Lecture 6: Adrenal Glands Flashcards
Bilateral cortical hyperplasia of the adrenal glands is seen in which variants of Cushing Syndrome?
ACTH-dependent —> ACTH-producing pituitary adenoma or Ectopic ACTH-producing tumors
Atrophic adrenals would be expected in which variant of Cushing Syndrome?
“Iatrogenic” Cushing Syndrome from administration of exogenous glucocorticoids
What are the 2 most common underlying causes of ACTH-independent Cushing Syndrome?
- Adrenal adenoma
- Adrenal carcinoma
What are the serum levels of cortisol and ACTH like in adrenal adenomas/carcinomas?
- ↑↑↑ serum cortisol
- ↓↓↓ serum ACTH
What is the most common morphological alteration observed in the pituitary resulting from high levels of endogenous or exogenous glucocorticoids called?
Crooke hyaline change
Crooke hyaline change of the ACTH-producing cells of the anterior pituitary seen in Cushing Syndrome is the result of the accumulation of what?
Intermediate KERATIN filaments in the cytoplasm
What is a major morphological difference between adrenocortical adenomas and adrenocortical carcinomas?
- Adenomas tend to be smaller w/ thin- or well-developed capsules
- Carcinomas are MUCH larger and are UNencapsulated masses
Both benign and malignant adrenocortical adenomas are more common in which sex and age range?
Women in their 30s to 50s
Hypercortisolism causes selective atrophy of fast-twitch myofibers resulting in what clinical manifestations?
- Decreased muscle mass
- Proximal limb weakness
Which cause of Cushing Syndrome will have elevated levels of ACTH which is completely insensitive to low or high doses of exogenous dexamethasone?
Ectopic ACTH-producing tumors
Which 4 settings of HTN should raise suspicion of Primary Hyperaldosteronism (“Conn’s syndrome”)?
- Refractory HTN
- Adrenal mass + HTN
- HTN at a young age
- Severe HTN (>160/100 mmHg)
What is the most common underlying cause of primary hyperaldosteronism and what is seen morhphologically in the adrenal glands?
- Bilateral idiopathic hyperaldosteornism (IHA)
- Characterized by bilateral nodular hyperplasia of adrenal glands
Germline and somatic mutations of which gene are present in familial idiopathic hyperaldosteronism and some aldosterone-secreting adenomas?
KCNJ5 encoding a K+ channel
Glucocorticoid-remediable hyperaldosteronism is an uncommon cause of primary familial hyperaldosteronism and may be due to which genetic rearrangement and involving what chromosome?
Rearrangement on Cr. 8 placing CYP11B2 (gene encoding aldosterone synthase) under control of the ACTH-responsive CYP11B1 gene promoter
In glucocorticoid-remediable hyperaldosteronism what is the function of ACTH?
ACTH is able to stimulate the production of aldosterone synthase
Due to the unusual circumstance in glucocorticoid-remediable hyperaldosteronism where aldosterone production is under the control of ACTH, how can this production be suppressed?
Suppressible by dexamethasone
Secondary hyperaldosteronism occurs in response to conditions which do what?
Activate the RAAS
List 5 conditions where there is an increased activation of RAAS which may lead to secondary hyperaldosteronism?
- Diuretic use
- ↓ renal perfusion (i.e., arteriolar nephrosclerosis, renal a. stenosis)
- Arterial hypovolemia (i.e., CHF, cirrhosis, nephrotic syndrome)
- Pregnancy (estrogen-induced ↑ in plasma renin substrate)
- Renin-secreting tumors
How does activity of the RAAS and levels of renin differ between primary and secondary hyperaldosteronism?
- Primary assoc. w/ suppression of RAAS and ↓ renin
- Secondary assoc. w/ activation of RAAS and ↑↑↑ renin
Do aldosterone-secreting adenomas typically produce visible enlargement?
NO, often small (<2 cm) and buried within the gland
What is a characteristic histological feature of aldosterone-secreting adenomas?
Eosinophilic, laminated cytoplasmic inclusions –> Spironolactone bodies
Is hypokalemia a mandatory feature of primary hyperaldosteronism?
- NO, although many patients will be hypokalemic
- Increasing numbers of patients who are normokalemic are being diagnosed
Diagnosis of primary hyperaldosteronism is confirmed by what screening test, and if postive, what test must be performed?
- ↑↑↑ ratios of plasma aldosterone: plasma renin activity
- Confirmed w/ aldosterone suppression test
What is the best therapy for primary hyperaldosteronism caused by an adenoma vs. bilateral hyperplasia?
- Adenomas are amendable to resection
- Bilateral hyperplasia is best managed w/ aldosterone antagonists i.e., spironolactone
Adrenocortical neoplasma associated with virilization are more likely to be of what type?
Androgen-secreting adrenal carcinomas
Androgen-secreting adrenal carcinomas often elaborate what other hormone?
Cortisol and are known as “mixed syndromes”
What is the inheritance pattern of the inherited metabolic errors causing congenital adrenal hyperplasia?
Autosomal recessive
Which enzyme involved in the biosynthesis of cortical steroids is most commonly seen as deficient?
21-hydroxylase deficiency
Which syndrome associated with 21-hydroxylase deficiency has a complete lack of the enzyme activity?
Salt wasting syndrome
What are the levels of mineralocorticoids, cortisol, and sex steroids like in salt wasting syndrome?
- NO mineralocorticoids or cortisol
- ↑↑↑ sex steroids
Salt wasting syndrome comes to attention soon after birth with what serum electrolyte abnormalities?
- Salt wasting –> HYPOnatremia
- HYPERkalemia
- HYPOtension
How does the presentation of salt wasting syndrome differ in males vs. females at birth?
- Females will present w/ easily recognizable virilization at birth
- Males don’t usually come to clinical attention until 5-15 days after birth due to some salt-losing crisis
Patients w/ severe salt-wasting 21-hydroxylase deficiency will have adrenomedullary dysplasia which predisposes them to what long term consequences?
- ↓ catecholamine secretion
- HYPOtension
- Circulatory collapse
Simple virilizing adrenogenital syndrome without salt wasting is associated with what type of 21-hydroxylase activity and how does this typically present clinically?
- Partial lack of enzyme activity; some mineralcorticoids and small amount of cortisol, NOT enough to prevent ACTH overproduction
- Presents as genital ambiguity
The most common form of 21-hydroxylase deficiency presents as nonclassic or late-onset adrenal virilism; what are the clinical manifestations?
- May be virtually asymptomatic
- Mild manifestations such a precocious puberty, acne and hirsutism at the time of puberty
In all cases of congenital adrenal hyperplasia what is the morphological change seen in the adrenals?
BILATERAL hyperplastic; some times ↑↑↑ 10-15x normal weights
Pt’s with CAH are treated with what?
- Exogenous glucocorticoids, provides adequate levels AND suppresses ACTH levels
- Mineralocorticoid supplementation given in salt-wasting variants
What are 2 means of diagnosis of congenital adrenal hyperplasia?
- Serum 17-hydroxyprogesterone levels will be ↑↑↑
- ACTH-stimulation test, which would normally ↑ glucocorticoids (but fails to do so in CAH)
Disseminated bacterial infection causing massive adrenal hemorrhagic necrosis and resultant primary acute adrenocortical insufficiency is known as what?
Waterhouse-Friderichsen Syndrome
Amyloidosis, sarcoidosis, and hemochromatosis may all lead to what type of adrenal dysfunction?
Primary adrenocortical insufficiency
In which 3 clinial settings does primary acute adrenocortical insufficiency most often occur?
- As a crisis in pt with chronic adrenocortical insufficiency precipitated by any form of stress
- Rapid withdrawl of steroids or failure to ↑ dose in response to acute stress
- Massive adrenal hemorrhage, as occurring in newborns following prolonged/difficult delivery; pt’s on anticoagulant therapy who develop DIC; and in Waterhouse-Friderichsen Syndrome
Adrenal hemorrhage leading to primary acute adrenocortical insufficiency may occur in what 5 clinical settings?
- Sepsis: Waterhouse Friderichsen syndrome
- Neonatal period
- Trauma
- Postsurgical patients
- Coagulopathy