All UK Exam Boards included

Kidney failure

Download Topic

Kidney disease, whether acute or chronic, is usually a symptom of underlying causes including high blood pressure and diabetes. One of the endpoints of this disease is kidney failure where its function of clearing waste products from blood no longer takes place. The symptoms of this include fatigue, swelling, nausea, diarrhoea, less or more frequent urination, bone damage, muscle cramping, irregular heart beat and others, depending on severity and other factors.


The mechanisms of development of these symptoms are high levels of urea in the blood (nausea, weight loss, bloody urine), build-up of phosphates in the blood (itching, bone damage, muscle cramps), buildup of potassium in the blood (arrhythmia, paralysis), and failure to remove excess fluids (swelling, shortage of breath).



Addressing the underlying issues priming kidney disease, such as lifestyle factors like diet can revert kidney disease in its incipient stage. Once kidney function has ceased, kidney failure can be treated with dialysis or a kidney transplant.


Dialysis comes in two flavours: hemodialysis and peritoneal dialysis.



Hemodialysis requires a machine and is usually done out of home, a few times a week. The machine cleans the blood which is drawn out of the patient and then returned back through a tube connected between an artery and a vein. Hemodialysis requires a commitment to trips out at specific intervals to undergo dialysis, but is advantageous due to no participation required on the part of the patient during the procedure.


Peritoneal dialysis involves using the abdominal cavity as the site of filtering. The abdominal cavity has a membrane called the peritoneal membrane which acts as a filter between the fluid in the abdomen (around the intestines) and blood circulation. A tube is placed through the membrane, and a special fluid is delivered into the cavity by the patient at home. This is then collected back after around 30 minutes in a waste bag, and repeated a few time daily. Alternatively, it can be done at night on a special machine called a cycler which switches the fluid to renew it several times automatically while the patient sleeps.


This method requires extreme caution keeping the tube insertion site in the abdomen clean as to avoid infection. Both methods require a strict diet, water intake and certain vitamins, and both methods might not be available to all patients, depending on their specific health situation.


The membranes used in dialysis are semipermeable and allow the filtering of waste products and salts by diffusion across certain concentration gradients. This ensures that some contents like sugars and proteins remain the blood, while excess salts and urea are removed, simulating kidney function as closely as possible.



Kidney transplantation involves using a dead or live donor’s kidney to rescue kidney function of a patient on dialysis, or preemptively before they require dialysis. It is a 3-hour operation that attaches the new kidney to the patient’s blood supply, without removing the old kidneys (their removal has been shown to increase surgery outcome problems). Kidney transplants successfully increase lifespan, with better results seen the sooner it is performed relative to time on dialysis.


Donors are relatives, friends, altruistic strangers or sellers on the kidney market which is legal and supported in some parts of the world, such as Iran. Different locations have different approaches to kidney donation, with some prohibiting payment, and others openly encouraging donation through financial incentives. Successful donation chains have been established in some countries. They work by passing on incompatible kidneys from donors aimed at their relatives, onto strangers who are compatible with their kidney. In exchange, they get a compatible kidney from another stranger, and so on and so forth, creating a donation chain that addresses compatibility issues while encouraging kidney donation and extending the available organ pool.


Patients reach healthy kidney function following the transplant within a few days to weeks, and must adhere to a strict immunosuppressant drugs course indefinitely to maximise the success of their transplant.


Ok byeeeeee





Sorry! There are no posts.

Sorry! There are no posts.

Your Reviews

Thank you for making all the content btw!

Serena Kutty YouTube

I bookmarked the site 

translucent The Student Room

I got A* in A-level biology (Cambridge), thanks! I love your videos

Sherif Negm Facebook

You're such a G. Helped me so much, finally found someone who breaks biology down into something I can understand!!!

Alex Contact Form

Good topic notes and cool videos. I'll definitely recommend it to my students.

Seema Sehgal AQA Examiner and biology teacher on LinkedIn