Rheumatoid arthritis: diagnosis

Currently, the diagnosis of rheumatoid arthritis is based on classification criteria (1987).

[1], [2], [3], [4]

Indications for consultation of other specialists

Elderly patients, as well as identifying the risk factors for the development of cardiovascular pathology in patients of any age, are shown by the cardiologist.

If there are intercurrent diseases and complications of the disease or treatment (infection, diabetes, kidney pathology with a need (biopsy and so on), it is necessary to consult an infectious disease specialist, a purulent surgeon, an endocrinologist, a nephrologist, an otorhinolaryngologist and other specialists.

If there is a suspicion of the development of systemic manifestations of the RA requiring verification (scleritis, neurologic manifestations, lung lesions), consultation of an ophthalmologist, a neurologist, a pulmonologist is indicated.

To plan a prosthesis or another type of surgical treatment, an orthopedic surgeon is invited.

Diagnostic criteria of rheumatoid arthritis

[5], [6], [7], [8]

Morning stiffness

Morning stiffness in the joints or near-articular areas lasting at least 1 hour to the maximum improvement (for 6 weeks or more)

Arthritis of three or more articular regions

Swelling of the soft tissue or exudate (but not bony growths), determined by the doctor, in three or more areas of the following 14: proximal interphalangeal, metacarpophalangeal, wrist, elbow, knee, ankle, metatarsophalangeal joints (for 6 weeks or more)

[9], [10], [11], [12],

Arthritis of the joints of the brushes

Swelling in the proximal interphalangeal, metacarpophalangeal or radiocarpal joints (within 6 weeks or more)

[13], [14],

Symmetrical defeat

Simultaneous (on both sides) lesion of the same articular regions of the 14 named (proximal interphalangeal, metacarpophalangeal, radiocarpal, elbow, knee, ankle, metatarsophalangeal joints) (for 6 weeks or more)

Rheumatoid nodules

Subcutaneous nodules located above the bony protuberances, extensor surfaces of the extremities, or periarticular regions, defined by the physician

Rheumatoid factor

Elevated levels of RF in the blood serum (the determination is made by any method that gives a positive result in no more than 5% of healthy people)

X-ray changes

Changes characteristic of rheumatoid arthritis on radiographs of wrists and wrist joints in a direct projection, including bone erosion or significant decalcification of bones in the affected joints or near-articular regions (isolated changes characteristic of osteoarthritis are not taken into account)

The patient is diagnosed with rheumatoid arthritis, if at least 4 of the 7 criteria listed above are identified, it should be emphasized that the first 4 criteria should be present for at least 6 weeks.

These criteria were developed for epidemiological and clinical studies. In this regard, they have insufficient sensitivity and specificity and can not be used for early diagnosis of rheumatoid arthritis.

It should be noted that 5 out of the 7 criteria are clinical and are identified when the patient is examined. At the same time, the need for an objective approach is clear: the swelling should be distinct, the doctor evaluates it, while only the patient's anamnestic indications and complaints to the pain are clearly not enough.

Early diagnosis of rheumatoid arthritis

The development of a subclinical immunopathological process occurs for many months (or years) before the appearance of obvious signs of the disease. According to the biopsy of the synovial membrane, signs of chronic synovitis are revealed already at the very beginning of the disease, not only inflamed, but also "normal" joints. In "conditionally" healthy people, who subsequently fell ill with rheumatoid arthritis, they detect various immunological disorders characteristic of RA (an increase in the level of RF, anti-CCP antibodies, CRP), long before the appearance of the first clinical symptoms of the disease.

In 2/3 patients, structural changes (erosions) occur very quickly, already within the first two years from the onset of the disease. It is established that the prevention of structural damage in the debut of the RA contributes to the preservation of the functional activity of patients in the long term. However, the time interval when active DMAP therapy can effectively inhibit the progression of the lesion (the so-called "window of opportunity") is very short and sometimes only a few months from the onset of the disease.

Obviously, rheumatoid arthritis is a vivid example of a disease in which a long-term prognosis depends largely on how early the diagnosis was made and active pharmacotherapy was started. In this respect, RA to some extent resembles such diseases as diabetes mellitus and arterial hypertension. However, if early diagnostics of arterial hypertension and diabetes mellitus is overwhelming in most cases, because it is based on an assessment of clinical manifestations well known to general practitioners and the use of available laboratory and instrumental methods, the diagnosis of rheumatoid arthritis in the onset of the disease is much more difficult (sometimes unsolvable) problem. This is due to a number of objective and subjective circumstances. First, the symptoms of early RA are often nonspecific, they can be observed with an extremely wide range of both rheumatic and non-rheumatic diseases, and the generally accepted classification criteria for a valid RA are not suitable for early diagnosis. Secondly, in order to establish such a diagnosis, special knowledge and skills are needed to assess the clinical and radiological signs of the lesion, as well as the ability to interpret laboratory (immunological) tests that are unfamiliar to general practitioners.

Thus, one of the reasons for the unfavorable prognosis in RA is the long period between the onset of the disease and the admission of the patient under the supervision of a rheumatologist. Obviously, an important factor contributing to the improvement of prognosis in patients with rheumatoid arthritis, active diagnosis of this disease at the polyclinic stage by general practitioners.

A group of European and American rheumatologists (under the auspices of the European Antirheumatic League) has developed an algorithm that allows for more active identification of patients with early RA at a polyclinic stage. As the diagnostic feature of early RA (as well as the index of disease activity), the duration of morning stiffness (more than 10 minutes) and, when examining patients, the "lateral compression test" of metacarpophalangeal and metatarsophalangeal joints is taken into account. Positive results reflect the onset of joint inflammation. Despite the fact that rapid progression of the lesion is more likely at high titers of rheumatoid factor, an increase in ESR and the level of CRP, it should be remembered that these indicators at an early stage of the disease often correspond to the norm. In this regard, the negative results of laboratory diagnosis do not exclude the diagnosis of rheumatoid arthritis, and, therefore, suggest the need to refer patients to a rheumatologist.

[15], [16], [17], [18], [19], [20], [21]

Anamnesis

When collecting an anamnesis, it is necessary to clarify the following information.

• Duration of symptoms.
• The duration of morning stiffness (RA is characterized by a duration of 1 hour or more, at the early stage of the disease 30 minutes or more).
• The presence of a daily rhythm of pain in the joints with characteristic enhancement in the early morning hours.
• Persistence of signs of defeat (6 weeks or more).
• In addition, information should be obtained on the concomitant pathology, Prior treatment, as well as bad habits (smoking, alcohol abuse, etc.). These data may influence the choice of methods for treating rheumatoid arthritis and long-term prognosis.

[22], [23]

Physical examination

In the physical examination of the joints, the following parameters should be evaluated.

• Signs of inflammation (swelling, defoguration due to effusion, local skin hyperthermia).
• Painful on palpation and movement.
• The amount of movement.
• The emergence of persistent deformation due to the proliferation of tissues, subluxations, contractures.

Laboratory Diagnosis of Rheumatoid Arthritis

Objectives of conducting laboratory studies.

• Confirmation of the diagnosis.
• Exclusion of other diseases.
• Assessment of the activity of the disease.
• Estimation of the forecast.
• Evaluation of the effectiveness of treatment.
• Detection of complications of the disease.

Changes in laboratory indicators revealed in rheumatoid arthritis.

• Anemia (hemoglobin level less than 130 g / l in men and 120 g / l in women). The index of disease activity. Anemia is detected in 30-50% of cases. There are any forms of anemia, but more often anemia of chronic inflammation and, more rarely, iron deficiency anemia. If this condition is found, gastrointestinal bleeding should be avoided.
• Increased ESR and the level of SRV. Criterion for the differential diagnosis of rheumatoid arthritis and non-inflammatory joint diseases. Allows to evaluate the activity of inflammation, the effectiveness of treatment, the severity of the disease, the risk of progression of destruction.
• Hypoalbuminemia. Often due to nephrotoxicity of drugs used to treat RA.
• Increased level of creatinine. Due to the nephrotoxicity of drugs used to treat RA.
• Leukocytosis (thrombocytosis, eosinophilia). Indicator of severe RA, often with extra-articular (systemic) manifestations. They note the combination with a high level of RF. Consider an indication for the appointment of GC. When identifying this condition, it is necessary to exclude the development of the infectious process.
• Neutropenia. Sign of the development of Felty syndrome.
• Increase in the level of liver enzymes. The index of disease activity. The change may also be due to the hepatotoxicity of drugs used for treatment, or is associated with infection with hepatitis B or C viruses.
• Increased glucose level. It is associated with the use of HA.
• Dislipidemia. It is associated with the use of HA, but can be due to the activity of inflammation.
• An increase in the RF level. 70-90% of patients are diagnosed. High titers in the debut of the disease correlate with the severity, speed of progression of the pathological process and the development of systemic manifestations. However, the dynamics of titres do not always reflect the effectiveness of treatment. Nevertheless, the RF level is not sensitive enough and a specific marker of the early stage of RA (in the debut it is revealed in about 50% of patients). Specificity is also low among the elderly.
• An increase in the level of anti-CCP antibodies. A more specific marker of the RA than the RF level. The increase in titers and RF, and anti-CCP antibodies makes it possible to diagnose RA with a higher sensitivity and specificity than an increase in the level of only one of these indicators. Detection of anti-CCP antibodies is considered a criterion for differential diagnosis of RA at an early stage with other diseases occurring with polyarthritis (primary Sjogren's syndrome, SLE, viral hepatitis B and C, etc.). In addition, to increase the level of anti-CCP antibodies predict a risk of destruction in patients with early RA.
• An increase in the level of ANF. Identify in 30-40% of cases, usually with severe RA.
• Increase in the level of immunoglobulins (^ C. ^ M, 1 & A), concentration of complement components. CEC. The changes are not specific, therefore, it is not recommended to use the definition of these indicators as routine research.
• Definition of HbA CD4. Marker of heavy current of RA and unfavorable forecast.
• Identification of markers of the hepatitis B virus, C and HIV. In this case, the appointment of hepatotoxic drugs should be avoided.
• Changes in cerebrospinal fluid (decrease in viscosity, loose mucinous clots, leukocytosis (more than 6-109 l), neutrophilia (25-90%) .The study has an auxiliary value, which is used for differential diagnosis of RA by other joint diseases, primarily microcrystalline and septic inflammatory processes .
• Change and pleural fluid protein more than 3 g / l (exudate), glucose more than S mmol / l, lactate dehydrogenase more than 1000 units / ml, pH 7.0, titer RF more than 1: 320, level of complement (CH50) decreased, lymphocytes (neutrophils, eosinophils)]. The study is necessary for differential diagnosis with other diseases of the lungs and pleura.

It should be remembered that laboratory studies specific for the diagnosis of rheumatoid arthritis have not been developed.

Instrumental diagnosis of rheumatoid arthritis

Instrumental diagnosis is important for confirming the diagnosis and differential diagnosis of rheumatoid arthritis.

X-ray diagnostics. Radiography of brushes and with gop is necessary to confirm the diagnosis of RA, to establish the stage and evaluate the progression of destruction. Characteristic for RA changes in other joints (at least in the early stages of the disease) are not observed. To evaluate the progression of joint destruction by X-ray, the modified Sharpe method and the Larsen method are used.

Experts of the European anti-rheumatic league recommend Parsen's method when changes are evaluated by several researchers. If the assessment of destruction is carried out by one specialist, it is better to apply the modified Sharpe method (more sensitive).

To identify subluxation in the atlanto-axial articulation or cervical spondylolisthesis, it is advisable to perform a roentgenography of the cervical spine.

Doppler ultrasonography. A more sensitive method for the detection of synovitis of the knee than radiography, but not for diagnosis of synovitis of small joints of the hands and feet.

MRI diagnostics. A more sensitive method of detecting synovitis in the onset of RA than radiography. Changes detected by MRI (synovitis, edema and bone tissue erosion) allow us to predict the progression of joint destruction (according to the X-ray study). However, similar changes are sometimes found in clinically "normal" joints, so the importance of MRI for early diagnosis and prediction of RA outcomes requires further study. In addition, MRI can be used for early diagnosis of osteonecrosis.

CT diagnostics. To detect lung lesions, it is advisable to use CT with a high resolution.

Arthroscopy. It is necessary for differential diagnosis of rheumatoid arthritis with a vinous-nodular synovitis, arthrosis, traumatic injuries of the joint and others.

Radiography by the organ of the thorax. They are used to detect and differential diagnosis of rheumatoid involvement of chest organs with sarcoidosis, tumors of localization, tuberculosis and other infectious processes.

Esophagogastroduodenoscopy. Performed for patients receiving NSAIDs and for detecting anemia.

Echocardiography. Applied for the diagnosis of rheumatoid arthritis, complicated by pericarditis and myocarditis, heart lesions associated with atherosclerotic process.

Biopsy. The study takes samples of tissues (mucous membrane of the gastrointestinal tract, subcutaneous fat layers, gums, kidneys and other organs) with suspected amyloidosis.

X-ray absorptiometry. The method is used to diagnose osteoporosis. With its help define MGTK. Investigation of the IPC is useful in identifying the following risk factors for the development of osteoporosis.

• Age (women over 50, men - 60 years).
• High activity of the disease (persistent increase in the level of SRV more than 20 mg / l or ESR more than 20 mm / h).
• The corresponding functional status is the Steinbroker III-IV stage or the HAQ (Health Assessment Questionnaire) index value of more than 1.25.
• Body weight less than 60 kg.
• Reception GK.

Sensitivity (in the identification of three out of five criteria) for the diagnosis of osteoporosis in rheumatoid arthritis is 76% in women, 83% in men and 54% in specificity, respectively.

Rheumatoid arthritis: differential diagnosis

The range of diseases with which it is necessary to differentiate rheumatoid arthritis is very wide.

Most often, the need for differential diagnosis occurs in the onset of the disease with joint damage in the form of mono- and oligoarthritis. First of all, it is necessary to pay attention to such typical signs of RA as the symmetry of arthritis, the primary damage of the joints of the hands with the violation of their functions, the development of the erosive process in the joints of the hands, the detection of the RF and, especially, anti-CCP antibodies.