Hydromyelia is an expansion of the central canal of the spinal cord caused by various disorders of cerebrospinal fluid dynamics. The condition becomes a consequence of congenital anomalies of the craniocervical junction, back injuries, diseases of the spine or spinal cord. Pathology is manifested by pain syndrome, sensitivity disorders, motor dysfunction. Diagnosis of the disease includes MRI spinal, myelography, ENMG. Surgical treatment is considered a radical method of correction, if necessary, physiotherapy, drug therapy (analgesics, neurometabolites, cholinomimetics) is prescribed.
The disease has an unofficial medical name “spinal cord dropsy”. It is not uncommon for publications on neurology to confuse between hydromyelia and syringomyelia when these two medical terms are used synonymously, although there is a key difference between them. With hydromyelia, a central-channel cavity filled with cerebrospinal fluid is formed, whereas with syringomyelia, such formations are located in the substance of the spinal cord. The prevalence of hydromyelia is 2.5-2.7 cases per 100 thousand population.
The pathology is based on the blockade of the outflow of cerebrospinal fluid at different levels of the spinal canal or at the level of the large occipital foramen. Among all the causes of the disease, up to 80% is associated with Chiari malformation (CM), mainly type 1, dislocation of the tonsils of the cerebellum, combined with disorders of cerebrospinal fluid dynamics. In addition, pathology can be caused by the following reasons:
- Injuries. Often, hydromyelia develops months or years after mechanical damage to the back. It occurs as a result of the adhesive process in the subarachnoid space or post-traumatic necrosis.
- Spinal factors. There are several diseases that are potentially complicated by hydromyelia. These include malformations (diastematomyelia, “rigid end thread”), degenerative lesions of the spine.
- Lesions of the craniocervical zone. The group of probable causes of hydromyelia includes tumors of the posterior cranial fossa, supratentorial tumors, basilar impersia. Pathology is often formed against the background of the Dandy-Walker anomaly, arachnopathy.
In the mechanism of formation of cavities of the spinal canal, an increase in the pressure gradient of the cerebrospinal fluid, intramedullary accumulation of cerebrospinal fluid is crucial. Such processes are observed in the presence of an obstacle to free circulation through the spinal canal and ventricular system of the brain. This mainly occurs in patients with anomalies at the junction of the bones of the skull and spine.
In modern neurology, the stages of the development of the disease have been established. At the initial stage, there is a longitudinal edema of the spinal cord, which is clearly visible during instrumental diagnosis. This is a reversible state that disappears after decompression of the subarachnoid space. If the hydromyelia is not eliminated at an early stage, a cavity is formed that squeezes the substance of the spinal cord, causing a variety of pathological manifestations.
At the beginning of the disease, most patients suffer from a sensitive area, which is caused by compression of the substance of the posterior horns of the spinal cord. 90% of people complain of pain in the chest, neck and occipital area or in the hands. This is due to the frequent localization of hydromyelia in the thoracic part of the spinal canal. The pains have a dull, aching or dragging character, appear without connection with physical exertion.
In addition to pain syndrome, numbness, a feeling of “crawling” of goosebumps, various violations of temperature sensitivity are bothering. Due to inadequate perception of thermal stimuli, patients may receive pain-free burns or frostbite. A characteristic feature of hydromyelia is the preservation of tactile and proprioceptive sensitivity.
Later, motor disorders join. Peripheral paresis of the hands, primarily the small muscles of the hands, is specific for hydromyelia, which makes it difficult for a person to perform work that requires well-developed motor skills. Gradual muscle atrophy is noted, fibrillar twitching is not uncommon. Sometimes the disease is accompanied by lateral paresis of the legs.
Since the condition is usually provoked by pathologies of the craniocervical site, patients have corresponding symptoms. The triad of typical manifestations includes headache (81%), damage to the visual apparatus (78%), otoneurological disorders (74%). A specific feature of headache is its intensification during neck movements, coughing, sneezing, straining.
With the existence of hydromyelia for more than 8-10 years, 48% of patients have noticeable sensitivity disorders, and 12% of patients face severe neurological deficiency. Disorders of the motor sphere, as a rule, lead to the loss of special professional skills. With the progression of the process, respiratory disorders, swallowing, and cardiac activity increase. Secondary infection (pneumonia, pyelonephritis, urethritis) often joins.
Hydromyelia is characterized by a polymorphic clinical picture, often occurs under the guise of other diseases. Therefore, it is often not possible for a neurologist to establish a correct preliminary diagnosis during a physical examination. To identify the condition, evaluate anatomical changes in the central nervous system, determine the severity of disorders, the following diagnostic methods are prescribed:
- MRI of the spinal cord. The study is recognized as the “gold standard” for the examination of patients with suspected hydromyelia. According to MRI images, central cavities ranging in size from 2 mm to 25 mm, an increase in the diameter of the spinal cord, compression of nerve roots are detected. To clarify the cause, an MRI of the head and spine is performed.
- Myelography. X-ray examination with contrast is prescribed if it is impossible to conduct an MRI. According to the diagnostic results, it is possible to assess the patency of the spinal canal, to identify its local extensions.
- ENMG. The diagnostic method is indicated to exclude pathologies of the peripheral nervous system, which may be accompanied by similar clinical signs. The study involves an assessment of the nerve impulse in response to stimulation, demonstrates the degree of preservation of neuromuscular transmission.
Drug treatment is symptomatic, used for uncomplicated forms of hydromyelia, non-severe neurological deficit. Due to the unstable stabilization of the process, the variety of clinical symptoms, therapy should be comprehensive and continuous. The following medications show good effectiveness in preventing the progression of the condition:
- Analgesics. With mild and moderate pain syndrome, drugs from the group of nonsteroidal anti-inflammatory drugs are successfully used, which, according to indications, can be enhanced by local administration of anesthetics.
- Cholinomimetics. This group of medications serves to improve the conduction of nerve impulses, reduce sensory and motor disorders.
- Neuroprotectors. Medications are taken in long courses to provide nutrition and blood supply to the spinal cord tissue. Also, for this purpose, B vitamins, balanced vitamin and mineral complexes are prescribed.
- Psychotropic drugs. The drugs are effective in the treatment of central neuropathic pain, which cannot be corrected by analgesics. Tricyclic antidepressants and anticonvulsants are used.
If surgical correction is impossible, as well as in the postoperative period, a non-drug therapy program is carried out. To restore motor skills, special complexes of physical therapy are recommended, and massage courses help to slow down the atrophy of muscle tissue. To improve all types of sensitivity, acupuncture and electrostimulation are used.
The help of neurosurgeons is required for patients with signs of involvement of the bulbar department, the presence of hypertension-hydrocephalus syndrome, a rapid increase in neurodeficiency. The main method of treatment is subcutaneous decompression craniectomy, which normalizes the circulation of the cerebrospinal fluid. In post-traumatic hydromyelia, operations on the spine and spinal cord are indicated.
Prognosis and prevention
Patients who have been operated on show good long‒term results: improvement is observed in 56-94% of cases, stabilization – in 6-25% of cases. The prognosis is less favorable when prescribing isolated conservative therapy, in which up to 47% of people suffer from worsening neurological deficits and only 11% report normalization of well-being.
Patients from risk groups are recommended to limit actions that violate cerebrospinal fluid dynamics: exercises with imitation of taking Valsalva, lifting weights, sports loads. For the prevention of complications, medical and social expertise, career guidance work is carried out at the onset of the disease in youth. If the diagnosis is established, it is necessary to follow up with a neurologist with repeated control MRI every 2-3 years.