Hyperaldosteronism and Conn's Syndrome

hi this is tom from zero defiance calm in this video i'm going to be talking through hyperaldosteronism you can find written notes on this topic at zero defiance calm slash hyperaldosteronism or in the endocrinology section of the zero finals medicine book let's start with some basic physiology where we need to go through the renin-angiotensin-aldosterone system in the afferent arteriole in the kidneys they're special cells called the juxtaglomerular cells and these cells are responsible for monitoring the blood pressure in these vessels when they sense a low blood pressure in these vessels in that arterial they secrete a hormone called renin the liver secretes a protein called angiotensinogen and renin acts to convert angiotensinogen into angiotensin one angiotensin 1 converts to angiotensin 2 in the lungs with the help of angiotensin converting enzyme or ace and then angiotensin 2 stimulates the release of aldosterone from the adrenal glands now aldosterone which is what we're talking about when we talk about hyperaldosteronism is a mineralocorticoid steroid hormone so this means it acts on the kidneys to increase sodium reabsorption in the distal tubules secretion in the distal tubule and increase hydrogen secretion in the collecting ducts the net effect is that we increase sodium reabsorption into the blood from the urine increased potassium secretion and increase hydrogen secretion let's talk about primary hyperaldosteronism and this is what we referred to when we talk about Conn's syndrome primary hyperaldosteronism is when the adrenal glands are directly responsible for producing too much audio strain the serum renin will be low as it's being suppressed by the high blood pressure entering the kidneys and there's several possible reasons for the adrenal glands to produce too much audio strain one is an adrenal adenoma so this is an hour dosterone secreting tumor of the adrenal glands and this is the most common cause of primary hyperaldosteronism another causes bilateral adrenal hyperplasia another causes familial - then there's adrenal carcinoma secondary hyperaldosteronism is where excessive renin is stimulating the adrenal glands to produce more aldosterone serum random will be high in secondary hybrid austrane as this is the cause of the high aldosterone secretion and there are several causes of a high renin level and these occur when the blood pressure in the kidneys is disproportionately lower than the blood pressure the rest of the body this will occur in renal artery stenosis renal artery obstruction and it may occur in heart failure renal artery stenosis is narrowing of the arteries supplying the kidney and this is found in patients with atherosclerosis as an atherosclerosis 'el or the renal artery that's supplying the kidneys and this happened in a similar way to how the coronary arteries are narrowed in angina and it can be confirmed with a Doppler ultrasound or CT angiogram or a magnetic resonance angiography or an MRA scan so because the blood flow is obstructed from entering the kidneys the blood pressure in the kidneys is lower than the blood pressure in the rest of the body so those juxtaglomerular cells sends a lower blood pressure secrete renin that in turn causes a high aldosterone level and increased blood pressure however that increase in blood pressure never reflects into the kidneys because of that narrowing so the kidneys themselves continue to get a low blood pressure and secrete more renin let's talk about investigations the best screening tool for someone that you might suspect has hyperaldosteronism is to check the Renan aldosterone levels and calculate a Renan how dosterone ratio a high aldosterone and a low renin indicates primary hyperaldosteronism and a high aldosterone and a high Renan indicates secondary hyperaldosteronism other investigations that relate to the effects of our da strain you can check the blood pressure where you're likely to find hypertension you can check serum electrolytes where you may find hypokalemia or low potassium and you can take a blood gas analysis where you might find an alkalosis if there's a high l dosterone level then you need to investigate for the possible cause and the way to do this would be a CT or an MRI to look for an adrenal tumor and a renal Doppler ultrasound or CT angiogram or MRA to look for renal artery stenosis or renal artery obstruction so what's the management of hyperaldosteronism you can use our dosterone antagonists and these are things like a player known or spironolactone and you can also treat the underlying cause by either surgically removing the adenoma or if you find those renal artery stenosis you can do percutaneous renal artery angioplasty so you go in via the femoral artery and you expand a balloon or stent the renal artery so you improve the blood flow to the kidneys finally a little tom tip hyperaldosteronism em burring as it's the most common cause of secondary hypertension so if you have our patient with high blood pressure that's not responding to normal treatment consider screening them for hyperaldosteronism by doing a simple renin aldosterone ratio blood test and one clue that might prompt you to test for hyper aldosterone is that there may be a low potassium level in the blood however be aware that potassium levels can still be normal in hyperaldosteronism so it's worth testing if you have any suspicion so thanks for watching I hope you found this video helpful if you did don't forget there's plenty of other resources on the zero to finals website including loads and loads of notes on various different topics that you might cover in medical school with specially made illustrations there's also a whole test section where you can find loads of questions to test your knowledge and see where you're up to in preparation for your exams there's also a blog where I share a lot of my ideas about a career in medicine and tips on how to have success as a doctor and if you want to help me out on YouTube you can always leave me a thumbs up give me a comment or even subscribe to the channel so that you can find out when the next videos are coming out so I'll see you again soon

Channel: Zero To Finals

Views: 73,185

Keywords: medical, education, medicine, doctor, endocrinology, hyperaldosteronism, physiology, renin, angiotensin, aldosterone, pathophysiology

Id: oSqLwPv8bb4

Length: 7min 48sec (468 seconds)

Published: Thu Dec 27 2018