Symptoms of juvenile dermatomyositis

The symptoms of juvenile dermatomyositis are varied, due to generalized damage to the microcirculatory bed, but the leading syndromes are cutaneous and muscular.

Skin changes

Classical skin manifestations of juvenile dermatomyositis are Gottron's sign and heliotrope rash. Gottron's sign is erythematous, sometimes flaky skin elements (Gottron's sign), nodules and plaques (Gottron's papules) rising above the skin surface of the extensor surfaces of the proximal interphalangeal, metacarpophalangeal, elbow, knee, and rarely ankle joints. Sometimes Gottron's sign is represented only by a dull erythema, which is subsequently completely reversible. Most often, erythema is located above the proximal interphalangeal and metacarpophalangeal joints and subsequently leaves scars.

The classic heliotrope rash in juvenile dermatomyositis is a purple or erythematous periorbital skin rash on the upper eyelids and the space between the upper eyelid and eyebrow (the "purple glasses" symptom), often in combination with periorbital edema.

Erythematous rash is also located on the face, chest, neck (V-shaped), upper back and upper arms (shawl symptom), abdomen, buttocks, thighs and shins. Often, patients have livedo dendriticum in the shoulder girdle and proximal extremities (which is typical for younger patients), possibly on the face. Severe vasculopathy leads to the formation of superficial erosions, deep skin ulcers, causes residual hypopigmentation, atrophy, telangiectasia and sclerosis of varying severity. An early sign of the disease is changes in the nail bed (hyperemia of the periungual folds and proliferation of the cuticle).

Skin manifestations of juvenile dermatomyositis precede muscle damage by several months or even years (on average, by six months). Isolated skin syndrome is more common at onset than muscular or muscular-cutaneous. However, in some cases, these skin manifestations appear months after the onset of myopathy.

Skeletal muscle damage

The cardinal symptom of juvenile dermatomyositis is symmetrical weakness of the proximal muscle groups of the limbs and trunk muscles of varying severity. Most often, the muscles of the shoulder and pelvic girdles, neck flexors and abdominal muscles are affected.

Usually parents begin to notice that the child has difficulty performing actions that previously did not cause problems: climbing stairs, getting up from a low chair, bed, potty, floor. The child has difficulty sitting on the floor from a standing position; he has to lean on a chair or his knees to pick up a toy from the floor; when getting out of bed, he helps himself with his hands. The progression of the disease leads to the fact that the child has difficulty holding his head up, especially when lying down or getting up, cannot dress himself, comb his hair. Often, parents consider these symptoms to be a manifestation of general weakness and do not focus their attention on them, so when collecting anamnesis, you should specifically ask them about this. With severe muscle weakness, the child often cannot lift his head or leg off the bed, sit up from a lying position, and in more severe cases, cannot walk.

Lesions of the eye muscles and distal muscle groups of the limbs are not typical. Involvement of the distal muscles of the limbs is found in young children or in severe and acute cases of the disease.

The severe symptoms of juvenile dermatomyositis are damage to the respiratory and swallowing muscles. Involvement of the intercostal muscles and diaphragm leads to respiratory failure. When the pharyngeal muscles are damaged, dysphagia and dysphonia occur: the timbre of the voice changes - the child begins to speak nasal, choke, there are difficulties in swallowing solid and sometimes liquid food, rarely liquid food spills out through the nose. Dysphagia can lead to aspiration of food and cause the development of aspiration pneumonia or death.

Patients often complain of muscle pain, although weakness may not be accompanied by pain syndrome. At the onset and peak of the disease, examination and palpation may reveal dense swelling or density and soreness of the muscles of the limbs, mainly proximal ones. Symptoms of muscle damage may precede skin manifestations. However, if the skin syndrome is absent for a long time, then we are talking about juvenile polymyositis, which is 17 times less common than juvenile dermatomyositis.

Inflammatory and necrotic processes in muscles are accompanied by dystrophic and sclerotic changes, leading to muscular dystrophy and the formation of tendon-muscle contractures. In moderate cases, they develop in the elbow and knee joints, and in severe cases, they are widespread. Timely treatment leads to complete regression of contractures. On the contrary, a long-term untreated inflammatory process in muscles causes persistent changes, leading to the patient's disability.

The degree of muscular dystrophy and atrophy of subcutaneous fat (lipodystrophy) is directly proportional to the duration of the disease before the start of treatment and is most typical for the primary chronic variant of juvenile dermatomyositis, when the diagnosis is made late and treatment begins several years after the onset of the disease.

Soft tissue damage

Soft tissue calcification (mainly muscles and subcutaneous fat) is a feature of the juvenile variant of the disease, developing 5 times more often than in adult dermatomyositis, especially often in preschool age. Its frequency ranges from 11 to 40%, most often accounting for about 1/3 of patients; the development period is from 6 months to 10-20 years from the onset of the disease.

Calcification (limited or diffuse) is the deposition of calcium salts (hydroxyapatites) in the skin, subcutaneous fat, muscles or intermuscular fascia in the form of isolated nodules, large tumor-like formations, superficial plaques or widespread. With superficial location of calcifications, an inflammatory reaction of the surrounding tissues, suppuration and rejection in the form of crumbly masses are possible. Deeply located muscle calcifications, especially isolated ones, are detected only by X-ray examination.

The development of calcinosis in juvenile dermatomyositis reflects the degree of severity, prevalence and cyclicity of the inflammatory necrotic process. Calcinosis often develops with a delayed start of treatment and, according to our data, 2 times more often with a recurrent course of the disease. Its appearance worsens the prognosis due to frequent infection of calcifications, the development of joint-muscle contractures in the case of their location near joints and in fascia.

Joint damage

Joint syndrome in juvenile dermatomyositis is manifested by arthralgia, limited mobility in the joints, morning stiffness in both small and large joints. Exudative changes are less common. As a rule, changes in the joints regress during treatment and only rarely, in the case of damage to small joints of the hands, do they leave behind a spindle-shaped deformation of the fingers.

Heart failure

Systemic muscular process and vasculopathy cause frequent involvement of the myocardium in the pathological process, although in juvenile dermatomyositis all 3 membranes of the heart and coronary vessels may suffer up to the development of myocardial infarction. However, the low severity of clinical symptoms and their non-specificity explain the difficulty of clinical diagnosis of carditis. In the active period, patients experience tachycardia, muffled heart sounds, expansion of the heart borders, and heart rhythm disturbances.

Lung damage

Respiratory system involvement in juvenile dermatomyositis is quite common, primarily due to the involvement of the respiratory muscles (with the development of respiratory failure) and pharyngeal muscles (with impaired swallowing and possible development of aspiration pneumonia). At the same time, there is a group of patients with pulmonary interstitial involvement of varying severity - from increased pulmonary pattern on radiographs and absence of clinical symptoms to severe rapidly progressing interstitial process (like Hamon-Rich fibrosing alveolitis). In these patients, pulmonary syndrome takes on a leading role in the clinical picture, is poorly treatable with glucocorticosteroids and determines an unfavorable prognosis.

Gastrointestinal tract damage

The main cause of gastrointestinal tract damage in juvenile dermatomyositis is widespread vasculitis with the development of trophic disorders, impaired innervation and smooth muscle damage. In the clinic of dermatomyositis in children, complaints of pain in the throat and along the esophagus, increasing when swallowing; abdominal pain, which is mild and diffuse, are always alarming. The basis of the pain syndrome can be several reasons. The most serious reasons are esophagitis, gastroduodenitis, enterocolitis, caused by both catarrhal inflammation and erosive-ulcerative process. In this case, minor or profuse bleeding (melena, bloody vomiting) occurs, perforations are possible, leading to mediastinitis, peritonitis and, in some cases, to the death of the child.

Other clinical manifestations

Juvenile dermatomyositis is characterized by lesions of the mucous membranes of the oral cavity, less often - the upper respiratory tract, conjunctiva of the eye, vagina. In the acute period, moderate liver enlargement and polylymph node adenopathy are often detected, usually with a concomitant infectious process. With active juvenile dermatomyositis, polyserositis may develop.

Approximately 50% of patients develop subfebrile temperature, reaching febrile numbers only with an accompanying infectious process. In acute and subacute cases of the disease, patients complain of malaise, fatigue, and weight loss. Many patients, more often younger ones, exhibit irritability, tearfulness, and negativism.

Variants of the course of juvenile dermatomyositis proposed by L.A. Isaeva and M.A. Zhvania (1978):

• sharp;
• subacute;
• primary chronic.

Acute course is characterized by a rapid onset (the patient's severe condition develops in 3-6 weeks) with high fever, severe dermatitis, progressive muscle weakness, difficulty swallowing and breathing, pain and edema syndrome, visceral manifestations. Acute disease is observed in approximately 10% of cases.

In the subacute course, the full clinical picture appears within several months (sometimes within a year). The development of symptoms is more gradual, the temperature is subfebrile, visceral lesions are less common, calcification is possible. Subacute course is typical for most patients (80-85%).

The primary chronic course (5-10% of cases) is characterized by a gradual onset and slow progression of symptoms over several years in the form of dermatitis, hyperpigmentation, hyperkeratosis, and minimal visceral pathology. General dystrophic changes, muscle atrophy and sclerosis, and a tendency to develop calcifications and contractures predominate.

Degrees of process activity:

• 1st degree;
• II degree;
• III degree;
• crisis.

The division of patients according to the degree of activity of the process is carried out on the basis of the severity of clinical manifestations (primarily, the degree of muscle weakness) and the level of increase in “muscle breakdown enzymes”.

Myopathic crisis is an extreme degree of severity of damage to striated muscles, including respiratory, laryngeal, pharyngeal, diaphragmatic, etc.; the basis is necrotic panmyositis. The patient is completely immobilized, myogenic bulbar and respiratory paralysis develop, creating a life-threatening situation due to respiratory failure of the hypoventilation type.

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