Tuberculous tenosynovitis

This is a rare condition. If it occurs in the hand a soft ganglion appears which seems to be multilobulated (the compound palmar ganglion). If this is drained surgically the characteristic finding will be of a synovitis with a synovial effusion full of fibrinous ‘melon-seeds’. The treatment is as for tuberculous septic arthritis.

Crystal deposition disorders

Gout, pseudogout and hydroxyapatite deposition are three types of crystal deposition in joints and around joints, and can cause pain and inflammation. In the long term they may actually cause destruction of the joint. They can he confused with infection.

Crystal deposition disorders

Type: Crystal deposited:
• Gout • Monosodium urate crystals
• Pseudogout Calcium pyrophosphate
• Chondrocalcinosis • Hydroxyapatite

Gout. Normally the patient is unable to metabolise purine normally. This leads to hyperuricaemia and orate crystal deposition in the joints. The condition is very common in men hut may be seen in women after the menopause. Most cases are congenital. Secondary causes can be divided into those resulting from overproduction of uric acid or failure of excretion. Myeloproliferative disorders may lead to tissue breakdown and overproduction. Any form of renal failure may prevent excretion.

Presentation. The patient suffers sudden attacks of acute arthritis and/or tendonitis as a result of monosodium urate crystals being deposited in the joint in tendon sheaths or in tophi. The patients may also be prone to renal calculi. Any minor trauma or a bout of drinking alcohol may precipitate an attack. This normally occurs in the first metatarsal phalangeal joint of the big toe, the ankle, the finger joints and the olecranon bursa. The joint becomes hot and extremely tender. The skin over it is tense and glassy. If the joint is aspirated birefringent crystals can be seen under polarised light. These confirm the diagnosis. Chronic gout leads to degenerative changes in the joints. Tophi may form on the extensor surfaces of joints and in the ears.

  Diagnosis of gout

History — previous attacks, acute-onset arthritis

  Examination — hot, red, painful site

  Investigation — birefringement crystals in joint aspirate

  Differential diagnosis — septic arthritis

The differential diagnosis is septic arthritis. The patient will usually have had an attack before and will therefore know the diagnosis, but otherwise aspiration of the joint and the finding of crystals rather than pus will give the diagnosis. The X-rays are compatible with an erosive arthritis.

Treatment. The treatment is resting the joint and anti-inflammatories. Allopurinol can be used as a prophylactic agent hut must not be started during an acute attack When it is started, a anti-inflammatory should be given at the same time, as otherwise it may actually cause an acute attack.

Pseudogout. Pseudogout involves the deposition of calcium pyrophosphate crystals. It is part of the normal ageing process of a joint. However, patients can develop an acute arthritis resembling gout. It normally occurs in large joints such as the knee. On X-ray the articular cartilage and menisci can be seen to be calcified. Once again, the diagnosis is made by finding birefringent crystals in the synovial fluid. An attack can be treated by aspirating the joint and injecting corticosteroid.

Hydroxyapatite deposition. Hydroxyapatite crystals can also be deposited in a joint, in a bursa or in a tendon sheath. They most commonly give problems in the shoulder, where they can be seen on

ray as a small area of radio-opacity.

Treatment. The treatment of gout can he divided into the management of an acute attack and the prevention of future acute attacks in patients with an underlying metabolic disorder which predisposes them to further acute attacks.

Treatment of an acute attack of gout

  Analgesia

Nonsteroidal anti-inflammatories

Rest

NOT allopurinol

Hyperuricaemia which is leading to acute attacks.

Treatment. Allopurinol.

 Management of an acute attack. The treatment is symptomatic with analgesia, nonsteroidal anti-inflammatories and rest. Check that any predisposing factors such as diuretics are stopped if possible.

Prevention of further attacks. Regular treatment with allopurinol should bring down the levels of uric acid in the blood and so reduce the chance of further attacks. However, allopurinol should not be started during an acute attack as in the short term it may exacerbate the con­dition rather than improve it. For the same reason patients need to be warned, when starting antimetabolism drugs, that an acute attack may be precipitated.

This is a rare condition. If it occurs in the hand a soft ganglion appears which seems to be multilobulated (the compound palmar ganglion). If this is drained surgically the characteristic finding will be of a synovitis with a synovial effusion full of fibrinous ‘melon-seeds’. The treatment is as for tuberculous septic arthritis.