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Inflammatory myelopathies

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Acute myelitis, transverse myelitis, and necrotizing myelopathy

Inflammatory myelopathies (myelitis) is a type of spinal cord disease in which it becomes inflamed. The clinical syndrome associated with myelitis develops in patients within a few days or weeks. With myelopathy, it is possible to form a syndrome of complete transverse lesions of the spinal cord (transverse myelitis), as well as its partial variants:

  • posterior columnar myelitis with ascending paresthesias and loss of vibration sensitivity
  • ascending myelitis, predominantly spinothalamic disorders
  • Brown-Séquard syndrome with leg paresis (on the side of the spinal cord injury) and spinothalamic-type sensory disorders (on the opposite side of the body)

In many cases, the cause of myelitis in patients is a viral infection. Most often, transverse myelitis is manifested by a feeling of back pain, progressive muscle weakness (paraparesis), and asymmetric ascending paresthesias in the legs. Later, the hands are also involved in the process, and therefore viral myelitis can be mistaken for Guillain-Barré syndrome.

To exclude the compressive nature of the spinal cord injury, it is necessary to conduct research - magnetic resonance imaging of the spinal cord (MRI).

MRI of the cervical spinal cord in infectious myelitis: a - the sagittal T2-weighted image shows a lesion with a hyperintense signal in the spinal cord at the C2 level of the vertebral body; b - on the T1-weighted image after the administration of the contrast agent, the enhancement of the pattern is noted.

In most patients, the cerebrospinal fluid (CSF, cerebrospinal fluid) contains 5-50 lymphocytes per 1 mm; sometimes more than 200 cells per 1 mm are found, occasionally polymorphonuclear cells predominate. The inflammatory process in patients with myelitis is more often localized in the middle and lower thoracic segments, although the spinal cord can be affected at any level. Chronic progressive cervical myelitis is considered a form of multiple sclerosis.

In some cases of myelitis, the necrosis of the spinal cord can be quite deep. Necrosis of the parenchyma of the spinal cord in a patient with myelitis can periodically increase over several months, capturing the adjacent intact areas. As a result, the spinal cord at the level of myelitis is reduced in size to a thin cicatricial cord, which is represented by glial cells. This condition in clinical practice is denoted by the term "progressive necrotizing myelopathy". Sometimes the entire spinal cord is involved in the pathological process with progressive necrotizing myelopathy ("necrotic panmyelopathy"). If a transverse necrotic lesion of the spinal cord occurs in a patient before or shortly after optic neuritis, then this condition is referred to as Devik's disease or opticomyelitis. It is possible that such Inflammatory myelopathies are associated with multiple sclerosis, and many of them are variants of it.

Systemic lupus erythematosus (SLE) and other autoimmune diseases can also accompany myelitis. Post-infectious demyelinating processes usually have a single-phase course and only occasionally can relapse. At the same time, patients often experience various symptoms, indicating damage to the same level of the spinal cord.

Systemic sarcoidosis can cause damage to the nerve tissue of the spinal cord, which can cause paresthesias and weakness of the upper and lower extremities in the patient. Spinal cord involvement with sarcoidosis is diagnosed using MRI. Treatment with methylprednisolone and azathioprine causes regression of neurological symptoms and restoration of the normal morphological picture of the spinal cord.

A - MRI of the spinal cord in the sagittal plane (T2 mode) revealed a hyperintense lesion of the spinal cord with edema in the redistribution of C2-C5 and C7-Th3 segments (indicated by arrows). B - MRI of the spinal cord with contrast (T1 mode) reveals an uneven point accumulation of contrast in the spinal cord (indicated by arrows). C - The almost complete restoration of the morphological picture of the spinal cord affected by sarcoidosis after treatment with corticosteroids (indicated by an arrow).

Lymph node histology in systemic sarcoidosis with spinal cord involvement. A nodular granuloma is visualized surrounded by a histocytic component.

 

Angiodysgenetic necrotizing myelopathy, Foix-Alajuanin disease, subacute necrotizing myelitis

Angiodysgenetic necrotizing myelopathy is also called Foix Alajuanin's disease (subacute necrotizing myelitis). Angio-dysgenetic necrotizing myelopathy includes lesions caused by vascular atrophy in combination with infarctions, localized most often in the lower thoracic and lumbar regions. Spinal cord injuries (myelopathy) are caused by progressive changes (vasodilation, hypertrophy of the vascular walls, symptomatic inflammation) in the initially abnormal intra- and extraspinal arteries and veins. In the clinic of a subacute or chronic disease, paraplegia of the legs dominates, at first mild and spastic, then sluggish, combined with muscle atrophy. Initial disorders of pain and temperature sensitivity are replaced by the loss of all types of sensitivity.

 

Infectious myelopathy

Viral spinal cord injury is accompanied by specific types of myelitis. In the past, the most common spinal cord infection was polio. Currently, the most common cause of viral myelitis is herpes zoster, which initially produces radicular symptoms. The pathological process in herpes zoster affects not only the gray matter of the spinal cord, as in poliomyelitis. In the cerebrospinal fluid (CSF, cerebrospinal fluid), lymphocytes are always found in patients.

MRI of the cervical spinal cord in infectious myelitis: c - the axial T2-weighted image shows that the lesion of the spinal cord occupies its central part; d - enhancement of the pattern of the spinal cord lesion on the axial T1-weighted image after the administration of the contrast medium.

Intramedullary abscesses of the spinal cord have been described in systemic infections of the spinal cord of bacterial and mycobacterial etiology. Chronic lesions of the spinal cord membranes in syphilis can lead to sluggish secondary subpial myelitis and radiculitis. Severe granulomatous, necrotic and inflammatory myelitis is typical of Schistosoma mansoni invasion. Granulomatous, necrotic and inflammatory myelitis is caused by a local reaction to tissue-breaking enzymes produced by the parasite's eggs.

Magnetic resonance imaging (MRI) of the spinal cord for myelitis due to Zika virus infection. A - MRI of the spine in T2 mode, showing an increase in the signal in the thoracic T5 – T8 region (indicated by an arrow) and an increase in the cervical spinal cord. B - MRI of the spine in STIR mode shows an increase in the signal in the cervical spinal cord C4 – C7 (indicated by an arrow).

Magnetic resonance imaging (MRI) of the spinal cord for myelitis due to Zika virus infection. A - MRI of the spine in T2 mode, showing an increase in the signal in the thoracic T5 – T8 region (indicated by an arrow) and an increase in the cervical spinal cord. B - MRI of the spine in STIR mode shows an increase in the signal in the cervical spinal cord C4 – C7 (indicated by an arrow).

 

Toxic myelopathy

Toxic non-inflammatory myelopathy sometimes occurs simultaneously with optic nerve atrophy. It is more often found in Japan and is due to the ingestion of antibacterial and antifungal drugs - clioquinol (iodochlorohydroxyquinoline), which is part of ointments for external use. Most patients recover, but many of them persist with persistent sensitivity disorders (paresthesias).

 

Spinal arachnoiditis

Spinal arachnoiditis is an inflammation accompanied by scar and fibrous thickening of the spinal cord arachnoid. Spinal arachnoiditis can compress the nerve roots and sometimes the spinal cord. Spinal arachnoiditis can also be a postoperative complication or aftereffect from the introduction of radiopaque substances (with myelography), antibiotics, and other chemicals into the subarachnoid space.

Anatomy of the spinal cord membranes and surrounding structures of the spinal canal.

Soon after an adverse effect, a large number of cells and a high concentration of protein can be found in the cerebrospinal fluid (CSF), but then the inflammatory process subsides. In the acute period of spinal arachnoiditis, the patient may have a slight increase in temperature. Bilateral asymmetric radicular pain in the extremities may also be expressed. With spinal arachnoiditis, signs of root compression are determined in the form of loss of tendon reflexes. Back pain and root irritation symptoms are associated with lumbar arachnoiditis more often than they should. In addition, Spinal arachnoiditis is not a common cause of spinal cord compression.

The approaches to the treatment of spinal arachnoiditis among neurologists and neurosurgeons are controversial. In some patients, improvement occurs after laminectomy (removal of part of the vertebral arch). Multiple meningeal arachnoid cysts along the nerve roots can be a congenital anomaly. As they grow in volume, these arachnoid cysts cause deformation or stretching of the spinal nerve roots and ganglia, causing severe radicular pain in adult patients.