Ok thanks for the additional information,
Well it seems to me that you have been worked up extensively for any causes of the hypertension, the low potassium is however making me think that this can be Conns syndrome which is hyperaldosteronism in which aldosterone which is a hormone secreted by the adrenal glands in high in amount and this leads to the devlopment of hypertension alongwith low potassium levels and high sodium levels. This can be diagnosed with the help of several tests, sometimes a CT scan can miss any growths on the adrenals and an MRI can be done to rule that out conclusively. This can also be dtected with the help of a PA/PRA ratio. If this is the cause then the appropiate treatment with drugs and surgery can be sought.
Now i know you said that your kidneys have been checked with an ultrasound but have they been checked specifically with a doppler ultrasoun to look at the arteries because a normal ultrasound will not tell anything about the arteries. Im saying this because a cause of hypertension can be renal artery stenosis and this is narrowing of the arteries leading to the kidney and thus causing hypertension. If this hasnt been excluded its worth talking to your dotor about, just ask him if renal artery stenosis has been excluded.
Now apart from Conns Syndrome and RAS, there are several other causes but most of them have been excluded by extensive testing. Pheochromocytoma, kidney failure, heart disease have all been excluded. Now if this has been excluded the next step is to look for hormonal causes of rise of blood pressure
such as in the case of Cushings disease in which the steroid levels in the body are elevated and it can present with weight gain, thinning of skin, hypertsnion increase glucose levels. The tests which are done for this are 24 hour urinary cortisol level, serum cortisol levels and if need be a dexathasone suppression test. This can then be treated depending on the site from where the excess steroids are being produced the adrenals or the pituitary in the brain.
There can be excessive hypertension also with increased thyroid
function such as in hyperthyroidisim.This can be simply checked with the help of normal thyroid function test.
there are other causes which can be looked as well, ill give you a useful link which you can use to discuss the causes with your doctor,http://www.mayoclinic.com/health/secondary-hypertension/DS01114
Now if no cause can be found even after this extensive testing and the additional infor i have given you then this is simply essential hypertension
and you will just eed to take your meds to control the BP. Sometimes it takes more than two or even more meds to control the BP and this can take sometime and we usually increase the doses and the drugs slowly. Lisinopril is a good choice to control the BP and if that doesnt work then a calcium channel blocker or a beta blocker can be added to the regimen to control the BP.
I hope this answers your question
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