Hydroxyapatite deposition disease is an inflammatory lesion of one or more joints associated with the deposition of calcium hydroxyapatite in its periarticular tissues. It is clinically manifested by restriction of movements in the joint, local soreness and swelling of tissues at the places of attachment of tendons to the joint. The most common lesion of the shoulder joint is noted. The diagnosis is based on the clinical picture, data from X-ray examination of joints, determination of calcium levels in blood and urine, examination of synovial fluid. Treatment is carried out with nonsteroidal anti-inflammatory drugs and physiotherapy.
Meaning
Hydroxyapatite deposition disease occurs mainly in patients after 40 years. According to some statistics, the average age of patients is 44 years. Among women, cases of hydroxyapatite deposition disease are more common than among men. In 75% of cases of hydroxyapatite deposition disease, there is a lesion of the shoulder joint. Further, the frequency of occurrence is followed by damage to the joints of the hand, wrist joint, spine and knee joints. In some cases, inflammation of the hip or ankle joint is possible, even less often — small joints of the foot.
Causes
The causes of primary form are still unknown. It is assumed that the deposition of calcium in the periarticular tissues may be due to metabolic disorders, exposure to occupational hazards or traumatic factors. Hyperparathyroidism, hemochromatosis, hemodialysis, prolonged use of vitamin D preparations can cause secondary hydroxyapatite deposition disease. Familial cases of hydroxyapatite deposition disease, frequent detection of HLA A2 and HLA B35 in patients indicate the presence of a genetic predisposition.
With disease, calcium hydroxyapatite crystals are deposited in the tendons surrounding the joint and the synovial membrane of the joint, which leads to the emergence of a reactive inflammatory process. From the synovial membrane, hydroxyapatite crystals can penetrate into the synovial fluid located in the joint, but they quickly dissolve there. Therefore, when conducting studies of synovial fluid, an increased content of calcium is detected in it, and the crystals themselves are found quite rarely.
Classification
Modern rheumatology distinguishes 4 clinical variants. Monoarthritis — this variant of hydroxyapatite deposition disease accounts for 65% of all cases of the disease. It is characterized by the defeat of one, maximum two, joints with pronounced symptoms of arthritis. Spinal injury is the second most common variant. It accounts for about 35% of cases. It is manifested by acute attacks of sciatica in various parts of the spine, accompanied by an increase in body temperature.
Acute pseudopolyarthritis is an acute multiple joint lesion accompanied by an increase in body temperature and a significant acceleration of ESR. His clinic resembles the course of rheumatoid arthritis or polyarthritis of infectious etiology. However, a thorough examination of the affected joints reveals the periarticular nature of inflammatory changes.
Chronic pseudopolyarthritis is characterized by a long course with constant arthralgia against the background of slightly pronounced inflammatory changes in the area of many joints. In this variant of hydroxyapatite deposition disease, acute attacks with the development of synovitis often occur, which do not lead to joint deformation.
Symptoms
Clinical manifestations of hydroxyapatite deposition disease are characterized by periodic attacks of acute or subacute arthritis of one or more joints and depend on the localization of the lesion. Most often, outside of the exacerbation, all clinical symptoms of the disease pass before the next attack. In some cases, there is a chronic course with the constant presence of low-intensity joint pain in the period between attacks.
The lesion of the tendons of the scapula and shoulder is manifested by the picture of shoulder-scapular periarthrosis. It is characterized by soreness and swelling in the area of attachment of the tendon to the joint, restriction of movements in the joint, to the greatest extent — a violation of the abduction. A similar pattern is observed in the hip joint when the muscles attached to it are affected.
Pathology in the area of the elbow joint is usually characterized by a picture of epicondylitis with limited movement and pain in the area of attachment to the joint of the triceps, the general extensor and flexor of the hand. Hydroxyapatite deposition disease of the hand and fingers is manifested by increasing dull constant pain at night, morning stiffness, slight swelling of the affected joints. The clinical picture may develop according to the type of flexor tenosynovitis, reactive arthritis, carpal tunnel syndrome. A distinctive feature is the absence of deformities in the joints of the hand.
Disease of the knee joint, as a rule, is expressed in its soreness when moving or standing. Soreness is detected locally at the points of attachment of the tendons, a slight local swelling is possible. Hydroxyapatite deposition disease of the joints of the foot can occur with the defeat of the metatarsophalangeal joint of the thumb, while simulating an attack of gout.
Diagnostics
In the acute period of hydroxyapatite deposition disease, acceleration of ESR, leukocytosis is observed in the clinical blood test. To identify the cause of hydroxyapatite deposition disease, a rheumatologist prescribes a determination of the level of calcium in the blood and urine, but this indicator may not be increased.
Typical for hydroxyapatite deposition disease is the detection of multiple calcifications in periarticular tissues during radiography of the spine and joints. At the same time, there is no correlation between the amount of calcifications and the severity of the clinical picture. The pronounced clinic of the disease may be accompanied by the absence of foci of calcification and, conversely, the X-ray calcification detected may not be accompanied by any manifestations of the disease. Typical is the disappearance of calcifications after an attack of hydroxyapatite deposition disease.
Synovial fluid is taken by puncture of the joint. With hydroxyapatite deposition disease, hydroxyapatite crystals are rarely detected in the synovial fluid, usually only an increased calcium content is noted. Differential diagnosis of hydroxyapatite deposition disease is carried out with rheumatoid arthritis, gout, osteochondrosis of the spine, deforming spondylosis, tendinitis, intermittent hydrarthrosis, palindromic rheumatism.
Treatment
Acute attacks are effectively stopped by taking nonsteroidal anti-inflammatory drugs (diclofenac, indomethacin, ibuprofen). Pronounced symptoms may be an indication for intra-articular administration of hydrocortisone, triamcinolone. It is possible to prick the soft tissues around the joint with these drugs. Physiotherapy methods are widely used in the treatment of chronic forms of hydroxyapatite deposition disease: hydrocortisone ultraphonophoresis, iodine electrophoresis, mud therapy, paraffin applications, hydrogen sulfide and radon baths.
