The Steinert's disease , Also known as myotonic dystrophy (DM) type I, is the most common form of muscular dystrophy in adults (Muscular Dystrophy Canada, 2016).
This pathology is characterized by three fundamental medical findings: muscular weakness, muscular atrophy and myotonia (Cózar Santiago, Cano Prous and Sarria Quiroga, 2012).
In addition, it is a multisystem disease that can greatly affect the facial areas, eyes, limbs, the cardiac system, the Central nervous system, digestive system or even metabolism (Asssociation Française contre les Myopathies and Spanish Association against Neuromuscular Diseases, 2002).
At the etiological level, Steinert's disease has a genetic origin related mainly to the presence of alterations in the DMPK gene, Located on chromosome 19 (The Muscular Dystrophy Association, 2016).
The diagnosis of Steinert's disease is made on the basis of family and individual medical history and clinical examinations, however, A genetic study is required for confirmation (Myotonic Dystrophy Foundation, 2016).
On the other hand, in terms of treatment, although there are no specific curative approaches, physical rehabilitation and control of Medical complications, such as essential medical intervention (Reina and Guasch, 2002).
Characteristics of Steinert's disease
Steinert's disease is a type of muscular dystrophy Of a multisystem nature that is usually manifested by various neuromuscular complications, as the atrophy , Weakness or Myotonia (Cózar Santiago, Cano Prous and Sarria Quiroga, 2012).
The term neuromuscular disease is used to classify a large group of pathologies of neurological origin, which usually affect the structures and Nervous components in charge of muscular control (Spanish Federation of Neuromuscular Diseases, 2016).
These pathologies can fundamentally affect the neuromuscular junctions, Motor neurons Or the peripheral nerves, producing a wide Symptomatological set, among which is muscle weakness, as a more characteristic feature (Spanish Federation of Diseases Neuromuscular, 2016).
At a specific level, Steinert's disease is a type of myotonic muscular dystrophy (DMM), that is, it is a pathology with degeneration, Weakness and progressive muscular contraction that, among other factors, fundamentally affects the ability to relax muscle tissue (The Muscular Dystrophy Association, 2016).
In addition, myotonic muscular dystrophy can be classified into two fundamental types (DM1 and DM2) depending on the specific clinical features, thus, the Steinert's disease is also known as myotonic muscular dystrophy type I (Myotonic Dystrophy Foundation, 2016).
Thus, the first clinical description of this pathology was made in 1909 by Hans Steinert. In his clinical report, this author described a series of Cases characterized by a multisystem disorder that affects the Central Nervous System , Skeletal muscles, heart, eyes, The gastrointestinal system and the endocrine glands (Barra-Lúzar, Estévez-Poy, Pérez-Zorrilla, Fernández-García, Villelabeitia-Jaureguizar and Cutillas-Ruiz, 2009).
About us
Epidemiological studies indicate that Steinert's disease is the most common form of adult-onset muscular dystrophy in the General population (Muscular Dystrophy Canada, 2016).
In general, myotonic dystrophies are the most common type of neuromuscular pathology in adults (National Institute Of Disability and Rehabilitation Research, 2016).
Specifically, more than 98% of people with myotonic dystrophy suffer from Type I or Steinert's disease, while only 2% suffer from Type II (National Organization for Rare Disorders, 2007).
Thus, it is estimated that Steinert's disease has a prevalence of 1 case per 8,000-12,000 inhabitants in the general population (Orphanet, 2014).
On the other hand, some organizations, Spanish Association against Neuromuscular Diseases (2002) or the Assocation Française contre les Myopathies (2002) report that the most common presentation period for Steiner's disease is between 20 and 25, although it is highly variable.
Signs and symptoms
Steinert's disease is considered a multisystem pathology due to the diffusion of secondary medical complications: muscular manifestations, Cardiovascular, neurological, digestive, etc.
However, muscle characteristics are the cardinal signs of Steinert's disease (Asssociation Française contre les Myopathies et Spanish Association against Neuromuscular Diseases, 2002):
Muscle weakness and atrophy
One of the first symptoms of Steinert's disease is the development of muscular fatigue, which means that it evolves towards the progressive loss of Strength and muscular capacity.
Generally, muscle atrophy has to occur symmetrically, affected equally to muscle groups on both sides of the body, including Smooth and fluted musculature.
The smooth muscle is involved in motor activities of an involuntary nature, being located mainly in the organic structures (Cardiac muscle, respiratory system, digestive system, etc.).
Thus, in the case of Steinert's disease, the most affected smooth muscle tissue is related to:
- The apparatus or digestive system.
- The uterus, fundamentally affected by the presence of abnormal and uncoordinated contractions.
- The ocular ciliary musculature.
On the other hand, the striated musculature is involved in voluntary motor activities, therefore, it is associated with the Body bone structure.
Thus, in the case of Steinert's disease, the most affected striated muscle tissue is related to:
- Muscular groups of the facial and neck areas.
- Distal muscle groups of the upper extremities, especially in the forearm.
- The dorsiflexor muscular structure of the feet.
- The muscular tissue of the diaphragm and the intercostal areas.
- The oculomotor muscles.
- The pharyngeal and lingual muscular structure.
- Pelvic muscle structures.
Myotonia
The Myotonia Is another of the fundamental clinical signs in Steinert's disease.
This medical condition is characterized mainly by an abnormal muscular relaxation, that is to say, when we contract voluntarily or provoked a Muscle group, the intensity or progression of the posterior relaxation is affected, occurring with a pattern of abnormal slowness.
At a more practical level, if we suffer from Steinert's disease with a significant myotonia and shake hands with a person, we will find a Difficulty in releasing it, since the muscular set takes a longer period than normal to lose the tension and therefore, in Allow us to withdraw our hand.
This pathological process can systematically affect the smooth and striated muscles, however, the most affected areas are the limbs and lower extremities.
What are the most common medical complications?
Together, the muscular alterations are going to provoke the following situations (AFM and ASEM, 2002; Mayo Clinic, 2014; National Organzation for Rare Disorders, 2001):
- Muscle stiffness after movements.
- Progressive loss of muscle strength.
- Difficulty in facial expression.
- Lowering of the upper eyelids.
- Reduced movement of the hands and forearms, legs and feet.
- Heart alteration characterized mainly by an abnormality in rhythm and conduction.
- Alteration related to the nervous system, characterized mainly by the development of disturbances of the sleep-wake cycles and the Development of depressive symptomatology.
- Alteration related to the digestive system, characterized mainly by the appearance of anomalies in swallowing and other pathologies Digestive diseases.
- Metabolic anomalies, fundamentally characterized by the development of diabetes .
Can Steinert's disease have different clinical courses?
Different authors, such as Turner and Hilton-Jones (2010), distinguish different courses of Steinert's disease depending on the time of onset and their Specific clinical form:
Congenital myotonic dystrophy
In this case, some of the characteristic signs and symptoms of Steinert's disease are already Present during gestation, characterized by a significant and abnormal reduction of intrauterine movements.
At the time of birth and The presence of muscular weakness can be distinguished with a serious affectation of the respiratory capacity. On the other hand, the rest of the clinical picture Usually develops during early adulthood. However, it is a subtype with a high mortality, since those affected usually do not exceed 45 years of age.
Myotonic dystrophy I onset in childhood
In the case of the early onset of Steiner's disease, those affected usually present
Significant delay in the acquisition of motor skills, usually Moderate intellectual disability .
The signs and More characteristic clinical symptoms of this subtype include dysarthria, manual myotonia and muscle weakness of facial structures.
Myotonic dystrophy I onset in adulthood
It is the subtype that usually presents the complete clinical form (muscular dystrophy, Myotonia, cardiac involvement, gastrointestinal involvement, cutaneous alterations, psychiatric problems, etc.) and usually develop between 10 and 30 year old.
As for the prognosis, the usual period of death is around 48-60 years, due to respiratory complications or Cardiovascular diseases.
Myotonic dystrophy I, late onset or asymptomatic
In this case, the onset can vary widely from the age of 20 to The 70, delaying considerably with respect to the clinical forms described previously.
The most significant signs and symptoms are Related to mild myotonia and the development of ocular alterations, such as cataracts.
Causes
Steinert's disease has a genetic origin Autosomal dominant , That is, the clinical picture of this disorder may develop even though Inherit or develop a single copy of the pathological gene (National Organization for Rare Disorders, 2007).
Specifically, Steinert's disease is related to the presence of genetic abnormalities on chromosome 19, location 19q13.2-q13.3, Associated with a specific mutation of the DMPK gene (National Organization for Rare Disorders, 2007).
Diagnosis
The first phase of the diagnosis of Steinert's disease begins with the analysis of individual and family medical history, with the objective of To identify possible differential pathologies that explain the clinical course.
On the other hand, physical examination is fundamental, especially the study of muscle function. In this case, one of the most Employed is the Electromyography and the Muscle biopsy .
On the other hand, in order to specify the medical complications that are present in each individual case, it is important to perform an evaluation Multidisciplinary, ie, an ophthalmological examination, cardiac, gastrointestinal, etc.
In addition, the definitive diagnosis is usually confirmed through a genetic analysis, with the objective of identifying the genetic abnormality that is associated with Steinert's disease.
Thus, the genetic study can be performed during the infant or adult stage through a blood sample, or in the phase Prenatal via amniotic fluid or chorionic villi, in cases where there is a high risk of heritability.
Treatment
There is still no cure for Steinert's disease, nor have treatments identified that could slow or slow the progression of this disease pathology. However, there are some approaches towards symptomatic treatment (Muscular Dystrophy Canada, 2016):
- Surgical procedures for the correction of ocular pathologies, such as cataracts.
- Drugs for muscle alterations, essentially for medical complications related to myotonia.
- Surgical and pharmacological procedures for cardiac pathologies.
- Pharmacological treatments for the treatment of alterations of the sleep-wake cycles.
- Mechanical ventilation in cases of respiratory failure.
- Rehabilitation and physical therapy.
In the treatment of Steinert's disease, the role of the rehabilitation specialist is crucial.
The medical complications associated with From early stages of life, such as limb weakness, delayed acquisition of Development of some musculoskeletal malformations, have a strong impact on the functionality of the affected person and, therefore, their quality of life.
Numerous cases of Steinert's disease have been identified. Depressive feelings , So it is often Psychotherapeutic intervention is required in addition to medical treatment.
References
- ASEM, & AFM. (2002). Steinert's Myotonic Dystrophy. ASEM.
- ASEM; ASEM. (2004). Steinert Myotonic Dystrophy. French Association against Myopathies.
- Canada, M.D. (2016). Myotonic Dystrophy Type I.
- Ibarra-Lúzar, J., Estévez-Poy, P., Pérez-Zorrilla, E., Fernández-García, C., Villelabeitia, K., & Cutillas-Ruiz, R. (2009). Myotonic dystrophy Congenital Electrophysiological and genetic clinical findings of our series. Rehabilitation (Madr)., 144-150.
- Mayo Clinic. (2014). Muscular dystrophy.
- MDA. (2016). Myotonic Muscular Dystrophy.
- MDF. (2016). What is myotonic dystrophy?
- NORD. (2007). Dystrophy, Myotonic.
- Orphanet. (2016). Steinert Myotonic Dystrophy. Orphanet Urgencies. Obtained from Or.
- Research, N.I. (2016). Steinert's Disease or Myotonic Dystrophy.
- Turner, C., & Hilton-Jones, D. (2012). Myotonic dystrophies: diagnosis and management. The myotonic dystrophies: diagnosis and magnament. Neurol. Arg., 127-141.