Makindo Medical Notes

Foix-Alajouanine syndrome is an extreme form of spinal dural AVF that affects a minority of patients. These patients present with rapidly progressive myelopathy due to venous thrombosis from spinal venous stasis.

About

• Spinal AVMs can cause acute, subacute, or chronic myelopathy.
• Often resemble AV fistulas, with high-pressure flow into the venous system, leading to venous hypertension.

Aetiology

• Type 1: Dural AVMs (85%)
  • Most common type; causes venous hypertension and bleeding.
  • Venous hypertension expands the lesion, increasing pressure on the spinal cord and reducing blood flow.
  • Affects corticospinal and posterior columns; middle-aged men most commonly affected.
  • Management: Spinal angiography and obliteration of the AVM.
• Type 2: Intradural AVMs or Glomus AVM
  • Can bleed at arterial pressure into the subarachnoid space, leading to myelopathy.
  • Common in younger patients; characterized by fluctuating myelopathy with periods of acute deterioration due to hemorrhage within the AVM.
• Type 3: Juvenile AVM
  • High-flow and high-pressure AVM, sometimes with an audible bruit.
  • Clinical presentation similar to Type 2.
• Type 4: Perimedullary Arteriovenous Fistula
  • Rare type of spinal AVM; presents with complex venous hypertension.

Clinical Features

• Painful radiculopathy, often associated with Type 1 AVMs.
• Symptoms of spinal cord compression, including gradual onset of weakness and sensory impairment.
• Bladder and bowel disturbances in advanced cases.
• Sudden haemorrhage may cause intense back pain and sudden weakness.
• Intradural lesions may present with subarachnoid haemorrhage, known as coup de poignard, due to excruciating back pain.

Investigations

• MRI/MRA of the brain and spinal cord to assess for AVM presence and structure.
• Arteriography: The standard imaging modality for visualizing arteriovenous malformations.

Management

• Surgical removal may be considered for accessible AVMs.
• Stereotactic radiosurgery: Used to scar the AVM, promoting clot formation and occlusion.
• Interventional neuroradiology/endovascular neurosurgery: Endovascular procedures can be used to insert an occlusive device within the AVM.