Pseudobulbar syndrome

Pseudobulbar palsy (supranuclear bulbar palsy) is a syndrome characterized by paralysis of the muscles innervated by the V, VII, IX, X, XII cranial nerves as a result of bilateral damage to the corticonuclear tracts to the nuclei of these nerves. In this case, bulbar functions are affected, primarily articulation, phonation, swallowing and chewing (dysarthria, dysphonia, dysphagia). But unlike bulbar paralysis, there is no muscle atrophy and there are reflexes of oral automatism: increased proboscis reflex; Astvatsaturov's nasolabial reflex appears; Oppenheim's reflex (sucking movements in response to stroke irritation of the lips), distant-oral and some other similar reflexes, as well as pathological laughter and crying. The study of the pharyngeal reflex is less informative.

[ 1 ], [ 2 ]

Causes of pseudobulbar palsy

Neurologists identify the following main causes of pseudobulbar paralysis:

1. Vascular diseases affecting both hemispheres (lacunar condition in hypertension, atherosclerosis; vasculitis).
2. Perinatal pathology and birth trauma, among others.
3. Congenital bilateral periaqueductal syndrome.
4. Traumatic brain injury.
5. Episodic pseudobulbar palsy in epileptiform opercular syndrome in children.
6. Degenerative diseases with damage to the pyramidal and extrapyramidal systems: ALS, primary lateral sclerosis, familial spastic paraplegia (rare), OPCA, Pick's disease, Creutzfeldt-Jakob disease, progressive supranuclear palsy, Parkinson's disease, multiple system atrophy, other extrapyramidal diseases.
7. Demyelinating diseases.
8. Consequences of encephalitis or meningitis.
9. Multiple or diffuse (glioma) neoplasm.
10. Hypoxic (anoxic) encephalopathy ("disease of the revived brain").
11. Other reasons.

[ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ]

Vascular diseases

Vascular diseases affecting both hemispheres are the most common cause of pseudobulbar palsy. Repeated ischemic cerebrovascular accidents, usually in people over 50, with hypertension, atherosclerosis, vasculitis, systemic diseases, heart and blood diseases, multiple lacunar cerebral infarctions, etc., usually lead to a picture of pseudobulbar palsy. The latter can sometimes develop with a single stroke, apparently due to decompensation of latent vascular cerebral insufficiency in the other hemisphere. In vascular pseudobulbar palsy, the latter can be accompanied by hemiparesis, tetraparesis, or bilateral pyramidal insufficiency without paresis. Vascular disease of the brain is revealed, usually confirmed by the MRI picture.

Perinatal pathology and birth trauma

Due to perinatal hypoxia or asphyxia, as well as birth trauma, various forms of cerebral palsy (CP) may develop with the development of spastic-paretic (diplegic, hemiplegic, tetraplegic), dyskinetic (mainly dystonic), ataxic and mixed syndromes, including those with a picture of pseudobulbar palsy. In addition to periventricular leukomalacia, these children often have unilateral hemorrhagic infarction. More than half of these children show symptoms of mental retardation; approximately one third develop epileptic seizures. The anamnesis usually contains indications of perinatal pathology, delayed psychomotor development, and residual symptoms of perinatal encephalopathy are detected in the neurological status.

The differential diagnosis of cerebral palsy includes some degenerative and hereditary metabolic disorders (glutaric aciduria type I; arginase deficiency; dopa-responsive dystonia; hyperekplexia (with rigidity); Lesch-Nyhan disease), as well as progressive hydrocephalus, subdural hematoma. MRI reveals some kind of brain disorder in almost 93% of patients with cerebral palsy.

Congenital bilateral aqueductal syndrome

This defect is encountered in pediatric neurological practice. It leads (like congenital bilateral sclerosis of the hippocampus) to a pronounced impairment of speech development, which sometimes even imitates childhood autism and a picture of pseudobulbar paralysis (mainly with speech disorders and dysphagia). Mental retardation and epileptic seizures are observed in about 85% of cases. MRI reveals malformation of the perisylvian gyri.

[ 8 ], [ 9 ], [ 10 ], [ 11 ], [ 12 ], [ 13 ]

Severe traumatic brain injury (TBI)

Severe craniocerebral trauma in adults and children often leads to various forms of pyramidal syndrome (spastic mono-, hemi-, tri- and tetraparesis or plegia) and pseudobulbar disorders with severe speech and swallowing disorders. The connection with trauma in the anamnesis leaves no reason for diagnostic doubts.

Epilepsy

Episodic pseudobulbar palsy is described in children with epileptiform opercular syndrome (paroxysmal oral apraxia, dysarthria, and salivation) observed in the slow phase of nocturnal sleep. The diagnosis is confirmed by epileptic discharges in the EEG during a nocturnal attack.

[ 14 ], [ 15 ]

Degenerative diseases

Many degenerative diseases involving the pyramidal and extrapyramidal systems may be accompanied by pseudobulbar syndrome. Such diseases include amyotrophic lateral sclerosis, progressive supranuclear palsy (these forms are more common as a cause of pseudobulbar syndrome), primary lateral sclerosis, familial spastic paraplegia (rarely leads to pronounced pseudobulbar syndrome), Pick's disease, Creutzfeldt-Jakob disease, Parkinson's disease, secondary parkinsonism, multiple system atrophy, and, less commonly, other extrapyramidal diseases.

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

Demyelinating diseases

Demyelinating diseases often involve the corticobulbar tracts bilaterally, leading to pseudobulbar syndrome (multiple sclerosis, post-infectious and post-vaccination encephalomyelitis, progressive multifocal leukoencephalopathy, subacute sclerosing panencephalitis, AIDS-dementia complex, adrenoleukodystrophy).

Metabolic diseases of myelin (Pelizius-Merzbacher disease, Alexander disease, metachromatic leukodystrophy, globoid leukodystrophy) can also be included in this group (“myelin diseases”).

[ 20 ], [ 21 ], [ 22 ], [ 23 ], [ 24 ]

Consequences of encephalitis and meningitis

Encephalitis, meningitis and meningoencephalitis, along with other neurological syndromes, may include pseudobulbar syndrome in their manifestations. Symptoms of the underlying infectious lesion of the brain are always revealed.

[ 25 ], [ 26 ], [ 27 ], [ 28 ], [ 29 ], [ 30 ]

Multiple or diffuse glioma

Some variants of brainstem glioma manifest variable clinical symptoms depending on its localization within the caudal, middle (pons) or oral parts of the brainstem. Most often, this tumor begins in childhood (in 80% of cases before the age of 21) with symptoms of involvement of one or more cranial nerves (usually VI and VII on one side), progressive hemiparesis or paraparesis, ataxia. Sometimes conduction symptoms precede damage to the cranial nerves. Headaches, vomiting, and swelling of the fundus join in. Pseudobulbar syndrome develops.

Differential diagnosis with pontine multiple sclerosis, vascular malformation (usually cavernous hemangioma) and brainstem encephalitis. MRI is of great help in differential diagnosis. It is important to differentiate between focal and diffuse glioma (astrocytoma).

Hypoxic (anoxic) encephalopathy

Hypoxic encephalopathy with serious neurological complications is typical for patients who have survived resuscitation measures after asphyxia, clinical death, prolonged comatose state, etc. The consequences of severe hypoxia, in addition to prolonged coma in the acute period, include several clinical variants, including dementia with (or without) extrapyramidal syndromes, cerebellar ataxia, myoclonic syndromes, Korsakoff's amnestic syndrome. Delayed post-anoxic encephalopathy with a poor outcome is considered separately.

Sometimes there are patients with hypoxic encephalopathy, in whom persistent residual effects consist of predominant hypokinesia of bulbar functions (hypokinetic dysarthria and dysphagia) against the background of minimally expressed or completely regressing general hypokinesia and hypomimia (this variant of pseudobulbar disorders is called "extrapyramidal pseudobulbar syndrome" or "pseudopseudobulbar syndrome"). These patients do not have any disorders in the limbs and trunk, but are disabled due to the above-mentioned manifestations of a peculiar pseudobulbar syndrome.

Other causes of pseudobulbar syndrome

Sometimes pseudobulbar syndrome manifests itself as a component of more extensive neurological syndromes. For example, pseudobulbar syndrome in the picture of central myelinolysis of the pons (malignant neoplasm, liver failure, sepsis, alcoholism, chronic renal failure, lymphoma, cachexia, severe dehydration and electrolyte disturbances, hemorrhagic pancreatitis, pellagra) and the overlapping "locked-in" syndrome (occlusion of the basilar artery, traumatic brain injury, viral encephalitis, post-vaccination encephalitis, tumor, hemorrhage, central myelinolysis of the pons).

Central pontine myelinolysis is a rare and potentially fatal syndrome that results in rapid development of tetraplegia (in the setting of underlying medical disease or Wernicke encephalopathy) and pseudobulbar palsy due to demyelination of the central pons that is visible on MRI and may lead to locked-in syndrome. Locked-in syndrome (isolation syndrome, de-efferentation syndrome) is a condition in which selective supranuclear motor de-efferentation leads to paralysis of all four limbs and caudal cranial innervation without impairment of consciousness. The syndrome results in tetraplegia, mutism (aphonia and anarthria of pseudobulbar origin), and inability to swallow while remaining conscious; communication is limited to vertical eye and eyelid movements. CT or MRI reveals destruction of the medioventral part of the pons.