Tofus in gout

Interstitial foci of compaction in the form of chalky nodes of various sizes with deposits of crystallized uric acid and its salts in them are defined in rheumatology as tophi in gout. They are one of the clinical manifestations of chronic gout and occur at any stage of the disease with a frequency of up to 25%.

The pathology has been assigned the ICD 10 code M10, class XIII (diseases of the musculoskeletal system and connective tissue).

Causes of Tophi in Gout

The pathogenesis of tophi, like gout itself, has a systemic metabolic nature and is associated with hyperuricemia - excessive blood levels of uric acid, which is constantly formed during the metabolism of nitrogenous bases. When the levels of free uric acid in the blood plasma are too high for a long time (with a norm of 1-1.2 mg / dl), and at the same time the acidity (pH) of the blood is increased, crystals form not only in the synovial fluid of the joints, joint bags (bursae) and fibrillar tissues of cartilage and tendons surrounding the joints, but also in other tissues, primarily skin.

That is, the key causes of tophi in gout are local accumulation of products of the abnormal altered uric acid cycle in the body brought by the bloodstream. The smallest insoluble crystals of uric acid and sodium monourate by infiltration or diffusion (it has not yet been completely clarified) enter the intercellular space of peripheral tissues and disrupt their structure in certain areas, where over time, voluminous pathological clusters appear. The mechanism of tophi formation resembles epithelioid cell granulomatosis, since in addition to concentrated urate crystals, granulomatous tissue with giant multinucleated cells and dead macrophages is present in tophi.

Tophi in gout come in different sizes and feel different (most often tight and quite dense); they have clear boundaries, as they are separated from intact tissue by a layer of fibrous fibers. They look like "bumps" protruding above the skin surface. Over time, their calcification or heterotopic ossification may be noted.

The most typical places for tophi to appear are the fingers and toes, feet, elbows (near the olecranon), knees, and auricles – that is, colder areas of the body where there are no large blood vessels, and temperature drops contribute to the process of crystal loss. However, tophi can also appear in bone tissue and in the tissues of internal organs (most often the kidneys).

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Symptoms of Tophi in Gout

Patients with gout may not notice the first signs of the tophus form of the disease, since at the initial stage the accumulation of crystals can occur in deeper layers of subcutaneous tissue. If you look closely, you can notice whitish spots - when the tophus grows closer to the surface of the skin, which gradually becomes paler in this place.

Obvious symptoms of tophi in gout are expressed in small, medium or quite large yellowish or white nodes under the skin - on the fingers, toes, flexor part of the elbows, near the heels (in the area of the Achilles tendon) or ankles and around the outer edge of the ear. In most clinical cases, tophi do not cause pain, or these sensations are insignificant. But as the size of the tophi increases, they begin to exert mechanical pressure, which can cause pain to intensify.

Tophi can break through the epithelium and subepithelial layer of the skin, and a fistula is formed. The contents of the tophus, which has a pasty or granular consistency, come out, and an ulcer remains on the skin at the site of the fistula.

The liquid contents of the tophus indicate an inflammatory process, however, as rheumatologists note, inflammation within an unopened tophus, as a rule, does not develop.

Tophi in gout, especially large ones, cause complications, deforming the joints. And the most serious consequences of the deposition of uric acid crystals in tissues are the destruction of cartilage and erosive bone defects.

Diagnosis of tophi in gout

Diagnosis of tophi in gout begins with their visual examination by a rheumatologist. Then you need to take tests:

• clinical blood test;
• biochemical blood test to determine uric acid levels;
• daily urine analysis.

Instrumental diagnostics are carried out using X-rays or, if necessary, ultrasound.

Gouty tophi may be mistaken for neoplastic calcinosis in basal cell carcinoma or sarcoidosis, pseudogout (with crystallization of calcium pyrophosphate), spondyloarthritis or osteoarthritis, as well as Kaposi's sarcoma, neurofibrosarcoma, dermoid cyst or, if localized on the auricle, for nodular chondrodermatitis of the cartilaginous helix of the ear. Therefore, differential diagnostics must be carried out. The final diagnosis of gouty tophi is established by detecting crystallized monosodium urates in the tophi or nearby joints, for which they are aspirated with fine needles and examined with polarized microscopy, which allows one to see crystals of uric acid or its salts. And to exclude neoplasms, the doctor prescribes a biopsy with histology.

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Treatment of tophi in gout

How to remove tophi in gout? It is necessary to have long-term but quite effective drug treatment of tophi in gout using uricosuric agents that reduce the level of uric acid in the blood.

Medicines that affect the uric acid cycle help reduce the size of tophi by increasing its excretion through the kidneys:

• Benziodarone is prescribed in a daily dose of 100 to 300 mg.
• Benzbromarone (analog of Benziodarone, differs in the presence of bromine in the composition); taken once a day, minimum dose - 0.05 g, maximum - 2 g.
• Probenecid (other trade names: Benemid, Santuril) is prescribed at 0.25-0.5 g twice a day.
• Etamid (Etabenecid) is a drug similar to Probenecid. The standard daily dose is 1-1.4 g (in four doses); it is taken in 10-day courses with weekly breaks.
• Sulfinpyrazone (Sulfazone, Anturan, Enturan) – take one tablet (0.1 g) three times a day (after meals, with milk).

But the action of the drug Allopurinol (Alloprim, Allohexal, Ziloprim, Ziloric, Milurit, Purinol) is based on the maximum reduction in the participation of the enzyme xanthine oxidase in the metabolism of uric acid. As a result, the synthesis of uric acid and, accordingly, its entry into the blood decreases. The usual dose is 1-3 g per day (the individual dosage is determined by the doctor based on the results of a blood test). The use of this drug requires an increase in the daily volume of fluid consumed to two liters.

Surgical treatment of gouty tophi is considered justified by specialists if the tophi: destroy joints or negatively affect tendon function; threaten to cause skin necrosis and ulcers; are accompanied by suppuration; compress nerves and cause pain; have an unsightly appearance. Surgical intervention is also performed in cases where the total volume of urates in the body can be reduced by removing easily accessible large tophi.

Folk treatment of tophi in gout consists of lubricating the cones with an alcohol solution of iodine, to which it is recommended to add several tablets of acetylsalicylic acid crushed into powder. Warm baths with Epsom salts (a tablespoon per glass of water) can help.

You can also try herbal treatment: take internally water infusions of medicinal plants such as stinging nettle, black elderberry (flowers), corn silk, lingonberry (leaves), etc.

Among the remedies recommended for tophi in homeopathy are the preparation with wild rosemary Ledum Palustre and the remedy Lycopodium clavatum (with club moss).

Prevention is the key to reducing the risk of gouty cones. And to reduce the level of uric acid, there is a special diet, for more details see - Diet for gout. It is imperative to drink enough clean water (at least 5-6 glasses a day).

Prognosis if untreated: Tophi are a source of uric acid that can return to the bloodstream, increasing its concentration and increasing the chances of further attacks of gouty rheumatism. In addition, tophi in gout can destroy the skin, tendons, ligaments and skeletal structures, which ultimately limits the capabilities of the musculoskeletal system and leads to disability.