Myelopathy is a generalized concept used in neurology to designate spinal cord lesions of various etiologies, usually having a chronic course. Clinically, they can manifest as disorders of muscle strength and tone, various sensory disorders, pelvic organ dysfunction. The task of diagnostic search in myelopathy is to identify the causal disease. For this purpose, spine radiography, MRI, EMG, ENG, angiography, cerebrospinal fluid analysis, biochemical blood tests, PCR diagnostics, etc. are carried out. Therapeutic tactics are based on the therapy of the underlying disease, symptomatic treatment and rehabilitation with the help of physical therapy, mechanotherapy, massage, acupuncture and physiotherapy.
General information
Myelopathy is a complex concept that includes any dystrophic changes in the spinal cord, regardless of their etiology. As a rule, these are chronic or subacute degenerative processes that occur as a result of impaired blood supply and metabolism of individual spinal segments. Often, myelopathy acts as a complication of degenerative-dystrophic diseases of the spine, vascular pathology, toxic effects, spinal injury, dysmetabolic changes or infectious processes. Therefore, in the specified diagnosis, the term “myelopathy” must necessarily indicate the nature of the spinal cord lesion. For example, “ischemic myelopathy”, “compression myelopathy”, etc.
Etiology and pathogenesis
In the vast majority of cases, the pathological processes leading to the development of myelopathy are localized outside the spinal cord. First of all, these are degenerative changes of the spine (osteochondrosis, spondyloarthrosis, spondylosis, involutive spondylolisthesis) and injuries (vertebral fracture, subluxation or dislocation of vertebrae, compression fracture of the spine). These are followed by vascular diseases (atherosclerosis, thrombosis of spinal vessels), spinal abnormalities, tumor processes in the spine, metabolic disorders (with dysproteinemia, diabetes mellitus, phenylketonuria, lysosomal accumulation diseases), tuberculosis and osteomyelitis of the spine. Radioactive and toxic effects on the body can lead to pathological changes in the spinal cord.
Less common are myelopathies caused by direct damage to the substance of the spinal cord. The root cause of their occurrence may be: spinal cord injury, infectious lesions and tumors of the spinal cord, hematomyelia, demyelination. The latter may be hereditary (with Russi-Levy syndrome, Refsum’s disease, etc.) or acquired (with multiple sclerosis). In exceptional cases, myelopathy develops as a complication of lumbar puncture.
Among the pathogenetic mechanisms of the occurrence of myelopathy, compression prevails. Compression of an intervertebral hernia, osteophytes, fragments at a fracture, a tumor, a post-traumatic hematoma, a displaced vertebra is possible. In this case, both direct compression of the spinal cord and compression of the spinal vessels occur, resulting in hypoxia and malnutrition, and then degeneration and death of nerve cells of the affected spinal segment. The occurrence and development of pathological changes is realized gradually with an increase in compression. The result is the loss of the function of neurons in this segment and the blocking of impulses passing through it along the conductive pathways of the spinal cord.
Classification
In modern neurology, myelopathy is traditionally classified according to the etiological principle.
- Spondylogenic (including discogenic) is associated with various degenerative processes of the spinal column.
- Ischemic (dyscirculatory, atherosclerotic, vascular) — develops against the background of chronic cerebrospinal circulation disorders.
- Post—traumatic is caused by both direct trauma to the spinal cord (concussion, bruise), and with the compression effect of a hematoma, displaced vertebrae or their parts during a fracture.
- Carcinomatous — is a manifestation of paraneoplastic CNS lesion in leukemia, lymphoma, lymphogranulomatosis, lung cancer, etc. oncological pathology.
- Infectious — occurs in HIV, syphilis (neurosyphilis), Lyme disease, enterovirus infection in children.
- Toxic — due to toxic effects on the central nervous system. It can be observed with diphtheria.
- Radiation — depends on the dose and time of radiation exposure. Radiation myelopathy can occur after radiation therapy of malignant neoplasms.
- Metabolic is a rare complication of endocrine and metabolic disorders.
- Demyelinating is the result of hereditary or acquired demyelinating processes in the central nervous system.
Myelopathy symptoms
Clinically, myelopathy is manifested by a number of neurological symptoms that have practically no specifics reflecting its etiology, and entirely depend on the level and degree of spinal cord damage. In general, the myelopathic symptom complex includes peripheral paresis/paralysis with muscle hypotension and hyporeflexia, developing at the level of the affected segments; central paresis/paralysis with muscle hypertonus and hyperreflexia, spreading below the level of localization of pathological changes; hypesthesia and paresthesia both at the level of the lesion and below it; pelvic disorders (retention or incontinence of urine and feces).
Discogenic myelopathy, infectious myelopathy and compression myelopathy are considered in the corresponding independent reviews.
Ischemic myelopathy
Spinal vessels are much less likely to undergo the formation of atherosclerotic plaques and thrombosis than cerebral (cerebral vessels). As a rule, this occurs in people over 60 years of age. The most sensitive to ischemia are the motor neurons located in the anterior horns of the spinal cord. For this reason, motor disorders occupy a leading place in the clinical picture of vascular myelopathy, which resembles manifestations of ALS. Disorders of the sensitive sphere are minimal and are detected only with a thorough neurological examination.
Post-traumatic myelopathy
It is a spinal syndrome that develops depending on the severity of the injury and the course of the immediate post-traumatic period. According to clinical manifestations, it often has much in common with syringomyelia, in particular, a dissociated type of sensory disorders: loss of surface (temperature, pain and tactile) sensitivity while maintaining deep (musculoskeletal and vibrational) sensitivity. Usually posttraumatic myelopathy is irreversible and forms the basis of residual trauma phenomena. In some cases, its progressive course with the progression of sensory disorders is noted. Often, post-traumatic myelopathy is complicated by intercurrent urinary tract infections (cystitis, urethritis, pyelonephritis); sepsis is possible.
Radiation myelopathy
It is most often observed in the cervical spinal segments in patients who have undergone radiation therapy for pharyngeal cancer or laryngeal cancer; in the thoracic region — in patients who have received radiation for mediastinal tumors. Develops in the period from 6 months to 3 years after radiation loads; on average after 1 year. In such cases, myelopathy needs differential diagnosis with spinal metastases of the existing tumor. Typically slow progression of the clinic, due to gradual necrosis of spinal cord tissues. A neurological examination may reveal Brown-Sekara syndrome. There are no changes in the cerebrospinal fluid.
Carcinomatous myelopathy
It is caused by the toxic effect of the tumor and the effect of biologically active substances synthesized by it, which ultimately leads to necrotic changes in spinal structures. The clinical symptom complex largely repeats neurological disorders in amyotrophic lateral sclerosis. Therefore, some authors attribute this type of myelopathy to a special form of ALS. Pleocytosis and moderate hyperalbuminosis may be detected in the cerebrospinal fluid.
Diagnostics
The diagnostic algorithm for detecting signs of myelopathy is aimed at excluding another pathology of the central nervous system, similar in clinical symptoms, and establishing the etiological factor underlying the dystrophic changes of the spinal cord. It includes general and biochemical blood test, spine radiography, MRI of the spine, electromyography (EMG), electroneurography (ENG), evoked potentials examination, MR or CT angiography of the spinal cord, lumbar puncture.
According to indications, in the absence of the possibility of MRI, in some cases, myelography and discography can be performed. If the infectious nature of myelopathy is suspected, a blood sterility test, an RPR test, PCR studies, and a culture of cerebrospinal fluid are performed.
In the course of a diagnostic search, a neurologist can involve other specialists in joint consultation: a vertebrologist, a phthisiologist, an oncologist, a venereologist; under the assumption of demyelinating hereditary myelopathy, genetics.
Myelopathy treatment
The tactics of treatment of myelopathy depends on its etiology and clinical form. It includes therapy of causal disease and symptomatic treatment.
In compression myelopathy, the first priority is to eliminate compression. For this purpose, removal of the Urban wedge, drainage of the cyst, removal of hematoma and tumor may be indicated. With narrowing of the spinal canal, the patient is referred to a neurosurgeon to resolve the issue of possible decompression surgery: laminectomy, facetectomy or puncture decompression of the disc. If compression myelopathy is caused by a herniated disc, then microdiscectomy or discectomy is performed depending on the degree of protrusion and the condition of the disc.
Treatment of ischemic myelopathy consists in the elimination of vascular compression factors and vascular therapy. Since the vascular component is present in the pathogenesis of almost any myelopathy, such treatment is included in the complex therapy of most patients. It includes antispasmodic and vasodilating agents (drotaverine, xanthinol nicotinate, papaverine, vinpocetine), drugs that improve microcirculation and rheological properties of blood (pentoxifylline).
In toxic myelopathy, detoxification is the basis of treatment, in infectious — adequate etiology of antibacterial therapy. The treatment of hereditary demyelinating myelopathy and carcinomatous myelopathy in hemoblastosis presents great difficulties. Often it comes down to symptomatic therapy.
Mandatory in the treatment of myelopathy are drugs that improve the metabolism of nervous tissue and reduce its susceptibility to hypoxia. These include neuroprotectors, metabolites and vitamins (pig brain hydrolysate, piracetam, calf blood hemoderivate, vit B1, vit B6). Many patients are advised to consult a physiotherapist for the optimal selection of methods of physiotherapy: diathermy, galvanization, UHF, paraffin therapy, etc.
In order to increase the volume of motor activity, develop self-service skills, prevent the development of complications (muscular atrophy, joint contractures, bedsores, congestive pneumonia) from the early stages of the disease, patients with myelopathy are shown to undergo physical therapy, massage and rehabilitation physiotherapy (electrostimulation, electrophoresis with neostigmine, reflexotherapy, SMT of paretic muscles, hydrotherapy). With deep paresis, exercise therapy consists of performing passive exercises and mechanotherapy.
Prognosis and prevention
In case of timely elimination of compression, compression myelopathy has a favorable course: with appropriate treatment, its symptoms can be significantly reduced. Ischemic myelopathy often has a progressive course; repeated courses of vascular therapy can temporarily stabilize the condition. Post-traumatic myelopathy is usually stable: its symptoms are not reduced and do not progress. Radiation, demyelinating and carcinomatous myelopathy have an unfavorable prognosis and a steadily progressive course.
Prevention of myelopathy consists in the prevention of diseases that can lead to its development. These are timely detection and treatment of spinal pathology and vascular diseases; stable compensation of endocrine and metabolic disorders; prevention of injuries, infectious diseases, intoxication with lead, cyanides, hexachlorophen, etc.
