Acute Kidney Injury
What is acute kidney injury?
Acute kidney injury is when the kidneys suddenly stop working. Normally, the kidneys filter the blood and remove waste and excess salt and water. The word “acute” means sudden.
Another term for acute kidney injury is “acute kidney failure.” or Acute renal failure.
What causes acute kidney injury?
Acute kidney injury can have different causes.
It can happen when:
- Less blood than usual flows to the kidneys. Different things can cause this to happen. For example, in a condition called heart failure, the heart might not be able to pump enough blood to the kidneys or sudden drop in blood pressure due to bleeding from the body, decreased water content of the body due to loss of water from the body. For example loose motions, vomiting, etc.
- The kidneys get damaged. Some causes of kidney damage are infections, cancer, certain medicines or toxins, and some autoimmune conditions. In an autoimmune condition, a person’s infection-fighting system attacks his or her body.
- Blockage in urine flow pathway. Some causes of blockages are prostate problems (in men) and cancer, stone formation, narrowing in a path called a stricture. The blockage of urine causes pressure on the kidney, which leads to damage.
So grossly causes of kidney injury are divided into 3 groups.
What are the symptoms of acute kidney injury?
Some people do not have any symptoms in the initial phase. Patients who are in the hospital might learn that they have acute kidney injury after they have blood tests for another reason.
When people do have symptoms, the symptoms can include:
- Drop-in the amount of urine they pass or no urine formation at all
- Reddish colored urine
- Swelling, especially over the legs and or face
- Vomiting, or loss of appetite
- Feeling weak, or getting tired easily
- Abnormal behavior or confusion
- Seizures – Seizures are waves of abnormal electrical activity in the brain. They can make people pass out, or move or behave strangely.
Acute Kidney injury classification (RIFLE and AKIN)
Is there a test for acute kidney injury?
Your doctor will ask about your symptoms and do an exam. To check how well your kidneys are working, he or she will do blood and urine tests. These normally include but not restricted to – Hemogram, Kidney function tests, Urine analysis, tests for autoimmune diseases if required.
Most people will have an imaging test called ultrasound to look for blockages in the urinary system. Imaging tests can create pictures of the inside of the body.
Your doctor might do other tests to look for other causes of your acute kidney injury. These can include X-rays or other imaging tests of your belly or kidneys.
If these tests don’t show what’s causing your acute kidney injury, your doctor might do a test called a biopsy. For a biopsy, the doctor will put a needle into your back and into your kidney. He or she will remove a tiny sample of tissue. This is examined under the microscope to find out the exact cause of kidney injury.
How is acute kidney injury treated?
Treatment depends on what’s causing your acute kidney injury and how severe kidney injury is.
If your acute kidney injury is caused by a medicine, your doctor will have you stop taking that medicine. Plus, to help your kidneys heal, he or she might also give you medicines called steroids. If your acute kidney injury has another cause that can be treated, your doctor will treat it. For example, doctors can treat infections with antibiotics, correct dehydration, stop bleeding from the body, relieve obstruction in the path of urine if present, etc.
Until your kidneys can work normally again, you might need treatments to help make sure your body has the right amount of fluid, salt, and nutrients.
Treatment of Acute Kidney Injury
- Medicines to reduce nausea and vomiting, to increase urine output(diuretics)
- Changes in your diet
- Renal replacement therapy – This treatment takes over the job of your kidneys until they can heal. It involves either:
- Hemodialysis – Hemodialysis is a procedure in which a machine takes over the job of the kidneys. The machine pumps blood out of the body, filters it, and returns it to the body People have hemodialysis at least three times a week.
- Peritoneal dialysis – Peritoneal dialysis is a procedure that people do at home every day. It involves piping a special fluid into the belly. This fluid collects waste and excess salt and water from the blood. Then the used fluid drains out of the belly.
Most of the time, a person’s kidneys will heal and work normally again. But it can take weeks to months for the kidneys to heal completely.
In some patients ( less than 15 to 20%) kidneys may not recover completely and some residual damage may persist or few may remain dialysis-dependent. This can happen especially in those patients who are having underlying kidney problems, long-standing diabetes mellitus or hypertension, severe drops in blood pressure for a long time, etc.
So in short AKI is a potentially recoverable condition if treated promptly and correctly. Even if the patient of AKI needs dialysis; there is a good chance for recovery and dialysis can be stopped once patient recovers.