00:00
Welcome back. Thanks for joining me on this discussion of pheochromocytoma in the section of general surgery.
00:07
Pheochromocytoma used to be one of my favorite topics as a medical student because the word is kind of fun to say.
00:14
I challenge you to say it ten times fast. Now, let’s get started.
00:18
Pheochromocytomas are catecholamine secreting tumors specifically located the vast majority of the time in the adrenal medulla.
00:27
Remember, the adrenal gland has multiple layers.
00:30
In the inner core called the adrenal medulla, norepinephrine and epinephrine are secreted.
00:36
Also important to remember, 10% of pheochromocytomas are actually outside of the adrenal gland.
00:44
The rule of 10 is important to mention with pheochromocytomas, as 10% are malignant and 10% are familial.
00:52
These are commonly called paragangliomas or organ of Zuckerkandl.
01:01
In this image marked in red is the organ of Zuckerkandl or a paraganglioma commonly found at the aortic bifurcation.
01:11
They contain neural crest tissue usually at the level of the aortic bifurcation or at the inferior mesenteric artery takeoff.
01:19
What are some of the common symptoms of pheochromocytoma?
Here, you see the gentleman with episodic headaches. They can be quite severe. Diaphoresis, also catecholamine-induced;
and very importantly, tachycardia. Now, the combination of episodic headaches, diaphoresis,
and tachycardia is a classic association and incredibly high-yield.
01:46
I recommend that you keep that in mind. However, clinically, this triad is actually a rare finding.
01:53
Remember very importantly, pheochromocytomas can result in potentially fatal cardiac arrhythmias.
02:00
Therefore, you must have a high index of suspicion in patients with difficult to treat hypertension.
02:06
Speaking of which, most patients with pheochromocytoma result in hypertension
and the reason is because of the increased catecholamine secretions.
02:19
Let’s take a look at what laboratory findings may help you diagnose a pheochromocytoma.
02:26
Unfortunately, your general chemistries and your CBCs may not be very helpful.
02:31
However, specific to the diagnosis of pheochromocytoma are urine or plasma metanephrines.
02:39
Plasma metanephrines are more sensitive but less specific and conversely,
urine catecholamines and metanephrines are less sensitive but more specific.
02:50
A downfall of urine catecholamines is that it requires a 24-hour urine collection.
02:56
That can be difficult on an outpatient basis.