What do kidneys do? - The kidneys are a pair of bean-shaped organs at the back of the body. Each kidney is attached to the bladder, which is a distensible bag that collects urine. The kidneys make the urine, flowing downwards through two tubes called the ureters, and collects in the bladder. Normal kidney function keep in balance many things in the body by altering the composition of urine they produce.

The functions of the kidneys include:

• Control the amount of salt and water in the body
• Get rid of waste products of the body in the urine
• Enable the body to form adequate red blood cells by producing a hormone called erythropoietin
• Regulate and maintain the health of bones by making an active form of vitamin D and maintaining the balance of calcium and phosphate in the body
• Control the acid level in the body as well as many other minerals and salts of the body

What is it? - Chronic kidney disease (CKD) is a condition when the kidneys stop working as well as they should. The kidneys are critical for survival; without them, patients develop multiple problems. These may range from excessive water retention, breathlessness, sleeplessness, poor appetite, and high blood pressure. In chronic kidney disease, the kidneys slowly lose their functions, and in time, the kidney can stop working altogether.

​The kidneys have a large reserve, and a large amount of kidney must be damaged before a person develops symptoms of chronic kidney disease. For this reason, a patient may have significant kidney damage but still feel perfectly well and see a doctor only very late in the course of his condition. A patient with mild chronic kidney failure may not have any symptoms initially and may feel totally well. However, as the kidney disease progresses, symptoms become more apparent. Patients may develop:

• High blood pressure
• Swelling of the legs (called oedema)
• Breathlessness
• General symptoms of poor sleep, loss of appetite and lethargy
• A bad smell in the breath called a uraemic fetor
• Cramps
• Numbness of the feet
• Passing a lot of urine, especially at night (called nocturia), or conversely too little urine.
• Chronic generalised itch
• Blood in the urine, which usually reflects the underlying kidney disease
• Soapy urine or frothy urine, which may reflect the presence of protein in the urine

Not every patient develop all these symptoms. Some may develop these symptoms at different stages of their disease. Also, it is important to realise that these symptoms do not necessarily only mean that one has kidney disease. Each disease affects each patient differently and to a different extent.

​There are many causes of kidney disease. These affect the kidney to different degrees, causing them to fail at different rates. Some of these are inherited, while others are related to existing conditions such as diabetes, other inflammatory diseases or infections. A list of common causes of kidney failure are as follows:

 A) Diabetic nephropathy

Diabetic nephropathy is kidney failure resulting from long-standing and poorly controlled diabetes. It is now the most important cause of end-stage kidney disease in Singapore and elsewhere in the world. Patients with diabetes mellitus commonly have many other associated problems such as heart attacks, strokes, eye disease, gangrene, numbness of the feet, and rapid swings in blood pressure from a lying to a standing position. They are also prone to infections of the abdomen, skin, ears, and feet.

B) Chronic glomerulonephritis

Chronic glomerulonephritis refers to a group of different kidney diseases that initially affect a specific microscopic structure of the kidney called the glomerulus. The most common form is called Ig A (pronounced as I G A) nephropathy. This kidney disease can take 3 to 40 years before reaching end-stage kidney disease. There are many other forms of glomerulonephritis, such as focal and segmental glomerulosclerosis, membranous glomerulopathy, membranoproliferative glomerulonephritis, to name a few.

C) Polycystic kidney disease

This is a form of inherited kidney disease associated with the development of multiple sacs of fluid (cysts) within the substance of the kidney. These patients tend to develop hypertension, kidney stones, and recurrent urine infection or infections of the cysts of the kidney. They can have other associated problems, the most serious of which is a rupture of the brain's blood vessels (called a leaking berry aneurysm), which can bring on a sudden and severe headache.

 D) Lupus Nephritis

Systemic lupus erythematosus (SLE) is an autoimmune condition that can affect various parts of the body. Patients with SLE commonly develop kidney disease, namely lupus nephritis. The patterns of kidney disease vary widely, and their responses to therapy vary. Patients with SLE usually suffer from many other manifestations, including hair loss, joint pain of the hands, wrists and knees, facial rash, mouth ulcers, and gut, lungs, and blood involvement.

 E) Reflux nephropathy

This is another inherited disease characterised by recurrent urine infection in childhood associated with a backwash of urine from the bladder upwards into the kidney during urination. This leads to kidney scarring, loss of kidney tissue and kidney failure.

​Kidney disease can be silent in the early stages and the patient may be perfectly well without any symptoms. However, patients usually need urine and blood tests to detect renal disease apart from a physical check-up.

The urine is usually tested for:

• the presence of blood, a condition known as haematuria.
• the presence of protein or proteinuria
• cellular debris (also called casts)
  
  The blood is also tested for abnormally high levels of substances that accumulate in the body in the presence of kidney failure. They include:

• the blood urea level
• the blood creatinine level
• other substances such as potassium and bicarbonate
  
  The initial screening tests can be done at a clinic with a sample of freshly collected urine. The urine is tested using a urine test strip. The urine test strip is a strip adhered to several chemicals pads that change their colour when there are abnormal amounts of blood, protein, or sugar in the urine. In the presence of abnormal urine test strip testing, patients may need to collect their urine for 24 hours. This will allow the attending doctor to better assess the urine to confirm or exclude any urinary abnormality. Some patients may eventually need a kidney biopsy to distinguish the type of kidney disease and evaluate the eventual kidney prognosis. A kidney biopsy is a minor surgical procedure in which a needle is inserted into the kidney (with local anaesthesia), and a piece of the kidney is taken for microscopic examination.
  
  It is important to realise that the presence of a single abnormal lab result does not necessarily equate to the presence of renal disease. An abnormal laboratory result implies that the patient needs to see a doctor. The doctor may consider either a repeat test or more extensive testing for the patient. While many people can benefit from having these tests done, certain patients at higher risk of kidney disease should have regular renal function tests. These groups include patients with:

• High blood pressure
• Diabetes mellitus
• Gout
• History of haematuria (blood in the urine)
• Recurrent urine infections
• History of protein in the urine
• Family history of kidney disease

​Once chronic kidney disease is advanced, it usually will progress to end-stage kidney failure. Nevertheless, some common treatments can benefit most patients with established kidney disease.

 General Measures:

• Restrict salt intake and lose weight if you are overweight
• Keeping blood sugar in a healthy range if you have diabetes
• Quit smoking, if you smoke
• Avoid medicines known as "nonsteroidal anti-inflammatory drugs" or NSAIDs.
  
• Treat hypertension (high blood pressure)
  It is important to treat high blood pressure. Regular clinic visits or home blood pressure monitoring gives the doctor the needed information to adjust blood pressure medications to suit the patients' needs and achieve appropriate blood pressure levels. Apart from reducing the progression of kidney disease, blood pressure control has the significant added advantage of reducing the risk of heart attacks and strokes. 

• Anti-proteinuric therapy
  Some kidney diseases are associated with protein loss in the urine. Certain medications can decrease/lower the amount of protein excreted in the urine. This group of drugs (called angiotensin-converting enzyme inhibitors or angiotensin receptor blockers) needs to be prescribed by a doctor. These drugs are usually prescribed more commonly in the early stage of chronic kidney disease. While on this treatment, the patient will need to have regular checks of the kidney function. This group of medications can effectively reduce the progression of chronic kidney disease. Not all patients are suitable for this form of treatment, nor do all patients tolerate this medication equally well. They can be associated with intolerable cough, and like any medications, may cause some patients to develop an allergic rash.
  

What happens when the kidneys stop working (end-stage kidney disease)

Chronic kidney disease can progressively worsen over time. Some patients will eventually need to consider starting dialysis or getting a kidney transplant . Planning for dialysis in advance is an important component of treatment for patients with CKD. There are two types of dialysis: haemodialysis and peritoneal dialysis. Some patients may choose not to start dialysis when it is unlikely to extend their life or improve quality of life.