Bulb syndrome

Bulbar syndrome develops with damage to the caudal parts of the brain stem (medulla oblongata) or its connections with the executive apparatus. The functions of the medulla oblongata are diverse and have a vital meaning. Nuclei IX, X, and XII nerves are centers of control for the reflex activity of the pharynx, larynx, and tongue and are involved in providing articulation and swallowing. They receive interoceptive information and are related to many visceral reflexes (coughing, swallowing, sneezing, salivation, sucking) and various secretory responses. In the medulla, the medial (posterior) longitudinal bundle passes, which is important in regulating head and neck movements and coordinating the latter with eye movements. It contains relay cores of auditory and vestibular conductors. Ascending and descending paths pass through it, linking the lower and higher levels of the nervous system. The reticular formation plays an important role in alleviating or suppressing motor activity, regulating muscle tone, conducting afferentation, in postural and other reflex activity, in controlling consciousness, as well as visceral and vegetative functions. In addition, through the vagus system, the medulla oblongata is involved in the regulation of respiratory, cardiovascular, digestive and other metabolic processes in the body.

Here we consider the expanded forms of bulbar paralysis, developing with bilateral lesions of the nuclei IX, X and XII nerves, as well as their roots and nerves inside and outside the skull. Here we attributed the lesions of the corresponding muscles and synapses, which lead to the same disturbances of the bulbar motor functions: swallowing, chewing, articulation, phonation and respiration.

[1], [2], [3]

Causes of bulbar syndrome

1. Diseases of the motor neuron (amyotrophic lateral sclerosis, spinal amyotrophy Fazio-Londe, Kennedy bulbospin amyotrophy).
2. Myopathies (okulofaringealnaya, Kearns-Sayre syndrome).
3. Dystrophic myotonia.
4. Paroxysmal myoplegia.
5. Myasthenia.
6. Polyneuropathy (Guillain-Barre, post-vaccination, diphtheria, paraneoplastic, with hyperthyroidism, porphyria).
7. Poliomyelitis.
8. Processes in the brain stem, posterior cranial fossa and cranio-spinal region (vascular, tumor, syringobulbia, meningitis, encephalitis, granulomatous diseases, bone abnormalities).
9. Psychogenic dysphonia and dysphagia.

[4], [5]

Diseases of the motor neuron

The final stage of all forms of amyotrophic lateral syndrome (ALS) or the onset of its bulbar form are typical examples of impaired bulbar function. The disease usually begins with bilateral lesion of the nucleus XII nerve and its first manifestations are atrophy, fasciculation and paralysis of the tongue. In the first stages, dysarthria without dysphagia or dysphagia without dysarthria may occur, but a progressive deterioration of all bulbar functions is observed rather quickly. At the onset of the disease, the difficulty in swallowing liquid foods is observed more often than solid foods, but as the disease progresses, dysphagia develops when taking solid foods. In this case, the weakness of the tongue is joined by the weakness of the masticatory and then the facial muscles, the soft palate hangs down, the tongue in the oral cavity is immobile and atrophic. It shows fastsikulyatsii. Anartria Constant salivation. Respiratory muscle weakness. In the same area or in other regions of the body, symptoms of involvement of the upper motor neuron are detected.

[6], [7], [8], [9], [10]

Criteria for the diagnosis of amyotrophic lateral sclerosis

• presence of signs of damage to the lower motor neuron (including EMG - confirmation of the anterior process in clinically preserved muscles); clinical symptoms of lesion of the upper motor neuron (pyramidal syndrome); progressive course.

"Progressive bulbar paralysis" is today regarded as one of the variants of the bulbar form of amyotrophic lateral sclerosis (just like "primary lateral sclerosis" as another type of amyotrophic lateral sclerosis that occurs without clinical signs of lesion of the anterior horns of the spinal cord).

Increasing bulbar paralysis may be a manifestation of progressive spinal amyotrophy, in particular, the terminal stage of Werdnig-Hoffmann amyotrophy (Werdnig-Hoffmann), and in children, Fazio-Londe spinal amyotrophy. The latter relates to autosomal recessive spinal amyotrophy with early childhood debut. In adults, X-linked bulbar spinal amyotrophy is known, beginning at the age of 40 years and older (Kennedy disease). The weakness and atrophy of the muscles of the proximal parts of the upper limbs, spontaneous fasciculations, limited volume of active movements in the hands, decreased tendon reflexes with the biceps and triceps muscles are characteristic. As the disease progresses, bulbar (usually non-coarse) disorders develop: puffing, tongue atrophy, dysarthria. Leg muscles get involved later. Characteristics: gynecomastia and pseudohypertrophy of the gastrocnemius muscles.

With progressive spinal amyotrophies, the process is limited to damage to the cells of the anterior horns of the spinal cord. Unlike amyotrophic lateral sclerosis, here the process is always symmetrical, it is not accompanied by symptoms of involvement of the upper motor neuron and has a more favorable course.

[11], [12], [13], [14], [15],

Myopathies

Some forms of myopathy (oculofaryngeal, Kearns-Sayre syndrome) may manifest as impaired bulbar functions. Oculopharyngeal myopathy (dystrophy) is a hereditary (autosomal dominant) disease, which is characterized by late debut (usually after 45 years) and muscle weakness, which is limited to the muscles of the face (bilateral ptosis) and bulbar muscles (dysphagia). Ptosis, swallowing disorders and dysphonia are slowly progressing. The main maladaptive syndrome is dysphagia. On the limbs, the process spreads only in some patients and in the later stages of the disease.

One of the forms of mitochondrial encephalomyopathy, namely Kearns-Sayre syndrome (“ophthalmoplegia plus”), is manifested, in addition to ptosis and ophthalmoplegia, a myopathic symptom complex, which develops after eye symptoms. The involvement of bulbar muscles (larynx and pharynx) is usually not quite rude, but it can lead to changes in phonation and articulation, gagging.

[16], [17], [18], [19]

Obligatory signs of Kearns-Sayre syndrome:

• external ophthalmoplegia
• retinal pigment degeneration
• conduction disturbances of the heart (bradycardia, atrioventricular block, syncope, sudden death is possible)
• increased protein in the liquor

[20], [21]

Dystrophic myotonia

Dystrophic myotonia (or myotonic distorofiya Rossolimo-Kurshman-Steinert-Batten) is inherited in an autosomal dominant manner and affects men 3 times more often than women. Her debut comes at the age of 16-20 years. The clinical picture is made up of myotonic, myopathic syndromes and extramuscular disorders (dystrophic changes in the lens, testicles and other endocrine glands, skin, esophagus, heart, and sometimes in the brain). Myopathic syndrome is most pronounced in the muscles of the face (chewing and temporal muscles, which leads to a characteristic facial expression), neck and in some patients in the extremities. The defeat of the bulbar muscles leads to a nasal hue of the voice, dysphagia and gagging, and sometimes respiratory disorders (including sleep apnea).

[22], [23], [24], [25], [26], [27]

Paroxysmal myoplegia (recurrent paralysis)

Paroxysmal myoplegia - a disease (hypokalemic, hyperkalemic and normokalemic form), manifested by generalized or partial attacks of muscle weakness (without loss of consciousness) in the form of paresis or plegia (up to tetraplegia) with a decrease in tendon reflexes and muscle hypotension. The duration of attacks varies from 30 minutes to several days. Provocative factors: rich in carbohydrates abundant food, abuse of salt, negative emotions, exercise, night sleep. Only in some attacks there is involvement of the cervical and cranial muscles. Rarely in the process is involved in varying degrees, the respiratory muscles.

The differential diagnosis is carried out with secondary forms of myoplegia, which are found in patients with thyrotoxicosis, with primary hyperaldosteronism, hypokalemia in some gastrointestinal diseases, kidney diseases. There are described iattrogenic variants of periodic paralysis in the appointment of drugs that promote the removal of potassium from the body (diuretics, laxatives, licorice).

Myasthenia

Bulbar syndrome is one of the dangerous manifestations of myasthenia. Myasthenia gravis (myasthenia gravis) is a disease, the leading clinical manifestation of which is abnormal muscle fatigue, decreasing until complete recovery after taking anticholinesterase drugs. The first symptoms are more often dysfunctions of the eye muscles (ptosis, diplopia and restriction of the mobility of the eyeballs) and the facial muscles, as well as the muscles of the limbs. Approximately one-third of patients experience masticatory, pharyngeal, laryngeal, and tongue involvement. There are generalized and local (mainly ocular) forms.

The differential diagnosis of myasthenia is carried out with myasthenic syndromes (Lambert-Eaton syndrome, myasthenic syndrome in polyneuropathy, myasthenia-polymyositis complex, myasthenic syndrome in botulinum intoxication).

[28], [29], [30], [31]

Polyneuropathy

Bulbar paralysis with polyneuropathy is observed in the picture of generalized polyneuropathic syndrome on the background of tetraparesis or tetraplegia with characteristic sensitive disorders, which facilitates the diagnosis of the nature of bulbar disorders. The latter are characteristic of such forms as acute Guillain-Barre demyelinating polyneuropathy, post-infectious and post-vaccination polyneuropathy, diphtheria and paraneoplastic polyneuropathy, as well as polyneuropathy in hyperthyroidism and porphyria.

[32], [33], [34], [35], [36], [37]

Poliomyelitis

Acute poliomyelitis, as the cause of bulbar paralysis, is recognized by the presence of general infectious (pre-paralytic) symptoms, the rapid development of paralysis (usually during the first 5 days of illness) with a greater damage to the proximal than the distal ones. The period of the reverse development of paralysis soon after their appearance is characteristic. Spinal, bulbar and bulbospinal forms are distinguished. Lower extremities are more often affected (in 80% of cases), but it is possible that syndromes develop along the hemitip or cross. Paralysis are sluggish in nature with loss of tendon reflexes and the rapid development of atrophy. Bulbar paralysis can be observed with the bulbar form (10-15% of the entire paralytic form of the disease), in which not only the IX, X (less often XII) nerves, but also the facial nerve suffer. Damage to the anterior horns of the IV-V segments can cause respiratory paralysis. In adults, the bulbospinal form is more likely to develop. Involvement of the brainstem reticular formation can lead to cardiovascular (hypotension, hypertension, cardiac arrhythmias), respiratory (“atactic respiration”) disorders, swallowing disorders, and wakefulness disorders.

Differential diagnosis is carried out with other viral infections that can affect the lower motor neuron: rabies and herpes zoster. Other diseases often requiring a differential diagnosis with acute polio include Guillain-Barré syndrome, acute intermittent porphyria, botulism, toxic polyneuropathy, transverse myelitis, and acute compression of the spinal cord in epidural abscess.

[38], [39],

Processes in the brain stem, posterior cranial fossa and craniospinal region

Some diseases sometimes easily involve both halves of the medulla oblongata, given the small size and compact form of the caudal part of the brainstem: intramedullary tumors (gliomas or ependymomas) or extramedullary (neurofibromas, meningiomas, hemangiomas, metastatic tumors); tuberculosis, sarcoidosis and other granulomatous processes may resemble the clinical symptoms of a tumor. Volumetric processes are sooner or later accompanied by increased intracranial pressure. Parenchymal and subarachnoid hemorrhages, traumatic brain injury and other processes accompanied by intracranial hypertension and the medulla oblongata penetrating into the foramen magnum, can lead to hyperthermia, respiratory disorders, coma and death of the patient from respiratory and heart failure. Other causes: syringobulbia, congenital abnormalities and anomalies of the craniospinal region (platibasia, Paget's disease), toxic and degenerative processes, meningitis and encephalitis, leading to dysfunction of the caudal regions of the brain stem.

[40], [41], [42], [43], [44], [45]

Psychogenic dysphonia and dysphagia

Psychogenic disorders of the bulbar functions sometimes require a differential diagnosis with true bulbar-bar paralysis. Psychogenic disorders of swallowing and phonation can be observed both in the picture of psychotic disorders and in the framework of conversion disorders. In the first case, they are usually observed against the background of clinically obvious behavioral disorders, in the second, they are rarely a monosymptomatic manifestation of the disease and in this case their recognition is facilitated by the detection of polysyndromic demonstrative disorders. It is necessary to use both positive criteria for the diagnosis of psychogenic disorders, and exclusion of organic diseases using modern paraclinical examination methods.

[46], [47], [48], [49], [50],

Diagnostic tests for bulbar syndrome

General and biochemical blood test; general urine analysis; CT scan or MRI of the brain; EMG of the muscles of the tongue, neck and limbs; clinical and EMG tests for myasthenia gravis with pharmacological stress; oculist examination; ECG; liquor study; esophagoscopy; consultation of the therapist.

[51], [52], [53], [54]