It has been known since the time of Bright that an association exists between the kidneys and blood pressure, commonly known as essential hypertension (also called primary or idiopathic hypertension) because this condition continues to evade clinical research, to precisely identify the cause. Until that day comes, unfortunately your doctor will refer to high blood pressure as essential or idiopathic hypertension. In other words there are too many variables; moreover too pervasive to give a reason. However this must not be misunderstood that doctors cannot control or treat this disease. The difference between diabetes and blood pressure is that the former has a precise diagnosis and well defined pathology. It is not the same as essential hypertension.
Some light was thrown on this obscure relationship when Goldblatt [ref. not found] produced hypertension in a dog when clamping the renal artery [ editors comment] . This type of research is not permitted today. It should be mentioned at this time, if having dental work done, it is of paramount importance that none of the local anesthetic which contains epinephrine be accidentally administered intravascularly. The epinephrine will enter into the blood circulation and into the heart. This can lead to serious complication such as fainting and to even more catastrophic episodes.
As the years went by, it became more evident that various kidney, experimental as well as clinical, were associated with high blood pressure and high blood pressure in turn was associated with kidney deterioration. How ever, the temporal relationship between blood pressure and kidney disease remains a mystery. They continue to be many and varied hypothesis.
Due to these many hypotheses, I will attempt to highlight some of the changes in kidney function where blood pressure, however caused, eventually leads to what is called a loop. E.g anxiety leads to depression and depression accelerates anxiety. The term used to express a healthy kidney is the Glomerular Filtration Rate (GFR). The results of this filtration will tell your doctor how prone you are to develop high blood pressure. Since we as lay people do not experience any physical symptoms, high blood pressure is commonly referred to as the silent killer.
Substantial reduction in kidney function occurs with advancing age. Starting at an early middle age and even in the absence of cardiovascular and kidney disease, the ability of the kidney to function as a filtration organ decreases as it reaches a value of 50% of normal by ages between 50 - 70. The reduction to filter is even greater in elderly patients. Filtration function of the kidney is not to be confused with prostate enlargement and the reduction in one’s powerful stream when they void. The kidney function to filter has to do with the separation and excreting sodium (salt) and retaining potassium in the right ratio. Hence the use of water pills to regulate the right proportions.
Congestive heart failure in the elderly, systemic infection or dehydration adds a further burden to an already pair of kidneys which are not filtering properly. This is the beginning of what is called renal failure and the physician will work to balance and to rid the patient of fluid which will start to build up around the heart. Such fluids with sodium and potassium are called electrolytes and must be precisely balance. If too much potassium is excreted while removing the sodium then there is the possibility to cause the heart to malfunction and develop irregular beats. "Water pills" in addition to other medication to reduce blood pressure are critical but they must not excrete potassium to cause arrhythmia. When one is on a "water pill" it is suggested to increase foods which are high in potassium such as bananas and the juice of the Caribbean coco-nut water.
A perfect blood pressure is measured in mm/Hg (120) over mm/Hg (80). It should be measured at approximately the same time each day, preferably first thing in the morning. Measure kits can be bought at a pharmacy or on-line. They are very easy to use. Contrary to urban legend, age does not matter. If you are healthy your pressure should be plus or minus 120/80 mm-Hg.
by HAYNES DARLINGTON M.SC. PHARMD.
Saturday, July 4, 2009
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