Lab Tests

Check AM cortisol:

  • If >15 mcg/dL, AI unlikely.
  •  Level fluctuates during the day. The available assay measures TOTAL cortisol, not physiologically active free cortisol. Total cortisol varies by protein state and binding affinity (e.g., pregnancy, critical illness). Free cortisol may be normal.

  • If <3 mcg/dL, AI ruled in. Check ACTH.

High = 1°Adrenal insufficiencyI:Loss of adrenal gland (glucocorticoid AND mineralocorticoid) function

  • Autoimmune, infection (TB, CMV, MAI), hemorrhage, malignancy.

low = central AI.

  • If 3–15 mcg/dL, check ACTH and do cosyntropin test:
    • Administer cosyntropin 250 mcg (ACTH analog). Cortisol <18.0 mcg/dL 60 minutes after cosyntropin confirms AI.



1. Loss of adrenal gland (glucocorticoid AND mineralocorticoid) function
  • Autoimmune, infection (TB, CMV, MAI), hemorrhage, malignancy.

2. Central: loss of function upstream of adrenal gland (pituitary or hypothalamus) → loss of glucocorticoid function only.

  • loss of pituitary ACTH secretion, e.g., Sheehan syndrome, pituitary tumor.

  • loss of hypothalamic CRH secretion, e.g., due to exogenous steroids.




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Complications of Injecting Drug Use

  • Local problems—Abscess (Figures 240-2 
    Image not available.

    A 32-year-old woman with type 1 diabetes developed large abscesses all over her body secondary to injection of cocaine and heroin. Her back shows the large scars remaining after the healing of these abscesses. (Courtesy of ­Richard P. Usatine, MD.)

    and 240-3; Abscess), cellulitis, septic thrombophlebitis, local induration, necrotizing fasciitis, gas gangrene, pyomyositis, mycotic aneurysm, compartmental syndromes, and foreign bodies (e.g., broken needle parts) in local areas.2
    • IDUs are at higher risk of getting methicillin-resistant Staphylococcus aureus(MRSA) skin infections that the patient may think are spider bites (Figure 240-4).
    • Some IDUs give up trying to inject into their veins and put the cocaine directly into the skin. This causes local skin necrosis that produces round atrophic scars (Figure 240-5).
  • IDUs are at risk for contracting systemic infections, including HIV and hepatitis B or hepatitis C.
    • Injecting drug users are at risk of endocarditis, osteomyelitis (Figures 240-6and 240-7), and an abscess of the epidural region. These infections can lead to long hospitalizations for intravenous antibiotics. The endocarditis that occurs in IDUs involves the right-sided heart valves (see Chapter 50, Bacterial Endocarditis).2 They are also at risk of septic emboli to the lungs, group A β-hemolytic streptococcal septicemia, septic arthritis, and candidal and other fungal infections.


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  • How does empiric steroid administration alter results of cosyntropin test?1,2

    — All steroids will suppress the adrenal axis. Hydrocortisone/prednisone is artifactually measured along with native cortisol in the cortisol assay.

    Dexamethasone is not; a cosyntropin test can still be interpreted accurately.

  • How does workup and management of AI differ in critically ill patients?

    — No agreed upon diagnostic criteria for random cortisol level.

    — Concept of "relative adrenal insufficiency" (i.e., protracted hypotension in critically ill patient with normal cortisol) is controversial. Steroids should be given to reduce inflammatory response rather than treat adrenal dysfunction.


Arlt  W. Chapter 342: Disorders of the adrenal cortex. In: Longo  DL, Fauci  AS, Kasper  DL, Hauser  SL, Jameson  J, Loscalzo  J, eds.Harrison's Principles of Internal Medicine. 18th ed. New York, NY: McGraw-Hill; 2012.
Lin Liew  EC, Sheehy  AS, Wood  KE, Coursin  DB. Chapter 151: Adrenal insufficiency. In: McKean  SC, Ross  JJ, Dressler  DD, Brotman  DJ, Ginsberg  JS, eds. Principles and Practice of Hospital Medicine. New York, NY: McGraw-Hill; 2012.


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