ESTER Reumatologia common mistakes
ESTER Reumatologia · Understand the traps and how to avoid them.
Diagnosing gout on the basis of a normal or only mildly raised serum urate drawn during an acute flare, and therefore withholding urate-lowering therapy.
Serum urate falls during acute inflammation because of the acute-phase response and increased renal excretion, so a value inside the reference range does not exclude gout; candidates treat the single number as a rule-out test.
What to do instead
Interpret urate only in context: repeat it at least two weeks after the flare resolves, and in a patient with typical podagra or tophus use synovial fluid polarised microscopy (needle-shaped, negatively birefringent crystals) as the decisive test. Base the decision to start allopurinol on the confirmed diagnosis and comorbidity profile, not on the acute-phase value.
Starting allopurinol at a fixed 300 mg dose and leaving it there, or stopping it during flares, without titrating to a urate target.
The familiar 300 mg tablet is memorised as 'the dose', and the old belief that urate-lowering drugs worsen acute attacks leads candidates to interrupt therapy; both habits produce recurrent flares and tophi.
What to do instead
Titrate allopurinol from 100 mg (50 mg in CKD) upward every 2-4 weeks until serum urate is below 6 mg/dL (360 micromol/L), or below 5 mg/dL in severe tophaceous disease, and never stop it during a flare. Prescribe prophylaxis with colchicine or an NSAID for the first 3-6 months of titration.
Treating a positive rheumatoid factor or anti-CCP as diagnostic of rheumatoid arthritis in a patient with non-inflammatory joint pain, and conversely dismissing RA because RF is negative.
Candidates conflate association with causation: RF is present in a proportion of healthy elderly people and in many other conditions, while 20-30% of RA patients are seronegative.
What to do instead
Apply the ACR/EULAR 2010 classification criteria explicitly: require at least one joint with definite clinical synovitis not explained by another disease, then score joint involvement, serology, acute-phase reactants and symptom duration. Use anti-CCP for specificity and remember seronegative RA exists; classification criteria are for research and should support, not replace, clinical diagnosis.
Attributing a swollen, stiff hand in an older patient to osteoarthritis and missing the inflammatory pattern, or the reverse: labelling Heberden nodes and mechanical pain as inflammatory arthritis.
Both conditions affect the same joints, and candidates rely on the presence of nodes or on a single X-ray rather than on the history of morning stiffness duration, soft-tissue swelling and response to activity.
What to do instead
Characterise the pattern first: inflammatory disease gives morning stiffness over 60 minutes, improvement with use, soft boggy swelling and raised ESR/CRP; OA gives stiffness under 30 minutes, worsening with use and bony hard nodes. Use ultrasound or MRI when examination is ambiguous, and remember erosive OA and CPPD as mimics.
Missing axial spondyloarthritis in a young adult with chronic low back pain because plain radiographs of the sacroiliac joints are reported as normal.
Radiographic sacroiliitis lags years behind symptom onset, and candidates equate a normal X-ray with absence of disease instead of applying the inflammatory back pain features.
What to do instead
Screen for inflammatory back pain (onset before 45, insidious onset, improvement with exercise, no improvement with rest, night pain), then check HLA-B27, CRP and MRI of the sacroiliac joints with STIR sequences for active inflammation. Treat the MRI-positive, radiograph-negative patient as non-radiographic axial spondyloarthritis rather than dismissing the presentation.
Interpreting a low bone mineral density T-score as the whole diagnosis of osteoporosis without excluding secondary causes or assessing fracture risk with FRAX.
Candidates treat DXA as a stand-alone test and forget that a T-score of -2.5 in a 30-year-old woman, or in a man, or in a patient on glucocorticoids, has a different meaning and requires a workup.
What to do instead
Before treating, exclude secondary causes (hyperparathyroidism, hyperthyroidism, coeliac disease, myeloma, hypogonadism, glucocorticoid excess) and calculate 10-year fracture probability with FRAX. Treat on the basis of prior fragility fracture, T-score, FRAX thresholds and glucocorticoid exposure, not the T-score alone, and use Z-scores rather than T-scores in premenopausal women and men under 50.
Prescribing bisphosphonates indefinitely without review, or stopping them abruptly, and ignoring the dental and renal checks before the first dose.
Candidates learn 'alendronate weekly for osteoporosis' as a fixed prescription and do not connect duration, drug holidays, creatinine clearance and osteonecrosis of the jaw to the decision.
What to do instead
Check creatinine clearance and correct vitamin D and calcium before starting; perform dental review before intravenous agents. Reassess at 3-5 years: consider a drug holiday in lower-risk patients after 5 years of oral therapy, continue in high-risk patients, and never stop without planning sequential therapy because of rapid bone loss.
Failing to recognise polymyalgia rheumatica and giant cell arteritis as one spectrum, and delaying glucocorticoids while awaiting a temporal artery biopsy in a patient with visual symptoms.
Candidates separate the shoulder-girdle pain from the headache and jaw claudication, and they treat biopsy as an emergency prerequisite rather than a confirmatory test that remains informative for up to two weeks after steroids start.
What to do instead
In a patient over 50 with bilateral shoulder and hip girdle pain and a raised ESR/CRP, diagnose PMR clinically and start low-dose prednisolone. Ask specifically about headache, scalp tenderness, jaw claudication and visual loss; if any are present, give high-dose glucocorticoids immediately, arrange urgent ophthalmology review and temporal artery ultrasound or biopsy, and do not wait for histology before treating.
Managing suspected septic arthritis as a flare of known gout or rheumatoid arthritis, and treating it with intra-articular or oral steroids without aspiration.
A previous diagnosis anchors the clinician, and a moderately raised white cell count in synovial fluid is misread as 'inflammatory but not septic'; candidates also overestimate how reliably fever and peripheral leukocytosis are present.
What to do instead
Aspirate every hot monoarthritis before steroids. Send synovial fluid for cell count, Gram stain and culture, and request blood cultures; a synovial white cell count above 50,000/microlitre with a polymorph predominance raises concern, but lower counts do not exclude infection, especially in immunosuppressed or prosthetic-joint patients. Start empirical intravenous antibiotics after aspiration and involve orthopaedics for washout.
Reading a positive antinuclear antibody titre as a diagnosis of systemic lupus erythematosus, or ordering ANA as a screening test in patients with nonspecific fatigue and pain.
ANA is positive in a substantial proportion of healthy people at low titre, and candidates treat the immunofluorescence result as a confirmatory test rather than as an entry criterion requiring clinical features and more specific antibodies.
What to do instead
Order ANA only when the pretest probability is meaningful (photosensitive rash, oral ulcers, serositis, cytopenias, glomerular disease, inflammatory arthritis). Interpret titre and pattern with anti-dsDNA, anti-Sm, anti-Ro/La and complement, and apply the classification criteria requiring clinical plus immunological domains; refer equivocal cases rather than treating a titre.