Kidney Disorders and Support Systems
Think of your kidneys as the body's master filtration plant. Every drop of your blood passes through them about 300 times a day. They sort out what to keep — water, salts, nutrients — and what to throw away: urea, creatinine, excess acids, and other metabolic waste. When this filtration system breaks down, waste builds up in the blood. That is the core problem behind every kidney disorder.
Uraemia — When the Filter Clogs
Uraemia literally means "urine in the blood." It is the condition that results when the kidneys fail to remove nitrogenous wastes (mainly urea) from the blood. Normally, urea is filtered out and excreted in urine. When filtration stops, urea accumulates.
Symptoms include nausea, vomiting, fatigue, confusion, and eventually coma. The skin may develop a characteristic "uremic frost" — white crystals of urea deposited on the skin as the body tries to sweat out what the kidneys cannot remove. Uraemia is not a disease itself; it is the consequence of kidney failure.
Uraemia is a medical emergency. Without intervention, it is fatal. The only treatments are dialysis or a kidney transplant.
Renal Failure — Acute vs Chronic
Renal failure means the kidneys have lost their ability to filter blood adequately. It comes in two forms:
Acute renal failure happens suddenly — from a severe infection, a drug overdose, a blocked urinary tract, or a sudden drop in blood flow to the kidneys. It is often reversible if the underlying cause is treated quickly.
Chronic renal failure develops slowly over months or years, usually from long-standing conditions like diabetes, high blood pressure, or glomerulonephritis (inflammation of the kidney's filtering units). Damage is progressive and irreversible. The patient moves through stages: from mild loss of function (stage 1) to end-stage renal disease (stage 5), where the kidneys are working at less than 15% of normal capacity.
Chronic renal failure is silent in early stages. By the time symptoms appear — swelling, fatigue, itching, loss of appetite — significant damage has already occurred.
Renal Calculi — Stones in the Plumbing
Renal calculi are kidney stones — hard deposits of minerals and salts that form inside the kidneys. Most are made of calcium oxalate, but uric acid, struvite, and cystine stones also occur.
Stones form when urine becomes too concentrated in certain substances, allowing crystals to clump together. Dehydration, a diet high in oxalate (spinach, nuts, chocolate), and certain metabolic disorders increase the risk.
A small stone may pass unnoticed. A larger one can lodge in the ureter, causing excruciating pain (renal colic) that radiates from the flank to the groin. Blood in the urine, nausea, and frequent painful urination are common.
Treatment depends on size: small stones pass with hydration and pain relief; larger ones may need lithotripsy (shock waves to break them up) or surgical removal.
Dialysis — The Artificial Kidney
When kidneys fail, dialysis takes over their job. There are two main types:
Haemodialysis — Blood is pumped out of the body through a tube, passed through a dialyser (a machine with a semipermeable membrane), cleaned, and returned. The dialyser acts like an artificial kidney: waste products diffuse from the blood into a dialysis fluid (dialysate) that has the correct concentration of electrolytes. This is done 3–4 times a week, each session lasting 3–5 hours.
Peritoneal dialysis — A catheter is placed into the abdominal cavity. Dialysis fluid is introduced, and the peritoneum (the membrane lining the abdomen) acts as the filter. Waste diffuses from blood vessels in the peritoneum into the fluid, which is then drained out. This can be done at home, often overnight.
Dialysis principle: Diffusion of waste down a concentration gradient across a semipermeable membrane. Blood has high waste concentration; dialysate has zero waste. Waste moves from blood → dialysate.
Dialysis is life-saving but not a cure. It replaces filtration but not the kidney's other functions — hormone production (erythropoietin for red blood cells, calcitriol for bone health) and precise electrolyte balance. Patients on dialysis often develop anaemia and bone disease.
Kidney Transplantation — The Permanent Fix
A kidney transplant is the surgical placement of a healthy kidney from a donor into a patient with end-stage renal disease. The donor can be a living person (usually a relative) or a deceased donor. …