How Dangerous is Acute Kidney Injury? by Dr. Rahul Patibandla

• Inputs by Dr. Rahul Patibandla, Nephrologist, NephroPlus Dialysis center at Citizens Hospital, Hyderabad

Acute kidney injury (AKI) is an abrupt onset and rapid deterioration of kidney function within a few hours or days. It is a dangerous condition that leads to the accumulation of water, electrolytes and metabolic waste in the body. Declining kidney function can affect every organ but especially the heart and hence needs immediate treatment. How badly the kidneys are affected is determined by the accumulation of creatinine (a waste product) in the blood and decrease in daily urine production, both of which are removed from the body by well-functioning kidneys.

What Causes AKI?

The name of the condition can be misleading as there is no physical injury involved. The causes of AKI are classified depending on the location of injury as pre-renal (injury at the level before the kidney), intrinsic (injury directly of the kidney), and post-renal (injury at the level beyond the kidney- obstructive causes).

Some of the common causes are listed below:

A) Pre-renal

1) Loss of fluid or blood volume: Excessive vomiting or diarrhea (dehydration), burns, sepsis (infection), bleeding, etc can decrease the volume to a dangerous level and lead to the decreased blood supply to the kidneys.

2) Congestive Heart Failure: When the heart’s pumping mechanism fails, less blood reaches the kidney, leading to its injury.

B) Intrinsic

Glomerulonephritis: Injury to the glomerulus (microscopic portion of kidney, which functions as a filter) and kidney blood vessels due to drugs like acyclovir (anti-viral), NSAIDS like ibuprofen, vancomycin (anti-bacterial), contrast dye (used in procedures)

C) Post-renal

       1) Enlarged prostate, which is a common condition seen in elderly males.

       2) Bladder or Cervical cancer 

       3) Kidney stones

       4) Urethral stricture is a condition in which the tube carrying urine from the bladder is narrowed. So, urine flow is weak and it collects within the bladder creating back pressure on the kidneys.

All the post-renal causes block the metabolic waste leaving the kidney. This leads to the accumulation of the metabolic waste products and ultimately creates reverse pressure on the kidneys causing injury.

What are the Symptoms of AKI?

1) Decreased urination: As the kidneys are injured, they cannot create a normal amount of urine and thus you will ‘pee’ less than usual.

2) Tiredness 

3) Swelling of feet: You will often notice that shoes are getting tighter.

4) Difficulty breathing or feeling of pressure on the chest.

5) The confused state of mind

Acute kidney injury usually occurs in the background of the grave or chronic illness. The at-risk patients are those who are admitted to the hospital, undergoing procedures, suffering from chronic heart, liver or kidney diseases, elderly and patients on nephrotoxic drugs. These patients should always be aware of the symptoms and get their kidney function tests done regularly. 

What are the Tests done to Diagnose AKI?

Creatinine is a muscle waste product which is removed from the body by kidneys. If its level rises in the blood, it indicates that the kidney is injured and unable to eliminate creatinine from the body. So, the first test done to diagnose and determine the degree of acute kidney injury is to find out the serum creatinine levels. 

What is the Treatment of AKI?

1) Urgent admission to emergency care

2) Treating reversible causes such as dehydration, fluid loss, blood loss, and obstruction. Volume assessment should be done carefully and then Renal Replacement Therapy (RRT) with iv fluids should be started. X-rays, Ultrasound, MRI and CT can be done to diagnose obstruction and hydronephrosis (kidney enlargement). Surgery can be done to remove the obstruction

3) Dialysis in-case of poisoning 

4) Increased potassium levels should be corrected

5) Nephrotoxic drugs should be identified and stopped. These drugs should be replaced with alternative options but if eliminating the drug from the regime is not possible, then patients should be warned against overdosing and advised to increase fluid intake while on these drugs.

AKI is a fatal condition if left untreated. The symptoms of AKI can be subtle and go undiagnosed if the patient is not around healthcare professionals. Hence at-risk patients should be aware of the symptoms, use medications judiciously and follow an instructed diet if they have comorbid conditions that can cause acute kidney injury.