Introduction:
Individuals with cortisol deficiency have an excess mortality when faced with acute stressors.(1, 2) However, there is no consensus on the assessment of adrenocortical dysfunction in individuals with hypoalbuminaemia and presumably low cortisol-binding globulin (CBG) levels.
Case presentation:
A 62 year old man was admitted with recurrent fevers and confusion. He was malnourished and had multiple opportunistic infections in the context of receiving a liver transplant 14 months prior, with good graft function. He was hypotensive, and the 0730am serum cortisol was low at 161 nmol/L (RR 170-500), serum ACTH was 19.1 pmol/L (RR ≤10), and serum albumin was 17 g/L (RR 33–48). Plasma renin was 607 fmol/L/sec (RR 130-2350), aldosterone was 186 pmol/L (RR 60-980), and the aldosterone/renin ratio was low at 0.2 (RR 0.4-1.5). A Short Synacthen Test (SST) was abnormal (baseline serum cortisol 149 nmol/L, peak cortisol 249 nmol/L at 60 mins). There was no history of long-term glucocorticoid therapy. Adrenal gland CT did not demonstrate any abnormality. He was receiving long-term fluconazole treatment for pulmonary cryptococcosis. He was commenced on hydrocortisone and fludrocortisone therapy, and responded well clinically.
Discussion:
Approximately 70–80% of circulating cortisol is bound to CBG, 10-20% is albumin-bound, and the remainder (<10%) is available as free cortisol.(3-7) A large randomised trial suggested that hydrocortisone and fludrocortisone therapy was associated with reduced risk of death in critically-ill patients with ‘relative adrenal insufficiency’ (determined using SST).(8) Another study reported that ~40% of critically-ill patients with hypoproteinaemia had lower baseline and cosyntropin-stimulated serum total cortisol concentrations, but similar baseline and cosyntropin-stimulated serum free cortisol concentrations, compared with those with near-normal albumin concentrations.(9) This presentation will review the evidence regarding the interpretation of serum cortisol levels in individuals with hypoalbuminaemia, and the utility of assessing serum free cortisol and salivary cortisol measurements.