Case study Renal failure and high blood pressure(B Patient A was given antibioti
ID: 3479723 • Letter: C
Question
Case study Renal failure and high blood pressure(B Patient A was given antibiotics and loop diuretics. The symptoms disappeared, but the patient developed arrhythmia. The electrolyte analysis revealed hypokalemia. The doctor prescribed ACE inhibitors (ACE= angiotensin converting enzyme). Why did he do this? In order to answer this question, you need to do the following: 1) Explain the effects of loop diuretics on the medullary osmotic gradient. 2) Loss of sodium through the nephronal tubule will trigger Renin- Angiotensin- Aldosteron- system (RAA). Explain the effect of RAA-system on Nat and K+- balance. 3) Explain the effect of ACE-inhibitorsExplanation / Answer
Answer-
1: Medullary osmotic gradient is the key element that concentrates urine, it does so by active transporting Na+ through the thick ascending limb into the interstitium from the lumen side. The concentration gradient is created by the loop of henle, and it also recycles urea. Loop diuretics causes diuresis by acting on the ascending limb of the loop of henle, they are generally used to treat hypertension and edema. Loop diuretics inhibits Na+, Cl- and K+ reabsorption by acting on the thick ascending limb of the loop of henle. It also inhbit reabsorption of Mg and Ca, the inhibition of the ions reabsorption cause the concentration of the medulla to fall due to its inability to generate hypertonic renal medulla, which ultimately cause high urine production because water loses it osmotic driving force to leave the collecting duct due to these actions of the loop diuretics.
2- Loss of nacl in the causes juxtaglomerular cells to release renin, renin helps synthesizing angiotensin II by the action of ACE( angiotensin converting enzyme). Angiotensin causes vasoconstriction and release of aldosterone from the adrenal glands, which is RAAS (renin-angiotensin-aldosterone system). Loss of Na+ and K+ decreases blood volume and, the vasoconstrictive action on the glomerular arterioles of angiotensin II leads to increased systemic arterial blood pressure and decreased blood flow. Decreased medullary blood flow through the vasa recta decreases the washout of NaCl and urea in the kidney medullary space. More and more sodium is absorbed in the ascending limbs of the loop of henle and proximal tubule through Na+/H+ ion exchanger. Angiontensin caused release of aldosterone, whose action on the renal tubules cause to reabsorb more sodium and water from the kidney and dump potassium in return.
3- ACE inhibitors are drugs primarily used for hypertension, they do so by relaxing blood vessels and by decreasing blood volume which help lower the blood pressure. They inhibit Angiotensin converting enzyme which is an important component in the RAA(renin angiotensin aldosterone system), It inhibits the conversion of angiotensin I to angiotensin II by the action of the enzyme ACE, angiotensin II causes systemic vasoconcstriction and increased blood volume which increases blood pressure, angiotensin II inhibition leads to lower arteriolar resistance and increased venous capacity, and decreased resistance in the blood vessels in the kidney which leads to sodium excretion in urine and decreased blood volume.