Bulbar syndrome: what is it?

One of the most formidable neurological disorders is bulbar syndrome. This symptom complex is associated with a combined peripheral lesion of several pairs of cranial nerves of the caudal group. Potentially dangerous for life is the rapidly emerging and increasing in severity bulbar syndrome. In this case, an emergency hospitalization of the patient is necessary to monitor his condition and perform intensive therapy.

Pathogenesis

Depending on the etiology of the underlying disease, there is a disruption of the synaptic transmission, with relative structural preservation of the main formations, destruction of the nuclei or pronounced compression of the nerve structures. At the same time, there is no violation of impulses along the cortical and nuclear pathways and damage to central motoneurons in the frontal brain region, which distinguishes bulbar syndrome from pseudobulbar. This is important not only for diagnosing the level of lesions in the central nervous system and determining the cause of the formation of the main symptoms, but also for assessing the prognosis of the disease.

Bulbar syndrome develops with simultaneous defeat of IX, X and XII pairs of cranial nerves. The pathological process can capture their motor nuclei in the medulla oblongata( formerly called the bulb), the rootlets on the base of the brain, or already formed nerves. Defeat of nuclei is usually bilateral or bilateral, the mosaic for this syndrome is not typical.

The paralysis of the muscles of the tongue, soft palate, pharynx, epiglottis and larynx, which develop in case of bulbar syndrome, is referred to as peripheral. Therefore, they are accompanied by a decrease or loss of the palatine and pharyngeal reflex, hypotension and subsequent atrophy of paralyzed muscles. It is not excluded and the appearance of fasciculations, visible when examining the tongue. And the subsequent involvement in the pathological process of the neurons of the respiratory and vasomotor centers in the medulla oblongata, the violation of parasympathetic regulation, cause the development of life-threatening conditions.

The main causes of

The cause of bulbar syndrome can be:

• vascular catastrophes in the vertebrobilar basin, leading to ischemic or hemorrhagic craniospinal injury;
• primary and metastatic tumors of the trunk and medulla oblongata, sarcomatosis, granulomatosis of various etiologies;
• states that give a positive mass effect without a clearly defined formation in the posterior cranial fossa and threaten to wedge the brain into the large occipital foramen( hemorrhage, edema of the nervous tissue with strokes of neighboring regions or acute diffuse brain damage);
• tumors of the cerebellum, resulting in compression of the medulla oblongata;
• fracture of the base of the skull;
• syring-bulbia;
• meningitis and encephalitis of various etiologies;
• polyneuropathy( paraneoplastic, diphtheria, Guillain-Barre, postvaccinal, endocrine), poliomyelitis;
• amyotrophic lateral sclerosis, as well as genetically determined Kennedy spinal bulbar amyotrophy, Verdig Hoffmann's spinal amyotrophy, and children's bulbospinal amyotrophy( Fazio-Londe disease);
• inhibition of brain motoneurons by botulinum toxin.

Many authors refer to the bulbar syndrome as changes in the defeat of the muscles of the soft palate, pharynx and larynx. In this case, their cause is a violation of neuromuscular transmission or primary damage to muscle tissue in myopathies, myasthenia gravis, or dystrophic myotonia. The oblong brain( bulba) remains intact in myopathic diseases, so they speak of a special form of bulbar paralysis.

Clinical picture of

A characteristic feature of bulbar syndrome is the deviation of the tongue towards the lesion.

The combined peripheral lesion of the glossopharyngeal, vagal and sublingual nerves leads to paresis of the muscles of the palate, pharynx, larynx, and tongue. Characteristic is the combination of the triad "dysphonia-dysarthria-dysphagia" with paresis of half the tongue, the sagging of the palatine curtain and the disappearance of pharyngeal and palatine reflexes. The changes seen in the oropharynx are most often asymmetric, the appearance of bilateral bulbar symptoms is a prognostically unfavorable feature.

Upon examination, the deviation( deflection) of the tongue towards the focus is detected. His paralyzed half becomes hypotonic and sedentary, in it fasciculations may appear. With bilateral bulbar paralysis there is almost complete immobility of the entire tongue, or glossoplegia. Because of the growing atrophy of the paretic muscles, the affected half of the tongue gradually becomes thinner, acquiring a pathological folding.

The paresis of the muscles of the soft palate leads to immobility of the palatine arch, sagging and hypotension of the palatine curtain with deviation of the palatine tongue to the healthy side. Together with the loss of pharyngeal reflex, a violation of the functioning of the muscles of the pharynx and epiglottis, this becomes the cause of dysphagia. There are difficulties in swallowing, puffing, throwing food and liquids into the nasal cavity and the respiratory tract. Therefore, patients with bulbar syndrome have a high risk of developing aspiration pneumonia and bronchitis.

When the parasympathetic portion of the sublingual nerve is affected, vegetative innervation of the salivary glands is disrupted. The resulting increase in saliva production, together with impaired swallowing, causes salivation. Sometimes it is so pronounced that patients are forced to constantly use a handkerchief.

Dysphonia in bulbar syndrome is manifested by nasal, deafness and hoarseness of voice due to paralysis of vocal cords and paresis of soft palate. Nasal shade of speech is called nasolalia, such a nasalization of sound production can appear even in the absence of obvious violations of swallowing and poperyvaniy. Dysphonia is combined with dysarthria when speech indistinctness occurs due to impaired mobility of the tongue and other muscles involved in articulation. The defeat of the medulla oblongata often leads to a combination of bulbar syndrome with paresis of the facial nerve, which also affects the intelligibility of speech.

When paralysis of the muscles of the palate, pharynx and larynx is expressed, asphyxia can occur due to mechanical closure of the lumen of the respiratory tract. With bilateral damage to the vagus nerve( or its nuclei in the medulla oblongata), the work of the heart and respiratory system is inhibited, which is caused by a violation of their parasympathetic regulation.

Treatment of

Treatment requires not the bulbar syndrome itself, but the underlying disease and emerging life-threatening conditions. With the increase in the severity of symptoms and the appearance of signs of cardiac and respiratory failure, the patient needs a transfer to the intensive care unit. According to the indications, ventilation is carried out, a nasogastric tube is installed.

To correct disorders in addition to etiotropic therapy, prescribe drugs of various groups with neurotrophic, neuroprotective, metabolic, vascular action. Reduce hypersalivation with atropine. In the recovery period or with chronic diseases, to improve speech and swallowing, massage is prescribed, exercises with a speech therapist, kinesiotherapy.

Bulbar syndrome is a formidable sign of the defeat of the medulla oblongata. Its appearance requires compulsory treatment to the doctor to clarify the etiology and address the need for hospitalization.

Petrov KB, MD, professor, offers you a slide show about clinical variants of bulbar syndrome and non-drug treatment methods for this condition: