Fight or Flight Response: Review of New 2015 CHEP Recommendations & the 10% tumour

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:

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:

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