Hypopituitarism laboratory findings
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: {IQ}
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Overview
- An elevated/reduced concentration of serum/blood/urinary/CSF/other [lab test] is diagnostic of [disease name].
- Laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].
- [Test] is usually normal among patients with [disease name].
- Some patients with [disease name] may have elevated/reduced concentration of [test], which is usually suggestive of [progression/complication].
OR
- There are no diagnostic laboratory findings associated with [disease name].
Laboratory Findings
- A subnormal/reduced concentration of pituitary hormones is diagnostic of hypopituitarism.[1]
- Any history of a lesion causing hypopituitarism or a symptom suggestive of hypopituitarism is an indication for testing for hypopituitarism.
CORTICOTROPIN:
Basal ACTH secretion:
Normal range of serum cortisol is 5 to 25 mcg/dL (138 to 690 nmol/L). Serum cortisol levels are measured at 8 to 9 am and results are interpreted as follows:
| Serum cortisol | Basal ACTH |
|---|---|
| Low: ≤3 mcg/dL (83 nmol/L) | Cortisol deficiency |
| High: ≥18 mcg/dL (497 nmol/L) | No cortisol deficiency even in times of stress |
| Intermediate: >3 mcg/dL (83 nmol/L)
but <18 mcg/dL (497 nmol/L) |
Needs evaluation for ACTH reserve |
ACTH reserve:
Patients with intermediate cortisol levels need to be tested for ACTH reserve. There are several tests to check the ACTH reserve. Metyrapone test is preferred over others as it is applicable to all adults with no age restriction and has good correlation with stress related cortisol response. It has a drawback that it needs inpatient observation for blood pressure and pulse monitoring to prevent postural hypotension. Insulin-induced hypoglycemia test is not preferred as it needs continuous monitoring for neuroglycopenic symptoms during the first hour of insulin administeration in patients who are elderly and have cardiovascular or cerebrovascular issues or a seizure disorder. Hypoglycemia is treated with intravenous glucose. The standard or low dose cosynotropin stimulation test is not recommended as it can give falsely normal results.[2][3][4][5][6][7][8][9][10][11][12]
Metyrapone test:
Metyrapone blocks 11-beta-hydroxylase (CYP11B1), an enzyme that catalyzes the last step in cortisol production resulting in decreased cortisol and increased 11-deoxycortisol concentration. In this test 750 mg of metyrapone is administerred orally every 4hrs for 24hr. Serum cortisol and 11-deoxycortisol concentration is checked at 8am after 24hr and the results are interpreted as follows:
| Cortisol level | 11-deoxycortisol level | |
|---|---|---|
| Normal subjects | < 7 mcg/dL (172 nmol/L) | ≥10 mcg/dL (289 nmol/L) |
| Patients with decreased ACTH reserve | <7 mcg/dL (172 nmol/L) | <10 mcg/dL (289 nmol/L) |
THYROTROPIN :
| Serum T3 | Serum free T4 | Serum TSH | |
|---|---|---|---|
| Central hypothyroidism | Low or normal | Low or low-normal | Low, normal, or slightly high |
GONADOTROPINS:
GROWTH HORMONE:
PROLACTIN:
- Laboratory findings consistent with the diagnosis of hypopituitarism include:
| Hormonal deficiency | Lab finding |
|---|---|
| ACTH | |
| TSH | |
| Gonadotropins | |
| Growth hormone | |
| Prolactin | |
| ADH | |
| Oxytocin |
References
- ↑ Fleseriu M, Hashim IA, Karavitaki N, Melmed S, Murad MH, Salvatori R, Samuels MH (2016). "Hormonal Replacement in Hypopituitarism in Adults: An Endocrine Society Clinical Practice Guideline". J. Clin. Endocrinol. Metab. 101 (11): 3888–3921. doi:10.1210/jc.2016-2118. PMID 27736313.
- ↑ Spark RF (1971). "Simplified assessment of pituitary-adrenal reserve. Measurement of serum 11-deoxycortisol and cortisol after metyrapone". Ann. Intern. Med. 75 (5): 717–23. PMID 4330677.
- ↑ Jubiz W, Meikle AW, West CD, Tyler FH (1970). "Single-dose metyrapone test". Arch. Intern. Med. 125 (3): 472–4. PMID 4313728.
- ↑ Landon J, Greenwood FC, Stamp TC, Wynn V (1966). "The plasma sugar, free fatty acid, cortisol, and growth hormone response to insulin, and the comparison of this procedure with other tests of pituitary and adrenal function. II. In patients with hypothalamic or pituitary dysfunction or anorexia nervosa". J. Clin. Invest. 45 (4): 437–49. doi:10.1172/JCI105358. PMC 292718. PMID 5949228.
- ↑ Streeten DH, Anderson GH, Bonaventura MM (1996). "The potential for serious consequences from misinterpreting normal responses to the rapid adrenocorticotropin test". J. Clin. Endocrinol. Metab. 81 (1): 285–90. doi:10.1210/jcem.81.1.8550765. PMID 8550765.
- ↑ Soule SG, Fahie-Wilson M, Tomlinson S (1996). "Failure of the short ACTH test to unequivocally diagnose long-standing symptomatic secondary hypoadrenalism". Clin. Endocrinol. (Oxf). 44 (2): 137–40. PMID 8849565.
- ↑ Dickstein G, Shechner C, Nicholson WE, Rosner I, Shen-Orr Z, Adawi F, Lahav M (1991). "Adrenocorticotropin stimulation test: effects of basal cortisol level, time of day, and suggested new sensitive low dose test". J. Clin. Endocrinol. Metab. 72 (4): 773–8. doi:10.1210/jcem-72-4-773. PMID 2005201.
- ↑ Mayenknecht J, Diederich S, Bähr V, Plöckinger U, Oelkers W (1998). "Comparison of low and high dose corticotropin stimulation tests in patients with pituitary disease". J. Clin. Endocrinol. Metab. 83 (5): 1558–62. doi:10.1210/jcem.83.5.4831. PMID 9589655.
- ↑ Soule S, Van Zyl Smit C, Parolis G, Attenborough S, Peter D, Kinvig S, Kinvig T, Coetzer E (2000). "The low dose ACTH stimulation test is less sensitive than the overnight metyrapone test for the diagnosis of secondary hypoadrenalism". Clin. Endocrinol. (Oxf). 53 (2): 221–7. PMID 10931104.
- ↑ Nye EJ, Grice JE, Hockings GI, Strakosch CR, Crosbie GV, Walters MM, Torpy DJ, Jackson RV (2001). "Adrenocorticotropin stimulation tests in patients with hypothalamic-pituitary disease: low dose, standard high dose and 8-h infusion tests". Clin. Endocrinol. (Oxf). 55 (5): 625–33. PMID 11894974.
- ↑ Suliman AM, Smith TP, Labib M, Fiad TM, McKenna TJ (2002). "The low-dose ACTH test does not provide a useful assessment of the hypothalamic-pituitary-adrenal axis in secondary adrenal insufficiency". Clin. Endocrinol. (Oxf). 56 (4): 533–9. PMID 11966747.
- ↑ Ospina NS, Al Nofal A, Bancos I, Javed A, Benkhadra K, Kapoor E, Lteif AN, Natt N, Murad MH (2016). "ACTH Stimulation Tests for the Diagnosis of Adrenal Insufficiency: Systematic Review and Meta-Analysis". J. Clin. Endocrinol. Metab. 101 (2): 427–34. doi:10.1210/jc.2015-1700. PMID 26649617.