Low-risk and high-risk pheo

Happy Thanksgiving! This will be the last piece for 2013. I wish everyone a great holiday season and a wonderful year of 2014!

When we, health care professionals and lay people alike, talk about pheo, we seem to assume all pheos are the same. In medical textbooks, pheo is mostly discussed in a way that gives the reader the impression that if one has a pheo, one will have all the classical signs and symptoms of pheo. In the lay communications, the heterogeneity of pheo is even less appreciated. One pheo, however, can be very different from another. I have written about clinically “silent” pheo, pheo associated with normal blood pressure, pheo that causes frank cardiovascular problems, small pheo, pheo caused by genetic mutations, etc. Understanding the heterogeneity of pheo is critical to tailor pheo management to an individual patient with a particular pheo.

Preoperative management of pheo has been controversial since the very beginning. I myself have advocated careful preoperative preparation for every patient with pheo. On the other hand, there are many different ways of preoperative preparation used by experts, all with similar excellent outcome. Recently, one review article proposes risk stratification for pheo, which may help reconcile the paradox.

The article divides pheos into 3 categories: low-, intermediate-, and high-risk, according to the risk of heart complications a particular pheo can impose on a patient. Low-risk pheos are those smaller than 3 cm in diameter. This article proposes that specific preoperative preparation is not needed for low-risk pheos. High-risk pheos are those that already cause obvious cardiovascular complications such as arrhythmia, heart attack, heart failure, or stroke. Careful preparation is needed for high-risk pheos and the doctors need to coordinate their care so that the preparation regimen is safe and effective. Intermediate-risk pheos are those that are none of the above. The preparation regimen should be individualized. The higher the relative risk of cardiovascular complications a pheo has, the more careful and longer the preparation it requires. 

It needs to be emphasized that this risk stratification is based on clinical observation and just a proposal. It has not been prospectively tested. What am I doing? I currently still carefully prepare everyone. If a patient does have a low-risk pheo, I am more relaxed with the regimen.

Dr. Pheo

Sorry but I missed many of you!

I just realized 2 days ago that my email software had placed all the alert messages from the Dr. Pheo blog in a strange new folder. You can see that obviously I am not very savvy on software stuff. I have been wondering lately why readers do not ask questions any more. At one time, I entertained thoughts that perhaps I had answered most questions so that readers wouldn't ask any more. Then 2 days ago, I tried to see the content of a strange folder in my email software and saw 30 questions from this blog.

I have since dutifully answered all of them but the answers are quite untimely. I apologize. The lesson learned is that if I do not see questions from this blog, I should check all the email folders.

Dr. pheo

Another "dopamine-producing" pheo

Some days ago, I got a call from a physician asking me for suggestions on how to proceed with a “dopamine-producing” pheo. The patient was an elderly man with labile blood pressure and varying heart rate. Pheo was suspected. Urine dopamine levels were >5000 mcg/24 hours (normal reference range: 60-450). But was it a pheo?

I usually get 1 or 2 calls on potential "dopamine-producing" pheo every year. True dopamine-producing pheos are extremely rare and do not cause clear symptoms. These tumors are usually localized outside the adrenal glands and may present as metastatic tumors. They are usually clinically silent until they grow very big and causing abdominal discomfort. Specifically they do not cause hypertension per se. Only about half of the patients have high dopamine only and the other half have high dopamine and high epinephrine or norepinephrine as well.

In any given situation, the most common cause of very high urine or plasma dopamine is the medication Carbidopa-Levodopa (Sinemet) for Parkinson disease. These patients usually have every high dopamine but normal or slightly elevated epinephrine or norepinephrine. Levodopa is presumably converted into dopamine which is then detected by the catecholamine measurement. Parkinson disease and related conditions such as multiple system atrophy often cause sympathetic instability in the forms of fluctuating blood pressure and heart rate, orthostatic hypotension, and syncope, all of which resemble pheo symptoms.

I therefore asked the physician if the patient had Parkinson disease. He was reasonably surprised and told me the patient did have Parkinson. I then asked if the patient took Sinemet. He checked the medication list but Sinemet was not on the list. I was not swayed. Many patients think Parkinson is a disease of old age and Sinemet some kind of food supplement so they do not tell their doctor they are taking it. Luckily the patient was still in the clinic. The physician told me he would ask the patient about Sinemet and call me back. He didn't call me back. I assumed the patient was taking Sinemet, as all of the patients I had been asked about are.

Dr. Pheo

P.S. I have not written about pheo for 7 months for various reasons. My job is more demanding, to be sure. Also, there has not been a major advancement in the pheo field in the last 7 months, in my opinion. 

Pheo and heart II

I first wrote about pheo and heart 4 years ago (April 2009). At that time, my instinct was that heart damage is a key issue for pheo. Over the years, after seeing more patients with heart complications caused by pheo and discussing with colleagues about the issue, I increasingly appreciate the intricacies of pheo-induced cardiomyopathy.

Pheo-induced cardiomyopathy is not a new finding. The first two cases of pheo known to medicine were both about pheo-induced cardiovascular collapse in modern terms. The correlation of pheo and cardiomyopathy was clearly and convincingly reported in the 1960s. Hundreds of case reports of pheo-induced cardiomyopathy have been published in the last 50 years. The problem is that pheo is very rare and pheo-induced cardiomyopathy is even rarer. Many cardiologists and endocrinologists simply are not aware of the concept of pheo-induced cardiomyopathy. Part of the reason why pheo-induced cardiomyopathy is not well known is that there are few, if any, systemic studies on pheo-induced cardiomyopathy.

In the last year, two very similar systemic studies were published on pheo-induced cardiomyopathy. Both studies were retrospective review of experience of a large single medical center (in Prague and Los Angeles, respectively). In both studies, the authors focused on patients without known history of pheochromocytoma but presenting with cardiovascular complications such as arrhythmia, heart attack, heart failure, or stroke. Their results were strikingly similar as well. The Prague study included 145 patients, 28 of them (19%) presented with cardiovascular complications. The Los Angeles study was about half the size with 76 patients, but still 9 of them (12%) presented with heart complications. Because both medical centers are large tertiary referral centers and tend to see sicker patients, the incidence of cardiovascular complications may be overestimated but the 12-19% incidence is at least true in large hospitals. Both studies showed that there are no good predictors on which patients will get cardiovascular complications. Specifically, most patients with cardiovascular complications do not have hypertension. There may be a higher risk for cardiovascular complications if the pheo is biochemically very active and large. I have mentioned in a previous post that pheos smaller than 3 cm do not cause cardiovascular complications. Both studies showed that once correctly diagnosed and managed, the pheo-induced cardiomyopathy is reversible. The moral of the studies is that if a patient presents with cardiovascular complications, pheo is a possibility, even if the patient has no history of hypertension. It is also reassuring that the cardiomyopathy is reversible after pheo removal.

Dr. Pheo