In our #AMreport today at Women’s College Hospital. We reviewed the two (2) new major recommendations from the 2015 CHEP (Canadian Hypertension Education Program) guidelines and a case of pheochromocytoma. Pheochromocytomas are quite rare and if your suspicion is low for pheochromocytoma look at the pee first. #choosingwiselycanada
CHEP 2015 Two new major recommendations:
1. Measurement using validated electronic upper arm devices is preferred over auscultation for accurate office BP reading.
2. If the initial visit BP is increased but <180/110 mm Hg, out of office blood pressure preferably ambulatory blood pressure monitoring or home blood pressure monitoring should be performed before follow-up visit to rule out white coat hypertension.
Detailed guidelines can be found here: http://www.hypertension.ca/images/CHEP_2015/CHEP2015_Manuscript.pdf
Take Home points for Pheochromocytoma
The plasma metanephrine test has excellent sensitivity and a negative result is a great tool for ruling out pheochromocytoma particularly when pre-test probability is high. See systematic review here: http://www.biomedcentral.com/1472-6823/4/2
It is called the “10% tumour” since it pretty much does most things around 10% of the time:
- ~10% malignant.
- ~10% bilateral.
- ~10% extra-adrenal (eg..paraganglion system, organ of Zuckerkandl).
- ~10% familial.
- ~10% associated with MEN syndromes.
- ~10% recurrence rate within a decade of surgical resection.
Order plasma metanephrines (High suspicion) in the following scenarios*:
1. Previous pheochromocytoma resection.
2. Family history of MEN2 or pheochromocytoma.
3. An incidental adrenal mass with high Hounsfield units OR with delayed contrast washout <50% at 10 minutes or size > 4 cm.
*Not an exhaustive list but also limited availability in Canada to get plasma metanephrine test.
Order 24 hr urine free metanephrines (low suspicion) in the following scenarios*:
1.Refractory hypertension with treatment with ≥3 agents (many other causes of refractory HTN such as untreated OSA and pheo is still less likely)
2. An incidental mass on imaging with low Hounsfield units, rapid contrast washout >50% at 10 minutes and other features not in keeping with pheochromocytoma.
*Not an exhaustive list