Alcoholic myopathy is an acute or chronic muscle damage caused by prolonged intoxication with ethanol and other toxic components of alcohol. The risk of developing the disease increases with protein-energy deficiency, concomitant renal pathology. Main symptoms: sudden or gradually increasing weakness of the proximal muscles of the extremities, myalgia, swelling of the affected muscles. The results of EMG, biopsy, and biochemical blood tests are necessary for diagnosis. Treatment involves the rejection of alcoholic beverages, the appointment of vitamins, electrolytes, restorative drugs.
ICD 10
G72.1 Alcoholic myopathy
General information
For the first time, the symptoms of muscle weakness in alcoholics with long experience were established by the American Dr. J. Jackson in 1822. According to modern data, alcoholic myopathy occurs in 40-60% of people who abuse alcohol, is one of the most common injuries of muscle tissue. Despite this, the problem is still poorly understood, its pathogenetic mechanisms are not fully understood, which causes neurologists difficulties in making a diagnosis, selecting effective therapy.
Causes
Alcoholic myopathy is recognized as a multifactorial disease, the mechanism of its occurrence is complex. The main cause of muscle damage is prolonged (longer than 5-10 years) abuse of large doses of alcohol. The highest probability of the formation of symptoms of pathology in people who take more than 100 ml daily in terms of pure ethanol. Predisposing factors include the following:
- Nutritional insufficiency. Negative nitrogen balance, reduced intake of proteinogenic amino acids, deficiency of vitamins and trace elements are typical problems for chronic alcoholism, which are prerequisites for muscle pathologies.
- Concomitant bad habits. The likelihood of symptoms of the disease increases significantly when alcohol dependence is combined with prolonged smoking, the use of psychoactive or narcotic substances.
- Kidney damage. With prolonged alcohol abuse, the functional ability of the renal filter decreases, as a result of which the decomposition products of ethanol are retained in the blood, have a toxic effect on the entire body, including skeletal muscles.
Pathogenesis
When alcohol is consumed, protein synthesis slows down in the muscles due to a decrease in the content of initiation and translation factors. In addition, ethanol neutralizes the anabolic effect of some growth factors, disrupts the functioning of intracellular signaling pathways in skeletal muscles. In some patients suffering from alcohol dependence, muscle damage is caused by the formation of insensitivity of cellular receptors to growth hormones.
In acute alcohol poisoning, denervative spontaneous activity is observed – fibrillation, a decrease in the amplitude of the action potentials of motor units (APMU). Morphological diagnosis visualizes the death of muscle fibers (rhabdomyolysis). As a result, a large amount of decay products accumulates in the blood, which creates an increased load on the kidneys, can cause acute renal failure.
Muscle fibers are divided into 2 types depending on the content of isoforms of the contractile protein myosin. In chronic alcoholic myopathy, studies reveal a lesion of the second type of fibers (fast glycolytic, oxidative-glycolytic) with relative intact myofibrils of the first type. However, atrophic changes are rarely accompanied by inflammation or necrosis, which distinguishes pathology from the acute form.
Classification
Alcoholic myopathy today is a separate nosological unit, which is often accompanied by alcoholic polyneuropathy. Taking into account the cause, the rate of development of the disease and the intensity of symptoms in modern neurology, there are 4 variants of pathology:
- Acute alcoholic myopathy. It accounts for 1-5% of all cases of the disease, with severe binge drinking, symptoms appear in a matter of days, but under favorable conditions, their complete regression is possible.
- Hypokalemic myopathy. Like the previous form, it begins acutely, against the background of a critical decrease in the level of potassium in the blood due to ethanol-induced electrolyte disturbances.
- Asymptomatic alcoholic myopathy. It is manifested by a change in the biochemical parameters of the blood, but there are no clinical symptoms.
- Chronic alcoholic myopathy. The condition occurs with a frequency of up to 200 cases per 10 thousand population, is characterized by proximal paresis, typical gait changes.
Symptoms
In the acute variant, there is a sudden weakness in the proximal muscles of the upper and lower extremities (muscles of the shoulders, hips). In the necrotic variant of the disease, the patient is concerned about sharp muscle pain, the affected areas are edematous. The hypokalemic form also manifests muscle weakness, but there are no symptoms of pain and swelling of skeletal muscles.
The chronic form of muscle damage in alcoholism is manifested by a gradual decrease in muscle strength in the proximal part of the limbs. Symptoms of the disease include disorders during walking (“duck gait”, increased lumbar lordosis), impaired coordination of movements, decreased performance. Over time, patients develop joint contractures, movements in the extremities are sharply limited.
When the process spreads to the facial muscles, specific symptoms occur: impoverishment of facial expressions, inability to smile or pull out the lips with a tube, inability to frown. The defeat of the circular muscle of the mouth causes difficulties in pronouncing words, unclear diction. Occasionally there are problems with swallowing due to myopathic laryngeal paresis.
Complications
In the case of chronic alcoholism, a constant increase in consumed doses of ethanol, the condition has a progressive character. The volume of muscles is reduced by 30% or more. At the same time, symptoms can regress only in acute forms of the disease, and chronic damage is irreversible. With a detailed morphological study, it was found that even 5 years after giving up alcohol, myopathic disorders persist.
In 15-35% of cases, alcoholic myopathy is complicated by cardiomyopathy, which is manifested by cardiac arrhythmias, circulatory insufficiency, coronary heart disease. In the absence of treatment, due to low blood flow, symptoms of chronic hypoxia increase, the work of all internal organs is disrupted. At the advanced stage, combined lesions of the nervous, cardiovascular, and urinary systems occur, often ending in death.
Diagnostics
Examination of patients with complaints of muscle weakness is carried out by a neurologist, a narcologist, a psychiatrist, a cardiologist can be involved in the assessment of symptoms. A clinical examination reveals a decrease in muscle strength and tone, an asymmetry of reflexes, and sensory disorders are possible. To confirm the diagnosis of alcoholic myopathy, the following diagnostic methods are required:
- Electrophysiological studies. With the help of needle myography, the duration and amplitude of APMU, the presence of fibrillations are estimated. The chronic variant is characterized by a nonspecific myopathic EMG pattern, which is identical to other types of primary muscular pathologies.
- Muscle biopsy. It is the “gold standard” in the diagnosis of a chronic form of the disease. Biomaterial is studied by immunohistochemical, morphometric methods for typing various isoforms of myosin chains, estimating the cross-sectional area of myofibrils. In the acute form of the disease, pathomorphological symptoms of necrosis and inflammation are present.
- Examination of the heart. To confirm or exclude concomitant alcoholic cardiomyopathy, an EchoCG is performed to visualize the structure of the heart chambers and valves, an ECG to study the electrical activity of the organ. According to the indications, load tests and Holter monitoring are assigned.
- Analyzes. A biochemical blood test determines typical laboratory symptoms — a sharp increase in creatine kinase and/or a decrease in potassium to 1.4-2.1 mmol/l. Concomitant kidney damage is indicated by an increase in the level of urea, creatinine, and electrolyte disturbances. When examining urine, myoglobinuria is detected.
Treatment
Conservative therapy
The basis for the treatment of any form of myopathy is the patient’s refusal to take alcohol, as well as the removal of ethanol residues and its toxins from the body. This allows you to prevent the progression of disorders. Further treatment is selected by a neurologist differentially, taking into account the symptoms, clinical form, severity of the disease. Standard therapy regimens:
- In acute necrotic myopathy, correction of water–electrolyte metabolism, control of urinary excretion, intake of B vitamins, and hemodialysis is indicated for symptoms of severe kidney damage.
- In hypokalemic myopathy, intravenous infusions of potassium chloride are used until the homeostasis parameters are normalized, after which the transition to oral administration of potassium preparations is ensured under regular laboratory monitoring of blood and urine.
- In chronic myopathy – specific treatment has not been developed, vitamin and mineral complexes, balanced nutrition with high protein content, adaptogens, metabolic drugs are used.
When the acute symptoms of pathology disappear, the question of how to correct alcohol dependence, the treatment of which is necessary to prevent complications, is solved. Patients need long-term work with psychiatrists-narcologists, psychologists, addictologists. Therapy is carried out on the territory of closed drug treatment centers or on an outpatient basis.
Experimental treatment
Scientists are working on the creation of new drugs to eliminate the symptoms of alcoholic myopathy, which are based on the correction of protein synthesis disorders. The role of leucine-containing amino acid mixtures for restoring nitrogen balance has been proved in experimental studies. Scientists managed to accelerate the growth of fast muscle fibers, which are the first to suffer from alcohol intoxication.
Prognosis and prevention
The prognosis is determined by the severity of muscle damage, alcohol experience, the presence of concomitant somatic pathologies. In 50% of patients with acute myopathy, symptoms regress, but the remaining cases end with irreversible necrosis or death from kidney failure. Chronic myopathy can be stabilized by abstaining from alcohol, but a complete cure is impossible. Preventive measures are reduced to the prevention of alcoholism.
