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I'm David Spence. I'm a Professor of Neurology and
Clinical Pharmacology at Western University in London,
Canada, and this talk is about Controlling Resistant Hypertension.
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The topics that I'll get into are the causes of resistant hypertension,
and approach to individualized therapy for
resistant hypertension based on the patient's physiology.
Some special issues for black patients who tend to have low plasma renin levels,
and a brief discussion of patients with multiple causes of hypertension.
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So, in the Global burden of disease, April 9 of
2012, hypertension reached the top
of the list as the cause of death and disability in the world.
It's a huge problem in Africa.
In Nairobi, hypertension clinics,
75 percent of the treated hypertensives have poor blood pressure control.
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The causes of resistant hypertension include three broad categories or maybe more.
First is non-compliance.
So, about half the patients will admit that they're not taking pills.
Compliance is better with drugs that have less adverse effects.
One of the problems obviously is the cost of medication,
so keeping medication inexpensive is helpful with
possible, particularly in impoverished areas.
Second broad category is things that patients
put in their mouth that aggravates their hypertension,
which includes salt, licorice, non-steroidals,
too much alcohol, birth control pills, and decongestants.
Patients who salt their food before tasting, are on average,
consuming about 10 grams a day of salt,
and the body only needs about half a gram.
So, desirable salt intake for patients with
hypertension is around two to three grams a day, which means,
not only no added salt but also avoidance of
salty foods such as pickles and canned soups and cured meats.
The only non-steroidal anti-inflammatory agent
that does not raise blood pressure is Sulindac.
That was a paper in Lancet 1986,
David Wong was the first author and I was the second.
And too much ethanol can be
a significant problem that the patient may not tell you about, so you need to ask.
The problem with licorice is that it has a mineralocorticoid
effect so, it can cause high blood pressure with low potassium,
and it can look like primary aldosteronism and also cause a low renin.
However, the aldosterone level will also be low because of the salt and water retention.
Now the third broad category is secondary hypertension
an underlying cause of the hypertension that can be diagnosed.
And the most neglected of these,
bilateral adrenocortical hyperplasia causing primary hyperaldosteronism,
and variants of Liddle syndrome,
and other sodium channel mutations in the renal tubule causing salt and water retention,
and these may be especially important in African-Americans and in Africans.
The fourth category of problem is,
consensus guidelines, that assumes that all patients are the same.
And the fifth broad category is doctors who don't think.
