Adrenal disease Flashcards
1
Q
What are the adrenal glands?
size, location
What are the two parts?
How are they regulated?
A
- The adrenal glands are multifunctional and secrete a variety of hormones
- Located just above each kidney, no larger than a walnut and wighing < a grape
- Two parts of the adrenal glands:
- Cortex (makes up 80-90% of gland)
- zona glomerulosa
- zona fasciculata
- zona reticularis
- Medulla (makes up 10-20% of gland)
- Cortex (makes up 80-90% of gland)
- Regulation- by hypothalamus, anterior pituitary, and adrenal cortex (HPA axis)
2
Q
What does the adrenal cortex release?
A
- Glucocorticoids (cortisol)
- Mineralcorticoids (aldosterone)
- Androgens
3
Q
What does the adrenal medulla release?
A
- Epinephrine (80%)
- Norepinephrine (20%)
4
Q
What are the physiologic functions of the adrenal gland?
A
- Blood glucose regulation
- protein turnover
- fat metabolism
- Na, K, and Ca balance
- maintenance of cardiovascular tone
- modulation of tissue response to injury or infection
- Survival as a result of stress- most important
5
Q
What is cushing’s syndrome?
What are the two causes?
A
- Hypercorticism- excessive cortisol secretion
- ACTH dependent
- Pituitary corticotroph tumors (microadenomas)
- Non-endocrine tumors of lung, kidney, or pancrease that cause extopic corticotropin syndrome
- ACTH independent
- benign or malignant adrenocortical tumors
- (the adrenal gland releasing cortisol without being told to do so by the release of ACTH)
6
Q
What are the signs and symptoms of Cushing’s?
A
- Sudden weight gain (usually central)
- thickening of the facial fat (moon face)
- Electrolyte abnormalities
- systemic hypertension
- glucose intolerance
- menstrual irregularities
- decreased libido
- skeletal muscle wasting
- depression and insomnia
- osteoporosis
7
Q
How is cushings disease diagnosed?
A
- Plasma and urine cortisol levles
- 24 hr urine- 17-hydroxycorticosteroids
- plasma cortisol levels
- if both are elevated, pt has cushing’s syndrome
- CRH stimulation test- used to determine cause of cushings
- inject pt with CRH and if they have increase in ACTH then it is a pituitary adenoma. (isnt that supposed to happen???)
- Dexamethasone suppression test- Dexamethasone should suppress cortisol levels. W/pituitary adenoma, it will do that d/t negative feedback
- if you have a lung ACTH releasing tumor or something on the adrenal, it will not have negative feedback
- Inferior petrosal sinus sampling- injecting with ACTH and measuring ACTH levels in sinuses and compare to a more peripheral site. Not often used.
- CT & MRI once diagnosis is confirmed
8
Q
How is cushings treated?
A
- Surgical
- transphenoidal microadenectomy- via the sphenoid sinus to remove the adenoma from the pituitary gland
- Adrenalectomy- remove the adrenal gland; may have to be removed bilaterally
- Irradiation
9
Q
What are your preoperative considerations for a pt with cushings syndrome?
A
- HTN- may be on medications, may have cardiac compromise d/t htn
- Intravascular volume- are they on diuretics? Often Spironolactone
- Electrolytes- hypokalemia, hypernatremia
- Acid/bas status- hypokalemic metabolic alkalosis
- Cardiac compromise- CHF
- EKG, do they have angina?
- Diabetes- check BS
- control with small amounts of insulin, 1-5 units q hour
10
Q
What are your positioning considerations for a pt with cushing’s syndrome?
A
- High risk of fractures- Osteoporosis and osteomalacia
- Obesity- but oddly distributed fat (cone shaped arm, difficut to fit with appropriate BP cuff)
- Use appropriate padding
- may need to ramp d/t fat pad on back of neck
- Check position throughout case
- Be careful when moving to and from stretcher, very fragile
11
Q
Patients with Cushing’s syndrome have muscle weakness. How can we address this?
A
- Hypokalemia is a contributing factor- treat pre-op with 80-100 mEq/day oral K
- Decrease doses of muscle relaxants
- Use a peripheral nerve stimulator
- maintain 1 or 1/2 twitch at all times if possible so you know you can reverse
- May need post-op ventilatory support
12
Q
What medication do you need to give a pt who has had a unilateral or bilateral adrenalectomy?
A
- 100 mg glucocorticoid/24 hours- usually started intraoperatively
- Dose is reduced over 3-6 days to a maintenance dose
- may also need mineralcorticoid supplementation
- continued therapy may not be needed if only one glad was removed–depends on the function of the remaining gland
13
Q
How much blood loss do you expect to see with an adrenal removal surgery?
A
- May be significant blood loss
- Type and screen before case (laproscopic)
- type and cross for major surgery (open)
- CVP/swan
- A-line
14
Q
What do you need to consider regarding anesthetic agents for a pt with cushing’s syndrom or an adrenal surgery?
What about epidural?
A
- Drugs or techniques are not likely to influence attempts to decrease cortisol levels
- all inhaled agents depress adrenal response to stress and ACTH
- Etomidate- inhibits enzymes involved in cortisol and aldosterone synthesis- long term infusion can cause adrenocortical suppression
- Changes caused by anesthetic agents or drugs are insignificant when compared to the increase in cortisol secretion with surgical stress
- Can do an epidural but it might be difficult to get d/t osteoporosis
- other option for post-op pain is a PCA pump
15
Q
What are some complications you might expect in a transphenoidal microadenomectomy surgery?
A
- VAE
- pt will be in high sitting position, will need central line and doppler to monitor
- transient diabetes insipidus
- meningitis
