Saturday May 20, 2006
Hypoproteinemia and cosyntropin test
43 year old malnourished patient admitted with septic shock. You started early goal directed therapy protocol. Patient blood pressure remained low despite showing signs of clinical improvement. You suspected adrenal insufficiency and ordered cosyntropin test. Patient failed to respond. You started low dose hydrocortisone. Next day you received call from lab that they also performed 'free cortisol' response to cosyntropin and found it appropriate to label patient as responder ?
Severe hypoproteinemia (as in this malnourished patient) may give false results and responders may get wrongly labelled as non-responders. In blood, about 90 percent of cortisol is bound to protiens (20 percent of cortisol is loosely bound to albumin and 70 percent is tightly bound to cortisol-binding globulin). Only 10 percent cortisol is in the free state. This is a major pittfall and deception to fall in while prescribing steroids in septic and hypoproteinemic patient under presumption of 'nonresponder'.
An important study reported about 2 years ago from Cleveland 1, looked into 66 critically ill patients with 36/66 had hypoproteinemia (albumin 2.5 g/dl or less) and 30/66 had near-normal serum albumin concentrations (above 2.5 g/dl). Baseline and cosyntropin stimulated serum total cortisol level as well as baseline and cosyntropin stimulated serum free cortisol level were measured. Study found that, nearly 40 percent of critically ill patients with hypoproteinemia had subnormal serum total cortisol levels, even though their adrenal function was normal as measured by free cortisol level.
Related previous pearl: Low dose steroid, yes or no ? - responder or non-responder ? - low-dose corticotropin stimulation test or high dose?
References: click to get abstract/article
1. Measurements of Serum Free Cortisol in Critically Ill Patients - Volume 350:1629-1638, April 15, 2004, NEJM
2. Septic Shock and Sepsis: A Comparison of Total and Free Plasma Cortisol Levels - The Journal of Clinical Endocrinology & Metabolism Vol. 91, No. 1 105-114
3. Adrenal Insufficiency - Roberto Salvatori, MD JAMA. 2005;294:2481-2488
