Among lesions of the musculoskeletal system (MSA) of various origins, infectious pathology plays a significant role. In infectious diseases (ID), the clinical manifestations of lesions of the musculoskeletal system are very polymorphic. They occur in the form of ossalgia, arthritis, osteoarthritis, spondyloarthritis, synovitis, myalgia, fibromyalgia, less often in the form of osteomyelitis, tendonitis, bursitis, fasciitis, chondritis, etc.

The pathogenetic basis of damage to the musculoskeletal system in IB is intoxication, infectious-allergic and inflammatory processes. In this regard, with various IBs, the clinical picture of changes in the musculoskeletal system may be dominated by intoxication lesions, reactive and inflammatory mono- and polyarthritis, and other infectious-allergic lesions of the musculoskeletal system.

There is practically no IB that is not accompanied by pain (algia) in various anatomical structures of the musculoskeletal system. In some of them, algia is especially difficult for patients to tolerate. Painful and sometimes painful, they are accompanied by groans from the patient, other symptoms of intoxication and fever. Infectious toxicosis due to bacterial, especially streptococcal, infections (erysipelas, tonsillitis) and some viral infections (influenza, etc.) are significantly more severe. Among the diseases accompanied by severe pain in the bones (ossalgia), one should highlight, first of all, Dengue fever (bone fever). "Dengue" in Spanish is derived from the English word "dandy". The name of the disease was assigned by the London College of Physicians in 1986. Due to severe pain in the bones and joints, the patient acquires a “dandy gait” (walks without bending his legs). Ossalgia and arthralgia in Dengue fever are accompanied by retro-orbital headache. Patients with Volyn fever report severe pain in the tibia (tibialgic fever).

Excruciating bone pain, especially in the tibia and skull bones, worsening at night, is observed in patients with syphilis in the second period. At the sites of lesions, painful compactions are palpated due to the development of specific periostitis. Treponema pallidum can be detected in biopsy material from them. In the early and late stages of syphilis, synovitis, osteoarthritis, and osteomyelitis occur in adult patients. Much more often, osteochondritis, periostitis and osteoperiostitis are observed with early congenital syphilis. Chronic intermittent benign hydrarthrosis occurs in patients with late congenital syphilis (4-15 years and later). Old doctors believed that severe pain in the sacrum in a febrile patient was pathognomonic of smallpox, and in the period before the appearance of the rash they attached great diagnostic importance to this symptom.

Patients with brucellosis in the acute stage of the disease are bothered by “flying” pain, mainly in large joints (hip, knee, ankle, shoulder) and especially in the sacroiliac joint (sacroiliitis). With chronic brucellosis, joint pain is more constant. At this stage, peri- and paraarthritis, synovitis, bursitis, osteoarthritis, and spondyloarthritis are noted. On the anterosuperior surface of the vertebral bodies, most often the lumbar ones, erosions form, which quickly become sclerotic, and rough osteophytes are formed like a parrot's beak. I. L. Tager considered the presence of calcifications to be an important radiological sign of joint damage in brucellosis. Joints with brucellosis usually do not suppurate, which distinguishes brucellosis from bacteremic metastatic lesions in sepsis, less often in furunculosis and other purulent-inflammatory processes.

Fever is well tolerated by patients with brucellosis, in contrast to other infectious diseases, in particular from acute inflammatory lesions of the joints. The marked sweating of patients with brucellosis is noteworthy. In the subcutaneous tissue of various areas of the body, especially in the lumbosacral region, hardenings are found, sometimes spindle-shaped (cellulitis, fibrositis). Damage to the musculoskeletal system in brucellosis causes stiffness of the patient, movements in the joints are limited due to pain in them (G. P. Rudnev).

Lesions of the musculoskeletal system in brucellosis must be differentiated from tuberculosis.

In tuberculosis, damage to joints and bones is secondary, occurring in the form of chronic monoarthritis with damage to the epiphysometaphyseal sections of tubular bones and vertebrae. The hip and knee joints are most often affected, less often the small joints of the bones and feet. During the dissemination of a specific infection, which usually occurs under the influence of weakening factors (stress, diabetes mellitus, long-term steroid or immunosuppressive therapy, etc.), tuberculous osteomyelitis develops. It can have a benign slow course with a predominance of proliferative reactions in the joint or rapid development with exudative and destructive (caseous) changes.

Radiologically, in contrast to brucellosis, destructive lesions are observed in the form of marginal bone defects with the formation of limited bone cavities with the presence of sequesters, and narrowing of the joint space. At a younger age (20-30 years), tuberculous spondylitis occurs more often with damage to two adjacent vertebrae in the thoracic spine (a hump is formed), less often in the lumbar spine. Early radiating pain appears along the roots. When the hip joint is affected, early pain in the groin is characteristic.

Since the 70s of the 20th century, attention began to be drawn to lesions of the musculoskeletal system in Lyme disease (tick-borne borreliosis), described for the first time in Lyme (Connecticut, USA). As it became known, this natural focal disease, transmitted by tick bites, is very common in Russia. In some endemic areas, antibodies to Borrelia are found in 13-25% of residents.

In addition to tick-borne erythema migrans, lesions of visceral organs (often the heart), and the nervous system, lesions of the musculoskeletal system are quite common. At the onset of the disease, migrating arthralgia, ossalgia and myalgia are observed, which are not accompanied by external changes in the joints and are short-term in nature. They are often preceded or accompanied by the presence of a typical ring-shaped erythema, reaching the size of a palm with a pale center. Despite the erased clinical symptoms, in patients with Lyme borreliosis, arthritis is characterized by pronounced inflammatory changes - synovitis, effusion into the joint cavity, the formation of Baker cysts, edema of periarticular tissue and muscles. A scintigraphic study showed a polyarticular nature of the lesion with hyperfixation of radionuclide in the joint with clinical signs of inflammation. Chronic joint damage, which develops in a small number of patients who have not received timely and adequate antibiotic therapy, is associated with immunogenetic dependence. Thus, in the USA, with chronic Lyme arthritis, HLA-DR4 is detected in 57%, HLA-DR2 in 43% of those examined. In patients with Lyme borreliosis examined in Russia, HLA-DR4 was detected significantly more often (53%) compared to healthy controls (27.5%). In patients with arthritis, both HLA-DR4 and HLA-DR2 were found much more often than in examined individuals without arthritis. At the suggestion of the Institute of Rheumatology of the Russian Academy of Medical Sciences (V. A. Nasonov), arthritis due to Lyme borreliosis is included in the mandatory list of nosological forms subject to differential diagnosis of diseases occurring under the guise of other rheumatic diseases - reactive arthritis, rheumatism, seronegative spondyloarthritis, rheumatoid arthritis (RA) , systemic lupus erythematosus (SLE), etc.

Reactive arthritis occurs in many IBs, giving peculiar shades to their clinical picture. They often occur with urogenital infections and intestinal pathologies of infectious origin (shigellosis, salmonellosis), as well as in patients with ulcerative colitis (UC). There are patients with UC in whom the articular syndrome dominates the clinic, obscuring intestinal disorders. The latter, as has been repeatedly observed in our practice, can be insignificant, and lesions of the colon are detected only with a targeted examination. Thus, in patient F., 33 years old, with arthritis of the knee, ankle and metatarsophalangeal joints on the left, Salmonella enteritidis group D1 was cultured from feces after short-term diarrhea 2 weeks ago. During colonoscopy, UC with an unknown time of onset was diagnosed for the first time.

Paroxysmal migratory polyarthritis with short-term attacks is observed in the prodromal period of Whipple's disease, the etiology of which is believed to be a systemic infection caused by bacteria that have not yet been accurately identified. Usually there is symmetrical damage to the joints (usually the knee, ankle, wrist) in the form of arthralgia or arthritis. Arthritis in this disease has a complex pathogenesis and is a consequence of systemic damage and malabsorption in the small intestine (malabsorption syndrome). Articular syndrome manifests itself in its most severe form during its clinical manifestation. In such patients, ESR, levels of leukocytes, platelets, and C-reactive protein are often elevated. The development of malabsorption leads to a decrease in the blood levels of iron, calcium, potassium, vitamin B12, folic acid, cholesterol and albumin. Sometimes the content of circulating immune complexes is increased and the levels of T-lymphocytes are decreased, but their function is not changed. In the early stages of the disease, a morphological study of the synovial membrane helps make a diagnosis (N.V. Bunchuk).

Common in modern conditions, in addition to syphilis and gonorrhea, sexually transmitted infections (chlamydia, viral hepatitis B and C, HIV infection) are also accompanied by joint damage. Gonorrheal arthritis occurs as a result of the generalization of gonococcus and its direct penetration into the periarticular tissue and joint cavity. Usually two or more joints are affected, most often large ones and on the lower extremities. Initially, there is pain and limitation of movement in the affected joint, then signs of acute inflammation appear (hyperemia, edema, swelling, increased temperature of the skin over the joint), and limitation of movement in it. With gonococcal septicopyemia, polyarthralgia, asymmetric arthritis, and tenosynovitis with damage to the tendon sheaths of the hands and feet are possible. The defeat of the musculoskeletal system in gonorrhea is accompanied by fever, polymorphic rashes on the skin from pinpoint erythematous or hemorrhagic elements to pustular and necrotic.

Chlamydial arthralgia and arthritis are clinically often combined with catarrhal or catarrhal-purulent unilateral or bilateral conjunctivitis, sometimes iritis and keratitis, characterized by a torpid course. Small joints of the hands and feet are most often affected without pronounced acute inflammatory manifestations. As a rule, patients complain of burning and discharge from the urethra. In men, prostatitis is often diagnosed, in women - inflammatory processes of the endometrium and appendages.

The diagnosis is confirmed by the detection of chlamydia in scrapings from the urethra, conjunctiva and serology. Chlamydial lesions of the mucous membranes are possible not only through sexual transmission. For people involved in livestock farming, the routes of infection are the same as for brucellosis. Clinically, in these cases, multiple organ lesions are observed, including not only the musculoskeletal system, but also the visceral organs. The diagnosis of these forms of chlamydia is established on the basis of clinical and epidemiological data and serological studies.

Negative serological reactions do not exclude chlamydia, which requires a broad differential diagnosis and subsequent adequate antibacterial therapy. The often observed joint damage in yersiniosis was the basis for identifying an independent clinical variant of this zoonotic infection (V.I. Pokrovsky, N.Yu. Yushchuk et al., 1986)

Transient joint syndrome is also observed with some viral infections. Arthralgia is common in the prodromal period of viral hepatitis B and C and less commonly of hepatitis A, they disappear with the appearance of jaundice, recur with exacerbations of the disease and accompany the chronic recurrent course of hepatitis B and C. Pain is usually noted in the shoulder, elbow, hip joints and less often in the knee and in the spine.

Lesions of the interphalangeal joints of the hands and feet are more common in elderly people with previous diseases of the musculoskeletal system. The joints are not externally changed, the skin over them is warmer than in other areas, but there is no hyperemia or swelling. Polyarthralgia is observed in patients with rubella, sometimes with the development of monoarthritis of the interphalangeal joints, less often of the elbow, wrist and knee. They usually precede the appearance of rubella rash or occur simultaneously with it. Polyarthralgia and arthritis are observed with varying frequency in patients with measles, enterovirus, adenovirus and herpetic infections. In recent years, lesions of the musculoskeletal system have begun to be noted in cases of HIV infection, viral infections caused by parvovirus B19, a-viruses, and human T-lymphotropic virus type I (E. L. Nasonov, 1997). With viral infections, unlike bacterial infections, no radiological changes are observed in the joints. They are purely reactive in nature.

Reactive (non-purulent) arthritis must be differentiated from many connective tissue diseases - SLE, periarteritis nodosa, and sometimes vasculitis, for example Henoch-Schönlein disease and such a relatively rare disease as periodic disease. They are united by the absence of purulent inflammation in the joints, as well as the presence of extra-articular lesions. Currently, there are two main groups of reactive arthritis that develop after an illness with enterocolitic and urogenital clinical manifestations. Reiter's syndrome, including arthritis, conjunctivitis, and urethritis, occupies a prominent place among arthropathies of various origins. It is diagnosed with shigellosis, salmonellosis, yersiniosis, and chlamydia.

Reiter's syndrome is a frequent companion to chronic intestinal diseases (UC, Crohn's disease, Flexner's chronic dysentery). In some systemic diseases, Reiter's syndrome is combined with erythema nodosum, usually localized on the lower extremities. In most cases, men with urogenital nongonorrheal infection develop damage to the joints of the toes, their “sausage-shaped” configuration appears, followed by the formation of a flat foot. The skin of the feet and palms is affected in the form of keratoderma. Balanitis or balanoposthitis is sometimes observed. Often, as a result of heel tendonitis and bursitis, a heel spur is formed. In patient S. with a chlamydial infection that developed 1.5 months after the onset of cat scratch disease (benign lymphoreticulosis), we observed severe chondroperichondritis of the auricle, tenonitis of both eyes and fasciitis of the skull.

In addition to the participation in the etiology of reactive arthritis of various pathogens of intestinal infections, excluding those mentioned, they may be Campylobacter, clostridia, and in the group of urogenital infections, in addition to chlamydia, they attach importance to ureaplasma and associations with HIV infection. Reactive arthritis usually develops in individuals who have the histocompatibility antigen HLA-B 27.

Inflammatory (purulent) lesions of the joints and other structures of the musculoskeletal system develop in cases when microorganisms from foci of inflammation or from their natural habitats penetrate the periarticular tissues, the joint cavity by hematogenous route and often affect bone tissue. They usually occur when the body's immune defense is weakened (secondary immunodeficiency). The etiological factor is most often gram-positive cocci (staphylococci, streptococci) and gram-negative cocci (gonococcus, meningococcus), as well as other bacteria (Escherichia coli, salmonella, Pseudomonas aeruginosa and hemophilus influenzae), clostridia and anaerobes. In particularly weakened patients, the participation of mixed microflora is possible.

Clinically, monoarthritis of the knee, hip, ankle, wrist, and elbow joints develops more often, and less often - small joints of the feet and hands. Damage to joints and other formations of the musculoskeletal system (meniscites, discitis, tendinitis, etc.) is acutely inflammatory in nature. Pain, movement restrictions, swelling, redness appear, body temperature rises, sometimes with stunning chills; in children and the elderly, the temperature may remain normal. In the blood there is neutrophilic leukocytosis and increased ESR.

Blood and synovial fluid cultures are often positive. According to some reports, in recent years, infectious arthritis has become more frequent in patients with RA due to long-term use of glucocorticoids.

In 2 patients with gram-negative sepsis we observed, destructive lesions of the spine were diagnosed. In patient F., 68 years old, the causative agent was Salmonella typhimurium, in patient M., 76 years old, it was Escherichia coli. In this case of coliform sepsis complicated by spondylitis (in zone LII-LIII), against the background of a dissecting aneurysm of the abdominal aorta, surgical treatment with endoprosthetics was undertaken. The patient died on the 11th day after surgery.

A 48-year-old patient, after severe hypothermia (lying on the cold ground in April), developed discitis in the area of ​​the thoracic vertebrae (DI-DII) with limited leakage. Blood culture was negative. After 3.5 months of massive antibiotic therapy and rest, recovery was achieved without surgical treatment. A positive result of conservative therapy was also observed in patient K., 49 years old, with staphylococcal sepsis (Staphylococcus aureus culture was isolated). Inflammatory sacroiliitis was diagnosed, which occurred due to local hypothermia (in winter, she hung laundry on the balcony and leaned against a brick wall).

In rare cases, spondylitis is observed in patients with typhoid fever, the causative agent of which is also Salmonella typhi. We had the opportunity to observe a patient with chronic typhoid bacteria carriers, who, many years after suffering from typhoid fever, developed chondritis and osteomyelitis of the 7th rib on the right. Surgical treatment was required.

Part of the rib was resected. S. typhi continued to be isolated from the discharged fistula for a long time.

In some IBs, the clinical picture is dominated by skeletal muscle damage. Thus, with enterovirus Coxsackie infection, an independent form is distinguished - epidemic myalgia (Bornholm disease, epidemic pleurodynia). The leading symptoms of the disease are muscle pain, headache, and fever. Muscle pain occurs in paroxysms, is spastic in nature and completely disappears between attacks.

There are thoracic, abdominal forms and with a predominance of pain in the extremities (S. G. Cheshik). Muscle pain in the initial period of Coxsackie infection must be differentiated from those in some nosological forms of connective tissue diseases - polymyalgia rheumatica, SLE, periarteritis nodosa. In patients with polymyalgia rheumatica, which usually develops in people over 50 years of age, severe muscle pain is usually localized in the neck, shoulder and pelvic girdle. It is often combined with temporal arteritis (Horton's disease). Unlike enterovirus infection, pain outside of these locations is usually not observed. Laboratory signs of an inflammatory reaction are detected in peripheral blood. In cases of polymyalgia rheumatica, glucocorticoids are very effective. In SLE, along with focal myositis, lesions of the skin, joints and visceral organs are characteristic. With periarteritis nodosa, against the background of prolonged fever and weight loss, pain is usually localized in the calf muscles; pain in one or more joints is possible, sometimes with the development of arthritis, which brings periarteritis nodosa at the onset of the disease closer to RA. In addition, it is characterized by damage to the skin, nervous system in the form of polyneuropathies and neuritis, as well as visceral organs.

Muscle damage along with constant or intermittent fever, swelling of the eyelids ("puffiness"), skin rash, changes in peripheral blood (leukocytosis, hypereosinophilia, increased ESR) are a constant sign of trichinosis. The pain is most often localized in the muscles of the neck, lower back, calves, sometimes in the chest and chewing muscles, which makes breathing and chewing difficult. Palpation of the affected muscles is painful. The diagnosis is helped by a well-collected epidemiological history - eating (usually 10-25 days before the onset of the disease) products made from raw or lightly cooked and fried meat of slaughtered animals, most often pork. Recently, in the absence of proper veterinary control over the private sale of meat, cases of trichinosis have become more frequent. If trichinosis is not recognized in a timely manner and without etiotropic therapy, deaths are possible. For diagnostic purposes, a biopsy of affected skeletal muscles, in which Trichinella larvae are found, is justified.

Accurate verification of the etiological diagnosis of clinically polymorphic lesions of the musculoskeletal system in various IBs is possible after conducting laboratory tests to detect the pathogen, specific antibodies to it and other special diagnostic methods. Their choice is purposefully determined by the entire clinical picture inherent in one or another nosological form of IB.