Adrenal Physiology Flashcards
Why is hyponatremia seen in adrenal insufficiency?
- Hypovolemia
- When cortisol is lacking, this causes an absence of cortisol inhibitory effects on ADH and there is a relative excess of ADH
In primary adrenal insufficiency, what is the expected level of ACTH?
a. low
b. normal
c. high
c. high; there is a lack of cortisol feeding back so the ACTH keeps going up to get the cortisol to go up
In central adrenal insufficiency, what is the expected level of ACTH?
a. low
b. normal
c. high
a. low (low/normal)
If you have adrenal insufficiency and a normal ACTH, what can potentially be causing the AI?
a. primary AI
b. secondary AI
c. tertiary AI
d. b & c
d. b & c
When do you expect to see hyperkalemia?
a. primary adrenal insufficiency
b. central adrenal insufficiency
a. primary; all three (GFR layers of cortex) will be affected which will result in aldosterone deficiency and so you are unable to waste K+ so these people get hyperkalemic, these people are also volume depleted because they cannot hold onto salt
In a patient with primary AI, your long term management would include:
a. glucocorticoid replacement
b. mineralocorticoid replacement
c. medic alert bracelet
d. a & c only
e. all of the above
e. all of the above; they have lost GFR so they need everything!
In a patient with central AI, your long term management would include:
a. GC replacement
b. mineralocorticoid replacement
c. medic alert bracelet
d. a & c only
e. all of the above
d. a & c only; central is only affecting F and R so they do not need mineralocorticoid replacement
When do you expect to see skin hyper-pigmentation?
a. primary
b. central
a. primary
What kind of shock do you expect in AI?
Hypovolemic, cardiogenic, distributive
What are the differentiating features of primary AI (compared to central AI)?
Cravings for salt (salt wasting)
Increased pigmentation
Hyperkalemia
Vitiligo
A 37 year old female is seen in ER after she falls off a horse. An emergency CT abdomen is done and shows no ruptured spleen, however, a 2.5cm R adrenal mass is seen. The patient’s history, exam and review of systems are unremarkable. What would you do now?
A. Recommend surgical removal of the mass
B. Order aortic angiography
C. Order fine-needle aspiration of the mass under CT guidance
D. Repeat CT in 3-6 mos
E. Order 24hr urine metanephrines
E. Order 24hr urine metanephrines - You need to rule out pheochromocytoma (it is life threatening)!
A 42 year old woman is going in for surgery to remove a potentially malignant ovarian cyst, and you are assessing her the morning of the surgery. Her history is significant for a MVA 3 mos ago from which she sustained a cerebral contusion that was treated with dexamethasone 4mg q6hrs for 4 weeks. What would you do in managing this patient?
A. Order an insulin tolerance test
B. Order a measurement of cortisol and ACTH
C. Order a 24hr urine cortisol
D. Prescribe hydrocortisone 100mg IV q8hrs starting just before the induction of anesthesia and taper off after surgery.
D. Prescribe hydrocortisone 100mg IV q8hrs starting just before the induction of anesthesia and taper off after surgery.
This patient NEEDS surgery and we can probably assume that her axis has been suppressed and if you don’t do this she could go into adrenal crisis. If this was an elective test then you could order a measurement.
A 54 year old man with a 5- year history of HTN, facial fullness and truncal obesity presents with several days of midthoracic back pain. The pain started suddenly after he tripped on the stairs and landed on his buttocks.
Exam shows a cushingoid appearance with a BP of 160/100. Serum K is 3.0 (3.5-5.0. FBG 12.0). 24hr urine collection for cortisol is 2.5x normal.
Thoracic spine X-ray shows a compression fracture at T8. What would you do next?
A. Order a low dose 1mg ON
DST
B. Order CT abdomen C. Order MRI Sella
D. Order ACTH level
E. Arrange for IPSS (Infrapetrosal sinus sampling)
D. Order ACTH level
