Pheochromocytoma: Clinical sciences

Chapters:

Watch video only

Introduction0:00–0:53

A pheochromocytoma is a neuroendocrine tumor that develops from chromin cells. These cells are part of the sympathetic nervous system.
So they secrete excessive catecholamines such as norepinephrine and epinephrine which causes severe hypertension. The majority of pheochromocytomas develop in the adrenal gland.
However, extraadrenal pheochromocytomas also called paragangliomas can develop in other locations such as the thorax, abdomen and pelvis.
Pheochromocytomas are commonly linked to genetic conditions like multiple endocrine neoplasia. Type two neurofibromatosis type one and von Hippel lindau disease, but they can also occur sporadically in patients without a genetic condition.

Unstable Patient0:53–2:09

Now, if your patient presents with chief concerns, suggesting pheochromocytoma, you should first perform an ABCD E assessment to determine if they are unstable or stable.
If the patient is unstable, stabilize the airway breathing and circulation. Next, obtain IV access and put your patient on continuous vital sign monitoring including BP, heart rate and pulse oximetry.
Finally, if needed, provide supplemental oxygen. Now, here's a high yield fact, patients with pheochromocytoma classically present with paroxysmal hypertension when systolic BP is above 180 or diastolic BP is above 120 millimeters of mercury.
That's called a hypertensive crisis, which can lead to end organ damage like heart failure, pulmonary edema and intracranial hemorrhage.
So, urgent treatment with an intravenous antihypertensive such as nitroprusside is essential. Keep in mind that BP should be lowered gradually over a 24 hour period to avoid cerebral and myocardial hypoperfusion.
All right. Now that we're done with unstable patients, let's go back to the ABCD E assessment and discuss the stable ones.

Stable Patient2:09–3:38

First, obtain a focused history and physical examination. Classically, patients with pheochromocytomas report episodes of severe hypertension associated with headaches, profuse sweating and palpitations.
They might also present with anxiety, chest pain, weakness as well as nausea and weight loss. Additionally, there might be a history of hypertension that has been unresponsive to antihypertensives.
On the flip side. Physical exam findings typically include hypertension which can be episodic or sustained tachycardia and orthostatic hypotension.
Lastly, you may notice restlessness, tremor and power. Of note the physical exam in some patients can be normal outside hypertensive episodes.
Now, here's a high yield fact, the most common symptoms of pheochromocytoma can be remembered as the five ps, which are increased BP, pain, representing headache, perspiration, palpitations and pallor.
However, note that pheochromocytoma is known as the Great masquerader and it can present with isolated hypertension along with highly variable symptoms.
So, always consider the possibility of pheochromocytoma in any patient with hypertension. All right, if you come across these findings, you should suspect pheochromocytoma.

Suspect pheochromocytoma3:38–5:06

Next order, labs including 24 hour urine fractionated metanephrines or plasma free metanephrines. If metanephrines are not elevated, consider alternative diagnoses.
However, if metanephrines are elevated, proceed with imaging such as a CT or MRI of the abdomen. If imaging reveals no adrenal lesions, again, consider alternative diagnoses.
But if imaging reveals a well defined adrenal mass, you can diagnose pheochromocytoma. Now, here's a clinical pearl to keep in mind, pheochromocytomas follow the rule of 10 where 10% are bilateral.
So found in both adrenal glands, 10% occur in extraadrenal areas. 10% are malignant and 10% affect the pediatric population.
So, if metanephrine levels are elevated but no adrenal tumor is visible on the initial CT or MRI consider imaging extra adrenal locations.
Also note that you can use a pet scan to detect metastatic pheochromocytoma located in the lungs, liver or bones. All right.
Now, moving on to treatment, the only treatment for pheochromocytoma is surgical removal. But preoperative management of hypertension is also important.

Management5:06–6:12

Typically 10 to 14 days prior to surgery, you'll start your patient on selective alpha one adrenergic blockers like prazosin, terazosin and doxazosin or phenoxybenzamine.
Once you achieve adequate alpha blockade, which usually takes around two days, you can start your patient on beta blockers like metoprolol and propranolol to prevent reflex tachycardia.
So keep in mind alpha blockers ahead beta blockers behind. That's because giving beta blockers without blocking the alpha receptors first can cause vasoconstriction and precipitate a hypertensive crisis.
So, the key point here is to give alpha adrenergic blockers. First.
This way, you're going to block catecholamine induced vasoconstriction. Once the tumor has been removed, you should assess for an underlying cause such as a genetic syndrome.
Around one third of pheochromocytomas are linked to genetic syndromes. So, it's essential to assess for conditions like multiple endocrine neoplasia.

Genetic syndromes6:12–8:35

Type two or men two neurofibromatosis type one or NF one and von Hippel lindau disease or VHL for short, all of which are inherited in an autosomal dominant pattern.
First, let's start with men two, which comes in two flavors. Men two A and men two B with both men two A and men two B.
In addition to pheochromocytoma, patients can also have a personal or family history of medullary thyroid carcinoma. However, as a distinguishing factor, if your patient has a personal history of parathyroid hyperplasia or parathyroid adenomas, suspect men two.
A. Alternatively, if the physical exam reveals mucosal neuromas and a marfanoid body habitus suspect men two B in both cases.
Order genetic testing for men two. And if you identify the ret mutation, your diagnosis is confirmed moving on to neurofibromatosis type one.
If the physical exam reveals neurofibromas, cafe oa spots, axillary freckling and lisch nodules on your patient's Iris, you should suspect NF one next order genetic testing.
And if the NF one mutation is identified, you can diagnose neurofibromatosis type one. Finally, let's go over Von Hippel Lindau disease.
If your patient has a history of renal cell carcinoma, retinal or brainstem hemangioblastoma. And physical exam reveals cavernous hemangioma of the skin and mucosa suspect this condition.
Next order genetic testing for VHL. And if the VHL mutation is identified, that confirms the diagnosis.
If genetic cause is identified, management relies on treating any associated conditions as well as screening first degree relatives.
Additionally, all patients should be followed up annually with metanephrine measurement to screen for recurrence. Now, let's take a look at idiopathic pheochromocytoma.

Idiopathic pheochromocytoma8:35–8:57

Finally, if your patient's history and physical exam do not suggest an associated genetic syndrome, diagnose sporadic pheochromocytoma.
In this case, only annual follow ups for the measurement of metanephrines are needed to screen for recurrence. All right, as a quick recap.

Review8:57–9:57

A pheochromocytoma is a tumor that secretes catecholamines and is most commonly found in the adrenal gland. If you suspect pheochromocytoma order urine or plasma metanephrines, if the levels are elevated, order A CT or MRI of the abdomen, if an adrenal mass is detected, it confirms the diagnosis of pheochromocytoma.
Treatment involves preoperative management of hypertension with alpha blockers, first followed by beta blockers and surgical removal of the tumor.
Next, assess for underlying causes such as men two A and B NF one and VHL. If there are no indications of an associated genetic syndrome based on the history and physical examination, the diagnosis is sporadic pheochromocytoma