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Posts Tagged ‘renal artery stenosis’

The much fancied criteria   “suspect secondary  HT” if the  onset of  hypertension  is   before 30 years   later than  55  years ,may be useful  .But a caution about this criteria  : It does not mean you should not hesitate to  diagnose renal HT  between 30 -55 years.  The  real onset may be   < 30years , but  the patient may report to the physician  late  in his /her  40 or 50s !

  1. Diastolic blood pressure > 120
  2. Sudden acceleration blood pressure
  3. Blood pressure which is  resistant to control with three or 4 drugs ,that shall typically include a  diuretic.
  4. An episode of left ventricular failure (Often referred to as  called flash pulmonary edema)
  5. Presence of  Hypertensive retinopathy
  6. Para umbilical bruit
  7. HT associated with significant CAD
  8. Marked LVH in echocardiography
  9. Finally , most importantly , worsening of renal function with ACE inhibitor is a  strong clue the kidney is under perfused  and  the   renal circulation  is dependent on  elevated angiotenisn 2 (Which ,if blocked worsens the GFR ).This implies every physician should take a baseline serum creatinine  and urea before starting them on ACEI.(Which is rarely followed , as far as my country is concerned !)

Is there any simple way to  differentiate  reno vascular from renal parenchymal HT ?

It is very difficult to differentiate between these two clinically. It makes things more difficult , as  combination of both occurs. Prolonged renal ischemia can result in parenchymal damage as well.

The simplest way is to do a rapid ultrasound imaging to assess kidney size and texture (Loss of cortical-medullary differentiation indicating early renal contraction phase ).Of course , our nephrology colleagues are always there to help you out .

* It need to be remembered the functional renal HT -Renal tubular acidosis,  Adrenal HT (Conn’s /chromo-pheocytomas  has to be ruled out , as these entities also occur in the same age group ).The combination of hypokalemia and mild alkalosis is a  good clue to rule out many of these  defects.

* The CT scan image used in the above illustration  courtesy

http://www.ajronline.org/cgi/content-nw/full/189/3/528/FIG21

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We know diabetes, smoking, hyperlidemia, hypertension are major risk factors for progressive vascular disease. They damage the vascular endothelium either directly or indirectly ,   by aggravating the atheroscelortic process .  Diabetes apart from affecting the medium sized arteries , also affect the microvasculature.  Smoking  has a direct effect on endothelial function .It depletes vascular nitric oxide. High levels of circulating lipids injures the sub endothelial structures and invades the media by entering macrophages .So , all these 4 risk factors either operate independently or interact with each other and result in progressive vascular    disease.

While we  believe  , these risk factors do not have any bias in attacking the human vascular  tree, in the real world it is observed they have their own  behavior pattern and  have unique predilection and a deadly alliance .

For example , in  chronic smokers TAO is the commonest manifestation , thrombo angitis is far too less common to occur in the coronary arteries.

Similarly  hypertension  per se  rarely results in an acute coronary syndrome while it is  the  single  important  cause for cerebro vascular  disease. Diabetes especially in women has very strong predilection for CAD , while diabetic per se is a lesser risk for stroke. Hyperlipedimia may be the one which has fairly even risk throughout the vasculature. Similarly there is  a difference in renal and   carotid arterial involvement with reference to  the conventional  risk factors .

SHT diabetes dyslipidemia coroanry risk factor

Why this apparent difference ?

We are unlikely  to get an answer to this question in the near future .  Left to the youngsters  . . . of tomorrow !

* Note of  clarification

The source for the above chart is collected from various studies and also a huge observational data from our hospital. There could be some geographical variation , a given individual may respond differently to these risk factor depending upon his genetic predisposition and susceptibility . So the above data can be applied to general population and not to a individual.

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