ACTH Hormone Deficiency
From Holoprosencephaly
ACTH hormone deficiency
ACTH is a protein hormone secreted from the anterior pituitary gland. ACTH stimulates the adrenal cortex (the central portion of the adrenal glands located above each of the kidneys) to produce the glucocorticoid hormone, cortisol and mineralocorticoid hormone, aldosterone. Cortisol is involved in the response to stress; it increases blood pressure, blood sugar levels and suppresses the immune system. Cortisol also inhibits the secretion of corticotropin releasing hormone (CRH), resulting in feedback inhibition of ACTH secretion. Some researchers believe that this normal feedback system may break down when there is exposure to chronic stress. Aldosterone helps maintain blood pressure and water and salt balance in the body by helping the kidney retain sodium and excrete potassium. When aldosterone production falls too low, the kidneys are not able to regulate salt and water balance, causing blood volume and blood pressure to drop.
Symptoms of ACTH hormone deficiency Fatigue Muscular weakness Weight loss Low blood pressure Anorexia Nausea Pale skin Dizziness
Testing
The aim of testing is first to determine whether levels of cortisol are insufficient and then to establish the cause. In CRH stimulation testing, synthetic CRH is injected intravenously and blood cortisol is measured before and 30, 60, 90, and 120 minutes after the injection. Patients with primary adrenal insufficiency have high ACTHs but do not produce cortisol. Absent ACTH response points to the pituitary as the cause; a delayed ACTH response points to the hypothalamus as the cause. The levels of ACTH vary with the body's circadian rhythms (the pattern of physiologic changes that occurs on a 24-hour cycle). This test is most accurate if it is performed early in the morning. An insulin tolerance test may be given to determine if cortisol levels rise when hypoglycemia is induced. If they do not rise, there is insufficient reserve of cortisol, indicating an ACTH deficiency. If the insulin tolerance test is not safe for a particular patient, a glucagon test offers similar results.
Treatment
Cortisol is replaced orally with hydrocortisone tablets, a synthetic glucocorticoid, taken once or twice a day. If aldosterone is also deficient, it is replaced with oral doses of a mineralocorticoid called fludrocortisone acetate (Florinef), which is taken once a day. This treatment requires the assistance of a pediatric endocrinologist.
Click on the links below to learn more about hormonal deficiencies in children with Holoprosencephaly:
[Will my child develop hormonal deficiencies over time?]
[How can hormonal deficiencies be life threatening?]
Sources http://www.healthatoz.com/healthatoz/hypopituitarism.jsp http://endocrine.niddk.nih.gov/pubs/addison/addison.htm
