those things about tophi's diagnosis and treatment.

Wen | Yu Yuhua, Department of Rheumatology, Fujian Provincial People's Hospital

Source | Dr. Yu Yuhua, Department of Rheumatology, Provincial People's Hospital

Tongfengshi is a granulomatous substance formed by mononuclear cells and multinucleated giant cells wrapped in urate crystals. It is more common in the chronic stage of gout. 3% patients with gout without regular treatment can form tophi within 5 years, usually within 1 years after diagnosis of gout.

tophus is a characteristic change of gout, which is related to the course of disease and the level of serum uric acid. The longer the course of disease or the poor control of serum uric acid for a long time, the greater the probability of tophus formation. The more the number and the larger the volume of tophus, it indicates that hyperuricemia is not well controlled. The tophus can be distributed in all parts of the body, with no obvious symptoms in the early stage. With the development of the disease, local ulceration or even necrosis can occur, and secondary infection is rare. The tophus located in the bone joints can cause the destruction of the bone joints, and in severe cases, it can lead to deformity and amputation.

1. Clinical manifestations of mild tophi:

① The tophi is stable in size and grows slowly, involving a single joint;

② There is no abnormal component in joints;

③ No invasive mass or connective tissue destruction;

④ There was no serious chronic tophus arthritis.

Figure 1: Clinical manifestations of mild tophi

2. Clinical manifestations of moderate tophi:

The tophi is stable in size and grows slowly, involving 2-4 joints.

Figure 2: Clinical manifestations of moderate tophi

3. Clinical manifestations of severe tophi:

① There are more than 4 joints involved in tophi or abnormal secretions in joints;

② Invasive mass or destruction of connective tissue;

③ The risk of infection is high;

④ tophi is unstable and grows rapidly;

⑤ severe chronic tophus arthritis.

Figure 3: Clinical manifestations of severe tophi

What harm will tophi cause?

1. tophus can continuously release urate to the peripheral circulation, which makes blood uric acid difficult to control;

2. With the progress of the disease, tophus can be broken, and in severe cases, infection, necrosis, sepsis and so on can appear in local skin;

3. tophi located in joints, bones and other parts can erode bones, and at the same time cause acute inflammation of joints, resulting in persistent joint bone pain and limited activities. Some huge tophi or ulcerative tophi can cause joint deformity and serious damage to joint physical function;

4. Some rare tophi, such as spinal tophi, may have symptoms of nerve compression.

Research shows that the mortality of gout patients with tophi is significantly increased due to cardiovascular diseases. This shows that the formation of tophi not only affects the quality of life of patients, but also seriously threatens their lives.

examination and clinical diagnosis of tophi

the gold standard for the diagnosis of tophi is the discovery of urate crystals by needle aspiration biopsy. Besides, what other tests can find tophi?

Uric acid salt examination

Observing the joint synovial fluid or tophi extract with polarization microscope, we can see double refraction needle-shaped or rod-shaped urate crystals.

Figure 4: Uric acid salt examination of gout

X-ray examination

There is no characteristic X-ray manifestation in the early stage of gout, and the tophus may appear as an asymmetric leaf-like soft tissue mass after its formation. Characteristic "through-hole-like" bone erosion can appear in tophi near bones or joints, and bone erosion can be integrated with each other. The first metatarsophalangeal joint is the most common, followed by the fifth metatarsophalangeal joint, with hands and wrists accounting for about 2/3. It is not uncommon for knee joints to be involved, and even shoulder joints and sternoclavicular joints can be involved.

Figure 5: X-ray examination of tophus

Ultrasonic examination

Ultrasonic examination can not only find bone erosion, but also find urate deposition in articular cartilage, which is different from calcium pyrophosphate deposition (crystal deposition and fibrocartilage destruction). This disease is mainly characterized by "double track sign" on both sides of anechoic articular cartilage. In acute gout, inflammatory exudation of joint cavity can also be manifested as "snowstorm sign".

Figure 6: Double-track sign

Treatment principle of tophi

1. General treatment: Obese patients lose weight, eat low purine diet, drink more water, ensure the daily urine output of 2-25mL, and patients with chronic kidney disease can reduce it appropriately.

2. Drug treatment is the same as gout treatment, including colchicine, non-steroidal anti-inflammatory painkillers and glucocorticoids in acute stage.

under what circumstances does tophi need surgery

tophi is usually treated by surgery only under special circumstances (such as nerve compression, mechanical injury, serious deformity or infection, etc.). For patients with joint function loss caused by gout, venous thrombosis may be induced due to long-term activity limitation, and surgery can also be chosen.

It is generally recommended that the joint tophus should be operated in the quiescent period of gout. Because the operation can induce acute gout attack, active medical preventive treatment should be given during the perioperative period.

arthroscopic lithotomy

The advantage of arthroscopy is that it provides a good intra-articular vision. A large number of crystals, tophus and intra-articular free bodies can be directly removed by washing with liquid and planing and cutting with instruments, and the surgical incision is small, the time is short and the infection probability is small.

Figure 7: Arthroscopic lithotomy

Joint replacement and joint fusion

Precautions during and after operation

There are many tophi in soft tissues of hands and feet, and urate crystals on the surface of the affected tissues should be thoroughly removed during operation. The joint capsule and surrounding important ligaments should be preserved as much as possible to prevent limb dysfunction and tendon adhesion after operation.

If the tendon and peritendinous tissue are invaded and cannot be preserved, they should be completely removed, and at the same time, one-stage tendon transplantation and reconstruction should be performed. It is very important to cover the wound, otherwise the wound will be delayed or not healed.

Rehabilitation training was conducted under the guidance of specialists after operation.

Patients with broken and refractory tophi

For those infected with tophi, the wound takes a long time to heal itself. We can insist on applying silver sulfadiazine to the wound dressing change (similar to the dressing change of burn wounds), and generally the wound can heal in 7-1 days.

prognosis of tophus

generally, after effective uric acid reduction treatment, tophus can shrink and gradually dissolve after long-term blood uric acid reaches the standard, so that patients can maintain normal life and work. The long-term existence of tophus indicates that the control of serum uric acid is poor, which not only affects the quality of life of patients, but also increases the incidence of cardiovascular diseases and threatens their lives.

When the blood uric acid level of gout patients is not up to standard, it should be checked at least once a month. After the blood uric acid level reaches the standard, it should be reviewed at least once every 3 months.

References:

1. What stage has your tophus developed? From gout encyclopedia

2. Li Changgui. Practical gout. Beijing: People's Military Medical Publishing House, 216.

3. Miao Zhimin. Hyperuricemia and gout. See: Lu Zaiying, Zhong Nanshan. Internal Medicine. 9th edition. Beijing: People's Medical Publishing House, 28: 83-834.

4. Dai Gang. Clinical study of arthroscopic joint cavity cleaning for gouty knee arthritis. Chinese Journal of Joint Surgery, 29, 3: 192-196. < P > 5. Zhang Xiangyi, Wan Shengxiang, Jiang Changqing, et al. Clinical comprehensive treatment and effect of multiple giant tophus. Journal of Rare Diseases, 28, 15 (2): 36-.