Cerebellar disorders

Cerebellar disorders occur due to a variety of causes, including congenital malformations, hereditary ataxia and acquired diseases. Diagnosis is based on clinical data, sometimes by neuroimaging and / or genetic testing. 

[1], [2], [3], [4], [5], [6], [7]

Causes of the cerebellar disorders

The cerebellum is divided into 3 parts: the old part (vestibulocerebellum) includes the scrapie-scapular portion located in the medial zone, closely connected with the vestibular nuclei, helping to maintain balance and coordinate movements of the eyes, head and neck; the ancient part (paleocerebellum) - located along the middle line of the cerebellar worm, helps to coordinate the movements of the legs and trunk, its lesions lead to disruption of the posture and gait; a new part (neocerebellum) - the hemispheres of the cerebellum control the fast and precisely coordinated movements of the limbs, mainly the arms.

[8], [9], [10]

Congenital malformations

Developmental flaws are almost always sporadic, often found as part of complex anomalies (for example, the Dandy-Walker syndrome) involving other parts of the central nervous system. Defects develop in the early stages of life and do not progress. Depending on the structures involved, the symptoms vary greatly; but ataxia is usually present.

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Hereditary ataxia

Hereditary ataxia can be transmitted autosomally recessively or autosomally dominant. Among the autosomal recessive Friedreich ataxia (the most common), ataxia-telangiectasia, abetalipoprotenemia, hereditary ataxia due to vitamin E deficiency, and cerebro-tenninous xanthomatosis.

Friedreich's ataxia is associated with the mutation of the gene responsible for the synthesis of the mitochondrial protein frataxin. Pathological expansion of DNA repeats GAA (glycine-alanine-alanine) leads to a decrease in the level of frataxin, a violation of the functions of mitochondria and accumulation of iron in their matrix. The instability of the gait manifests itself to 5-15 years, which is accompanied by ataxia of the upper limbs, dysarthria and paresis (especially the hands). Cognitive functions are often reduced. Tremor is minimal or absent. Reflexes, vibrational and proprioceptive sensitivity are lost. Typical deformities of the feet, scoliosis and progressive cardiomyopathy.

Spinocerebellar ataxia (SCA) is predominantly inherited in an autosomal dominant type. There are 15 different loci of gene mutations, respectively, 15 types of SCA (SCA 1-8,10-14,16 and 17), respectively, 9 of which are characterized by the expansion of DNA repeats. In 6 types, DNA CAG repeats encoding amino acid glutamine (as in Huntington's disease) were detected. Symtomas vary. In SCA 1-3, the parts of the peripheral and central nervous system are often multiplely affected, neuropathy, pyramidal symptoms, restless legs syndrome, and ataxia are characteristic. SCA 5,6,8, 11 and 15 are usually manifested only by cerebellar ataxia.

Acquired ataxia

Acquired ataxia can develop with non-hereditary neurodegenerative diseases (eg, multiple systemic atrophy), systemic diseases, toxic effects and idiopathic diseases. Among systemic disorders, alcoholism (alcoholic cerebellar degeneration), sprue, hypothyroidism and vitamin E deficiency. Toxic substances include carbon monoxide, heavy metals, lithium, phenytoin and some organic solvents.

In children, the cause may be primary brain tumors (medulloblastoma, astrocytoma), for which the median parts of the cerebellum are the most frequent localization. Occasionally, in children after a viral infection, reversible diffuse cerebellar dysfunction develops.

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Symptoms of the cerebellar disorders

Symptoms depend on the cause, but usually include ataxia (abnormal gait on widely spaced legs due to impaired coordination).

Ataxia is a typical sign of cerebellar dysfunction, other motor disorders are possible.

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Diagnostics of the cerebellar disorders

The diagnosis is based on clinical data, taking into account the family history after the elimination of acquired systemic diseases and performing MRI. With a positive family history, genetic testing is carried out.

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Treatment of the cerebellar disorders

Treatment of cerebellar disorders is symptomatic if the cause is not acquired and reversible.

Some systemic diseases (eg, hypothyroidism, sprue) and intoxication are curable, sometimes an operation is effective (swelling, hydrocephalus), in other cases, cerebellar disorders are treated symptomatically.