Treatment Of isolated Diastolic Hypertension

Diastolic blood pressure is the lowest blood pressure between the two heartbeats. Normal blood pressure of a healthy adult is 120/80 mm of Hg. 120 is systolic blood pressure while 80 is the diastolic blood pressure. Increase in diastolic blood pressure above the normal ranges is called diastolic hypertension.

We are here to discuss 

PHYSIOLOGIC PRINCIPLES UNDERLYING THE TREATMENT OF HIGH

DIASTOLIC HYPERTENSION BY THIOCYANATES

AND SYMPATHECTOMY

The effects of sympathectomy and thiocyanate treatment on the diastolic blood pressure and the adrenal gland were studied by  LOYAL DAVIS, (M.D)., JOSEPH TARKINGTON, (M.D)., AND ROBERT K. ANDERSON, (M.D)

Only the summary and important points of their study are stated here;

Before reading this you must have sufficient knowledge about the different functions and layers of Adrenal gland.

Important points are;

• Patient response well to Sympathectomy followed by treatment with thiocyanate than treatment with a single agent alone.

other points include;

1. There is a depletion of lipid granules in the three layers of the adrenal cortex of the experimental renal hypertensive dog which has received thiocyanates. This depletion is most marked in the zona glomerulosa. Zona glomerulosa is responsible for the secretion of mineralocorticoids especially Aldosterone. which control blood volume and blood pressure. High aldosterone level means high blood pressure and vice versa. Hence thiocyanate decreases the production of aldosterone by the adrenal cortex and tends to decrease the blood pressure.

2. Withdrawal of the thiocyanates is followed by the reappearance of these sudanophilic fatty granules in the adrenal cortex and return of the blood pressure to the original high level.

3. These changes in the distribution of the lipid granules are similar to those which occur in the adrenal cortex of patients with essential hypertension who have received thiocyanates.

4. The depletion of the lipid granules in dogs with experimental renal hypertension

is more marked after bilateral thoracolumbar sympathectomy. Thoracolumbar sympathectomy is done. sympathectomy decreases the secretion of epinephrine and norepinephrine from the adrenal medulla. low levels of epinephrine will result in low levels of ACTH. which in turn decreases the adrenal cortical secretions. which is responsible for hypotensive effects following adrenal medulla denervation. 

5. It is noticed experimentally that Partial occlusion of the portal vein permanently reduces the systemic blood pressure of dogs with experimental renal hypertension and produces a depletion of the lipid substances in the fasciculata and reticularis layers of the adrenal cortex, with a relative depletion in the zona glomerulosa. fasciculata layer secretes glucocorticoids mainly cortisol and zona reticularis secretes androgens. but partial occlusion of portal vein will result in chronic liver damage which in turn result in a reduction of hypertensinogen production by the liver.

6. If thiocyanate is given intravenously to a dog. it will result in an immediate decrease in blood pressure followed by a rapid rise in blood pressure to a higher value which afterwards slowly return to original hypertensive value. Removal of the adrenal glands is followed by the disappearance of the pressor response which immediately follows the primary depressor effect produced by the injection of thiocyanate in an acute experimental animal.

7. These observations point out that the thiocyanates and sympathectomy affect principally the glomerulosa layer of the adrenal cortex. Cytochemical studies of the lipid granules point to this layer as the important source of the 17-ketosteroids.

They also indicate that the depressor effect of a chronic, mild, insufficiency of the liver produced by partial occlhsion of the portal vein is accompanied by a depletion

pattern of the lipid granules in the adrenal cortex different from that produced by the thiocyanates.

BIBLIOGRAPHY

Davis, Loyal, and M. H. Barker. The Surgical

Problem of Hypertension. Ann. Surg., 107:

899, 1938.

2 Davis, Loyal, and M. H. Barker: Clinical and Experimental Experiences in the Surgical Treatment of Hypertension. Ann. Surg., 110: 1016,

1939.

3 Davis, Loyal, Howard A. Lindberg and N. V.

Treger: The Results of a Special Coordinated

Plan of Medical and Surgical Treatment of

Essential Hypertension. Ann. Surg., 128:

770, 1948.

4 Davis, Loyal, Carlos A. Tanturi and Joseph A.

Tarkington: The Combination of Sympathectomy and Thiocyanates in the Treatment of

Experimental and Essential or High Diastolic,

Hypertension. Ann. Surg., 132: 394, 1950.

5 Davis, Loyal, and Carlos A. Tanturi: The Liver

as a Factor in Experimental Renal Hypertension.