Diagnosis of systemic scleroderma

Diagnosis of systemic scleroderma, which is based on instrumental and laboratory research data, allows us to assess the degree of involvement of internal organs and the severity of pulmonary hypertension.

For this purpose, chest X-ray, electro- and phonocardiography, echocardiography (EchoCG), a 6-minute walk test to determine the FC of circulatory failure and pulmonary hypertension, assessment of external respiratory function, ventilation-perfusion scintigraphy of the lungs, angiopulmonography, catheterization of the right heart, multispiral computed tomography of the chest organs, as well as blood tests (clinical, biochemical, immunological, analysis for assessing hemostasis and rheological properties of blood) are performed.

ECG examination in systemic scleroderma most often reveals decreased voltage, heart rhythm disturbances (67%) - supraventricular and ventricular tachyarrhythmias, extrastoles, disturbances of intra-atrial (42%) and intraventricular (32%) conduction up to complete block requiring pacemaker implantation. "Infarction-like" ECG changes in SSD have been described.

EchoCG is one of the most informative non-invasive methods for assessing pulmonary artery pressure. In addition, the study allows one to evaluate the chamber sizes and wall thickness of the heart, the contractile and pumping function of the myocardium, and the dynamics and shape of intracardiac flows. Right ventricular dilation is best judged by an increase in the ratio of the right ventricle area to the left ventricle area (preferably from the apical 4-chamber position). A ratio of 0.6-1.0 indicates mild right ventricular dilation, while a ratio greater than 1.0 indicates severe dilation. Two-dimensional echoCG allows one to observe the kinetics of the interventricular septum - paradoxical systolic motion in severe pulmonary hypertension, which, along with a decrease in pulmonary venous inflow, leads to impaired isometric relaxation of the left ventricle. In most patients with systemic sclerosis, even with minor signs of myocardial damage, echocardiography reveals diastolic dysfunction of the left ventricle (50-80%). When symptoms of systolic dysfunction appear (decrease in the left ventricular ejection fraction of less than 55%), the risk of death in systemic sclerosis increases many times over.

Pulsed wave Doppler can measure the pulmonary artery pressure. The pulmonary artery systolic pressure is equivalent to the right ventricular systolic pressure in the absence of obstruction to blood flow from the ventricle. Right ventricular systolic pressure is estimated by measuring the tricuspid systolic regurgitant flow velocity (V) and an estimate of the right atrial pressure (RAP) applied in the formula:

Right ventricular systolic pressure = 4v2 + RAP.

The AP is either a standard value or is measured using the characteristics of the inferior vena cava or jugular venous distension. Tricuspid regurgitant flow can be assessed in most (74%) patients with pulmonary hypertension,

Based on the obtained values of systolic pressure in the pulmonary artery, the following degrees of pulmonary hypertension are distinguished: •

• mild - from 30 to 50 mm Hg;
• average - from 51 to 80 mm Hg;
• severe - from 81 mm Hg and above.

Despite all the unconditional advantages of echocardiography, there are limitations of the method in terms of diagnosing right ventricular dysfunction given the difficulty of visualization and the peculiarities of the anatomical structure of the right ventricle (the presence of trabeculae and moderator band). Studying the parameters of its functional activity using standard echocardiography techniques is not entirely correct. Thus, the problem of non-invasive assessment of the functional capabilities of the right heart becomes obvious. Currently, data have appeared in the literature on the possibility of using tissue Doppler echocardiography (TDE), the technique of which consists in determining the velocity of tissue structures and is intended for an in-depth study of myocardial function. This method will provide objective information on the state of global and segmental longitudinal myocardial function. A feature of the technique is the possibility of its use to determine the systolic and diastolic function of the myocardium of the right heart.

Catheterization of the right heart and pulmonary artery is the "gold standard" method for diagnosing pulmonary hypertension. The "direct" method allows for the most accurate measurement of pressure in the right atrium and right ventricle, pulmonary artery, pulmonary artery wedge pressure (PAWP), calculation of cardiac output (the thermodilution method is used more often, the Fick method is used less often), determination of the level of oxygenation of mixed venous blood (PvG, and SvC)). This method helps to assess the severity of pulmonary hypertension and right ventricular dysfunction, and is also used to assess the effectiveness of vasodilators (usually acute tests).

Magnetic resonance imaging (MRI) is a relatively new method for diagnosing pulmonary hypertension. MRI will allow a fairly accurate assessment of the wall thickness and cavity volume of the right ventricle, as well as the ejection fraction of the right ventricle.

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Diagnostic criteria for systemic sclerosis

The American Rheumatology Association has proposed the following diagnostic criteria for SSc.

Major criterion - proximal scleroderma: symmetrical thickening and induration of the skin of the fingers, extending proximally from the metacarpophalangeal and metatarsophalangeal joints. Changes may involve the face, neck, chest and abdomen.

Minor criteria.

• Sclerodactyly; the above skin changes limited to the fingers.
• Digital scars: areas of sunken skin on the fingertips or loss of substance from the fingertips.
• Bilateral basal pneumofibrosis: reticular or linear-nodular shadows, most pronounced in the basal areas of the lungs during standard radiographic examination, may be honeycomb-like manifestations.

To establish a diagnosis of SSD, one major or two minor criteria must be present. Using these criteria to recognize the early stages of the disease is impossible.

To assess the activity of SSc, indices developed by the European Group for the Study of Systemic Sclerosis are currently used. The points are summed up. The maximum possible point is 10, with an activity index of 3 points or higher the disease is considered active, less than 3 - inactive.

Assessment of the activity of systemic scleroderma

Parameter	Score	Characteristic
Skin count >14	1	A modified skin score is used, which is assessed on a scale from 0 to 3 in 17 areas of the body.
Scleredema	0.5	Thickening of soft tissues, mainly on the fingers due to induration of the skin
Leather	2	Worsening of skin manifestations over the past month, according to the patient
Digital necrosis	0 5	Active digital ulcers or necrosis
Vessels	0.5	Worsening of vascular manifestations over the past month, according to the patient
Arthritis	0 5	Symmetrical swelling of the joints
Heart / Lungs	2	Worsening of cardiopulmonary manifestations over the past month, according to the patient
ESR >30 mm/h	1.5	Determined by the Westergren method
Hypocomplementemia	1	Decreased C3 or C4 complement
Decrease in PLCO*	0.5	PLCO <80% of normal level

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Examples of diagnosis formulation

Systemic scleroderma, limited form, chronic course, active. Raynaud's syndrome, esophagitis, sclerodactyly, pulmonary arterial hypertension stage II, FC II.

Systemic scleroderma, diffuse form, rapidly progressive course, active, polyarthritis, functional class (FC) II, interstitial myositis, glomerulonephritis, chronic renal failure I, recurrent pneumonia, basal pneumosclerosis, respiratory failure I, myocarditis, frequent ventricular extrasystole, circulatory failure (CF) II A, FC III.

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