow higher arterial pressure from dural arteries to be transmitted to the intradural veins. Over time, this chronic increase in the intradural venous pressure leads to compromised perfusion of the spinal cord and ultimately spinal cord infarction.
This uncommon cause of pain and spinal cord compromise is usually diagnosed in the fifth decade, although the initial case reports by Foix and Alajouanine described two patients in their late twenties. Foix-Alajouanine syndrome occurs five times more commonly in males.
What are the Symptoms of Foix Alajouanine Syndrome
Patients with Foix-Alajouanine syndrome report the gradual onset nonradiating back and sacrococcygeal pain with associated lower extremity weakness, dysesthesias, and numbness.
Heaviness of the lower extremities as is seen in patients suffering from spinal stenosis may occur after walking a short distance. This pseudoclaudication improves with rest. As the spinal cord compromise continues, bowel, bladder, and sexual dysfunction may occur. Gait abnormalities are not uncommon.
On physical examination, central cognitive functions are preserved and examination of the lumbosacral spine is unremarkable.
An unsteady halting, rather than antalgic, gait is seen, and increased deep tendon reflexes, clonus, and Babinski signs will be present as the spinal cord compromise progresses. With spinal cord infarction, sensory and motor deficit below the level of infarction is easily identified. Paraparesis to complete paraplegia is usually the final result of cord infarction.
How is Foix Alajouanine Syndrome treated?
Because the neurological symptoms of vitamin B 12 deficiency, Lyme disease, syphilis myelopathy secondary to human immunodeficiency and T-cell leukemia virus presents in a similar manner to Foix-Alajouanine syndrome, laboratory testing to measure serum B 12 levels as well as testing for syphilis and human immunodeficiency and T-cell leukemia virus should be immediately undertaken.
Magnetic resonance imaging and magnetic resonance angiography of the spinal cord are indicated, although these tests as well as computed tomographic myelography may be nondiagnostic early in the course of the disease. With disease progression, on magnetic resonance imaging, hyperintense central spinal cord lesions are readily identifiable with spinal cord edema and decreased signal intensity identified on T1-weighted sequences.
With contrast administration, serpentine vascular enhancement as well as vessel enlargement with associated flow void phenomena within the subarachnoid space are often identified. Selective spinal angiography remains the gold standard for diagnosis as this imaging modality can best identify the extent of spinal-dural arteriovenous fistulas and may help identify specific offending arteries and veins.
Somatosensory evoked potential testing can help identify the presence and localize the level of spinal cord compromise, and electromyography and nerve conduction testing can help identify motor neuron disease such as amyotrophic lateral sclerosis.
In its early stages, Foix Alajouanine syndrome is difficult to diagnose on clinical grounds alone as its presentation mimics many much more common causes of lumbosacral pain and lower extremity pain and dysfunction.
Early in the course of the disease, the patient’s clinical symptomatology is often attributed to lumbar disc disease, spinal stenosis, cervical disc disease, spinal cord tumors, arachnoiditis, or lumbar spondylosis and treated as such. As the disease progresses, spinal cord tumors, anterior horn cell disorders such as amyotrophic lateral sclerosis, poliomyelitis/postpolio syndrome, and polyradiculopathies such as Guillain-Barré disease are often diagnosed.
As the upper motor neurons and the sacral segments are affected, the diagnosis becomes more obvious, but given its rarity, Foix Alajouanine syndrome remains a diagnosis of exclusion and one that is confirmed on radiographic grounds. As mentioned previously, human immunodeficiency virus, syphilis, human T-cell leukemia virus infection, and vitamin B12 deficiency can present in a similar manner to Foix Alajouanine syndrome.
Differential Diagnosis of Foix Alajouanine Syndrome
- • Lumbar disc disease
- • Lumbar spondylosis
- • Cervical disc disease
- • Human immunodeficiency virus infection
- • Vitamin B 12 deficiency
- • Human T-cell leukemia virus infection
- • Lyme disease
- • Multiple sclerosis
- • Amyotrophic lateral sclerosis
- • Spinal cord infarction
- • Arachnoiditis
- • Spinal artery thrombosis
- • Spinal cord tumors
- • Spinal cord arteriovenous malformations
- • Spinal cord trauma
- • Syringomyelia
- • Polyradiculopathy
- • Hereditary spastic paraplegias
- • Epidural abscess
Foix-Alajouanine syndrome is best treated by closure of dural arteriovenous fistulas using either surgical ligation of the vein draining the fistula or endovascular embolization with liquid polymers such as isobutyl 2-cyanoacrylate or n -butyl 2-cyanoacrylate. The use of intraoperative Doppler may improve surgical results. Postoperatively, dexamethasone may improve neurological deficits due to spinal cord edema.
An aggressive rehabilitation program with a multimodality approach to optimize function is always indicated. Neuropathic pain can be treated with gabapentin, pregabalin antidepressants, and anticonvulsants.
Heat modalities and deep sedative massage may help decrease aching lower extremity pain. Underlying sleep disturbance and depression are best treated with a tricyclic antidepressant compound, such as nortriptyline, which can be started as a single bedtime dose of 25 mg.
Failure to diagnose Foix-Alajouanine syndrome early in the course of the disease worsens patient outcome.
The early use of magnetic resonance imaging and selective angiography in any patient with pseudoclaudication of the lower extremities in the absence of spinal stenosis or in whom neurological findings seem out of proportion to the pain complaint will speed diagnosis and treatment.
The diagnosis of Foix-Alajouanine syndrome should be considered in any patient reporting back pain, symptoms of pseudoclaudication, and lower extremity weakness.
Imaging of the spine and its contents should be done earlier rather than later.
After definitive treatment with surgical ligation or embolization, physical therapy to improve function is crucial to improve outcomes.