Adrenal Cortex Flashcards
Serum cortisol secretion undergoes diurnal variation:
- Trough
- Peak
- Trough - Midnight (12 AM)
- Peak - 8 AM
Cushing syndrome is characterized not only by Elevated Serum Cortisol, but also loss of what?
Diurnal Variation
Elevated Midnight Serum Cortisol is highly suggestive of what?
Cushing Syndrome
Low 8 AM serum Cortisol is highly suggestive of what?
Adrenal Insufficiency
Urine Free Cortisol Test:
- Collection
- Measures (2)
24 hour urine collection
- Free (unbound) serum Cortisol
- Independent of time of day considerations
Dexamethasone Suppression Test results in Normal Endocrine function.
Dose of Dexamethasone will
-Supress both ACTH and Cortisol
Low-Dose Dexamethasone Suppression Test (DST):
-2 Forms
*Answers what question?
- Rapid (overnight) DST
- Standard (2 day) DST
- Does the Pt. have Cushing Syndrome (Hypercortisolism)?
- If impaired suppression - Yes
What question does the High-Dose Dexamethasone Suppression Test (DST) answer?
Is the Cushing syndrome caused by a Pituitary Adenoma
Cushing Disease
High-Dose Dexamethasone Suppression Test (DST):
- Suppression
- Nonsuppression (2)
Suppression
-Pituitary Adenoma (Cushing Disease)
Nonsuppression*:
- Ectopic ACTH production (tumor)
- Primary Adrenal Hypercortisolism
*distinguished by plasma ACTH measurements
What other test is used to determine the cause of Cushing Syndrome?
Cortisol Releasing Hormone (CRH) stimulation test
Cortisol Releasing Hormone (CRH) stimulation test:
- Exaggerated Elevation of ACTH/Cortisol
- No response (2)
Exaggerated Elevation of ACTH/Cortisol:
-Pituitary Adenoma
No Response:
- Adrenal Tumors
- Ectopic ACTH
Diagnosis of Cushing Syndrome (Hypercortisolism) requires the demonstration of persistent hypercortisolism. What are the 3 recommended Screening Tests?
- Low-Dose DST
- 24hr Urinary Free Cortisol
- Midnight Salivary or Serum Cortisol
ACTH-Dependent Cushing Syndrome is further evaluated by what tests? (3)
- Bilateral Inferior Petrosal Sinus Sampling (BIPSS)
- High-Dose DST
- CRH stimulation test
ACTH-Independent Cushing Syndrome:
- Must Exclude?
- Requires
- Surreptitious Glucocorticoid administration
- Adrenal Imaging
Most common cause of Cushing Syndrome in developed world.
Iatrogenic
-Corticosteroids for Tx of Inflammatory Disease
Cushing Disease is usually found in association with what?
Pituitary Microadenoma (<1.0 cm) -Basophilic cells (Corticotrophs)
What neoplasms are associated with Ectopic ACTH production? (7)
- Small Cell Lung Cancer
- Lung Carcinoid
- Pancreatic Endocrine Tumors
- Non-Small Cell Lung Cancer
- Thymic Tumors
- Medullary Thyroid Carcinoma
- Breast Cancer
Primary Adrenal Hypercortisolism may be due to? (3)
- Adrenal Adenoma
- Adrenal Carcinoma
- Bilateral Adrenal Hyperplasia
What are the Systemic Effects of Cushing Syndrome? (6)
- Hyperglycemia
- Hypokalemia
- Protein Catabolism
- Osteoporosis
- Centripetal Fat Deposition
- Skin Thinning w/ Striae
What are causes of Pseudo-Cushing syndrome? (4)
- Major Depression
- Anorexia Nervosa
- Alcoholism
- Pregnancy
Diagnosis Criteria for Addison Disease (Primary Adrenal Insufficiency). (2)
- Low 8AM serum Cortisol (and/or)
- Blunted increase in Cortisol following Cosyntropin Stimulation
The ACTH level is used to guide further evaluation of Addison Disease.
- Elevated ACTH
- Next tests
Elevated ACTH = Primary Adrenal Insufficiency
- Autoantibody studies (and/or)
- Adrenal Imaging
The ACTH level is used to guide further evaluation of Addison Disease.
-Normal or Low ACTH (2)
WNL/Low ACTH - Secondary Adrenal Insufficiency
- Pituitary Pathology
- Exogenous Glucocorticoids
Most common cause of Addison’s Disease (Primary Adrenal Insufficiency):
*Historically
Autoimmunity
*Tuberculosis - primary destruction of adrenal gland by granulomatous disease
What are the characteristic findings in Addisonian Crisis? (6)
- Altered Mental Status
- Hypotension
- Hypoglycemia
- Hyponatremia
- Hyperkalemia
- Metabolic Acidosis
Clinical Features of Addison’s Disease (Primary Adrenal Insufficiency)? (7)
- Fatigue
- Weakness
- Weight Loss
- Mood Alteration
- Postural Hypotension
- Skin Hyperpigmentation
- Hypoglycemia
Most cases of Secondary Adrenal Insufficiency is cause by Exogenous Glucocorticoids, which lead to what?
Irreversible (or slowly reversible) suppression of endogenous ACTH production
Why is Secondary Adrenal Insufficiency not as severe as Addision’s Disease
Minearlocorticoid production is maintained in Secondary by the Renin-Angiotensin System
What is the finding in Secondary Adrenal Insufficiency? (1)
-What findings are NOT seen
Mild Hyponatremia
- Hyperkalemia is Absent
- Hyperpigmentation is NOT seen
Hyperaldosteronism is also known as what?
Conn Syndrome
Conn Syndrome (Hyperaldosteronism) is usually caused by what? (2)
- Adrenal Adenoma
- Bilateral Adrenal Hyperplasia
Conn Syndrome (Hyperaldosteronism): -Findings (3)
- HTN
- Hypokalemia
- Metabolic Alkalosis
What is the best screening test for Conn Syndrome (Hyperaldosteronism)?
*Confirmatory Test
Plasma Aldosterone Concentration (PAC) to Plasma Renin Activity (PRA)
-[PAC:PRA]
*24 hour urinary Aldosterone level
Secondary Hyperaldosteronisms is seen in what state?
-Causes (2)
Hyperreninemic States
- Renal Artery Stenosis
- Jutaglomerular Cell Tumor of Kidney (Renin Producing)
What is the most common cause of Congenital Adrenal Hyperplasia (CAH)?
-2nd MC
21-Hydroxylase deficiency
-11-Hydroxylase deficiency
Where is the gene for 21-Hydroxylase found? (2)
Chromosome 6 (6p21.3) -within HLA complex
What are the characteristic serum labs seen in CAH? (6)
- 17-Hydroxyprogesterone (High)
- Cortisol (Low)
- ACTH (High)
- Androgens (High)
- 17-ketosteroids (High)
- Aldosterone (Low)
21-Hydroxylase deficiency Vs. 11-Hydroxylase deficiency - Both show Adrenal Hyperplasia and Virilzation. What findings differ between the two?
21-Hydroxylase deficiency
-Salt Wasting
11-Hydroxylase deficiency
-HTN
