Acute kidney disease or acute renal failure is a condition which occurs when the kidneys stop functioning.
The main function of the kidneys is to filter waste products from the blood, and remove extra fluid, thereby forming urine which flows to the bladder and is removed.
The kidneys are essential to maintain the required levels of sodium, calcium and especially potassium in the blood. If this function is disturbed, the chemical balance of the body is affected, and waste may get accumulated back in the blood, reaching dangerous proportions.
Acute kidney failure can develop rapidly and become fatal sometimes. It is common in patients who are already hospitalised for serious conditions like
- cardiac surgery
- due to complications from diabetes,
- in people with existing chronic kidney disease, and
- in people who require intensive care.
Symptoms
Some commonly seen symptoms of acute renal failure are:
- Generalised swelling, including in the legs, due to fluid retention.
- Reduced urine output.
- A metallic taste.
- Difficulty in breathing due to fluid build-up in the lungs.
- Presence of blood in stool
- Chest pain due to excess potassium causing irregular heartbeats.
- Confusion, feeling of nausea, tiredness.
Sometimes, there are no signs of acute renal failure and diagnosis is made after seeing the results of lab tests that were done for other reasons.
Causes
The reasons for acute kidney failure can be broadly classified into three kinds.
Pre-renal conditions that reduce blood flow to the kidneys as in these situations:
- Blood or fluid loss due to trauma
- Blood pressure medicines
- Heart attack
- Severe infection, burns or allergic reaction
- Liver disease
- Long term use of NSAIDs (non-steroidal anti-inflammatory drugs)
Kidney damage occurring due to the following reasons:
- Blood clots in the vessels around the kidneys
- Cholesterol deposits that block blood flow to the kidneys.
- Acute nephritis – a rapidly progressing, acute inflammation of tiny filters in the kidneys called glomeruli.
- Viral infections like COVID-19 and certain auto-immune diseases.
- Drugs used for chemotherapy and ingestion of toxins like heavy metals.
- Toxins released due to muscle tissue injury.
- Toxins released due to breakdown of cancerous cells.
Post-renal causes– which arise because of obstruction to urinary output:
- Cancer of urinary bladder, colon or prostate gland.
- Kidney stones
- Damage to the nerves that control the urinary bladder.
Diagnosis
The urine output for 24 hours is first observed to see if the function is impaired.
The following blood tests indicate kidney dysfunction:
- Glomerular Filtration Rate (GFR) tests are done at regular intervals to determine kidney function. The lower the GFR level, the more advanced is the kidney damage.
- A Blood Urea Nitrogen (BUN) test determines the levels of urea, a waste product that the kidney filters and eliminates through urine.
- Serum sodium and potassium levels must be monitored.
- The serum creatinine test is done to determine the levels of creatinine, another waste product in blood.
Urine analysis tests are also done to know creatinine clearance.
An ultrasound can be used to diagnose acute kidney failure.
X-ray, CT scans, and MRIs of the abdomen region can determine if there is any blockage in the urinary tract.
Treatment
The main treatment objectives are to identify the underlying cause for the acute kidney failure.
Next, the resulting complications have to be managed,
- First the fluid imbalance is corrected. If there is excess swelling, diuretics are given to increase urine output.
- On the other hand, if there is dehydration, intravenous fluids are given.
- Electrolytes in the blood must be balanced, especially any excess potassium is removed by administering insulin, calcium or other medication.
- Antibiotics are prescribed to treat any infection.
- Blood transfusion is carried out in case of severe blood loss.
- Corticosteroids are given to limit the effects of auto-immune disorders.
Diet
The diet must essentially have high amounts of carbohydrates and low amounts of salt, potassium and proteins. The consumption of liquids is strictly controlled.
Dialysis
If medication does not bring down the toxins accumulated in the blood and if potassium remains at a high level, temporary dialysis is required. Dialysis is a procedure where a machine performs the function of a damaged kidney.
There are a couple of ways to perform this. In haemodialysis, blood is pumped out of the body and passes through a machine (dialyser) that functions of the kidneys and filters the toxins and excess fluids out. The purified blood is then infused back into the body.
In peritoneal dialysis, a cleaning fluid is passed into the abdominal space through a catheter. Filtration is done using the linings of the abdomen. The fluid with the accumulated toxins then passes out of the body through the catheter.
Acute kidney disease could be fatal without intensive treatment. Timely and appropriate management will prevent it from progressing into chronic kidney disease, which has its own complications.
In an otherwise healthy patient, acute kidney disease can usually be reversed to a nearly normal kidney function.
