Two papers on risks of familial pheo appear in the May, 2009 issue of the Journal of Clinical Endocrinology and Metabolism. One Paper describes experience in about 500 Italian patients, the other over 200 Spanish patients. The paper on Italian patients is particularly informative. With the three large studies now available (the original landmark study in 2002 published in the New England Journal of Medicine and these two new papers), I feel it is time to quantify the probability of having familial pheo. I have prepared a calculator of risks for familial pheo. The calculator is based on the 3 above large studies. The calculator has only five input variables:
1) Primary location of your pheo/paraganglioma
2) Age at diagnosis
3) Family history of pheo or paraganglioma (Yes/No)
4) Single or multiple pheo/paraganglioma (Single/Multiple)
5) Do you have any of the following diseases in addition to pheo/paraganglioma (Yes/No): medullary thyroid cancer, hyperparathyrodism, hirschsprung's disease, mucosa neuroma, hemangioblastoma, renal cell carcinoma, pancreatic neuroendocrine tumor, and skin neurofibroma?
As this is a blog format, I can not post the calculator on line. If you tell me the answer to the 5 variables, I will tell you your risk of having a familial pheo. The calculator has its intrinsic limitations and perhaps even errors; and the results are only as good as the accuracy of the 5 variables. Also I can not tell you the chances of any particular mutated genes.
Of course, the calculator only gives you an estimate of risk and only your doctor and you shall decide whether to do genetic testing. You should use the results of the calculator responsibly and at your own risk; I can not be held liable for any adverse consequences.
Dr. Pheo
Tuesday, May 26, 2009
Monday, May 11, 2009
Silent? No way!
You may have heard the term “silent pheo”. The sole purpose of this post is to convince you that “silent pheo” is a dangerous term and should be avoided at all cost. So next time you hear someone mentioning “silent pheo”, you tell the person there is no such a thing. Every time I hear the term, I get goose bumps and try to correct the person.
The term “silent pheo” or “subclinical pheo” apparently refers to a pheo in a patient who does not have hypertension or paroxysmal attacks. There are quite a few situations where a patient indeed has a pheo or paraganglimoa but does not have classical symptoms of pheo. Most paragangliomas in the neck and chest do not produce significant amounts of catecholamines. I would rather call these tumors "nonfunctional" rather than "silent". Very small pheos produce only small amounts of catecholamines so that they do not cause clinical symptoms. In the above two situations, blood tests for pheo show normal results. Most pheos in adrenal glands, retroperitoneal space, and bladder do produce catecholamines and are therefore "functional". The majority of patients with pheo have at least subtle symptoms that can be elicited by experienced physicians or realized in retrospect after removal of the tumor.
Some patients indeed have no apparent hypertension in spite of very functional pheos. These patients tend to be mismanaged and are at the highest risk of complications around surgery. Here are the reasons. These patients tend to be young and healthy before they have pheo. Their bodies try very hard to accommodate the bombardment of catecholamines by shrinking their blood volume. My experience is that their blood pressure may be normal while sitting or standing but rises when they lie down. An inexperienced doctor may think they have so-called "desensitization" of catecholamine receptors and can go ahead with surgery without preparation. Disaster happens if they do. They will have very high blood pressure while the tumor is manipulated and profound hypotension after the tumor is resected. Then they will get a lot of intravenous fluid their hearts can not handle. It will be a mess!
The bottomline is that if a patient has normal blood test results, whatever tumor the patient has may not be sufficiently functional. If the patient has elevated blood markers for pheo, the patient should be treated as having a functional pheo and undergo careful preoperative preparation, regardless of having hypertension or not. A young, otherwise healthy patient with a large pheo and high levels of markers but without hypertension is the most vulnerable one. That patient particularly deserves careful preoperative preparation.
Dr. Pheo
The term “silent pheo” or “subclinical pheo” apparently refers to a pheo in a patient who does not have hypertension or paroxysmal attacks. There are quite a few situations where a patient indeed has a pheo or paraganglimoa but does not have classical symptoms of pheo. Most paragangliomas in the neck and chest do not produce significant amounts of catecholamines. I would rather call these tumors "nonfunctional" rather than "silent". Very small pheos produce only small amounts of catecholamines so that they do not cause clinical symptoms. In the above two situations, blood tests for pheo show normal results. Most pheos in adrenal glands, retroperitoneal space, and bladder do produce catecholamines and are therefore "functional". The majority of patients with pheo have at least subtle symptoms that can be elicited by experienced physicians or realized in retrospect after removal of the tumor.
Some patients indeed have no apparent hypertension in spite of very functional pheos. These patients tend to be mismanaged and are at the highest risk of complications around surgery. Here are the reasons. These patients tend to be young and healthy before they have pheo. Their bodies try very hard to accommodate the bombardment of catecholamines by shrinking their blood volume. My experience is that their blood pressure may be normal while sitting or standing but rises when they lie down. An inexperienced doctor may think they have so-called "desensitization" of catecholamine receptors and can go ahead with surgery without preparation. Disaster happens if they do. They will have very high blood pressure while the tumor is manipulated and profound hypotension after the tumor is resected. Then they will get a lot of intravenous fluid their hearts can not handle. It will be a mess!
The bottomline is that if a patient has normal blood test results, whatever tumor the patient has may not be sufficiently functional. If the patient has elevated blood markers for pheo, the patient should be treated as having a functional pheo and undergo careful preoperative preparation, regardless of having hypertension or not. A young, otherwise healthy patient with a large pheo and high levels of markers but without hypertension is the most vulnerable one. That patient particularly deserves careful preoperative preparation.
Dr. Pheo
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