Discussion
NICE guidelines indicate that long-term glucocorticoids should only be
used for rheumatoid arthritis when all other disease-modifying treatment
options have been offered and long-term complications have been fully
discussed [39]. Short-term treatment may be considered for rapid
control of inflammation in newly diagnosed rheumatoid arthritis or
disease flares. For this patient, her arthritis is now controlled on
methotrexate and withdrawal of treatment should be attempted.
When she tries to withdraw glucocorticoids, she develops symptoms that
could be due to adrenal insufficiency or glucocorticoid withdrawal
syndrome. The long duration of treatment and symptoms at a prednisolone
dose below daily endogenous glucocorticoid secretion
(~7.5 mg prednisolone equivalent) increase the
likelihood that she has hypothalamic-pituitary-adrenal (HPA) axis
suppression and adrenal insufficiency. HPA axis testing is therefore
indicated to determine her long-term management.
A reasonable approach for this patient would be to ask her to repeat the
wean to prednisolone 5mg. She should then undergo measurement of 9am
cortisol at least 24 hours after her last dose of prednisolone, which
can otherwise interfere with the cortisol assay. If this test is
equivocal (9am cortisol 100-449nmol/L), further testing with a short
synacthen test will be required. Differentiating between adrenal
insufficiency, which requires adrenal replacement, and glucocorticoid
withdrawal syndrome, which may resolve if treatment is tapered very
slowly, is important to direct therapy.