title: Relative adrenal insufficiency in the critical care setting: debunking the classic myth.
abstract: BACKGROUND
  Classic teaching states that chronic adrenal insufficiency is associated with hyponatremia, hyperkalemia, hypercalcemia, hypoglycemia, and eosinophilia. We hypothesize that these diagnostic markers do not predict relative adrenal insufficiency (RAI) in the critically ill or injured patient.
  
  
  METHODS
  Chart review of surgical, trauma, and medical patients admitted over 7 years to a critical care unit was performed to evaluate cortisol levels drawn for suspicion of RAI, which was defined as a cortisol concentration <25 mcg/dl. Laboratory parameters were defined as hyponatremia <135 mmol/l, hyperkalemia >5.3 mmol/l, hypercalcemia >2.55 mmol/l (10.2 mg/dl), hypoglycemia <3.89 mmol/l (70 mg/dl), and eosinophilia >5%.
  
  
  RESULTS
  A total of 212 patients had cortisol levels drawn. Fifty-seven percent were male and their mean age was 59 years. Fifty-three percent had RAI. Average cortisol level was 30.5 μg/dl. No significant differences were seen in mean potassium, sodium, calcium, or glucose levels between RAI and non-RAI patients. Few patients had laboratory values consistent with RAI. In fact, many with RAI had opposite findings: 75% had hypernatremia, 90% had hypokalemia, 100% had hypocalcemia, and 97% had hyperglycemia. Eosinophilia was statistically significant (P = 0.026).
  
  
  CONCLUSIONS
  Hyponatremia, hyperkalemia, hypercalcemia, and hypoglycemia do not predominate in RAI and laboratory values are of minimal value in predicting patients with RAI.
authors.affiliation: Department of Surgery, Texas Tech University Health Sciences Center, Paul L. Foster School of Medicine, 4800 Alberta Ave., El Paso, TX 79905, USA.
authors.forename: Fatuma
authors.initials: F
authors.lastname: Kromah
authors.forename: Alan
authors.initials: A
authors.lastname: Tyroch
authors.forename: Susan
authors.initials: S
authors.lastname: McLean
authors.forename: Harold
authors.initials: H
authors.lastname: Hughes
authors.forename: Nina
authors.initials: N
authors.lastname: Flavin
authors.forename: Soyoung
authors.initials: S
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000309:Adrenal Insufficiency / Q000097:blood / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003422:Critical Care; D004802:Eosinophilia / Q000097:blood / Q000175:diagnosis; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D006934:Hypercalcemia / Q000097:blood / Q000175:diagnosis; D006947:Hyperkalemia / Q000097:blood / Q000175:diagnosis; D007003:Hypoglycemia / Q000097:blood / Q000175:diagnosis; D007010:Hyponatremia / Q000097:blood / Q000175:diagnosis; D007223:Infant; D008297:Male; D008875:Middle Aged; D009229:Mythology; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014947:Wounds and Injuries / Q000097:blood; D055815:Young Adult
chemical_list: D015415:Biomarkers; D006854:Hydrocortisone