Syringobulbia is a formed slit—like cavity in the region of the brain stem, which squeezes the nuclei of the lower pairs of cranial nerves, damages the sensory and motor pathways. The disease occurs against the background of Chiari anomaly, tumor, traumatic or ischemic lesions of the central nervous system. The condition is manifested by bulbar syndrome, disorders of sensory and motor functions, neuropathic pain. Diagnosis requires neurological examination, MRI of the brain and spinal cord, CT of the spine. Treatment includes neurosurgical methods of correction of cerebrospinal fluid dynamics, drug symptomatic therapy, long-term rehabilitation.
ICD 10
G95.0 Syringomyelia and syringobulbia
General information
Syringobulbia is a special case of syringomyelia: these two diseases are similar in etiopathogenesis, but differ in the localization of the defect in the central nervous system, respectively, have a different clinical picture. Unlike syringobulb cavities, syringomyelic cavities are located in the spinal cord. The true frequency of syringobulbia has not been statistically established, on average, the pathology is up to 3% of all diagnosed cases of syringomyelia. The disease is accompanied by a serious neurological deficit, requires timely comprehensive treatment, so it does not lose its relevance in modern neurology.
Causes
The main etiological factor causing up to 80% of cases of the disease is Chiari malformation type 1 (CM1) — dislocation of the cerebellar tonsils with a violation of the normal anatomical and functional arrangement of structures that contain the posterior cranial fossa. Other causes of syringobulbia are much less common, they can be grouped into the following categories:
- Lesions of the craniocervical zone (0.4-12%). Pathology of the brain stem develops with basilar impression, Dandy-Walker anomaly, small posterior cranial fossa. Occasionally, arachnopathies, supratentorial tumors become the cause of the disease.
- Traumatic factors (4-10%). Cavities in the brain stem are the result of post-traumatic necrosis, the formation of adhesions in the subarachnoid space. Often, combined syringomyelia and syringobulbia occur under the influence of trauma.
- Neuroinfections. With viral or bacterial encephalitis, there is an active accumulation of inflammatory cells that die, forming voids lined with glial cells inside the brain stem.
- Cerebral ischemia. In rare cases, the formation of pathological cavities in the cerebral trunk is associated with necrosis of the nervous tissue caused by a sudden cessation of blood circulation in a certain branch of the cerebral artery.
Pathogenesis
The key link in the mechanism of development of syringobulbia is a disorder of cerebrospinal fluid dynamics, which is accompanied by the penetration of cerebrospinal fluid into the substance of the brain stem along a pressure gradient. The formation of cavities also occurs with intramedullary accumulation of extracellular fluid due to a violation of its outflow into the subarachnoid space. Most often, disorders of cerebrospinal fluid dynamics act as a manifestation of pathologies in the area of the large occipital foramen.
Syringobulbic cavities are formed with a certain stage. First, longitudinal intramedullary edema develops in the trunk (the so-called “pre-syrings syndrome”), which is reversible, and is successfully eliminated with neurosurgical decompression. If the treatment is not carried out on time, a cavity forms inside the neural tissue, which can then spontaneously drain into the subarachnoid space — “post-syringes syndrome”.
Symptoms
The peak of manifestation occurs at the age of 20-40 years. The disease begins with nonspecific complaints of violation of different types of sensitivity. Patients report episodes of paresthesia (numbness, “crawling goosebumps”), inadequate perception of pain, pathologically increased sensitivity to the usual stimuli. More than 39% of patients complain of constant chilliness of the upper extremities.
Pathognomonic symptoms for the disease include bulbar disorders. Due to the dysfunction of the lower pairs of cranial nerves, patients experience problems with swallowing, often choke on solid and liquid food, notice segmental changes in the sensitivity of the facial skin. The defeat of the nerves of the articulatory apparatus is accompanied by hoarseness of voice, indistinctness of speech up to dysarthria.
Later, pain sensations appear, localized in the cervical-collar zone, chest, can be given to the arm. The pains are aching in nature, they occur spontaneously without connection with physical exertion or a change in body position. If syringobulbia is caused by Chiari malformation, up to 81% of patients experience severe headache, 78% have visual, and 74% have otoneurological disorders.
Ocular phenomena in syringobulbia include periodic flashes of light in front of the eyes, transient blurred vision, pain in the eye sockets. Photophobia worries less often, the fields of vision narrow, double vision begins. Typical otoneurological symptoms: imbalance, pressure and tinnitus, a feeling of “pitching” of surrounding objects.
Complications
The most serious consequence of syringobulbia is progressive bulbar paralysis, which is manifested by a triad of symptoms: dysphagia (inability to swallow), dysarthria (inability to articulate speech), dysphonia (disorder of voice formation). Without treatment, the condition ends with respiratory and cardiac arrhythmias, which becomes the main cause of death of patients.
The progression of syringobulbia causes serious damage to the motor nerves, which leads to spastic (central) paralysis, accompanied by hyperreflexia, muscle hypertonicity. At the same time, there is a risk of developing complete tetraparesis with disorders of pelvic organ functions. Often the disease is accompanied by secondary infectious complications in the form of bacterial pneumonia, urethritis, pyelonephritis.
Diagnostics
At the initial admission of a patient to a neurologist, it is necessary to find out the prerequisites for the appearance of symptoms, the nature of their progression, the severity of the condition. The hereditary history is carefully analyzed to confirm or exclude familial cases of Chiari malformation. To verify the diagnosis, a complete examination is prescribed, including the following methods:
- Assessment of neurological status. Physical examination reveals dissociated sensitivity disorders, decreased muscle strength, and atrophy of individual muscles. The detection of bulbar symptoms is a pathognomonic sign that allows you to distinguish syringobulbia from syringomyelia.
- MRI of the brain. With neuroimaging, it is possible to establish the presence, size, localization of a pathological cavity in the brain stem. To assess the movement of cerebrospinal fluid, to study the functional state of the cavity, the PC-cine MRI technique is used.
- MRI of the spine. Since syringobulbia often occurs as a complication of progressive syringomyelia, visualization of the spinal canal is necessary to search for cavities in the cerebrospinal substance. To clarify the diagnosis, CT of the cervical spine calving, myelography is performed.
- Electroneuromyography. The study of ENMG is indicated for the differential diagnosis of central and peripheral lesions of the nervous system. With syringobulbia, there is no pathology of nerve endings, since the lesion is localized in the trunk.
Treatment
Conservative therapy
Isolated medical treatment of syringobulbia was found to be ineffective. Drug therapy is considered as an auxiliary method for surgical intervention, as well as as an option for providing assistance to patients with temporary or permanent contraindications to surgery. To improve the neurological status , polypharmacotherapy is performed using the following groups of drugs:
- Analgesics. Non-narcotic painkillers together with local anesthetics are used to eliminate severe pain syndrome. In case of unbearable pain, he is considering the appointment of opioids.
- Antidepressants. The drugs show effectiveness in relieving resistant neuropathic pain, have a positive effect on the psychoemotional state of patients. According to indications, antidepressants are taken in combination with anticonvulsants.
- Neuroprotectors. They improve trophism and blood supply to the brain, prevent the progression of neurological deficit.
Surgical treatment
Neurosurgical care is the only radical method of treatment that can stop the progression of the disease. Most operations are aimed at eliminating pathological cerebrospinal fluid dynamics, which caused cavities. Most often, suboccipital decompression craniectomy is performed, coagulation of part of the tonsils of the cerebellum, decompression of the posterior cranial fossa with / without duroplasty.
The timeliness of neurosurgical correction is important. If the operation is performed in the first 2 years after the onset of symptoms, there is a chance to partially or completely restore the lost neurological functions, while interventions at a later stage are aimed only at stabilizing the condition. Surgical treatment is recommended for all patients, unless they have absolute contraindications.
Rehabilitation
An important stage of treatment is a rehabilitation program, which, in combination with adequate surgical correction, increases the chances of healing patients. Methods of physiotherapy (electromyostimulation, acupuncture), massage complexes, individual physical therapy sessions are used. To reduce the phenomena of dysarthria, classes with a speech therapist-defectologist are shown.
Prognosis and prevention
Persistent improvement of the condition after surgical treatment is noted in 82-86% of patients with uncomplicated course of the disease, in 50% of patients with large cavities. Given the severity of the disease and the high risk of complications, the prognosis is doubtful. Prevention consists in the timely detection and treatment of pathologies that provoke cavities, and dispensary observation of sufferers with syringobulbia with regular MRI monitoring.