Overview of Radiation Myelopathy
Radiation myelopathy is an injury caused by ionizing radiation (х, γ-neutrons, electron beam radiation, etc.) that exceeds the tolerance range of the spinal cord, usually due to industrial accidents and medical radiation therapy. The main clinical manifestations are pain in the corresponding areas and functional disorders (including motor, sensory, and bowel movements of the limbs), and the extent of the injury is related to the intensity and duration of radiation, the site of exposure, and the tolerance of the individual.
Causes
Radiation myelopathy is mostly seen in nasopharyngeal carcinoma, esophageal carcinoma, thyroid carcinoma, mediastinal tumor, spinal tumor after radiotherapy, and spinal cord lesions appear.
Symptoms
The incubation period of radiculospondylosis varies, and the clinical manifestations are diverse, mainly categorized into the following 4 types:
1. Chronic progressive radioactive spinal cord injury
This type is the most common, the onset of insidious, often appear on one side or both sides of the lower limbs sensory deficits such as limb numbness, tingling, electric shock, burning sensation, fatigue, etc., and then gradually progressing to the emergence of movement disorders, spinal cord semi-cutting damage or complete transverse damage.
2. Amyotrophic radiation spinal cord injury
This type is less common, mainly due to the damage of anterior horn cells of spinal cord, the clinical manifestation is flaccid paralysis of both lower limbs, which belongs to the damage of lower motor neurons, without obvious sensory and sphincter disorders.
3. Acute radiological spinal cord injury
The clinical manifestations are acute onset, developing into paraplegia or quadriplegia in a few hours or days, and then in a quiescent state due to radiation-induced infarction of the spinal cord, which is damage to the upper motor nerves, manifested by increased muscle tone, hyperreflexia, and positive pathological reflexes; accompanied by superficial and deep sensory deficits below the damage plane.
4. Transient radioactive spinal cord injury
The main manifestation is sensory abnormality and the typical low head and curved neck electrocution sign (Lhermitte’s sign), which usually occurs 1-6 months after radiation therapy, and can be completely disappeared after rest and medication, and individual serious cases can also develop into chronic progressive radiation myelitis.
Examination
1. Cerebrospinal fluid examination
The spinal canal is clear, and there may be a mild increase in protein.
2. Other blood tests
Including liver function, renal function, blood glucose, blood sedimentation routine examination; rheumatic series immunoglobulin electrophoresis, etc., and serological examination related to autoimmunity.
3. Other auxiliary examinations
(1) CT scan of cervical and thoracic segments or MRI of corresponding parts exclude tumor metastasis, early spinal cord edema in this disease; magnetic resonance shows white matter dotted flaky lesions with low signal in T1WI and high signal in T2WI, and peripheral annular enhancement signal in Gd-DTPA enhancement scan.
(2) Chest X-ray examination to exclude lung tumor, abdominal ultrasound myelography, radionuclide scan to exclude tumor metastasis.
(3) Electromyography and neurophysiological examination are of auxiliary diagnostic significance.
Diagnosis
Based on the history of radiation exposure and the manifestations of spinal cord lesions, it is not difficult to diagnose the disease after excluding spondylitis, spinal cord tumor, multiple sclerosis and other diseases.
Treatment
1. Whenever headache, nausea, vomiting, elevated body temperature, etc. occur during radiotherapy or after local large-dose accidental irradiation, radiotherapy should be immediately suspended and detached from rays, comprehensive treatment should be carried out, nutritional support should be strengthened, and care should be given to paralysis, urinary and fecal incontinence and urinary tract infection according to the corresponding symptoms.
2. Give vitamin B1, vitamin B12, vitamin B6 and gangliosides and other drugs to promote neurometabolic nutrition.
3. Steroid glucocorticoid commonly used methylprednisone, early shock amount, and then gradually reduce the amount to stop.
4. Surgery
For spastic paralysis caused by damage to upper motor neurons, selective posterior spinal nerve rhizotomy is feasible when the muscle tone is obviously increased.
5. Physical rehabilitation
Physical therapy and acupuncture should be applied at the same time.