Inclusion Body Myositis

Inclusion body myositis is an inflammatory disease of muscle tissue characterized by the formation of specific inclusions within myofibril cells that are visible under microscopic examination. This rare disease belongs to the group of myopathies and is usually manifested by progressive muscle weakness, flaccidity, muscle pain, and changes in the quality and structure of muscle tissue. Inclusion body myositis is often associated with systemic disorders such as dysphagia and mild respiratory disorders. The exact etiology of inclusion body myositis remains unclear, although a number of factors, including autoimmune and metabolic mechanisms, are suggested in the development of the disease.

History of the disease and interesting historical facts

Inclusion body myositis was first described in the 1970s, but its manifestations and characteristic morphological changes in muscles became the subject of scientific study only in the late 20th century. Initially, the disease was considered a type of polymyositis, but further studies revealed unique features, including specific morphological inclusions in myofibrils. Interestingly, inclusion body myositis was more often diagnosed in older people, and its association with other autoimmune diseases, such as scleroderma and systemic lupus erythematosus, further complicated the understanding of this pathology.

Epidemiology

Inclusion body myositis is considered a relatively rare disease, with an incidence of approximately 1-2 cases per 100,000 people. Research shows that the disease is more common in older people, with the average age at diagnosis being around 60 years. The disease is slightly more common in women than in men, with a ratio of approximately 2:1. Given the different geographic regions, there are local differences in the prevalence of the disease, which may be due to genetic, environmental, and cultural factors.

Genetic predisposition to this disease

There is evidence that inclusion body myositis may have a genetic predisposition. It has been found that certain genetic markers, including HLADRB1, may be associated with an increased risk of developing the disease. Studies also point to mutations in genes that control the function of cells responsible for regulating inflammation and tissue metabolism. Some authors note that dysfunction of the tumor suppressor p53 may also be involved in the pathogenesis of the disease, although this issue requires further study.

Risk factors for the development of this disease

There are several risk factors that may contribute to the development of inclusion body myositis, including:

• The influence of viral infections such as Epstein-Barr virus and cytomegalovirus.
• Environmental factors such as exposure to toxic chemicals including pesticides and heavy metals.
• Systemic diseases of connective tissue that can provoke inflammatory processes in the muscles.
• Age – the disease is more common in older people.
• Genetic predisposition, as already mentioned.

Diagnosis of this disease

Diagnosis of inclusion body myositis is a complex process that involves:

• The main symptoms are: characteristic muscle weakness, increased fatigue, muscle pain, difficulty swallowing and breathing.
• Laboratory tests: determination of the level of muscle enzymes (creatine kinase, lactate dehydrogenase) and specific antibodies.
• Radiological examinations: MRI allows visualization of the extent of muscle tissue damage.
• Other types of diagnostics: muscle biopsy, which confirms the presence of inclusions and inflammatory changes.
• Differential diagnosis: exclusion of other myopathies such as polymyositis, dermatomyositis and hereditary myopathies.

Treatment

Treatment of inclusion body myositis is multi-stage and may include:

• General treatment: physical therapy and rehabilitation measures to maintain muscle function.
• Pharmacological treatment: Corticosteroids and immunosuppressive drugs help reduce inflammation.
• Surgery: In rare cases, surgery may be needed to correct problems with breathing or swallowing that develop.
• Other treatments: use of physical therapy and alternative methods to improve the patient's overall condition.

List of medications used to treat this disease

Drugs used for inclusion body myositis include:

• Prednisolone
• Methotrexate
• Azathioprine
• Mycophenolate mofetil
• Cyclophosphamide

Disease monitoring

Effective monitoring of inclusion body myositis includes:

• Control stages: regular examinations are performed at intervals of 3 to 6 months.
• Prognosis: The disease is progressive, but early diagnosis and adequate treatment can improve the patient's quality of life.
• Complications: serious organ dysfunction is possible, especially in the lungs and esophagus.

Age-related features of the disease

Inclusion body myositis can present differently in different age groups:

• In young people, the disease often progresses faster than in older people.
• At age 60 and older, symptoms may be less obvious, but progression may be more pronounced.
• In children, inclusion body myositis is extremely rare and requires a special approach to treatment.

Questions and Answers

• What is inclusion body myositis? Inclusion body myositis is an inflammatory muscle disease characterized by the presence of specific inclusions in muscle tissue cells.
• How is inclusion body myositis diagnosed? Diagnosis is based on symptoms, laboratory and radiological tests, and muscle biopsy.
• What is the treatment for inclusion body myositis? Treatment includes corticosteroids, immunosuppressants, physical therapy and, in rare cases, surgery.
• What risk factors contribute to the development of inclusion body myositis? Risk factors include age, genetic predisposition, environmental factors and underlying medical conditions.
• What is the severity of inclusion body myositis? The severity can vary; in some cases the disease progresses slowly, in others quickly.

Advice from Dr. Oleg Korzhikov

Dr. Oleg Korzhikov emphasizes the importance of early diagnosis of inclusion body myositis and recommends paying attention to the following aspects:
— If you experience unbearable muscle weakness, do not delay your visit to the doctor.
— Physical therapy can significantly improve muscle function, so be sure to follow your physical therapist's recommendations.
— Monitoring your symptoms and clearly informing your doctor about any changes in your condition will help in timely adjustment of treatment.