secondary adrenal insufficiency (SAI)
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Introduction
Adrenal insufficiency due to pituitary insufficiency. Only glucocorticoid synthesis is affected. The renin-angiotensin- aldosterone axis remains intact.
Etiology
- suppression of the hypothalamic-pituitary-adrenal axis
- exogenous glucocorticoids (most common) or ACTH
- post surgical treatment for Cushing's disease
- chronic administration of drugs with corticosteroid activity: megestrol (Megace)
- pituitary or hypothalamic lesion resulting in ACTH deficiency
- tumors
- pituitary adenoma
- craniopharyngioma or Rathke cyst
- hypothalmic tumor
- sarcoidosis
- metastatic tumor
- surgery or trauma
- cranial irradiation
- pituitary infarction (Sheehan's syndrome)
- infectious or autoimmune adenohypophysitis
- tumors
Clinical manifestations
- signs & symptoms milder than Addison's disease
- no salt craving or postural dizziness
- tachycardia, nausea, weakness, dizziness, & hyponatremia[3]
- pigmentation absent
- no dehydration, only slight decrease in blood pressure
- other obnormalities of hypothalamic or pituitary function may be present
Laboratory
- cosyntropin (Cortrosyn) stimulation test
- generally increased response
- in long-standing disease, repeated daily injections of ACTH may be necessary to prime adrenal gland
- serum Na+: hyponatremia is often present
- serum K+: hyperkalemia is NOT a feature
- serum ACTH: low or inappropriately normal
- serum cortisol (NOT generally useful)
- useful in the setting of acute pituitary injury
- in the setting of acute stress, a normal serum cortisol is 20-120 ug/dL
- serum aldosterone: normal
- plasma renin: normal
- insulin tolerance test
- metyrapone stimulation test
Radiology
- MRI of the pituitary & hypothalamus
Management
- glucocorticoid
- prednisone 5 mg PO qAM & 2.5 mg PO qPM
- hydrocortisone 12-15 mg/m2/day (20-25 mg QD)
- for minor illness, stress, fever > 100 F, influenza
- double the oral maintenance dose
- for severe illness or injury
- hydrocortisone 100-150 mg/day IV divided every 6 hours
- septic shock: 150-200 mg/day[3]
- do not use dexamethasone for chronic glucocorticoid replacement therapy[3]
- when glucocorticoid therapy is > 3-4 weeks, a taper is necessary to minimize withdrawal & promote recovery of the hypothalamic-pituitary-adrenal axis
- a taper is unnecessary when glucocorticoid therapy is < 3-4 weeks, regardless of dose[6]
- see glucocorticoid taper
- mineralocorticoid replacement generally not necessary
- patient education
- glucocorticoid coverage at times of stress is indicated in patients who have taken potentially suppressive doses of glucocorticoids for more than 3 weeks the preceding year
More general terms
Additional terms
References
- ↑ DeGowin & DeGowin's Diagnostic Examination, 6th edition, RL DeGowin (ed), McGraw Hill, NY 1994, pg 862
- ↑ Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 653-656
- ↑ 3.0 3.1 3.2 3.3 Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15 16, 19. American College of Physicians, Philadelphia 1998, 2006, 2009, 2012, 2023
- ↑ Toogood AA, Stewart PM. Hypopituitarism: clinical features, diagnosis, and management. Endocrinol Metab Clin North Am. 2008 Mar;37(1):235-61 PMID: https://www.ncbi.nlm.nih.gov/pubmed/18226739
- ↑ Leinung MC, Liporace R, Miller CH. Induction of adrenal suppression by megestrol acetate in patients with AIDS. Ann Intern Med. 1995 Jun 1;122(11):843-5. PMID: https://www.ncbi.nlm.nih.gov/pubmed/7741369
- ↑ 6.0 6.1 Beuschlein F, Else T, Bancos I et a; European Society of Endocrinology and Endocrine Society Joint Clinical Guideline: Diagnosis and Therapy of Glucocorticoid-induced Adrenal Insufficiency. J Clin Endocrinol Metab. 2024 Jun 17;109(7):1657-1683. PMID: https://www.ncbi.nlm.nih.gov/pubmed/38724043 PMCID: PMC11180513 Free PMC article.