Diagnosis Of Adrenal Insufficiency

Author: Dr. Om J Lakhani

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ESTABLISHING THE DIAGNOSIS

Q. What morning cortisol value should be used for the diagnosis of Primary adrenal insufficiency [PAI]?
- < 5 mcg/dl – 100% specificity but less sensitivity
- This is the cutoff recommended by the Endocrine society
- However, a value of <3 ug/dl is suggested by other experts
Q. What upper limit of cortisol value rules out adrenal insufficiency?
- This is debatable
- Some say 10.8 ug/dl and some say 17 ug/dl
- However, the upper limit should not be used for diagnostic consideration
Q. Can morning salivary cortisol be used for diagnosis?
- Yes, but it has not been validated
- Value <1.8 ng/ml - most likely adrenal insufficiency is present
- Value >5.8 ng/ml – rules out
Q. Does 4 pm cortisol have any value?
- No
Q. Is Cosyntropin a complete ACTH molecule?
- No
- It is ACTH – 1-24 amino acids
- Normal ACTH is 1-39 amino acids
- However, it has full biological potency
Q. Is it necessary to perform ACTH stimulation in the morning?
- No
- However, normal people have the highest cortisol response in the morning
- Hence, doing the test in the morning would improve specificity and avoid false positives
Q. How is the low dose ACTH stimulation test performed?
- Get baseline cortisol first – no further testing required in the following conditions
  - S. Cortisol <3.6 ug/dl - Definitely low (NEW ENDOCRINE SOCIETY GUIDELINES)
  - S. cortisol >15 ug/dl - Definitely normal
- For Baseline cortisol 3 - 15 ug/dl perform Low dose ACTH stimulation test
  - Give 1 ug of Cosyntropin IV – 1 unit in 100 IU insulin syringe
    - Insulin syringe can be used for this purpose
    - 250 ug (2ml) of Cosyntropin is diluted in 250 ml of normal saline, giving a ratio of 1 ug/ml
    - Take 1 ml of this in an insulin syringe (alternatively, dilute in 500 ml of normal saline and take 2 ml in a normal 5 cc syringe)
    - 1 ml (1ug/ml dilution) is injected IV
  - Repeat Cortisol after 20 and 30 min
    - If peak cortisol >21.7 ug/dl – then suggestive of normal response (18 ug/dl according to Endocrine society guidelines)
Q. Why is cortisol collected at 20 min also in low dose ACTH stimulation?
- Because the peak may be achieved earlier
Q. In which conditions is the low dose ACTH stimulation test useful?
- Recent secondary Adrenal insufficiency - e.g., after pituitary surgery - within 1-2 weeks (< 4 months of Pituitary surgery)
- Chronic partial pituitary AI
Q. When should the 250 ug dose ACTH stimulation be performed after pituitary surgery?
- It is reliable 4 months after pituitary surgery
- Or 9 months after radiation therapy

ESTABLISHING THE LEVEL OF DEFECT

Q. What is the lab method for testing of ACTH?
- 2 site chemiluminescent assay
Q. What is the normal value of ACTH using the 2 site chemiluminescent assay?
- It is 20-52 pg/ml
Q. What ACTH value favors primary and what favors secondary adrenal insufficiency?
- More than 100 pg/ml - primary
- <20 pg/ml - Secondary adrenal insufficiency
- 20-100 pg/ml - gray zone
Q. When should the ACTH sample be drawn?
- Ideally, before the treatment is started
- However, if treatment is already started, then 24 hours after the last dose of hydrocortisone and a longer duration after the last dose of dexamethasone
- Alternatively, switch to hydrocortisone from dexamethasone for several days before measuring ACTH if dexamethasone is used
Q. What is the principle of a prolonged ACTH stimulation test?
- Atrophic adrenal glands in secondary and tertiary AI may not respond to a single ACTH stimulation but may respond to a prolonged ACTH stimulation test
- While in primary AI – they don't respond to prolonged ACTH stimulation
- Hence, it helps distinguish primary from secondary/tertiary AI
Q. What is the principle of the Metyrapone test?
- Metyrapone blocks 11 beta hydroxylase, reducing Cortisol further → stimulates ACTH → increase of 11 deoxycortisol
Q. What is the use of the metyrapone stimulation test?
- It is used for the diagnosis of partial ACTH deficiency, which may be missed with ACTH stimulation or even ITT
Q. Why does the metyrapone stimulation detect partial ACTH deficiency, which is missed by ITT?
- Hypoglycemia is a more potent stimulant for ACTH release than hypocortisolemia
- Hence, ITT may lead to a normal response in patients with partial ACTH defect
Q. What is the use of the CRH Stimulation test?
- It is used to differentiate secondary from tertiary AI
- ACTH increases in response to CRH in tertiary AI, while it does not in secondary AI
Q. Is the insulin tolerance test really required to make the diagnosis of AI?
- Generally no, unless it is also done to test for GH deficiency or in a very recent ACTH defect
Q. So which test to use in secondary AI?
- Chronic secondary AI - high dose ACTH stimulation test (4 months after pituitary surgery)
- Acute secondary AI - Low dose ACTH stimulation test / ITT
- Partial ACTH deficiency – Metyrapone stimulation test

USE OF ACTH STIMULATION TESTS FOR DIAGNOSIS OF ADRENAL INSUFFICIENCY

Q. Can Cosyntropin for a low dose be given IM?
- No
- For the full dose, both IM and IV are possible
- For a low dose, IM has not been evaluated
Q. Is 1mg the standard dose for Low dose ACTH stimulation, or can a lower dose be used?
- 0.5 mg/1.73 m2 has also been tested
Q. How is the solution for 1 ug/ml made?
- a. Take 0.2 ml of Cosyntropin 250 ug/ml with a Tuberculin/insulin syringe (0.2 ml will be 20 units in an insulin syringe of 100 IU)
- b. This is injected into 25 ml of normal saline – this makes it a solution of 2 ug/ml
- c. 0.5ml of this solution is taken and shaken thoroughly and injected IV using the same syringe
Q. What cut off must be used if the IM injection of Cosyntropin is used instead of IV?
- One paper suggests a lower cut off of 16 ug/dl instead of 18 ug/dl for the high dose ACTH stimulation test used IM instead of IV
Q. Summarize the role of various tests in the diagnosis of Adrenal insufficiency?
- 250 mcg ACTH stimulation test-
  - Diagnosis of Primary AI
  - Diagnosis of Secondary AI > 4 months after pituitary surgery
- 1 mcg ACTH stimulation test
  - Diagnosis of PAI (same sensitivity as 250 mcg)
  - Diagnosis of Acute ACTH deficiency (SAI) <4 months after surgery
- Prolonged ACTH stimulation test - Differentiate Primary from Secondary AI
- Metyrapone stimulation test - Diagnosis of partial ACTH deficiency
- CRH stimulation test - distinguish secondary and tertiary AI
- Insulin tolerance test - gold standard - used to evaluate the entire HPA axis
Q. What are the precautions taken before using the metyrapone stimulation test?
- Must be done in an indoor setup as it leads to further reduction of cortisol
- Leads to nausea and vomiting - avoid in patients with severe AI
Q. How is the metyrapone stimulation test performed?
- Earlier it was performed over 3 days
- Now it is done overnight
- Metyrapone 30 mg/kg (750 mg) is given at midnight
- ACTH, Cortisol, and 11 deoxycortisol are measured at 8:00 am in the morning
Q. What is the normal response?
- Normal values
  - ACTH >100 pg/ml
  - 11 deoxycortisol - > 7 ug/dl
  - Cortisol < 5 ug/dl
Q. What suggests adrenal insufficiency?
- 11 Deoxycortisol < 7 ug/dl
- Cortisol < 5 ug/dl
- This is diagnostic of PAI
Q. What is the importance of the ACTH value in the metyrapone stimulation test?
- It can help differentiate primary from secondary AI
- However, the values overlap with normal individuals, hence it cannot be used if the patient is not established to have AI
- In Partial Secondary AI – ACTH value is 10-200 pg/ml
- In PAI - >200 pg/ml
Q. Can a conventional Immunoassay be used in this test?
- No, it cannot be used because cortisol and 11 Deoxycortisol may cross-react
- Hence, it is better to use LC-MS/MS
Q. Can this test be used in Cushing's syndrome?
- Yes
- It can be used to distinguish Pituitary from Ectopic Cushing's
Q. How does it help in ACTH-dependent Cushing's?
- In Ectopic Cushing's – the natural HPA Axis is suppressed - hence there is a negative response (failure of 11 Deoxycortisol to raise) to Metyrapone
- In Pituitary Cushing's - ACTH increases, hence it responds
Q. Can DHEAS be used to make a diagnosis of adrenal insufficiency?
- Yes
- DHEAS <60 ug/dl goes in favor of adrenal insufficiency
- Also, in patients with secondary adrenal insufficiency early - the DHEAS response to low dose ACTH is lost first before the cortisol response
- Hence, stimulated DHEAS can be used for early diagnosis of secondary AI

Updates, 03-Aug-2023

Q. What is Dr. Om J Lakhani's protocol for the diagnosis of Adrenal insufficiency?
- Step 1:
- Step 2:
- Step 3:
- All Steps in one:

UPDATES - 06-Jan-2024

Q. What is the role of the low dose ACTH stimulation test done using ACTON Prolongatum (Porcine sequence corticotropin)?
- A study conducted by Appaiah et al found that the use of a low dose of ACTON prolongatum in the dose of 6 units achieves the same objective as a higher dose (24 units) of the same
Q. What is the new protocol for the ACTH stimulation test as suggested in the paper?
- Take a baseline cortisol sample
- Administer 6 units of ACTON Prolongatum (Porcine sequence corticotropin) intramuscularly
- Take samples for the Cortisol at 30 and 60 minutes
- Use the same cut-off >18 mcg/dl as suggested earlier

UPDATES - 31-December-25

DHEAS for Diagnosis of Adrenal Insufficiency

Adrenal Insufficiency Diagnostic Calculator using DHEAS based on Han Suresh et al

References:

Appaiah, Sonali; Shivanappanavar, Vishwanath; George, Belinda; Bantwal, Ganapathi; Ayyar, Vageesh. A Comparison of Lower Doses of Porcine Sequence Corticotropin with Standard Dose in Testing the Hypothalamic Pituitary Adrenal Axis in Healthy Individuals. Indian Journal of Endocrinology and Metabolism 27(5):p 421-425, Sep–Oct 2023. | DOI: 10.4103/ijem.ijem_56_23
Han AJ, Suresh M, Gruber LM, Algeciras-Schimnich A, Achenbach SJ, Atkinson EJ, et al. Performance of Dehydroepiandrosterone Sulfate and Baseline Cortisol in Assessing Adrenal Insufficiency. J Clin Endocrinol Metab. 2024;00:1–8. doi:10.1210/clinem/dgae855.