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.
• 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
• Nonsteroidal anti-inflammatories
• Rest
• NOT allopurinol
Hyperuricaemia
which is leading to acute attacks.
• Treatment. Allopurinol.
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.