General, Urology, Gynae Flashcards
What are the types of bariatric surgery?
Restrictive eg sleeve gastrectomy or malabsorptive eg roux-en Y bypass
What is the adrenal medulla?
- Modified sympathetic ganglion
- 90% adrenaline secreting
- 10% noradrenaline secreting
What is the adrenal cortex?
- Produces cholesterol derived hormones
- Glucocoriticoid
- Mineralocorticoid
- Androgens
What is Conn’s syndrome?
- Hyperaldosteronism
- 60% is due to excess secretion from an adenoma, 30% is due to bilateral adrenal hyperplasia and carcinoma is rare
How does Conn’s syndrome present?
- Hypertension and fluid overload
- Refractory hypokalaemia (Aldosterone saves water via Na reabsorption at expense of K)
- Metabolic alkalosis (aldosterone also exchanges Na for H)
What is the anaesthetic management for Conn’s syndrome and adrenalectomy?
- Correct hypokalameia and metabolic alkalosis pre op (usually achieved via spironolactone)
- Manage Analgesia as large incision
- manage haemodynamic instability due to adrenal handling
- Consider steroid replacement
- Careful positioning as prone and often jackknife
What is cushing’s syndrome and how does it present?
Excess glucocorticosteroid
- Can be endogenous eg Ant pituitary adenoma which is most common (increased ACTH) or adrenal adenoma/carcinoma (20-30%)
- presents with moon face, proximal muscle wasting, hypertension, LVH and osteoperosis
What are the anaesthetic issues with cushing’s syndrome?
- Poorly controlled hypertension, assess for end organ injury eg IHD
- Obestiy and metabolic changes such as OSA risk, impaired glucose tolerance and reflux
- Careful positioning as fragile skin and osteoperosis
- May need stress dosing of steroids
What is addisons disease and how does it present?
- Decreased or absent secretion of glucocoritcoids, usually associated deficiency in mineralocorticoid activity
- 80% is autoimmune mediated destruction of adrenal cortex, less common includes TB, bilateral adrenalectomy
- Sx include abdo pain, vomiting, dehydration and hypotension
- Also have hypoglycaemia, hyponatraemia and hyPER kalaemia
What are the issues with addison’s disease?
- Need steroid replacement, in a crisis needs 200mg IV hydrocort, fluid resus and then 100mg Q6H post op
- Need to check electrolytes
- Needs stress dosing at induction regardless of if in a crisis
What is a pheochromocytoma
- Catecholamine secreting tumours of the adrenal medulla
- ~25% are extra-adrenal
- ~25% are malignant
- produce a variable amount of noradrenaline, adrenaline and dopamine (rarely)
How do you diagnose pheochromocytoma?
measuring urine or plasma metanephrines (metabolites of adrenaline and noradrenaline)
What are the preoperative goals for a patient with a pheochromocytoma
○ Arterial blood pressure control
○ Reversal of chronic circulating volume depletion
○ Heart rate and arrhythmia control
○ Assessment and optimization of myocardial function
○Reversal of glucose and electrolyte disturbances
How to do you manage BP and volume in a pre op pheochromocytoma?
- Pre-operative alpha blockade to control blood pressure as well as normalise the circulating blood volume
- Opposes the alpha 1 vasoconstriction action of noradrenaline and adrenaline
○ Phenoxybenzamine:
Non-selective, non competitive long acting alpha blocker
Should be stopped 24-48hrs before surgery due to its long half life (and risk of post op hypotension)
Started 1-2 weeks prior to surgery
How do you know a preop pheo has adequate blockade?
- Blockade adequacy assessed by Roizen criteria (1982):
○ BP <160/90
○ Orthostatic hypotension (15% drop standing/lying) but not less than 80mmhg
○ ECG free of ST or T wave changes for 2 weeks
Although current BP aims are tighter than this (~<130 sys), resting HR 60-70
