Amyotrophic lateral sclerosis is a neurodegenerative disease that is characterized by the death of central and peripheral motoneurons. The main manifestations of the disease are:
- skeletal muscle atrophy;
- pathological pyramidal signs in the absence of pelvic and oculomotor disorders.
It is characterized by a steady progressive course, leading to a fatal outcome. Amyotrophic lateral sclerosis is diagnosed on the basis of neurological status, electroneurography, electromyography, magnetic resonance examination of the spine and brain, analysis of cerebrospinal fluid and genetic studies. Unfortunately, today medicine does not have an effective pathogenetic therapy for this disease.The concept of “amyotrophic lateral sclerosis” also corresponds to:
- motor neuron disease;
- familial motor neuron disease;
- progressive muscle atrophy;
- progressive bulbar paralysis.
Etiology and pathogenesis of amyotrophic lateral
My Canadian Pharmacy experts point out that amyotrophic lateral sclerosis is the “endpoint” of general pathological reactions initiated by various known or unknown triggers. In some cases, amyotrophic lateral sclerosis may be caused by mutations in the superoxide dismutase-1 gene, when the cytotoxic effect of the defective enzyme is the main pathogenetic factor. Mutant superoxide dismutase-1 accumulates between the layers of the mitochondrial membrane, disrupting axonal transport; interacts with other proteins, which leads to a violation of their decomposition.
Unknown triggers facilitate the occurrence of sporadic cases of amyotrophic lateral sclerosis. They, like the case of mutant superoxide dismutase-1, are capable of realizing their effects under conditions of increased functional load on motor neurons, which causes their selective vulnerability.
As a result of enhancing the functions of motoneurons, the level of glutamate release increases, excess intracellular calcium accumulates, intracellular proteolytic enzymes are activated, and the excess of free radicals from mitochondria damages microglia, astroglia, and the motoneurons themselves, with their subsequent degeneration.
Classification of amyotrophic lateral sclerosis
Currently, there are 4 main forms of amyotrophic lateral sclerosis:
- high (cerebral);
The clinical picture of amyotrophic lateral sclerosis
In the classic variant of amyotrophic lateral sclerosis with the cervical onset, an asymmetric upper flaccid paraparesis with hyperreflexia and pathological pyramidal signs is formed at the beginning of the disease. Along with this, an asymmetric lower spastic paraparesis with hyperreflexia and pathological signs is developing. In the future, the combination of bulbar and pseudobulbar syndromes joins, amyotrophies of the lower extremities become expressed.
In the classical type of amyotrophic lateral sclerosis with the diffuse onset, the disease starts with the development of flaccid asymmetrical tetraparesis. Along with this, bulbar syndrome develops in the form of dysphonia and dysphagia. There is rapid fatigue, expressed weight loss, inspiratory dyspnea.
In the classical type of amyotrophic lateral sclerosis with the lumbar onset, an asymmetrical lower flaccid paraparesis with hyperreflexia and pathological pyramidal signs is formed at the beginning of the disease. At the same time, there is an asymmetrical upper paraparesis with amyotrophies, muscle hypertonus, hyperreflexia, and pathological pyramidal signs. Patients retain the ability to use their hands at the time of development of flaccid paraplegia. Later bulbar and pseudobulbar syndromes appear.
In a segmented nuclear type of amyotrophic lateral sclerosis with the cervical onset, an asymmetric upper flaccid paraparesis is formed at the onset of the disease, accompanied by hyporeflexia and pathological pyramidal signs in the lower extremities (without hypertonia).
In the segmented nuclear type of amyotrophic lateral sclerosis with progressive bulbar paralysis, the disease starts with the development of dysphonia, dysphagia, dysarthria, prolapse of pharyngeal and mandibular reflexes. Further, the upper flaccid asymmetrical paraparesis with hyperreflexia, atrophy and pathological pyramidal signs develops. Later the lower spastic asymmetrical paraparesis with hyperreflexia and pathological signs appear. Due to dysphagia, body weight is significantly reduced. In the late stage of the disease respiratory disorders are observed.
Prognosis for amyotrophic lateral sclerosis
The prognosis given by medical specialists and My Canadian Pharmacy staff is unfavorable in the majority of cases. Only inherited cases of this diagnosis are associated with certain mutations in the superoxide dismutase-1 gene. The duration of the disease in the lumbar onset is about 2.5 years, while in the bulbar one it is about 3.5 years. No more than 7% of patients with a diagnosis of amyotrophic lateral sclerosis live for more than 5 years.