Spinal muscular atrophy manifests itself in early childhood. The first symptoms may appear as early as 2-4 months of age. This is a hereditary disease characterized by the gradual death of nerve cells in the brainstem.
Types of problems
Depending on when the first symptoms of the disease appear, on the severity of the course and the nature of atrophic changes, several types of the disease are distinguished.
Spinal muscular atrophy can develop along:
- first type: acute (Verdig-Hoffmann form);
- second type: intermediate (infantile, chronic);
- third type: Kugelberg-Welander form (chronic, juvenile).
Three types of the same disease arise, according to experts, due to different mutations of the same gene. Spinal muscular atrophy is an autoimmune disease that occurs when two recessive genes are inherited, one from each parent. The mutation site is located on chromosome 5. Hepresent in every 40 people. The gene is responsible for encoding a protein that ensures the existence of motor neurons in the spinal cord. If this process is disrupted, the neurons die.
Verdin-Hoffmann disease
You can suspect a problem even during pregnancy. If a child develops spinal muscular atrophy type 1, then sluggish and late fetal movement during pregnancy is often noted. After birth, doctors may diagnose generalized muscle hypotension.
Atrophies begin to appear in the first months of life. Often in the proximal sections, fascicular twitching of the muscles of the back, trunk, and limbs is noted. Bulbar disorders are also observed. These include sluggish sucking, a weak cry, a violation of the swallowing process. In children with Verdin-Hoffman disease, a decrease in vomiting, cough, pharyngeal, and palatine reflexes is often noted. They also have fibrillation of the tongue muscles.
But these are not all the signs by which spinal muscular atrophy can be determined. Symptoms characteristic of type 1 of this disease include weakness of the intercostal muscles. In this case, the chest of babies looks flattened.
In the first months of life, these children often suffer from respiratory infections, pneumonia and frequent aspirations.
Diagnosis of Verdin-Hoffman disease
You can determine the disease if you examine the child. There are a number of clinical signs by which specialists can determine that a baby has hereditary spinal muscularatrophy. Diagnosis includes:
- biochemical blood test (it will show a slight increase in aldolase and creatine phosphokinase);
- electromyographic study (the palisade rhythm will testify to the defeat of the anterior horns of the spinal cord);
- histological examination of skeletal muscles (clusters of rounded small fibers are detected).
Microscopy of the spinal cord (its anterior horns) shows that there are degenerative changes in the motor nuclei of the cranial nerves. There is a spherical swelling and / or wrinkling of motor cells, microglial or astrocytic proliferation, chromatolysis. These phenomena are accompanied by the appearance of dense glial fibers.
It is important to make a differential diagnosis to rule out organic aciduria, congenital or structural myopathies, such as pemaline, myotubular myopathy, or central rod disease.
Prognosis for type I atrophy
Depending on the extent of the lesion, Verdin-Hoffmann disease may begin to appear as early as the first days after birth. Specialists even in the position of the child may suggest that he has spinal muscular atrophy. Photos of these babies are similar: they lie in a frog pose. Their limbs are abducted at the hip and shoulder joints, and bent at the elbow and knee joints.
The proximal muscles of the lower extremities are the first to suffer. The process of defeat is on the ascending line. Muscles are affected as the disease progresses.larynx and pharynx. It happens that the disease manifests itself a little later. But the age limit is 6 months. Babies may even begin to lift their heads and roll over, but they never sit up.
Most babies die from heart failure, respiratory failure or previous infections in the first year of life. More than 70% of children die before 2 years of age. About 10% of these children survive to the age of 5.
Type II atrophy
In some cases, other scenarios are possible. Spinal muscular atrophy type 2 appears somewhat later. Usually the first signs are observed at the age of 8-14 months. These babies are characterized by generalized muscle weakness and hypotension.
The disease is indicated by thin fingers, a fascicular tremor in the muscles of the proximal extremities, in the fingertips. These babies have a period of normal development. At the right age, they begin to hold their heads, sit down. But there is no talk of independent walking.
Children can suck and swallow normally, and respiratory function is not disturbed in early infancy. But over time, muscle weakness begins to progress. At an older age, swallowing disorders appear, a nasal tone of voice appears. One of the most common complications in patients with significant life expectancy is scoliosis.
Prognosis for type II atrophy
Despite the fact that in the first months the child may develop normally, over timethe situation is getting worse. By the age of two, tendon reflexes of the extremities disappear in children. In parallel, the intercostal muscles weaken. As a result, the chest is flattened, there is a delay in motor development.
Only 25% of children diagnosed with spinal muscular atrophy can sit or stand with support. Late stages of the disease are characterized by the appearance of kyphoscoliosis. Many children die between the ages of 1 and 4. The most common causes of death are pneumonia or respiratory muscle damage.
When making a diagnosis of muscular spinal atrophy, it is necessary to make a differential diagnosis with congenital or structural myopathies, an atonic-astatic type of cerebral palsy.
More than 70% of patients live more than two years. The average life expectancy of such children is about 10-12 years.
Kugelberg-Welander disease
The most favorable prognosis is in those patients who have been diagnosed with type III spinal muscular atrophy. It can occur between the ages of 1 and 20. Most often, the first manifestations are recorded at the age of 2-7 years. The proximal pelvic muscles are the first to suffer.
Patients have difficulty walking, running, getting up from a squatting position and having to climb stairs. It is worth remembering that the clinical manifestations of this disease in this form are similar to progressive Becker's dystrophy.
Proximal arms and shoulder girdle affected only after a few yearsafter the first manifestations of the disease. Over time, the chest is deformed, fascicular tremor of the hands and uncontrolled contraction of various muscle groups appear. At the same time, tendon reflexes decrease and bone deformities begin to progress. The chest, feet, ankle joints are changing, and scoliosis of the spine appears.
Prognosis for type III disease
Kugelberg-Welander disease is adult spinal muscular atrophy. For many years, the disease complicates the life of patients somewhat, but does not lead to their severe disability. It progresses rather slowly. Therefore, most people with this diagnosis survive to adulthood.
Before starting treatment, it is important to make a differential diagnosis with various muscular dystrophies, type 5 glycogenosis and structural myopathies. There is a method by which spinal atrophy can be determined. This is direct DNA testing. It is necessary, because the clinical manifestations of Kugelberg-Welander disease can change.
Approximately 50% of patients lose the ability to walk from the age of 12. At the same time, muscle weakness only progresses with age. There is hypermobility and contractures of the joints, and an increased risk of fractures.
Important signs
Verdin-Hoffmann disease is usually diagnosed in the first months of life. If a child does not move from birth, then he does not live even to the age of one month.
Weakness and muscle contractions in infancyage, hand tremor and delayed motor development should alert both doctors and parents. These kids don't stand up. Only a quarter of all patients can stand with support. Toddlers are wheelchair-bound.
But the hardest thing to identify is Kugelberg-Welander disease. Indeed, in a quarter of patients, muscle hypertrophy is pronounced. Therefore, they may be misdiagnosed as muscular dystrophy rather than spinal muscular atrophy. The causes of this disease were established in 1995, when it was possible to identify the mutating SMN gene. Almost all patients have a homozygous deletion of SMN7, characterized by the loss of two telomeric copies of this gene and intact centromeric copies.
Treatment tactics
Unfortunately, spinal muscular atrophy is an autoimmune disease that cannot be prevented. Complicating the situation is the fact that there is no specific treatment.
In some cases, doctors can only alleviate the condition of patients a little with the help of physiotherapy. Special orthopedic devices help improve their quality of life.
Special attention should be paid to the nutrition of such patients. Often prescribe drugs that can improve metabolism. But that's not all that can be done if spinal muscular atrophy has been confirmed. Treatment also includes the appointment of gymnastics. Physical activity for such patients is important. They are necessary in order to improve the functioning of muscles and increase their mass. True, loadmust be calculated by a doctor. In this case, physical education will have a beneficial effect on the entire body as a whole. Its general strengthening effect will be obvious. It can be therapeutic or hygienic morning exercises, water exercises or just a general strengthening massage.
