Hypopituitarism laboratory findings: Difference between revisions
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==== Metyrapone test: ==== | ==== 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: | |||
*Laboratory findings consistent with the diagnosis of hypopituitarism include: | *Laboratory findings consistent with the diagnosis of hypopituitarism include: | ||
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Revision as of 18:47, 5 September 2017
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Hypopituitarism Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Hypopituitarism laboratory findings On the Web |
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Risk calculators and risk factors for Hypopituitarism laboratory findings |
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.
Corticotopin:
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.
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:
- 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.