subacute necrotizing myelitis
Introduction
Introduction to subacute necrotizing myelitis Subacutenecrotizing myelitis was first proposed by Foix and Alajouanine in 1926 and is therefore also known as Foix-Alajouanine syndrome (FAS). Clinically characterized by progressive spinal cord injury caused by spinal cord blood supply disorders, it is a special type of chronic spinal spinal radiculitis. The most common cause may be an intradural arteriovenous malformation. Localized spinal cord thinning, cystic changes and color loss. Microscopic examination showed demyelination and spinal cord necrosis along the spinal nerve roots in addition to the apparent thickening of the subarachnoid wall. basic knowledge Sickness ratio: 0.001%-0.005% Susceptible population: Most patients are men over 50 years old Mode of infection: non-infectious Complications: pneumonia, acne, urinary tract infection
Cause
Cause of subacute necrotizing myelitis
Dural arteriovenous fistula (25%):
Mainly distributed in the lower thoracic segment and the dorsal side of the cone, the supply of blood vessels from an artery and direct drainage to the arterial vein, the typical age of onset is 50 to 80 years old, more common in men, about 60% are spontaneous, 40% by Caused by trauma.
Vascular malformation (20%):
Located in the marrow, consisting of a cluster of vascular plexus, supplying blood vessels from multiple anterior and posterior vertebral arteries, mostly on the dorsal side of the cervical spinal cord, with a younger onset and more acute symptoms.
Juvenile arteriovenous malformation (25%):
For larger and complex vascular masses, both intramedullary and extramedullary can be involved, and the supply of blood vessels involves multiple vertebral planes.
Epidural extramedullary arteriovenous fistula (30%):
The supply of blood vessels is from the anterior spinal artery, which is completely outside the marrow. The onset age is 30 to 60 years old, and the clinical symptoms gradually develop.
Pathogenesis
The symptoms of subacute necrotizing myelitis are mainly caused by spinal cord blood supply disorder and spinal cord tissue ischemic infarction. Possible mechanisms include venous drainage disorder, venous stealing, vascular mass compression and abnormal blood vessel embolism.
Pathological changes: visual inspection showed that the dorsal surface of the spinal cord covered the blood vessels with flexion and convolution, the spinal cord became thinner, the cystic changes and color decreased, and the microscopic examination was performed along the epidural spinal nerve roots except for the obvious thickening of the subarachnoid wall. There is myelin loss and spinal cord necrosis. This manifestation can be focal or extended to transverse, and there is also obvious vascular proliferation in and outside the lesion.
Prevention
Subacute necrotizing myelitis prevention
There is no effective preventive method for arteriovenous malformation, prevention of trauma, early diagnosis and implementation of neurointerventional therapy, intensive care, embolization of blood supply can reduce blood supply, reduce venous congestion and improve spinal function. This technique is considered to be more effective in limited clinical trials. It is the main measure to improve spinal function. Pay attention to the prevention of secondary pneumonia, hemorrhoids, and urinary tract infections.
Complication
Subacute necrotizing myelitis complications Complications pneumonia acne urinary tract infection
Secondary pneumonia caused by progressive paraplegia, acne, urinary tract infections, etc.
Symptom
Subacute necrotizing myelitis symptoms Common symptoms Sensory disorder Neuropathic sciatica sphincter dysfunction
1. Most patients are men over 50 years old.
2. Clinically, progressive spinal cord radiculitis is the main manifestation, about half of which may have acute pain and sensory disturbances, or intermittent sciatica; it may also be a more complete transverse injury of the spinal cord; or a transient weakness Sensory disturbance, followed by progressive spinal nerve root symptoms.
3. There may be sphincter dysfunction.
Examine
Examination of subacute necrotizing myelitis
1. Cerebrospinal fluid examination of the spinal canal is generally no obstruction, CSF pressure is normal, the appearance is colorless transparent or yellow, the number of cells is normal, sometimes the protein content is normal or slightly increased, and the number of cells is normal.
2. Other optional examination items include: blood electrolytes, blood sugar, urea nitrogen, and carcinoembryonic antigen tests.
3. Spinal MRI disease changes venous malformations have airflow in the blood vessels, may have spinal cord atrophy, and sometimes can see high signals in the T2 image.
4. Spinal angiography can confirm the diagnosis.
Diagnosis
Diagnosis and diagnosis of subacute necrotizing myelitis
diagnosis
The diagnosis is mainly based on the above clinical manifestations and imaging examinations.
MRI of the spinal cord shows a phenomenon of airflow in the locally dilated blood vessels, which may have spinal cord atrophy, and sometimes a high signal can be seen in the T2 image, and spinal angiography can be clearly diagnosed.
Differential diagnosis
1. Acute infectious myelitis This disease is more common in young adults. It may have a history of infection such as fever before the disease. Most of them are complete spinal cord transverse damage. Sometimes it can also be expressed as anterior spinal artery syndrome. The initial cerebrospinal fluid is often mild. White blood cells increase.
2. Spinal cord hemorrhagic disease There is a history of traumatic intracranial hemorrhage, which is characterized by sudden onset of the disease, accompanied by severe back pain at the onset of the disease. Symptoms of severe spinal cord transverse damage appear after several minutes to several hours. A large amount of bleeding can be worn. Breaking the soft meninges makes the cerebrospinal fluid examination bloody, and the spinal imaging examination has changes such as traumatic spinal dislocation, which is more conducive to diagnosis, and can be confirmed by myelography, or confirmed by MRI.
3. Spinal cord metastasis This disease causes paraplegia to be very rapid, pain is more serious and extensive, lumbar puncture of the spinal canal obstruction, cerebrospinal fluid protein content is significantly increased or even yellow, the diagnosis of this disease can be by imaging examination and should find the primary lesion.
