The location of the mono-arthritis at the base of the big toe is characteristic. Indeed, gout usually affects the big toe, even if it can occur in any joint. It occurs as sudden episodes (“attacks”) of severe pain and swelling of a joint, and is one of the causes of acute arthritis.
Gout is a chronic disease, which means that the patient will have attacks – usually less than 2 years apart. So, sudden episodes tend to recur and can affect any joint in successive attacks.
The diagnosis of gout is clinical. It can be confirmed by:
- a blood test which allows the determination of uric acid levels with a uricemia of more than 360 mmol/L (often >420 mmol/L);
- a very rapid favourable response to treatment with colchicine which leads to a reduction in pain and inflammation.
Other tests may be useful:
- an ultrasound scan of the joints to see the uric acid deposits on the joint cartilage and to detect gouty areas not yet visible on clinical examination or X-ray;
- an X-ray of the affected bones and joints. This examination only reveals late arthropathic bone lesions and the presence of tophi around the joints;
- a fine needle puncture of joint fluid or a tophus, possibly guided by ultrasound. This examination reveals the presence of uric acid microcrystals.
There are also warning signs of a gout attack:
- Moderate pain in a joint: it hurts when you put your foot down, bend your arm or your toes, for example,
- Tingling in the joint: like “pins and needles”,
- Discomfort: it is difficult to put on a pair of shoes, for example,
- Limitation of mobility: it is difficult to bend the wrist, to clench the fist, to walk…
Symptoms of a gout attack are :
- Pain that comes on suddenly, often at night and/or at rest,
- A pain that pulses: similar to a burning or crushing sensation,
- Pain that persists for 6 to 12 hours,
- The affected joint (often the big toe) is red, swollen, very painful and warm to the touch,
- More rarely, fever and chills may be observed.