Chronic myelopathy

Myelopathy in a broad sense covers all diseases of the spinal cord.

The main symptoms of myelopathy are as follows. Back pain in chronic myelopathies (as opposed to acute ones) is rare and may accompany, for example, spondylosis or syringomyelia. Sensory disorders are more common and may reflect the involvement of the posterior roots, posterior horns, posterior columns and spinothalamic tracts in the lateral columns of the spinal cord. Motor manifestations are usually leading and slowly progress. Spastic monoparesis, paraparesis (usually asymmetrical) may be observed, for example, in multiple sclerosis, cervical spondylosis, disc herniation, myelopathy in AIDS, funicular myelosis, ALS, radiation myelopathy, spinal forms of spinocerebellar degeneration. Progressive myelopathy involving the anterior horn cells (ALS, syringomyelia, intraspinal tumor) will manifest itself as flaccid paresis with muscle atrophy, fasciculations and hypo- and areflexia at the level of the affected segments. Tendon reflexes in chronic myelopathies (as opposed to acute ones) often change towards an increase, Babinski's symptom is often present, as well as imperative urges to urinate and constipation.

At the same time, there are diseases in which there is no spinal lesion, but the clinical manifestations are similar to it and can be a source of diagnostic errors. Thus, bilateral involvement of the upper-medial parts of the frontal lobe (for example, sagittal meningioma) causes spastic paraparesis and gait apraxia. Thus, lower paraplegia (paraparesis) does not yet say anything about the level of damage: it can be the result of damage at many levels, starting with a parasagittal tumor and ending with the lower thoracic part of the spinal cord. In frontal processes, it is important to search for at least mild dementia, paratonia or grasping reflex.

Normal pressure hydrocephalus with characteristic gait disturbances (gait apraxia) and urinary incontinence may resemble myelopathy; however, there is no paresis, spasticity, or sensory disturbances; at the same time, dementia is one of the leading manifestations.

Psychogenic paraplegia (pseudoparaplegia, pseudoparaparesis) can be chronic, but usually develops acutely in an emotional situation, accompanied by multiple movement disorders (seizures, pseudoataxia, pseudostuttering, mutism), sensory and emotional-personality characteristics with preserved functions of the bladder and intestines in the absence of objective (paraclinical) confirmation of spinal cord involvement.

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The main causes of chronic myelopathy are:

1. Multiple sclerosis.
2. Cervical spondylosis, disc protrusion.
3. Other diseases of the spine and spinal cord (chronic ischemia, vascular malformation).
4. Subacute combined degeneration of the spinal cord (funicular myelosis).
5. Hereditary spastic paraplegia of Strumpell.
6. Syringomyelia.
7. Poliomyelitis (consequences).
8. Syphilis.
9. Other infectious spinal cord lesions (including vacuolar myelopathy in AIDS, Lyme disease).
10. Liver cirrhosis and portocaval shunt.
11. Myelopathy of unknown etiology (up to 25% of all cases of chronic myelopathy).

Multiple sclerosis

Multiple sclerosis rarely (10-15%) has a primary progressive form without typical remissions and exacerbations. In such cases, it is important to use diagnostic criteria (apparently, the Poser criteria are best), which require the patient aged 10 to 59 years to have at least two lesions (or one clinical and one paraclinically detected lesion) and two exacerbations ("reliable" multiple sclerosis). The two exacerbations must affect different areas of the central nervous system, last at least 24 hours, and their occurrence must be separated by an interval of at least one month. However, with the primary progressive form of multiple sclerosis, repeated exacerbations are absent, which creates real diagnostic difficulties. Of course, active questioning is necessary regarding the history of paresthesia or visual disturbances. MRI and evoked potentials (mainly visual and somatosensory), especially when both methods indicate damage to the corresponding conductors) confirm (or exclude) multiple sclerosis. Another reliable, but more difficult to access, method of diagnosing this disease is the detection of oligoclonal IgG groups in the cerebrospinal fluid.

Diagnostic criteria for multiple sclerosis:

I. The Schumacher criteria suggest that there must be "dissemination in place and time" in the age range from 10 to 50 years:

Based on the neurological examination or anamnesis (subject to examination by a competent neurologist), evidence of at least two separately located foci should be identified.

At least two episodes of functionally significant symptoms lasting more than 24 hours, separated by a period of at least one month, must be recorded. Remission is not a mandatory requirement. The existing neurological impairment cannot be adequately explained by another pathological process.

The Schumacher criteria (1965) still remain the “gold standard” for diagnosing multiple sclerosis.

II. McAlpin's criteria (1972) propose to distinguish between definite, probable and possible multiple sclerosis:

Definite multiple sclerosis: the anamnesis should indicate retrobulbar neuritis, diplopia, paresthesia, weakness in the limbs, which diminished or disappeared over time; the presence of one or more exacerbations. The examination should reveal signs of damage to the pyramidal tract and other symptoms indicating the presence of several foci in the central nervous system (gradual development of paraparesis with periods of deterioration and signs of damage to the brainstem, cerebellum or optic nerve).

Probable multiple sclerosis: history of two or more retrobulbar neuritis in combination with symptoms of pyramidal tract damage. During this exacerbation, there should be signs of multifocal CNS damage with good recovery. With long-term observation, nystagmus, tremor, and pallor of the temporal halves of the optic disc join the symptoms of pyramidal tract damage. There may be no clear exacerbations.

Possible multiple sclerosis: progressive paraparesis at a young age without signs of exacerbation and remission. With the exclusion of other causes of progressive paraparesis.

Also known are the McDonald and Halliday criteria (1977) and the Bauer criteria (1980), which are now used less frequently and we do not present them here.

The Poser criteria are most widely used in Europe, North America and Russia. They are intended for practicing neurologists and include, in addition to clinical data, the results of additional research methods (MRI, evoked potentials of the brain, detection of oligoclonal antibodies in the cerebrospinal fluid). The Poser criteria have only two categories: "certain" and "probable" multiple sclerosis. We have already mentioned them above.

Differential diagnosis of multiple sclerosis includes such diseases as autoimmune inflammatory diseases (granulomatous angiitis, systemic lupus erythematosus, Sjogren's disease, Behcet's disease, periarteritis nodosa, paraneplastic syndromes, acute disseminated encephalomyelitis, postinfectious encephalomyelitis); infectious diseases (borreliosis, HIV infection, neurosyphilis); sarcoidosis; metachromatic leukodystrophy (juvenile and adult types); spinocerebellar degenerations; Arnold-Chiari malformation; vitamin B12 deficiency.

Cervical spondylosis

Cervical spondylosis (a combination of degenerative changes in the intervertebral discs, facet joints, and yellow ligament) is the most common cause of myelopathy in mature and elderly patients (in Russian literature, the term "osteochondrosis" is used as a synonym). Cervical myelopathy develops in approximately 5-10% of patients with clinically manifested spondylosis. It develops more easily and quickly in the presence of congenital narrowing (stenosis) of the spinal canal (12 mm or less) and is caused by external compression of the spinal cord and its vessels (mainly the lateral and posterior columns). The degenerative process usually begins in the disc with secondary changes in the adjacent bone and soft tissues. The spinal cord is compressed by a herniated intervertebral disc, protrusion (hypertrophy) of the yellow ligament into the canal, or osteophytes. Neck pain is usually the first symptom; then numbness in the arms and mild gait disturbances appear, which gradually increase; minor bladder dysfunctions are possible (rarely).

There are several clinical variants of cervical myelopathy:

1. Spinal cord lesion involving the corticospinal (pyramidal), spinothalamic tracts and conductors in the posterior columns of the spinal cord (tetraparesis with weakness predominantly in the legs, with spasticity, sensory ataxia, sphincter disorders and Lhermitte's sign).
2. Predominant involvement of the anterior corneal cells and corticospinal tracts (ALS syndrome without sensory disturbances).
3. A syndrome of severe motor and sensory impairment with weakness in the arms and spasticity in the legs.
4. Brown-Sequard syndrome (typical contralateral sensory deficit and ipsilateral motor deficit).
5. Atrophy, loss of reflexes (damage to motor neurons of the spinal cord) and radicular pain in the arms. Weakness mainly in the 5th and 4th fingers.

Hyperreflexia is detected in approximately 90% of cases; Babinski's symptom - in 50%; Hoffman's symptom (on the arms) - in approximately 20%.

Other diseases of the spine and spinal cord

Chronic myelopathy may also develop in other diseases of the spine (rheumatoid arthritis, ankylosing spondylitis) and vascular diseases of the spinal cord. Slowly progressing paraparesis (with or without sensory impairment) in a mature or elderly patient suffering from a vascular disease (arteriosclerosis, arterial hypertension, vasculitis) may be associated with chronic spinal circulatory insufficiency; however, other possible causes of myelopathy must first be excluded: tumors, degenerative diseases of the motor neuron, funicular myelosis (subacute combined degeneration of the spinal cord), cervical spondylosis, and, occasionally, multiple sclerosis. Vascular malformation sometimes presents with a picture of chronic myelopathy.

Subacute combined degeneration of the spinal cord

Funicular myelosis develops with deficiency of vitamin B12 or folate, which leads to damage of the lateral and posterior columns of the spinal cord at the cervical and upper thoracic level of the spinal cord. Causes: achylic gastritis, gastrectomy, bowel surgery, AIDS, strict vegetarian diet, nitric oxide administration. The disease begins gradually with paresthesia in the hands and feet, weakness, gait disturbances. Sensory ataxia, spastic paraparesis are detected. Decreased visual acuity, symptoms of brainstem and cerebellar involvement are possible. The diagnosis is confirmed by studying the level of vitamin B12 in the serum and a positive Schilling test (it can be abnormal even with a normal level of B12 in the serum). Homocysteine and methylmalonic acid (precursors of vitamin B12) are elevated in 90% of patients with vitamin B12 deficiency. Symptoms of anemia are typical.

Folic acid deficiency results in a similar syndrome and occurs in malabsorption, alcoholism, the elderly, bowel disease, Crohn's disease, ulcerative colitis, and in patients receiving anticonvulsants. There is some risk of developing folate deficiency in pregnant women.

Hereditary spastic paraplegia of Strumpell

Strumpell's spastic paraplegia is an upper motor neuron disease that begins in childhood or early adulthood with complaints of stiffness in the leg muscles and unsteadiness when walking, which are based on progressive paraplegia with high tendon reflexes and pathological foot signs. Increased tone in the adductor muscles of the thigh is characteristic, which leads to a characteristic dysbasia with semi-bent legs and a rigid "crossing" step. Less "pure" forms have a variety of additional neurological syndromes (dementia, optic atrophy, retinal degeneration, parkinsonism, dystonia, epilepsy, muscle atrophy, heart disease). Family history and typical clinical manifestations are the basis for diagnosis.

Syringomyelia

Syringomyelia usually manifests itself as a cavity in the central gray matter, but the latter can extend into the anterior or posterior horns. The most common localization is the cervical or upper thoracic spinal cord (less often it can be observed in the lumbar region and in the trunk region). In adults, Arnold-Chiari malformation type I is often found; in children - a more severe malformation. Posttraumatic syringomyelia is detected in 1-3% of patients who have suffered a severe spinal cord injury. Spinal cord tumors and inflammatory processes can also lead to the formation of syringomyelic cavities. Pain, weakness and muscle atrophy of more often one arm, scoliosis and dissociated sensory disturbances (decreased pain and temperature with preservation of tactile and deep sensitivity) are cardinal manifestations of syringomyelia. In case of a large cavity, the posterior and lateral columns are involved (sensory ataxia in the legs and lower spastic paraparesis, pelvic dysfunction), as well as the autonomic conductors (Horner's syndrome, orthostatic hypotension). Syringobulbia is manifested by such typical symptoms as unilateral atrophy of the tongue, trigeminal pain or hypesthesia in the Zelder zones, paralysis of the muscles of the soft palate and larynx, dizziness and nystagmus. MRI helps in diagnosis.

Polio

Poliomyelitis is a viral disease that begins acutely after an incubation period of 2-10 days in the form of general infectious symptoms. After 2-5 days, asymmetrical progressive flaccid paralysis develops, most often affecting the proximal parts of the lower extremities. About a week later, atrophy begins to appear in the paralyzed muscles. In 10-15% of patients, the muscles of the pharynx, larynx, or facial muscles are involved. The diagnosis is confirmed by culturing the polio virus from a smear (nasopharyngeal secretions, feces) and rarely from cerebrospinal fluid or blood. It is also useful to take into account the epidemiological situation.

10-70 years after acute poliomyelitis, 20-60% of patients may develop new symptoms in the form of fatigue and increasing weakness in those muscles that were previously affected by poliomyelitis; but weakness and atrophy may appear in muscles not affected in the acute period - the so-called "post-polio progressive muscular atrophy". Its cause is unclear.

Syphilis

Syphilis with spinal cord involvement (myelopathy) may present with meningovasculitis (meningomyelitis), hypertrophic spinal pachymeningitis (usually at the cervical level) and spinal gumma; all of these are quite rare. A late form of neurosyphilis at the spinal level is tabes dorsalis. It is a progressive degeneration affecting mainly the posterior columns and posterior roots of the spinal cord. It usually develops late, 15-20 years after infection, progresses slowly, and affects men more often than women. Shooting pains are observed, most often in the legs, lasting from several minutes to several hours, sometimes grouped into "bundles". 20% of patients report periodic abdominal pain (tabetic crises). Later, sensory ataxia with a characteristic "stamping" (tabetic) gait and areflexia develop. Repeated injuries due to walking disorders with the formation of a typical "Charcot joint" in the knee joint area are typical. Argil-Robertson's symptom is present; optic nerve atrophy is possible, and other symptoms are less common.

Other infections

Among other infections, HIV infection is becoming the most relevant, which can also lead to myelopathy. Vacuolar myelopathy is observed in approximately 20% of AIDS patients and is characterized by damage to the posterior and lateral columns of the spinal cord, mainly at the cervical level. Clinical manifestations develop slowly and vary from mild lower paraparesis with sensory ataxia to paraplegia with severe pelvic disorders. MRI reveals hyperintensive signals in T2-weighted images in the area of the corticospinal tracts and posterior columns of the spinal cord. Microscopically (autopsy) - a picture of vacuolar myelopathy.

Lyme disease (borreliosis) has three stages. The first is characterized by characteristic erythema; the second, months after the first, occurs as meningitis or meningoencephalitis. One third of patients present with a polyneuropathic syndrome called Banwarth syndrome or Garin-Bujadoux syndrome. The third stage may appear months or even years after infection and is manifested by arthritis and symptoms of damage to the brain and spinal cord, cranial and peripheral nerves. Myelitis develops in approximately 50% of patients and is manifested by progressive para- or tetraparesis with sensory disorders and dysfunction of the pelvic organs. Transverse myelitis develops at the thoracic and lumbar level of the spinal cord. It remains unclear whether the third stage is caused by the direct damaging effect of the spirochete or is associated with parainfectious immune disorders. In the cerebrospinal fluid, there is pleocytosis (200-300 cells and above), high protein content, normal or low sugar level, increased IgG synthesis. In the blood and cerebrospinal fluid, there is an increased content of antibodies. MRI reveals focal or diffuse increase in signal intensity in the cervical spinal cord in some patients.

Liver cirrhosis, portocaval shunt

Liver cirrhosis and portocavity shunt may lead not only to encephalopathy but also to myelopathy with slowly progressive lower paraparesis. In some patients (rarely) this is the main neurological syndrome of liver failure. Hyperammonemia is characteristic.

Myelopathy of unknown etiology

Myelopathy of unknown etiology is common (up to 27% of all cases of chronic myelopathies), despite the use of modern diagnostic methods (MRI, myelography, cerebrospinal fluid analysis, evoked potentials and EMG). Its neurological profile has been studied quite well. The most typical symptom is paresis (or paralysis). It is observed in 74% of cases and is more often detected in the legs (72%) than in the arms (26%). In 71% of cases, these paresis are asymmetric. Hyperreflexia predominates (65%), often asymmetric (68%); Babinski's symptom occurs in 63%. Muscle tone is increased by the spastic type in 74%. Sensory disturbances are present in 63% of cases; sphincter disorders - in 63%. Myelopathy of unknown etiology is a "diagnosis of exclusion".

Diagnostic studies in patients with chronic myelopathy

General physical examination (to exclude systemic diseases, neurofibromatosis, infection, malignancy, liver disease, stomach disease, aortic disease, etc.), neurological examination to exclude cerebral disease and to clarify the level of spinal lesion; CT or MRI to measure the width of the spinal canal, to exclude intramedullary processes; myelography to exclude extramedullary compression of the spinal cord; evoked potentials to assess afferentation from peripheral nerves to the spinal cord and further to the brain; lumbar puncture (to exclude infectious myelitis, carcinomatous meningitis or multiple sclerosis); EMG is also necessary (for example, to exclude multifocal motor neuropathy or (encephalo) myelopolyneuropathy).

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