Adrenal insufficiency (Case study 2, box 2)
Patients taking long term systemic glucocorticoids are at risk of HPA
suppression. Where this has occurred, abrupt withdrawal of exogenous
glucocorticoids or physiological stress such as intercurrent illness or
surgery can cause life-threatening acute adrenal insufficiency. Although
not all patients taking long term glucocorticoids develop adrenal
insufficiency [22], it can be extremely difficult to distinguish
those who do from those who don’t. Potency, dose and duration of
glucocorticoid treatment are imperfect predictors, patients may be
asymptomatic even when therapy is withdrawn and blanket HPA testing is
considered impractical. A general clinical approach therefore is to have
a low threshold for suspecting HPA suppression in patients taking
glucocorticoids and to require a gradual withdrawal of treatment for all
those considered to have reached that threshold. Where treatment
withdrawal is hampered by the emergence of symptoms (e.g. Case study 2,
box 2), testing for HPA suppression can be useful to determine whether
these are manifestations of adrenal insufficiency.