Musculoskeletal for PLAB 1

A 54 year old man has severe pain and swelling of the right first metatarsophalangeal joint that developed over six hours overnight. The joint is red, hot and exquisitely tender, and he cannot bear the weight of a bedsheet on it. He is afebrile and systemically well. He takes bendroflumethiazide and drinks eight pints of beer at weekends. His serum urate today is 340 µmol/L. What is the SINGLE most likely diagnosis?

1. Pseudogout Sudden knee or wrist arthritis in an older patient, with a thin line of calcium on the X-ray (chondrocalcinosis) and rhomboid-shaped crystals that block light the opposite way (positively birefringent). That does not match a normal urate level during an acute attack in the big toe joint.
2. Gout correct Correct. A severe, fast-developing, extremely painful arthritis in one joint, the big toe joint, in a man on a thiazide water tablet who drinks beer. The clinical picture is close to a certain diagnosis.
3. Osteoarthritis Gradually worsening pain that is worse with use, with bony swelling. A sudden flare of this can be mistaken for crystal disease. But a normal urate level during an acute attack in the big toe joint does not point to it.
4. Reactive arthritis Arthritis affecting one side more than the other, in the legs, one to four weeks after a gut or genital infection. Here, a normal urate level during an acute attack in the big toe joint points elsewhere.
5. Septic arthritis A hot, swollen joint with fever and feeling unwell all over. This must always be ruled out before anything is called gout. It does not fit a normal urate level during an acute attack in the big toe joint.

The point: Gout is a severe, fast-developing infection-free arthritis in one joint (monoarthritis), most often the big toe joint (the first metatarsophalangeal joint). A blood urate level taken during an attack can come back normal, so a normal urate does NOT rule gout out. Measure urate at least two weeks after the attack has fully settled. Fluid taken from the joint (joint aspiration) shows needle-shaped crystals that block light in a specific way (negatively birefringent), and this test is essential whenever a joint infection is possible. Treat the attack with an anti-inflammatory painkiller (NSAID), colchicine, or a steroid, choosing based on the patient's other health problems: NSAIDs are avoided in kidney damage, heart failure and stomach ulcers, and colchicine's dose is limited by the diarrhoea it causes. Start allopurinol (a drug that lowers urate) after the attack, or during it with cover from another drug, and keep taking it through any further attacks rather than stopping. Aim for a urate level below 360 micromol per litre, or below 300 if the patient has urate lumps (tophi) or frequent attacks. Pseudogout, a different crystal disease, gives rhomboid-shaped crystals that block light the opposite way (positively birefringent), with a thin line of calcium seen on the joint X-ray (chondrocalcinosis).

Source: NICE NG219 — Gout: diagnosis and management NICE · tier 1, national regulator or guidance

A 54 year old man has severe pain and swelling of the right first metatarsophalangeal joint that developed over six hours overnight. The joint is red, hot and exquisitely tender, and he cannot bear the weight of a bedsheet on it. He is afebrile and systemically well. He takes bendroflumethiazide and drinks eight pints of beer at weekends. His serum urate today is 340 µmol/L. What is the SINGLE most appropriate initial investigation?

1. Plain radiograph of the joint Shows a thin line of calcium (chondrocalcinosis) in pseudogout, and punched-out bone damage with overhanging edges in long-standing gout with urate lumps. Here, a normal urate level during an acute attack in the big toe joint points elsewhere.
2. Renal function and review the drug chart Water tablets (diuretics) raise urate, and kidney damage limits which drugs can be used for the attack. It does not fit a normal urate level during an acute attack in the big toe joint.
3. Serum urate at least two weeks after the attack correct Correct. His level of 340 today means nothing, because urate falls during an attack. Repeating it in two weeks gives a real baseline and a target to aim for.
4. Blood glucose and lipids Gout tends to occur together with obesity, high blood pressure, diabetes and heart disease, and the attack is a good chance to check for them. But a normal urate level during an acute attack in the big toe joint does not point to it.
5. Calcium, magnesium, ferritin and thyroid function Checked for pseudogout in a younger patient, looking for iron overload (haemochromatosis), an overactive parathyroid gland, or an underactive thyroid. That does not match a normal urate level during an acute attack in the big toe joint.

The point: Gout is a severe, fast-developing infection-free arthritis in one joint (monoarthritis), most often the big toe joint (the first metatarsophalangeal joint). A blood urate level taken during an attack can come back normal, so a normal urate does NOT rule gout out. Measure urate at least two weeks after the attack has fully settled. Fluid taken from the joint (joint aspiration) shows needle-shaped crystals that block light in a specific way (negatively birefringent), and this test is essential whenever a joint infection is possible. Treat the attack with an anti-inflammatory painkiller (NSAID), colchicine, or a steroid, choosing based on the patient's other health problems: NSAIDs are avoided in kidney damage, heart failure and stomach ulcers, and colchicine's dose is limited by the diarrhoea it causes. Start allopurinol (a drug that lowers urate) after the attack, or during it with cover from another drug, and keep taking it through any further attacks rather than stopping. Aim for a urate level below 360 micromol per litre, or below 300 if the patient has urate lumps (tophi) or frequent attacks. Pseudogout, a different crystal disease, gives rhomboid-shaped crystals that block light the opposite way (positively birefringent), with a thin line of calcium seen on the joint X-ray (chondrocalcinosis).

Source: NICE NG219 — Gout: diagnosis and management NICE · tier 1, national regulator or guidance

A 54 year old man has severe pain and swelling of the right first metatarsophalangeal joint that developed over six hours overnight. The joint is red, hot and exquisitely tender, and he cannot bear the weight of a bedsheet on it. He is afebrile and systemically well. He takes bendroflumethiazide and drinks eight pints of beer at weekends. His serum urate today is 340 µmol/L. What is the SINGLE most appropriate immediate management?

1. Lifestyle advice on alcohol, purines and weight Has a modest effect compared with allopurinol, and is worth giving alongside it rather than instead of it. Here, a normal urate level during an acute attack in the big toe joint points elsewhere.
2. Aspirate the joint and start empirical antibiotics Used where a joint infection cannot be ruled out, and antibiotics are never held back waiting for the microscopy result. But a normal urate level during an acute attack in the big toe joint does not point to it.
3. Oral or intra-articular corticosteroid Used where neither an NSAID nor colchicine can be given, and only once infection has been ruled out. That does not match a normal urate level during an acute attack in the big toe joint.
4. Rest, ice and analgesia Supportive measures given alongside drug treatment for any acute crystal-related attack. It does not fit a normal urate level during an acute attack in the big toe joint.
5. Naproxen with gastric protection correct Correct. The first choice for an acute attack where kidney function is normal and there is no reason not to use it. Colchicine or a steroid would be the alternatives.

The point: Gout is a severe, fast-developing infection-free arthritis in one joint (monoarthritis), most often the big toe joint (the first metatarsophalangeal joint). A blood urate level taken during an attack can come back normal, so a normal urate does NOT rule gout out. Measure urate at least two weeks after the attack has fully settled. Fluid taken from the joint (joint aspiration) shows needle-shaped crystals that block light in a specific way (negatively birefringent), and this test is essential whenever a joint infection is possible. Treat the attack with an anti-inflammatory painkiller (NSAID), colchicine, or a steroid, choosing based on the patient's other health problems: NSAIDs are avoided in kidney damage, heart failure and stomach ulcers, and colchicine's dose is limited by the diarrhoea it causes. Start allopurinol (a drug that lowers urate) after the attack, or during it with cover from another drug, and keep taking it through any further attacks rather than stopping. Aim for a urate level below 360 micromol per litre, or below 300 if the patient has urate lumps (tophi) or frequent attacks. Pseudogout, a different crystal disease, gives rhomboid-shaped crystals that block light the opposite way (positively birefringent), with a thin line of calcium seen on the joint X-ray (chondrocalcinosis).

Source: NICE NG219 — Gout: diagnosis and management NICE · tier 1, national regulator or guidance