Concentric sclerosis of Balo is an acute specific form of multiple sclerosis, characterized by a multi—layered concentric structure of demyelinated areas of the brain. Clinical manifestations are similar to multiple sclerosis, but have a rapidly and steadily progressive course with a fatal outcome. It is diagnosed when specific foci with the structure of annual tree rings are detected on the MRI of the brain. Treatment includes corticosteroids, cytoprotectors, neurometabolites, anticonvulsants, plasmapheresis, exercise therapy, massage, but its effectiveness is insufficient.
ICD 10
G37.5 Concentric sclerosis [Balo]
General information
Concentric sclerosis of Balo is an acute demyelinating pathology of the central nervous system, the specific feature of which is the formation of foci of demyelination (destruction of myelin) in the form of concentric curls and rings in the white matter of the brain. It was first described by the Hungarian pathologist Joseph Balo in 1927 . At the autopsy of a patient with the clinic of acute multiple sclerosis, Balo found areas of destruction of the white brain matter in the form of concentric layers with intact axons preserved in them. In accordance with this picture, the author gave the disease the name periaxial leukoencephalitis. Subsequently, the term “Balo concentric sclerosis” or “Balo’s disease” became commonly used in neurology.
Along with Marburg’s disease, Schilder’s leukoencephalitis, Devik’s opticomyelitis, concentric sclerosis of Balo belongs to rare forms of multiple sclerosis. As of 1994, up to 100 clinical cases of concentric sclerosis have been described worldwide. Mostly young people get sick. This variant of multiple sclerosis differs from its classical form by an acute rapidly progressive course.
Causes
The etiology of the disease remains unclear, presumably has a multifactorial character, including a hereditary predisposition. Frequent indication of the manifestation of the disease after an infectious disease (mainly after ARVI), indicates the leading role of infectious agents (mainly viruses) in triggering pathological processes leading to the development of Balo disease. Separate studies show the primary role of herpes neurotropic viruses of the 6th type.
Unlike the classical form of multiple sclerosis, the pathogenesis of the Balo variant is probably based on other processes that cause the formation of ring demyelination pathognomonic for concentric sclerosis. However, it is still a mystery about which processes that lead to damage to oligodendrocytes are in question. A number of researchers have come to the conclusion about the leading role of hypoxic mechanisms, although their genesis remains unknown.
Morphologically, the areas of demyelination in Balo sclerosis are a ring-shaped alternation of zones of demyelination and cerebral tissue with preserved or restored, due to remyelination, myelin. Microscopically, deep degeneration of oligodendrocytes is determined, leading to their apoptosis (self-destruction).
Symptoms
The manifestation of the disease occurs at a young age. Among the cases of concentric sclerosis described in the literature, there were also asymptomatic forms diagnosed according to autopsy data. Often in the anamnesis of patients there is an indication of a previous infectious disease or an acute stressful situation. Balo sclerosis, as a rule, is characterized by a pronounced variable focal symptom complex, developing against the background of non-rough cerebral manifestations. The latter can be represented by headache with or without nausea, secondary generalized epilepsy. Asthenia is possible.
The most typical focal symptoms include signs of damage to the pyramidal tracts (spastic paresis with hyperreflexia and loss of sensitivity, pathological foot reflexes) and the extrapyramidal system (various hyperkinesis). Cerebellar ataxia (shakiness, dysmetria and discoordination, nystagmus), cognitive impairment (memory loss, amnesic aphasia, organic dementia), mental disorders (depression, euphoria, hysterical neurosis) are often noted. In most cases, there are visual function disorders of the type of retrobulbar neuritis. In a number of patients, the onset of concentric sclerosis of Balo was observed with isolated visual disturbances in the form of loss of half of the visual field in both eyes (hemianopia), in some with amnestic aphasia (speech disorders expressed in difficulty remembering and selecting the necessary word, as well as in a disorder of understanding complex utterances).
Diagnostics
In the course of the diagnostic search, along with neurological examination and research of cognitive functions, echo-encephalography, REG and electroencephalography are carried out. An ophthalmologist’s consultation is indicated. Checking visual acuity can reveal its decrease, however, in a number of patients visual acuity remains intact. When examining the fields of vision, it is possible to detect hemianopia, individual cattle (focal image loss in the visual field). Ophthalmoscopy data can vary from an almost normal fundus picture to pronounced signs of disc edema or optic nerve atrophy.
Examination of cerebrospinal fluid taken by lumbar puncture usually reveals lymphocytic pleocytosis, protein concentration within normal limits. Oligoclonal IgG pathognomonic for classical multiple sclerosis and reflecting chronic autoimmune processes in the central nervous system are detected only in 10% of cases of Balo’s disease.
Previously, it was possible to diagnose Balo’s concentric sclerosis only by autopsy results. After the introduction of MRI into neurological practice, neurologists were able to establish a diagnosis in vivo. Characteristic of Balo’s disease is the detection on MRI of the brain of pathological foci with a layered structure, represented by alternating ring-shaped hypo- and hyperintensive zones, which resembles the pattern of annual rings on a tree cut. The additional introduction of contrast during MRI makes it possible to assess the activity of the demyelinating process. Conducting a PET of the brain with methionine reveals foci of its reduced accumulation, coinciding with the areas visualized by MRI, which makes it possible to exclude the tumor nature of the detected foci and confirm their demyelinated nature.
Treatment and prognosis
Currently, the therapy is identical to the treatment of multiple sclerosis in the acute phase. Glucocorticosteroids (methylprednisolone, dexamethasone) are used; the beginning of treatment is possible with pulse therapy with methylprednisolone. Some clinicians use a combination of corticosteroids with mitoxantrone. In order to maintain the trophism of cerebral tissues, cytoprotectors, preparations of thioctic (alpha-lipoic) acid, pentoxifylline, hemodialysate from the blood of calves are prescribed in parallel. If indicated, decongestant therapy is used: magnesium sulfate, mannitol, mannitol, furosemide, etc. Patients with convulsive syndrome are additionally prescribed anticonvulsants (carbamazepine, valproic acid, diazepam). Discrete plasmapheresis is possible. Prevention of joint contractures in paresis is carried out with the help of physical therapy and massage.
Balo sclerosis refers to unfavorable rapidly progressive variants of multiple sclerosis. The fatal outcome is observed in the period from several months to 1-2 years from the moment of the onset of the disease. The literature describes isolated cases of improvement in the condition of patients against the background of intensive glucocorticoid therapy.