Your kidneys perform various crucial roles in your overall health. One of its most crucial functions is to filter waste items from the blood and excrete them via urine. The kidneys also have other important functions including regulating water, salt and minerals in the body to ensure they are in equilibrium. It also plays a significant role in maintaining the blood pressure, activating vitamin D and aid in stimulating the production of red blood cells through complex hormonal pathways.
The Difference Between Chronic Kidney Disease and Kidney Failure
“Chronic kidney disease” refers to an abnormality in the kidney function. This is detected by a blood or urine test or detected from scanning the kidneys. These tests will be repeated to confirm the condition and to ensure that we can track the changes of the kidney function over time. The are many causes of chronic kidney disease and the most common causes are diabetes mellitus and hypertension. Other causes would be inherited diseases (Fabry’s disease, polycystic kidney disease), kidney inflammation (glomerulonephritis), and cancer (myeloma).
Chronic kidney disease can be categorised to mild, moderate, severe and end-stage. Over time, the kidney function may deteriorate, especially if the person does not seek early treatment. This deterioration can range from months to years or even in decades.
If the damage is severe enough, your kidneys may cease to function. This condition is referred to as kidney failure or end-stage renal disease (ESRD). If your kidneys fail, the only treatment available to maintain life is dialysis or a kidney transplant.
What are the first signs and symptoms of Chronic Kidney Disease?
In the early stages of chronic kidney disease, there are typically very few symptoms. You should look out for foamy or bubbling in your urine, change in colour of your urine (turning red or dark brown in colour), if you pass small amounts of urine or notice you are urinating less frequently. More than 80-90% of the time, you would not have symptoms. Therefore, chronic kidney disease is detected during health screening tests which would include a blood or urine test. Your doctor would routinely repeat these tests, and will refer you for a review with a kidney specialist.
However, if your kidneys have severe failure, you may notice one or more of the following symptoms:
- swelling in ankles, feet, or hands.
- shortness of breath
- lack in appetite
- changes in urine (colour, blood, bubbly urine, reduced frequency or volume).
What are the 5 stages of kidney failure?
Chronic kidney disease (CKD) is classified into five stages, ranging from very mild damage in stage 1 to kidney failure in stage 5. The stages determine the estimate function of your kidneys and it’s ability to carry out it’s role in filtering waste products, maintaining water and salt balance, and normal blood pressure, blood count and vitamin D levels.
The estimated glomerular filtration rate (eGFR) is derived from your blood test for creatinine, your age and gender.
Chronic kidney disease stage 1 (CKD)
- eGFR 90 or more
- Kidney damage with normal eGFR
While this typically indicates that the kidneys are healthy and functioning normally, there are other indicators of kidney impairment, such as protein in the urine or structural damage to the kidneys (e.g. scarring in kidneys, kidney cysts, kidney stones, single kidney).
Chronic kidney disease stage 2 (CKD)
- eGFR between 60 and 89
- Kidney damage with mild decrease in eGFR
Stage 2 generally indicates that the kidneys have lower functioning status but will not cause any significant symptoms.
Chronic kidney disease stage 3 (CKD)
- eGFR of 30 and 59 is further divided into two stages.
- Stage 3a is defined as an eGFR of 45 to 59.
- Stage 3b is defined as an eGFR of 30 to 44.
- Moderate decrease in kidney function
While symptoms may not be apparent at this stage, you may experience changes in urination (reduced frequency, volume, changes in colour of urine, bubbling in urine) or swelling in the hands and feet, or back pain.
Complications of the disease such as high blood pressure, low blood count and bone disease causing pain are possible.
Chronic kidney disease stage 4 (CKD)
- eGFR between 15 and 29
- Severely decreased kidney function.
This is a critical stage: the final stage before renal failure.
Stage 4 symptoms and health concerns are the same as stage 3.
Patients with stage 4 renal disease should contact a nephrologist (kidney specialist) to plan for kidney failure, which may require dialysis or a kidney transplant.
Chronic kidney disease stage 5 (CKD)
- eGFR 15
- Kidneys are nearing or have failed.
- When the kidneys fail, waste accumulates in the blood, making patients extremely ill.
Itching, muscular cramps, nausea and vomiting, loss of appetite, swelling in the hands and feet, back discomfort, urinating less than average, difficulty breathing, and difficulty sleeping are just a few of the symptoms of kidney failure.
Patients with renal failure should be prepared to initiate dialysis or receive a kidney transplant to survive. However, certain patients may choose to only take medications to control the symptoms of kidney failure.
Types of kidney function tests and procedures
Renal abnormalities may not be recognised until specific tests to assess kidney function are performed. Here's everything you need to know about typical kidney function tests.
Creatinine is a waste product made by your muscles and removed by the kidneys. It‘s level indicates the kidneys' ability to remove this product from the body. When your kidneys are not working well, creatinine will not be clearly properly leading to an abnormally high level.
Estimate GFR (Glomerular Filtration Rate)
The estimated glomerular filtration rate, or eGFR, is a more accurate test in determining your current level of kidney function. It is a formula which takes into the account of your age, gender, ethnicity and serum creatinine. This formula has been validated in our Singapore population and can be used to estimate the status of your kidney function. The value will indicate the amount of blood that is being filtered by the kidney every minute.
A urinalysis is another frequently used test for determining potential problems with your kidneys. A urine sample is analysed and provides many information of the current state of your kidneys. The most important results for the urine sample are presence of red blood cells, white blood cells and urine albumin.
If albumin is detected in the urine, this may suggest that the kidneys have been damaged. This disorder is due to the kidney cells leaking albumin into the urine instead of conserving it. If there is presence of red cells or white cells in the urine, it could indicate that you have a urinary tract infection, kidney inflammation (glomerulonephritis), kidney stones or tumour.
Nitrogen Urea Blood
The blood urea nitrogen level (BUN) determines the amount of urea nitrogen in the blood. The blood urea nitrogen level is determined as part of regular blood work and is included in a metabolic panel. When this level is elevated, it likely indicates a kidney excretion problem.
A physician will interpret the results of routine kidney function testing. If the results are abnormal, they may order further specialised testing, including the following:
An ultrasonography of the kidneys
Ultrasounds use sound waves to create images of body parts. With a renal ultrasound, health care experts can determine whether the kidneys are blocked or scarred and whether there are any stones or cysts. It can also determine the blood flow supply fo the kidneys.
A CT scan of the kidneys
A CT scan is an imaging technology that doctors can use to check for blockages in the urinary tract, kidney stones, kidney tumours including benign tumour and cancerous tumours.
A biopsy of the kidney
This is a minimally invasive procedure, where kidney tissues are taking via a biopsy needle with the aid of ultrasound machine. The kidney samples will then be analysed under a microscope. This will provide important information about the underlying kidney condition, the severity of damage and other aid in the treatment of the condition.
Chronic kidney disease is often silent until you lose 90% of the kidney function. It is advisable to undergo screening test as early as 30 years of age, especially if you have certain risk factors (e.g. suffer from diabetes, high blood pressure or have a family history of kidney disease). Once the kidney damage has occurred, it is not reversible. However, this condition can be treated with the aim to slow or halt the progression of the disease to end-stage kidney failure.