Kidney disease – types, causes, symptoms, diagnosis, treatment and prevention

Kidneys are a pair of bean shaped organs placed below the ribs, one on each side of your spine. They are a vital part of the excretory system and perform the function filtering wastes from the blood. Each of the kidneys is made up of millions of tiny filtering units called nephrons that remove wastes from the blood under the influence of high pressure. Together the kidneys filter about 120-150 quarts of blood every day and the wastes along with fluid flow to the urinary bladder where it is stored for a while before getting expelled from the body.

Anything that interferes with the function of kidneys, reduce their filtration capacity or make them unable to carry out their function properly can cause kidney disease.

Types of kidney disease

Kidney disease is broadly classifies as:

Acute kidney disease or acute kidney failure (AKF): It occurs when the kidney function is reduced greatly or lost abruptly. After treatment of the underlying cause of reduced kidney function, they recover and can be even be fully functional as before.

Chronic kidney disease (CKD): It is an age related gradual loss of kidney function and is often symptomless in the initial stages. A person is said to have CKD when the kidneys are damaged for a period of 3 months or more. Because loss of kidney function is gradual in CKD, there are different stages of CKD.

Mild CKD: It occurs when the kidneys are damaged and cause slight decrease in GFR i.e., between 60 and 89 mL/min/1.73m²
Moderate CKD occurs when the GFR decreases further and may lie anywhere between 30 and 59 mL/min/1.73m².
In severe CKD, the filtration rate is reduced to 15-29 mL/min/1.73m².
Finally, when the GFR reduces below 15 mL/min/1.73m², the stage of kidney failure is reached, where the patient needs dialysis for carrying out the filtration function.

‘CKD is not life threatening in the conventional sense like a heart attack or respiratory arrest. However, presence of CKD even in early stages, with even small decrease in glomerular filtration Rate (GFR) can increase the risk of death or hospitalisation. The likelihood of developing heart disease or getting hospitalised increases with decreasing GFR and it is particularly higher once a person needs dialysis,’ says Dr Avinash Ignatius, senior consultant nephrologist.

‘Normal GFR is more than 90ml/min/1.73m2. Those with GFR between 89-60 ml/min are considered to have decreasing GFR but not labelled as CKD unless they have other associated abnormalities on urine examination like protein leakage or abnormal ultrasound examination. If the GFR is less than 60ml/min/1.73m2 on two occasions 3 months apart, even in the absence of any other abnormalities CKD can be diagnosed,’ he explains.

What causes kidney disease?

The cause of kidney disease depends on the type of kidney disease:

Causes of acute kidney disease or AKF include

Renal ischemia: Reduced blood flow to kidneys due to blocked blood vessel.
Drug induced kidney disease: Certain drugs can cause inflammation of the kidney
External Injury: Direct injury to the kidneys can damage the nephrons, thereby reducing kidney function
Medical conditions: In some medical conditions or diseases like malaria can result in acute kidney failure
Obstruction of urine flow: Conditions like enlarged prostrate can obstruct the flow of urine, causing the wastes to accumulate in the kidneys, reducing their function.

Causes of chronic kidney disease (CKD)

Chronic diseases: CKD is mainly a secondary disease developed due to an underlying primary condition, and according to statistics, chronic diseases like diabetes, high blood pressure, heart disease are the main causes of CKD.
Genetic factors: Certain genetic factors can cause kidney disease early in like. Polycystic kidney disease is a disorder in which several cysts arise in the kidneys. As the cysts grow, the kidney function reduces gradually and can also lead to kidney failure.
Immunological diseases: Some conditions such as lupus that affect the immune system can trigger loss of kidney function
Congenital factors: Structural and functional abnormalities can even develop in the fetus, causing kidney disease in the baby
Recurring infections: Recurring kidney infections (pyleonephrtits) and urinary tract infections can also lead to kidney disease.

Here are 11 classic risk factors of kidney disease you should know

Symptoms of kidney disease

Symptoms in acute kidney disease develop soon but in CKD the symptoms may not be seen until the kidney function is reduced to a great extent.

Here are some common symptoms of AKF

Reduced urine output
Fatigue
Nausea
Swelling in the feet

‘One of the earliest symptoms of CKD is frequent urination at night; although innocuous it should not be ignored. Most other symptoms of CKD develop only in late stages, only after 80% of function has been lost,’ says Dr Avinash. Here are some symptoms of CKD he points out:

Tiredness
Poor sleep
Poor appetite
Unexplained itchiness
Swelling of feet
Puffiness of face and eyes
Shortness of breath

Read in detail about 12 symptoms of kidney disease you shouldn’t ignore

Diagnosis of kidney disease

Generally, with acute kidney disease you’ll develop symptoms based on which the doctor will recommend tests for assessing your kidney function. In chronic kidney disease, the symptoms are not seen in the early stages but the same tests if taken early can help diagnose kidney disease.

‘It is difficult to identify gradual loss of kidney function without regular testing, as this very rarely produces any symptoms even after 80% of kidney function is lost. The only way to detect kidney disease early is by regular testing of urine, serum creatinine and calculating the eGFR (estimated GFR). Many standard labs do report your eGFR along with the creatinine. If not, this can be easily calculated online using MDRD or CKD-EPI formula. Any eGFR of less than 60ml/min/1.73m2 or /and any abnormality in the urine, should be further evaluated by a nephrologist,’ says Dr Avinash.

When you go for an annual screening of your kidney function, you will have to undergo some or all of the following tests:

1. Blood tests: Several markers in the blood can help identify the actual kidney function. Urea and creatinine are the gold standards to detect kidney disease.

2. Urine tests: The ratio of values for blood and urine marker can give the actual rate of clearance of kidneys.

3. Estimated GFR: eGFR is the estimate of filtration rate of the kidneys based on a formula that include serum creatinine values along with correction factors like age, gender and race.

4. Imaging tests: Imaging test like renal ultrasound uses ultrasonic waves to analyse the size and shape of the kidneys to identify renal injury and changes in filtration capacity of the kidneys.

Here are 8 tests for checking if your kidneys are functioning fine

Treatment of kidney disease:

Treatment for acute kidney disease:

Acute kidney failure is an emergency that requires hospitalization. The goal of the treatment is to prevent further complications. So you may need medicines to control blood pressure, reduce fluid buildup and restore calcium in the body. Sometimes, dialysis may also be needed.

Treatment for chronic kidney disease:

Medicines: ‘Chronic kidney disease by definition is a gradual irreversible loss of kidney function. However, a proper diet, certain medicines like angiotensin converting enzyme inhibitors (ACEi) and Angiotensin Receptor Blockers (ARBs) can significantly slow down the progression of kidney disease when under proper guidance and monitoring. A number of medications are available to control the other metabolic conditions caused due to CKD such as anemia, acidosis and bone disease, which are associated with CKD,’ says Dr Avinash. ‘It is also important to avoid self medication, even with over-the-counter medicines whether allopathic or herbal, as they may worsen kidney function,’ he says.
Dialysis: Once the kidney function reduces to between 7 – 15 ml/min/1.73m², depending on symptoms and other lab parameters, dialysis may be needed and transplant may have to be considered.

Prevention of kidney disease:

Factors like age, ethnicity or external injury to the kidneys cannot be controlled. But you can prevent other major risk factors leading to kidney disease. Also, minimizing stress on the kidneys right from the beginning can reduce your risk of developing CKD later in life. Dr Salil Jain, senior consultant, Nephrology and Renal Transplant, FMRI, offers some tips to prevent kidney disease:

People who have high BP should control it at the target set by their health care provider. This can delay or prevent kidney failure
If you have diabetes make sure you control your sugar levels with proper diet and regular exercise
Avoid excessive salt intake

Here are some expert tips to prevent kidney disease

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Published : May 15, 2014 4:31 pm | Updated:July 28, 2014 10:38 am

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