hey everyone this lesson is on pheochromocytoma in this lesson we're gonna talk about what you need to know for this condition including the classic triad of symptoms and we're also going to talk about the careful treatment and management of patients with this condition so let's get started pheochromocytoma is a condition due to a catecholamine secreting tumor which is formed by chromaffin cells within the adrenal medulla so the adrenal glands are the glands that sit atop of the kidneys and if we kind of were to take one of these adrenal glands off of a kidney and kind of transected there is a cortex to the adrenal gland which is the outer portion of it and there's also the inner portion which is called the medulla so the pheochromocytoma is a tumor of chromaffin cells inside the medulla this is often a single tumor and these tumors also have a malignant potential so about 10% of pheochromocytomas are found to be malignant they also have a similar presentation to paragangliomas which originated from sympathetic nervous tissue as opposed to pheochromocytomas which originated from chromaffin cells but the management and treatment are similar for both conditions the etiology of pheochromocytoma is often idiopathic so it's idiopathic in most cases but there can be some genetic component to developing a pheochromocytoma so any family history of individuals with pheochromocytoma would be important to know some of these genetic conditions include men 2a and men to be so those multiple endocrine neoplasia types syndromes and also von hippel-lindau so what is the pathophysiology of pheochromocytoma so if we were to take a look at that transected adrenal gland again we have the cortex on the outside medulla on the inside and in pheochromocytoma we've got a big tumor in the medulla in that tumor is composed of chromaffin cells now chromaffin cells in and of themselves are important in the medulla of a normal adrenal gland because they produce some of the catecholamines like norepinephrine and epinephrine but if we have a big tumor in there that is basically hyper secreting norepinephrine and epinephrine and smaller amounts of dopamine and these catecholamines can then act on adrenergic receptors like alpha 1 alpha 2 beta 1 beta 2 receptors etc so with regards to alpha 1 receptor activation alpha 1 receptors are located throughout the body in widespread areas but what I want to remember is alpha 1 receptor activation leads to vasoconstriction so peripheral vascular system has a lot of alpha 1 receptors activation of these receptors leads to vasoconstriction and smooth muscle contraction so when we have basic instruction we get an increase in blood pressure with regards to beta 1 receptor activation beta 1 receptors are located within the heart these lead to increased cardiac output increased heart rate and stroke volume so we can get tachycardia and beta 2 receptor activation is involved in smooth muscle relaxation in the respiratory system and this is by no means a complete list of adrenergic receptors and their downstream effects but I'll talk about more of these in a future lesson so what are some of the signs and symptoms of pheochromocytoma what I want you remember is the classic triad of pheochromocytoma the classic triad involves one a episodic pounding headache two palpitations in tachycardia and three diaphoresis so those are the classic triad of pheochromocytoma episodic pounding headache palpitations and tachycardia and diaphoresis some less common symptoms of pheochromocytoma include orthostatic hypotension weight loss polyuria and polydipsia constipation hyperglycemia in insulin resistance papilledema paroxysmal hypertension cardiac of sue Bo's due to increased exposure to catecholamines and what is important to recognize in patients with pheochromocytoma is that they can have triggers for some of their symptoms some of these triggers can include stress exertion anesthesia abdominal pressure in particular tyramine containing foods like cheese wine etc so how do we investigate whether a patient has pheochromocytoma or not if they have some of those classic triad of symptoms or there's other indexes of suspicion for pheochromocytoma perhaps they have a refractory hypertension we can then begin to investigate whether patient has pheochromocytoma or not but what we first want to do is we want to discontinue any interfering medications and some of those interfering medications include tricyclic antidepressants so before we go into investigating whether patient has pheochromocytoma or not we want to stop some interfering medications in particular tricyclic antidepressants so what are some of those investigations some of the investigations include a 24-hour you're in fractionated Mehta nephron and catecholamines so we can do look at 24-hour levels of meta nephrons and catecholamines meta nephrons our breakdown products of catecholamines or we can check a plasma fractionated meta nephrons taking a sample from an indwelling cannula and this is important because we don't want to take a sample from someone we just poped because they may have a surge in catecholamine levels and we want to take the sample after about 30 minutes of supine rest once we get our results back if the results are normal if they're normal levels of meta nephrons and catecholamines we can recheck again during a spell when the patients are having active symptoms but if the levels are still normal likely another diagnosis we want to think about something else but if we get our results back and it shows meta nephrons and catecholamines greater than or equal to about two times the upper limit of normal levels then the next step is to localize the tumor using adrenal or Abdo MRI or CT scan if the tumor is greater than 10 centimeters we want to use Eyal penguin I 123 scan and if we don't see a tumor on imaging we can still consider doing an a1 on three scan or a whole body MRI doesn't want to discuss genetic testing so because it's associated with men to syndromes and von hippel-lindau we can look for that ret proto-oncogene and men to syndromes and we could also look for a vhdl mutation and we also wanted to kind of discern if it's a malignant tumor or not once we've localized the pheochromocytoma treatment involves surgical resection and this is often curative but before surgery we have to do a couple of things the first thing is we have to do preoperative alpha-adrenergic blockade then we want to do beta adrenergic blockade in that order so alpha adrenergic blockade first then beta adrenergic blockade never beta adrenergic blockade first alpha adrenergic blockade involves about 1014 days of therapy before surgery we typically use phenoxy Ben's Amin and once we do phenoxy Ben's Amin we often do daily blood pressure monitoring and by about the second the third day of alpha blockade we want to get the patient to have a high sodium diet generally greater than five grams of sodium per day because the alpha blockade can lead to vasodilation and can often cause some drop in volume status if it's required we can move on to a long term alpha adrenergic blockade if it's longer than 10 to 14 days and we generally will use a more selective average alpha blocker like process in terrassa sanur Docs addison and for perioperative management we could use IV phentolamine once we achieve effective alpha adrenergic blockade we can move on to beta adrenergic blockade we use propanolol during the first day then we often switch to a long-acting beta blocker and for cases where the typical manage doesn't work we can use a catecholamine since this inhibitor like me tyrosine and again this is only when other therapies are ineffective I hope you found this lesson helpful this was a lesson on tequila como si Toma if you did find this lesson helpful please like and subscribe for more lessons like this one and also don't forget to check out some of my other endocrinology content thank you so much and I hope to see you next time