Dermatomyositis

Generality

Dermatomyositis is an idiopathic inflammatory disease that affects the muscles and the skin, causing muscular deficits (weakness, pain and atrophy) and some typical skin signs (rash and scleroderma).

Figure: cutaneous signs associated with dermatomyositis. From the site: twicsy.com

In an advanced stage, dermatomyositis can also affect the internal organs (esophagus, lungs and heart) and lead to serious consequences (difficulty swallowing, respiratory problems and heart failure).

Currently, the causes of dermatomyositis are unknown, but an immunological origin is assumed.

The diagnosis is based on a thorough physical examination, followed by several laboratory and instrumental tests.

The treatment methods currently available are only able to alleviate the symptoms and slow down the progression of dermatomyositis.

What is dermatomyositis?

Dermatomyositis is a chronic inflammatory disease of connective tissues, characterized by disorders in the skin ( rash and scleroderma ) and muscle (weakness, pain and atrophy). Not surprisingly, the name dermatomyositis derives from the union of the terms "dermato", which refers to the skin, and "myositis", which refers to an inflammation of the muscles.

If, in addition to voluntary skeletal muscles, dermatomyositis also affects the striated muscles of the heart and the smooth musculature of the digestive, circulatory and respiratory systems, it can seriously endanger the lives of affected individuals.

WHAT IS A MYOSITIS?

Myositis is the medical term used to indicate a particular pathological condition, characterized by an inflammation of the muscles of the body.

When a person suffers from myositis, the muscle fibers that make up his muscles suffer deterioration.

Depending on the triggering causes, myositis can be distinguished into:

• Idiopathic inflammatory myositis (NB: in medicine, the term idiopathic means "without identifiable causes")
• Infectious myositis
• Myositis associated with other diseases
• Ossifying myositis
• Drug-induced myositis

Epidemiology

According to US statistical research, dermatomyositis has a frequency of 5-6 cases per million people. Therefore, it is an uncommon disease.

It can affect both adults and children: in adulthood, it usually appears around the age of 40-50, while in childhood / adolescence it generally occurs between 5 and 15 years.

For a still unclear reason, women get sicker than dermatomyositis more than men.

Causes

The precise causes of origin of dermatomyositis are currently unknown.

Some researchers have tried to explain this disease as a result of a viral (Epstein-Barr virus) or bacterial infection ( Chlamydia pneumoniae and Chlamydia psittaci ). Other scholars hypothesize that dermatomyositis is a pathological manifestation (and therefore a symptom) of some autoimmune diseases, such as Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis or autoimmune vasculitis (NB: autoimmune diseases are special conditions, in which the immune system of a person, instead of defending the latter from threats from outside, turns against it by attacking its organs).

Because the causes are unknown, dermatomyositis is considered an idiopathic inflammatory myositis by doctors.

Symptoms and Complications

The progressive deterioration of muscle fibers, which occurs due to dermatomyositis, is the cause of:

• Myalgia . It is the pain in the muscles at the time of their contraction.
• Muscular asthenia . Synonymous with muscle weakness, it occurs mainly due to the voluntary proximal musculature (it affects the muscles that depart directly from the trunk). The areas most affected are therefore the neck, shoulders, hips and thighs.
• Figure: the first muscles affected by dermatomyositis. From the site: //mda.org Figure: the redness that accompanies dermatomyositis is characterized by uniform red-violet plaques. The rush tends to begin on the eyelids and then extend symmetrically to the face, arms, forearms and lower limbs. From the site: huidarts.com Muscular atrophy . It is the reduction of muscle mass (or tone). An atrophic musculature is less capable and less strong. Initially, muscle atrophy affects the muscles closest to the trunk (the same affected by asthenia); only later does it involve the distal musculature and that of the internal organs.
• Muscle soreness

Regarding the cutaneous manifestations, the typical eruption from dermatomyositis involves the onset of red-purple spots at the eyelids, thorax, face, back, hands and / or joints (knees and shoulders, in particular) .

The other characteristic sign of dermatomyositis, or scleroderma, generally affects the arms and legs, but could also involve internal organs, such as kidneys, heart, esophagus, intestine and lungs. Scleroderma literally means " hard skin "; in fact this disease is characterized by an abnormal thickening of the skin, the result of excessive synthesis and deposition of collagen.

WHEN TO REFER TO THE DOCTOR?

The onset without reason of muscular pains and the concomitant appearance of red-purple spots on the skin must induce the interested person to contact the doctor immediately, for a clarification of the situation.

COMPLICATIONS

When muscle deterioration and scleroderma affect the internal organs (esophagus, lungs, heart etc.), the patient suffering from dermatomyositis is in danger of life, as he is subject to:

• Swallowing difficulties ( dysphagia ), followed by nutrition problems and the so-called ab ingestis pneumonia . These difficulties all arise from an alteration of the smooth muscles of the digestive system (especially the first tracts). The resulting nutrition problems lead to a sharp drop in body weight and the onset of a serious state of malnutrition.

  NB: Ab ingestis pneumonia is the inflammation of the lungs caused by the entry, in the bronchial tree, of food, saliva or nasal secretions. Its typical symptoms are: cough, fever, headache, dyspnea and general malaise.

• Respiratory problems . When the intercostal muscles that allow breathing are involved, and when scleroderma involves the respiratory tract, people with dermatomyositis breathe with enormous difficulty.
• Heart problems . Due to an inflammation of the heart muscle (ie the myocardium), they can consist of arrhythmias of various kinds and heart failure.

Furthermore, especially among young patients, unusual calcium accumulations in the skin and muscle ( calcinosis ) may occur.

ASSOCIATED DISEASES

Dermatomyositis can be associated with other morbid states. In addition to the aforementioned autoimmune diseases, this pathology can be combined with:

• Raynaud's phenomenon . It is an excessive spasm of peripheral blood vessels, which causes a reduction in blood flow to the regions involved.

  The reaction can be triggered by cold and / or very intense emotional stress. The areas of the body most affected are the fingers and toes, the tip of the nose, the ear lobes, the tongue and, in general, all those parts of the body crossed by small vessels that are very susceptible to temperature changes.

  The typical symptoms of Raynaud's phenomenon are: pain, burning, numbness and tingling.

• Pulmonary interstitial disease . It is an alteration of the lining tissue of the pulmonary alveoli, ie the cavities within which gas exchange takes place. In its most advanced stages, interstitial disease is the cause of pulmonary fibrosis.
• Tumors in various organs of the body . In adult subjects (species of advanced age), dermatomyositis would seem to favor the onset of tumors in the uterine cervix, the lungs, the pancreas, the breast, the ovaries and the gastrointestinal tract.

Diagnosis

To determine whether certain signs and symptoms are attributable to dermatomyositis, the physician uses an objective examination and some instrumental and laboratory tests.

Among the various types of myositis, dermatomyositis is perhaps the simplest form to diagnose, as it combines muscle pain (which is common to many other diseases) with well-detailed signs on the skin.

EXAMINATION OBJECTIVE

During the physical examination, the doctor asks the patient to describe the symptoms experienced and the exact location of the pain. Afterwards, he dedicates himself to the observation of the cutaneous signs (rash) and to the palpation of the aching muscles (NB: in the case of dermatomyositis and myositis in general, the muscles are often soft and as if they had granules inside them). Finally, it analyzes the patient's clinical history, investigating the possible presence of current and previous diseases.

LABORATORY EXAMINATIONS

Laboratory exams consist of:

• Quantification of blood levels of creatine kinase, aldolase, autoantibodies and tumor antigens . Their dosage in a small blood sample is very useful for diagnostic purposes, because in an individual with dermatomyositis they are superior to the norm. For example, creatine kinase is very high, even 50 times more than normal (NB: elevated creatine kinase is a sign of muscle damage).
• Skin biopsy . It consists in the collection and subsequent analysis, in the laboratory, of a small sample of skin cells from the area affected by the eruption.

  This test represents one of the most reliable methods to diagnose dermatomyositis and to exclude pathologies with similar symptoms.

• Muscle biopsy . It consists in the collection and subsequent analysis, in the laboratory, of a small sample of muscle cells from the painful areas.

  Although it is useful for detecting any muscle damage or infection, it is less reliable than skin biopsy.

INSTRUMENTAL EXAMINATIONS

The possible instrumental exams are:

• Electromyography . It is used to measure the electrical activity of muscles. It is not at all invasive.
• Nuclear magnetic resonance (RMN) . Thanks to the creation of magnetic fields, the MRI provides a detailed image of the muscles. It is not an invasive exam.
• RX-chest . It is used to assess the state of health of the lungs. It is important when there is suspicion of a pulmonary involvement. It is considered an invasive examination because it exposes the patient to a minimal dose of ionizing radiation.

Treatment

At the moment, there is still no specific cure for dermatomyositis.

Current treatments available to patients only improve the symptoms (including complications) and slow down the progression of the disease.

Among the various treatments, corticosteroid and immunosuppressive drugs play an important role, as well as rehabilitation and surgery.

According to some scientific studies, first the symptomatic therapy begins and the greater the benefits the patient will enjoy.

PHARMACOLOGICAL THERAPY

As anticipated, corticosteroids and immunosuppressants are the drugs most used in dermatomyositis.

The former are powerful anti-inflammatory medicines, while the latter are used to lower the immune system . Both are administered with the ultimate intent of reducing inflammation and autoimmune response (NB: corticosteroids are also useful in maintaining muscle strength and in avoiding atrophy of muscles subject to deterioration).

If the aforementioned drugs are found to be ineffective, doctors can resort to a third possibility, represented by intravenous immunoglobulins . These, like the previous medicines, work by reducing the autoimmune response, but they are much more expensive.

What are the side effects of corticosteroids and immunosuppressants?

If taken for long periods and / or at high doses, corticosteroids can cause serious side effects, such as diabetes, osteoporosis, hypertension, increased body weight, cataracts, etc.

Immunosuppressants, on the other hand, make the person who uses them more fragile and more exposed to infections.

REHABILITATION THERAPY

Depending on the severity of the symptoms, patients with dermatomyositis may need to undergo:

• Physiotherapy . Thanks to the help of an experienced physiotherapist, the patient can maintain a discreet muscle tone, even in spite of the progressive deterioration to which the muscles go. It is essential that patients learn to perform motor exercises in full autonomy, so that they can perform them at home, in their free time.
• Language therapy . It is recommended for patients with swallowing problems, as it helps reduce their severity.
• Proper diet . Those who have problems eating, it is good to know which foods to eat for a correct nutritional intake. Therefore, a dietitian will prepare a diet commensurate with the age and needs of the patient.

SURGERY

The only surgical treatment that can be used in case of dermatomyositis is that for the removal of calcium deposits in the skin and muscle (calcinosis).

SOME ADVICES

Dermatomyositis weakens the skin, especially the areas affected by the rash.

Therefore, doctors recommend not to expose themselves too much to the sun or to do it only after having taken the necessary precautions (protective sunscreen, suitable clothing, etc.), as ultraviolet rays could further worsen the situation.

Furthermore, it is good practice:

• Contact your doctor for any information regarding dermatomyositis and possible associated diseases.
• Keep active, so as to tone the muscles of the body.
• In case of extreme tiredness, rest and allow your body to regain strength.
• If signs or symptoms ever appear before, contact your doctor immediately.
• If you are depressed because of the illness, confide in friends and relatives. In fact, closing in on oneself is not beneficial to therapies.

Prognosis

At one time, when current treatments did not yet exist, the prognosis was negative and the 5-year survival rate from symptom onset was very low.

Today, however, thanks to advances in medicine, the prognosis has improved a lot and survival rates at 5 and 10 years from the onset of dermatomyositis are respectively 70% and 57% (2012).