Surprisingly enough the BNF doesn’t actually have that much on renal failure, so I’ll have to wait for my clinical therapeutics book to arrive from amazon sometime next week to give this organ the full attention it deserves.*
On my hospital cross sector placement last week I did get to see some dialysis happening. It turns out that in advanced cases of kidney disease people can lose the function to produce urine. They don’t pee at all. A woman I talked to hadn’t peed in years.
The issue is that they then can’t get rid of any excess water. It fills up their blood vessels above capacity, and (as with any form of plumbing) leads to an increase in pressure (hypertension). This puts a strain on the heart and can lead to left ventricular hypertrophy, where basically the muscle of the left ventricle (which pumps blood to the rest of your body) enlarges because of all the extra work it has to do. The bigger it gets the less flexible it becomes (sort of like a huge body builder) and so it can’t pump as well. It also makes the ventricle smaller, so the output per pump is also smaller, exacerbating the back log and causing heaps of other problems.
The pressure in the vessels can get so high that the excess fluid actually seeps through the vessels and fills up any space it can find. When this happens in the lung it can lead to a shortness of breath (and eventually drowning, not nice).
The way to help alleviate all this water logging is to give huge doses of loop diuretics (very potent bad boys). In community I tend to see furosemide prescribed as 40 mg once a day. On the renal ward I was looking at doses of 250 - 500 mg. It harnesses whatever residual activity the kidney has to get rid of some of the excess water.
The best way to avoid these complication is to restrict your fluid intake. Some people are only allowed about 500 to 750ml of water a day. The sad thing is, they still feel thirsty but aren’t allowed to quench their thirst as much as they like. And hot weather is a nightmare because the sweating completely messes up their water requirements.
Basically, look after your kidneys kids.
*a prime example of procrastination.
