Rheumatology: Crystal arthritis, osteoarthritis and soft tissue pain

🩺 Crystal arthritis, osteoarthritis and soft tissue pain -page 3 of the Rheumatology chapter. Gout is the commonest inflammatory arthritis (about 1 in 40 UK adults) and is curable with urate-lowering therapy to a target -yet it is often undertreated. Osteoarthritis is the commonest joint disease of all, and exercise and weight loss are its main treatments. Chronic widespread pain (fibromyalgia) is common and needs a positive diagnosis, not endless tests. Septic arthritis is on the Trauma and Orthopaedics page; joint replacement and regional soft tissue problems (shoulder, elbow, foot) are there too.
Your four questions for every patient: Could this hot joint be infected -has it been aspirated? Is this crystal, degenerative or inflammatory disease -or pain without joint disease? What can the patient do themselves (exercise, weight, diet, alcohol)? For gout -is urate-lowering therapy indicated, and is the urate at target?

---

Gout -Causes and Risk Factors

• Gout -inflammation caused by monosodium urate crystals forming in and around joints when urate levels stay high (hyperuricaemia -above about 360 µmol/L, the saturation point).
• Most hyperuricaemia never causes gout -don't treat high urate without symptoms.
• Causes of high urate:
  • Reduced kidney excretion (about 90%) -CKD, diuretics (thiazides and loop), low-dose aspirin, ciclosporin and tacrolimus, pyrazinamide, ethambutol, dehydration, ketoacidosis, lead, hypothyroidism, genetics.
  • Increased production -high-purine diet (red meat, offal, seafood), alcohol (especially beer and spirits), sugary drinks (fructose), high cell turnover (myeloproliferative disease, psoriasis, haemolysis), tumour lysis, rare enzyme defects (Lesch–Nyhan).
• Risk factors -men (women after menopause), older age, obesity, metabolic syndrome, hypertension, diabetes, CKD, family history, organ transplant.
• Gout is linked with cardiovascular disease and CKD -assess CV risk in everyone with gout.
• Triggers of a flare -alcohol binges, large meals, dehydration, surgery or acute illness, trauma, new diuretics, starting or changing urate-lowering therapy (urate falls and crystals shift).

Gout -Clinical Features and Diagnosis

• Acute gout flare:
  • Sudden severe pain, peaking within 24 hours, often starting at night; can't bear the bedsheet touching the joint.
  • Red, hot, swollen, very tender joint; skin may be shiny and peel as it settles.
  • First MTP joint (big toe -"podagra") in over half of first attacks; also midfoot, ankle, knee, wrist, fingers, olecranon bursa.
  • Usually settles within 1–2 weeks even without treatment.
  • May have fever and raised CRP -can look like septic arthritis or cellulitis.
• Chronic gout -recurrent flares, more joints involved (polyarticular), persistent joint pain and damage, tophi (chalky white deposits of urate under the skin -ears, fingers, elbows, Achilles), kidney stones (urate), urate nephropathy.
• Diagnosis:
  • Gold standard -joint aspiration showing needle-shaped, negatively birefringent crystals (or aspirate from a tophus) -especially if the diagnosis is uncertain or infection is possible.
  • Often clinical in typical first MTP attacks with risk factors (NICE NG219).
  • Serum urate -can be normal during a flare (urate falls in acute inflammation) -repeat at least 2 weeks after the flare settles to confirm and to set a baseline.
  • Also check U&E, HbA1c, lipids, LFTs, FBC, BP (associated conditions).
  • Imaging -X-ray (erosions with overhanging edges -late), ultrasound (double contour sign), dual-energy CT (urate deposits).

Treating a Gout Flare

• Treat early -the sooner treatment starts, the better it works; patients should keep a "pill in the pocket".
• First-line options (NICE NG219) -choose by comorbidities and patient preference:
  • NSAID (e.g. naproxen) with a PPI -avoid in CKD, heart failure, peptic ulcer, anticoagulants.
  • Colchicine -best started within 24 hours; low dose (500 micrograms 2–4 times a day -see BNF for maximum course dose) is as effective as high dose with fewer side effects; diarrhoea is common; reduce or avoid in CKD; interactions -clarithromycin, erythromycin, ciclosporin, verapamil, diltiazem, some statins (toxicity, myopathy).
  • Short course of oral steroid (e.g. prednisolone 30–35 mg daily for 3–5 days) -useful when NSAIDs and colchicine are unsuitable (CKD, heart failure).
• Second-line -intra-articular steroid injection (once infection excluded) or IM steroid; IL-1 inhibitors (anakinra, canakinumab -specialist) if others are unsuitable.
• Supportive -rest, raise the limb, ice packs, fluids; avoid alcohol.
• Don't stop urate-lowering therapy during a flare if already taking it.
• Review diuretics -switch from a thiazide or loop diuretic if possible (e.g. for hypertension -consider losartan or amlodipine, which lower urate slightly). Don't stop diuretics needed for heart failure.

⚠️ Safety Pearl -a hot joint in a patient with "known gout" can still be septic. If the patient is unwell, febrile, immunosuppressed, has a prosthetic joint, or the attack is atypical -aspirate.

Urate-lowering Therapy

• Offer urate-lowering therapy (ULT) to everyone with gout after discussing it, especially if (NICE NG219):
  • Recurrent flares (2 or more a year).
  • Tophi.
  • Chronic gouty arthritis or joint damage.
  • CKD stage 3–5.
  • Diuretic therapy that can't be stopped.
  • Kidney stones, or young age at onset (under 40).
• When to start -usually 2–4 weeks after a flare settles (or during a flare if flares are frequent).
• Treat to target -serum urate below 360 µmol/L; below 300 µmol/L if tophi, chronic gouty arthritis or ongoing frequent flares (dissolves crystals faster). Once at target for some years and tophi have gone, a target under 360 is enough.
• Drugs:
  • Allopurinol (xanthine oxidase inhibitor) -first-line; start low (100 mg daily, or lower in CKD) and increase monthly (by 100 mg) according to urate until at target (often 300–600 mg or more; up to 900 mg); check urate monthly while titrating.
  • Febuxostat -if allopurinol is not tolerated or not effective; caution in major cardiovascular disease (MHRA) -allopurinol is preferred in those patients.
  • Uricosurics (benzbromarone, sulfinpyrazone -specialist; probenecid), pegloticase (severe tophaceous gout -rarely used).
• Flare prophylaxis when starting ULT -colchicine 500 micrograms once or twice daily (or low-dose NSAID or steroid if unsuitable) for up to 6 months; warn that flares may increase at first.
• Allopurinol hypersensitivity syndrome -rare but life-threatening (fever, rash -SJS/TEN or DRESS, hepatitis, kidney injury); higher risk in CKD, high starting doses, and people of Han Chinese, Thai or Korean descent with HLA-B*58:01 (test before starting in these groups). Stop at the first sign of rash.
• Interaction -azathioprine and mercaptopurine with allopurinol or febuxostat → severe marrow toxicity -avoid or greatly reduce the dose (specialist).
• Lifestyle -weight loss, regular exercise, reduce alcohol (especially beer and spirits), avoid sugary drinks, keep hydrated, stop smoking; diet alone rarely lowers urate enough.
• Long-term -ULT is usually lifelong; check urate annually once at target; adherence is the main problem (education helps).

Gout in Special Situations

• CKD -gout is common; colchicine and NSAIDs are limited -use steroids for flares; allopurinol is still used (start low, increase slowly to target -not limited by eGFR-based maximums if monitored); febuxostat needs no dose change in mild to moderate CKD.
• Heart failure -avoid NSAIDs; diuretics often unavoidable; colchicine or steroids for flares.
• Transplant recipients -ciclosporin and tacrolimus raise urate; colchicine interacts with ciclosporin; allopurinol interacts with azathioprine -specialist advice.
• Tumour lysis syndrome -chemotherapy for bulky leukaemias and lymphomas; high urate, potassium and phosphate, low calcium, AKI -prevent with IV fluids, allopurinol or rasburicase (high risk; avoid in G6PD deficiency) (see the Oncological Emergencies chapter).
• Women -gout before menopause is unusual -look for CKD, diuretics or a genetic cause.
• Gout in young people (under 25) or with kidney stones -consider enzyme defects or familial juvenile hyperuricaemic nephropathy.
• Hospital inpatients -flares are common after surgery, dehydration or diuretic changes; continue ULT during admission.

Calcium Pyrophosphate Deposition (Pseudogout)

• Calcium pyrophosphate (CPP) crystals deposit in cartilage; commonest in older people (most over 65).
• Forms:
  • Chondrocalcinosis -calcium in cartilage on X-ray (knee menisci, wrist triangular fibrocartilage, symphysis pubis) -often without symptoms.
  • Acute CPP crystal arthritis ("pseudogout") -sudden hot swollen joint, usually the knee or wrist; often during acute illness, after surgery or trauma; fever and confusion in older people.
  • Chronic CPP arthritis -OA-like disease in unusual joints (wrists, MCPs, shoulders, elbows) with flares.
  • Crowned dens syndrome -acute severe neck pain and stiffness with fever and high CRP in older people (CPPD around C2) -mimics meningitis or PMR; CT neck.
• Diagnosis -joint aspiration: rhomboid, weakly positively birefringent crystals; exclude infection (can coexist).
• Treatment of acute attacks -aspiration (relieves pain) and intra-articular steroid; NSAIDs or colchicine (with caution in older people); oral steroids. No treatment removes CPP crystals.
• Recurrent attacks -low-dose colchicine prophylaxis; methotrexate or hydroxychloroquine (limited evidence).
• Look for metabolic causes -especially if under 55 or with widespread chondrocalcinosis:
  • Haemochromatosis (ferritin, transferrin saturation).
  • Hyperparathyroidism (calcium, PTH).
  • Hypomagnesaemia (including Gitelman syndrome; PPIs).
  • Hypophosphatasia (low ALP).
  • Wilson's disease (rare).

Basic Calcium Phosphate Disease

• Basic calcium phosphate (hydroxyapatite) crystals -not visible on standard polarised microscopy.
• Calcific tendinopathy -calcium deposits in tendons, especially the supraspinatus (shoulder); acute calcific periarthritis causes sudden, severe pain, redness and swelling (mimics gout or infection); NSAIDs, steroid injection, ultrasound-guided barbotage.
• Milwaukee shoulder -older women; rapidly destructive shoulder arthritis with large, often blood-stained effusions and rotator cuff loss.
• Calcinosis -calcium deposits in the skin in systemic sclerosis (limited -CREST) and dermatomyositis (especially in children); may ulcerate and discharge chalky material.
• Metastatic calcification -high calcium–phosphate product (advanced CKD -calciphylaxis risk).

Osteoarthritis -Features and Diagnosis

• Osteoarthritis (OA) -the commonest joint disease; a process of joint damage and repair affecting cartilage, bone, synovium and ligaments -not simply "wear and tear".
• Risk factors -age, obesity (knees and hands), female sex, previous joint injury or surgery (meniscectomy, ACL tear), joint malalignment, occupation (kneeling, heavy lifting), genetics, muscle weakness.
• Joints affected -knees, hips, hands (DIP, PIP, thumb base), cervical and lumbar spine, first MTP; uncommon in the wrist, elbow, shoulder and ankle (think trauma, CPPD, or another cause).
• Symptoms -pain on use, eased by rest; short morning stiffness (under 30 minutes); "gelling" after inactivity; reduced function; night pain in advanced disease.
• Signs -bony swelling, crepitus, reduced and painful movement, effusion (cool), deformity (varus knee), quadriceps wasting, joint line tenderness.
• Diagnose clinically without imaging (NICE NG226) if:
  • Age 45 or over, AND
  • Activity-related joint pain, AND
  • No morning stiffness, or stiffness lasting no longer than 30 minutes.
• Consider other diagnoses if atypical -history of trauma, prolonged morning stiffness, rapid deterioration, a hot swollen joint (gout, CPPD, infection), night pain or weight loss (cancer), younger age.
• X-ray (if needed) -LOSS: Loss of joint space (asymmetric), Osteophytes, Subchondral sclerosis, Subchondral cysts. X-ray changes correlate poorly with symptoms.
• Blood tests are normal in OA.

Managing Osteoarthritis

• Core treatments for everyone (NICE NG226):
  • Exercise -tailored strengthening and general aerobic fitness (physiotherapy, group classes such as ESCAPE-pain); combine with education.
  • Weight loss if overweight -even 5–10% weight loss helps knee pain.
  • Information and self-management -OA is not inevitably progressive; activity does not "wear out" joints.
• Drug treatment (alongside core treatment):
  • Topical NSAIDs -first choice for knee OA (and hand OA).
  • Oral NSAIDs -lowest dose, shortest time, with a PPI, considering GI, renal and CV risks.
  • Don't routinely offer paracetamol (alone), weak opioids (unless short-term and other options unsuitable), strong opioids, glucosamine, chondroitin, or hyaluronic acid injections.
  • Intra-articular steroid -short-term relief (weeks) for flares when other treatments aren't enough.
• Aids -walking aids (stick in the opposite hand to the painful hip or knee), supportive footwear, assistive devices; acupuncture is not recommended; arthroscopic washout is not recommended (unless locking).
• Refer for joint replacement when symptoms substantially affect quality of life despite non-surgical treatment -don't exclude people based on age, weight, smoking or comorbidities alone (see the Trauma and Orthopaedics page).
• Also manage -sleep, low mood, other conditions; review regularly.

Hand Osteoarthritis

• Nodal OA -Heberden's nodes (DIP joints) and Bouchard's nodes (PIP joints); middle-aged women, family history; often painful early then less painful as nodes form.
• Thumb base OA (first carpometacarpal joint) -pain on pinching and gripping (opening jars), "squaring" of the thumb base; splints, injections, surgery (trapeziectomy).
• Erosive hand OA -painful, inflammatory attacks of the interphalangeal joints; "gull-wing" central erosions on X-ray; can look like inflammatory arthritis (bloods normal).
• Treatment -hand exercises, OT (joint protection, aids), splints, topical NSAIDs, oral NSAIDs for short periods, steroid injection (thumb base); hydroxychloroquine does not help.
• Mucous cysts -small cysts over DIP joints (linked with OA) -may cause nail grooves.
• DIP involvement differential -OA, psoriatic arthritis (nail changes, dactylitis), gout.

Fibromyalgia and Chronic Widespread Pain

• Fibromyalgia -chronic widespread pain (over 3 months) with fatigue, unrefreshing sleep and cognitive difficulties ("fibro fog"), often with headaches, IBS, bladder symptoms, anxiety and low mood; a disorder of pain processing (central sensitisation). It is a type of chronic primary pain.
• Who -more common in women, middle age; often follows stress, illness or injury; common alongside RA, SLE and other diseases.
• Diagnosis -clinical (ACR 2016 criteria -widespread pain index and symptom severity score); examination is normal apart from widespread tenderness; no swelling.
• Tests to exclude mimics (keep limited) -FBC, CRP/ESR, U&E, LFTs, bone profile, TFTs, CK, vitamin D, HbA1c, coeliac serology if relevant. Don't test ANA or RF without other features (false positives cause harm).
• Management (NICE NG193 -chronic primary pain):
  • Give a clear diagnosis and explanation -the pain is real; the body is not being damaged.
  • Exercise -graded, regular activity (supervised programmes).
  • Psychological therapies -CBT or acceptance and commitment therapy (ACT); acupuncture (NICE allows a course).
  • Antidepressants can be considered (e.g. amitriptyline, duloxetine, SSRIs) -for pain, sleep and mood.
  • Avoid starting -opioids, gabapentinoids, NSAIDs, paracetamol, benzodiazepines, local anaesthetics (NICE) -they lack benefit and cause harm.
  • Sleep hygiene, pacing, return-to-work support.
• Chronic fatigue syndrome / ME overlaps -see NICE NG206.

Joint Hypermobility

• Joint hypermobility -joints that move beyond the normal range; common and often harmless (dancers, gymnasts).
• Beighton score (out of 9) -little finger extension beyond 90° (1 each side), thumb to forearm (1 each side), elbow hyperextension over 10° (1 each side), knee hyperextension over 10° (1 each side), palms flat on the floor with knees straight (1). Hypermobility is usually 5 or more in adults (4 or more over 50).
• Hypermobility spectrum disorder and hypermobile Ehlers–Danlos syndrome (hEDS) -hypermobility with symptoms: joint pain, recurrent sprains, subluxations and dislocations, fatigue; associated POTS (postural tachycardia), gut symptoms, anxiety.
• Management -physiotherapy (strengthening, proprioception), pacing, pain management; avoid unnecessary surgery.
• Other heritable connective tissue disorders to recognise:
  • Vascular EDS (COL3A1) -thin translucent skin, easy bruising, arterial, bowel and uterine rupture -serious.
  • Marfan syndrome (FBN1) -tall, long limbs, lens dislocation (upwards), aortic root dilatation and dissection -echo and monitoring.
  • Osteogenesis imperfecta -fractures, blue sclerae, hearing loss.

Metabolic and Endocrine Arthropathies

Condition	Musculoskeletal features
Haemochromatosis	Arthropathy of the 2nd and 3rd MCP joints ("hook-like" osteophytes), CPPD, fatigue; check ferritin and transferrin saturation; venesection doesn't usually help the joints
Hypothyroidism	Myalgia, stiffness, raised CK, carpal tunnel syndrome, effusions, CPPD
Hyperthyroidism	Proximal myopathy, osteoporosis, thyroid acropachy (Graves')
Hyperparathyroidism	Bone pain, CPPD, osteoporosis, (osteitis fibrosa cystica rarely)
Acromegaly	Large joint OA-like arthropathy, back pain, carpal tunnel syndrome
Diabetes	Cheiroarthropathy (stiff hands -"prayer sign"), frozen shoulder, Dupuytren's, trigger finger, carpal tunnel, Charcot foot, DISH, diabetic muscle infarction
Sickle cell disease	Bone pain crises, avascular necrosis (femoral head), dactylitis in children, osteomyelitis (Salmonella), septic arthritis
Haemophilia	Recurrent haemarthroses → destructive arthropathy
Steroid use and alcohol	Avascular necrosis (hip, shoulder, knee), osteoporosis, myopathy (steroids)
Osteomalacia	Bone pain, proximal weakness, waddling gait, low vitamin D and phosphate, raised ALP (see Bone Medicine)

Other Joint Conditions to Know

• Diffuse idiopathic skeletal hyperostosis (DISH) -older men, obesity, diabetes; "flowing" ossification along the front of at least 4 vertebrae (right side of the thoracic spine), stiffness; sacroiliac joints are normal (unlike ankylosing spondylitis); dysphagia from cervical osteophytes.
• Avascular necrosis (osteonecrosis) -loss of blood supply to bone -steroids, alcohol, sickle cell disease, SLE, antiphospholipid syndrome, radiotherapy, decompression sickness, bisphosphonates (jaw); hip pain with normal early X-rays -MRI; protected weight bearing, core decompression or joint replacement.
• Charcot (neuropathic) joint -painless joint destruction with lost sensation (diabetes -foot; syringomyelia -shoulder; tabes dorsalis -knee); the acute hot swollen foot needs urgent offloading (see the Vascular Surgery page).
• Pigmented villonodular synovitis (tenosynovial giant cell tumour) -young adults; recurrent blood-stained effusions in one joint (knee); MRI; synovectomy.
• Lyme arthritis -tick bite (UK -New Forest, Scottish Highlands, Lake District); erythema migrans, then large-joint arthritis (knee) weeks to months later; serology; doxycycline (see the Infectious Diseases chapter).
• Rheumatic fever -2–4 weeks after streptococcal throat infection; flitting large-joint polyarthritis (Jones criteria -carditis, chorea, erythema marginatum, nodules) -rare in the UK now.
• Hypertrophic pulmonary osteoarthropathy -clubbing with painful wrists and ankles (periosteal new bone) -lung cancer (especially adenocarcinoma), bronchiectasis, mesothelioma.
• Paget's disease of bone -older people, bone pain, deformity, raised ALP with normal calcium (see the Bone Medicine chapter).

Crystal, Degenerative and Pain Conditions at a Glance

Condition	Key clues	Management
Acute gout	Sudden red hot big toe, peaks within 24 hours	NSAID, colchicine or steroid; ice; review diuretics
Chronic tophaceous gout	Tophi, recurrent flares, erosions	Allopurinol to urate under 300; colchicine cover
Pseudogout	Older person, hot knee, illness or surgery	Aspirate, intra-articular steroid; check metabolic causes if young
Crowned dens	Severe neck pain and fever in an older person	CT neck; NSAIDs or steroids
Calcific periarthritis	Sudden severe shoulder pain, calcium in tendon	NSAIDs, injection, barbotage
Knee or hip OA	Over 45, pain on use, stiffness under 30 min	Exercise, weight loss, topical NSAIDs; replacement if severe
Nodal hand OA	Heberden's and Bouchard's nodes	Hand exercises, splints, topical NSAIDs
Fibromyalgia	Widespread pain, fatigue, poor sleep, normal tests	Explanation, exercise, CBT, antidepressant; no opioids
Hypermobility spectrum disorder	Beighton 5+, pain, subluxations	Physiotherapy, pacing
Haemochromatosis arthropathy	2nd/3rd MCP OA, CPPD	Ferritin and transferrin saturation
Avascular necrosis	Hip pain on steroids or alcohol, normal X-ray	MRI; offload, decompression or replacement
DISH	Flowing anterior ossification, normal SI joints	Analgesia, physio

Spot the Diagnosis

Clue	Diagnosis
Excruciating red big toe overnight after a wedding, on bendroflumethiazide	Acute gout
Normal urate during an attack of probable gout	Urate falls in flares -recheck in 2 weeks
Chalky white lumps on the ear helix	Gouty tophi
Rash and fever 4 weeks after starting allopurinol in CKD	Allopurinol hypersensitivity -stop
Severe diarrhoea and myalgia after clarithromycin in a man on colchicine	Colchicine toxicity
Flare of gout 2 weeks after starting allopurinol	Mobilisation flare -continue ULT, add colchicine cover
Hyperuricaemia, AKI and high potassium after chemotherapy for lymphoma	Tumour lysis syndrome
Hot knee 3 days after a hip operation in an 80-year-old	Pseudogout (exclude infection)
Chondrocalcinosis in a 45-year-old with diabetes and a bronze tan	Haemochromatosis
Neck pain, fever and high CRP in an 82-year-old with no meningism	Crowned dens syndrome
Sudden severe shoulder pain with calcium in the supraspinatus tendon	Acute calcific periarthritis
Knee pain on walking in a 62-year-old, 10 minutes' morning stiffness	Knee osteoarthritis -clinical diagnosis
Pain at the thumb base on opening jars	First CMC joint OA
Painful inflamed DIPs with central erosions and normal bloods	Erosive hand OA
Widespread pain, poor sleep and fatigue with normal examination and bloods	Fibromyalgia
Recurrent shoulder dislocations, Beighton 7/9 and dizziness on standing	Hypermobility spectrum disorder with POTS
Easy bruising, thin skin and a ruptured colon at 30	Vascular Ehlers–Danlos syndrome
Stiff hands with a positive prayer sign in type 1 diabetes	Diabetic cheiroarthropathy
Hip pain with normal X-ray in a man on long-term prednisolone	Avascular necrosis -MRI
Flowing ossification on the right of the thoracic spine with normal SI joints	DISH
Recurrent blood-stained knee effusions in a 30-year-old	PVNS (tenosynovial giant cell tumour)
Clubbing with painful swollen wrists in a smoker	Hypertrophic pulmonary osteoarthropathy

Exam-style Scenarios

1. A 56-year-old man on bendroflumethiazide has his third attack of gout this year. His urate (2 weeks after the flare) is 520 µmol/L; eGFR 70. He has no tophi.
Answer: Recurrent gout -start urate-lowering therapy.

• Start allopurinol 100 mg daily, increasing by 100 mg every month according to urate (checked monthly) to a target below 360 µmol/L.
• Give colchicine 500 micrograms once or twice daily as flare prophylaxis for up to 6 months; provide a rescue plan for flares.
• Switch the thiazide (e.g. to losartan or amlodipine); assess CV risk, HbA1c and lipids; advise on alcohol, sugary drinks and weight.

2. An 81-year-old woman is admitted with pneumonia. On day 3 she develops a hot, swollen right knee and fever. The knee X-ray shows chondrocalcinosis.
Answer: Probable acute CPP crystal arthritis -but infection must be excluded.

• Aspirate the knee -Gram stain, culture and crystals; blood cultures.
• If CPP crystals with no infection -aspiration plus intra-articular steroid; or a short oral steroid course (NSAIDs and colchicine are riskier at her age).
• Calcium and magnesium check; mobilise when settled.

3. A 67-year-old woman with a BMI of 33 has 2 years of right knee pain on walking and stairs, with 15 minutes of morning stiffness. The knee is bony and creaky with no effusion. She asks for an X-ray and "something strong for pain".
Answer: Knee osteoarthritis -clinical diagnosis.

• No X-ray needed for diagnosis (age over 45, activity-related pain, short stiffness).
• Exercise (strengthening -physio-led programme) and support for weight loss; topical NSAID; avoid strong opioids.
• Consider intra-articular steroid for a flare; refer for replacement if symptoms severely affect quality of life despite these.

4. A 42-year-old woman has 2 years of widespread aching, exhaustion, poor sleep and poor concentration. Examination shows tenderness everywhere but no joint swelling. FBC, CRP, TFTs, CK, calcium and vitamin D are normal. She has been prescribed codeine and pregabalin.
Answer: Fibromyalgia (chronic primary pain).

• Make a positive diagnosis and explain it; avoid further investigations (ANA, RF) without new features.
• Graded exercise, CBT or ACT, sleep hygiene, pacing; consider amitriptyline or duloxetine.
• Plan to taper and stop codeine and pregabalin (not recommended for chronic primary pain); screen for depression.

5. A 48-year-old man with chronic tophaceous gout has had flares despite allopurinol 300 mg for a year. His urate is 450 µmol/L. He has a kidney transplant and takes azathioprine.
Answer: Uncontrolled gout with a dangerous drug interaction.

• Allopurinol plus azathioprine risks severe marrow suppression -check FBC urgently and contact the transplant team.
• Options -switch azathioprine to mycophenolate (transplant team) and then titrate allopurinol to a target below 300 µmol/L (tophi); or specialist alternatives.
• Flares -steroids preferred (colchicine interacts with ciclosporin; NSAIDs harm the graft).

Key Points

• Gout -sudden red hot joint (often the big toe) peaking within 24 hours; crystals are needle-shaped and negatively birefringent.
• Urate may be normal during a flare -recheck at least 2 weeks later.
• Flares -NSAID (+ PPI), colchicine or short oral steroid; don't stop ULT during a flare.
• Offer ULT to all with gout -especially recurrent flares, tophi, CKD, diuretics, young onset.
• Allopurinol first -start low, increase monthly to urate under 360 (under 300 with tophi).
• Colchicine cover for up to 6 months when starting ULT.
• Allopurinol plus azathioprine -dangerous; colchicine plus clarithromycin -toxic.
• Febuxostat -caution in major cardiovascular disease.
• Pseudogout -older people, knee or wrist, during illness; rhomboid positive crystals; look for metabolic causes if young.
• Always exclude infection in a hot joint, even with known crystal disease.
• OA -clinical diagnosis over 45 with activity pain and stiffness under 30 minutes; no X-ray needed.
• OA treatment -exercise and weight loss first; topical NSAIDs; avoid paracetamol alone and strong opioids.
• Heberden's nodes at the DIPs, Bouchard's at the PIPs; thumb base OA is common.
• Fibromyalgia -positive diagnosis, exercise, CBT, antidepressants; avoid opioids and gabapentinoids.
• Hypermobility -Beighton score; watch for vascular EDS and Marfan syndrome.
• Avascular necrosis -steroids, alcohol, sickle cell; MRI if X-ray normal.

Guidelines and Further Reading

• NICE NG219: Gout -diagnosis and management
• BSR: Guideline for the management of gout
• EULAR: Recommendations for calcium pyrophosphate deposition
• MHRA Drug Safety Update: Febuxostat -increased risk of cardiovascular death
• NICE NG226: Osteoarthritis in over 16s -diagnosis and management
• ESCAPE-pain programme (exercise for knee and hip pain)
• NICE NG193: Chronic pain (primary and secondary) in over 16s
• ACR 2016: Revised fibromyalgia diagnostic criteria
• Ehlers–Danlos Society: 2017 International classification of EDS and hypermobility spectrum disorders
• BNF -for current doses