How Acute Renal Failure Is Treated

Treatment for acute renal failure (ARF) may involve vasopressor drugs to help raise the blood pressure, intravenous fluids to aid in rehydration, diuretics to increase urine output, and hemodialysis to help filter the blood while the kidneys are healing.

The course of treatment is directed by the underlying cause, which is broadly classified into one of three groups:

  • Prerenal ARF, in which the blood flow to the kidneys is impeded.
  • Intrinsic ARF, in which the kidneys themselves are impaired.
  • Postrenal ARF, in which the flow of urine out of the body is obstructed.

Prerenal ARF Treatment

For prerenal ARF to occur, both kidneys would need to be affected. There are several common reasons for this, including dehydration (low blood volume), low blood pressure, congestive heart failure, and liver cirrhosis. All of these conditions directly or indirectly reduce the volume of blood received by the kidneys and facilitate the progressive (and sometimes rapid) build-up of toxins in the body.

The aim of treatment would be to restore the blood flow. There are several ways a doctor might do this.

Dehydration and Low Blood Pressure

Dehydration may be treated with intravenous fluids. The infusion of fluids would be monitored with a central venous catheter (CVC) to ensure that you are neither overhydrated nor underhydrated. If your low blood pressure persists despite intravenous fluids, vasopressor drugs may be used to raise the blood pressure.

Norepinephrine is a common option. Injected into the blood, the hormone causes blood vessels to contract, increasing the relative pressure within the vein. Side effects include headache, slowed heart rate, and anxiety.

Congestive Heart Failure

Congestive heart failure (CHF) occurs when the heart is unable to pump sufficiently to maintain the blood flow needed by the body.  When this happens, it can lead to a state known as cardiorenal syndrome (CRS). CRS is actually a two-way street in which the lack of blood flow from the heart can affect kidney function, while the failure of the kidneys can lead to the impairment of the heart.

In the former state, diuretics are commonly used to increase the output of urine and aid in excretion of toxins from the body. Lasix (furosemide) in the most commonly prescribed diuretic but one that needs to be managed to prevent drug resistance.

In addition, the combined use of ACE inhibitors (commonly used to treat high blood pressure) and statin drugs (used to reduce cholesterol) may help normalize kidney function.

While it may seem counterintuitive to use a drug that would further reduce blood pressure, the aim of therapy is to normalize the equilibrium between the heart and kidneys. While there may, in fact, be a slight deterioration in kidney function over the short-term, the continued, combined use of an ACE inhibitor and statin will ultimately have a protective effect on the kidneys.

Commonly prescribed ACE inhibitors include Capoten (captopril), Lotensin (benazepril), and Vasotec (enalapril). Commonly prescribed statins include Crestor (rosuvastatin), Lipitor (atorvastatin), Pravachol (pravastatin), and Zocor (simvastatin).

Liver Cirrhosis

Cirrhosis is the state where the progressive scarring of the liver leads to liver damage. Cirrhosis can either be compensated, meaning the liver is still functioning, or decompensated, meaning that it is not.

ARF most commonly occurs in the latter context, resulting in another irrelated condition known as hepatorenal syndrome (HRS). A liver transplant is considered the only definitive form of treatment.

In the absence of a transplant, your doctor may recommend the other interim approaches. Among them:

  • Transjugular intrahepatic portosystemic shunt (TIPS) is a procedure in which an artificial channel is created in the liver using a wire mesh stent. This reduces the vascular pressure within the liver which, in turn, alleviates the burden on the kidneys.
  • Hemodialysis (popularly referred to as dialysis) involves the mechanical filtering of blood to effectively take over the function of the kidneys.
  • Liver dialysis is a newer form of mechanical detoxification still in its infancy that, unlike hemodialysis, cannot be used for an extended period of time.
  • Vasopressor drugs like midodrine, ornipressin, and terlipressin may help normalize vascular pressure in people with HRS but may also adversely restrict the blood flow to the heart and other organs. The combined use of the vasopressor midodrine and the hormone Sandostatin (octreotide) may increase survival times in persons awaiting a donor liver.

Intrinsic ARF Treatment

There are myriad reasons why a kidney may not function as normal, including trauma, infection, toxins, vascular diseases, cancer, autoimmune disorders, and even complications of surgery.

While the approach to treatment will vary by the cause, the outcome will typically result in one of three conditions: glomerulonephritis (GN), acute tubular necrosis (ATN), and acute interstitial nephritis (AIN).

Glomerulonephritis

Glomerulonephritis (GN) is the acute secondary inflammation of the kidneys that develops in response to a primary disease. The diseases may include chronic illnesses like diabetes, autoimmune ones like lupus, or even an infection like strep throat.

Medications such as ACE inhibitors, nonsteroidal anti-inflammatory drugs (NSAIDs), and penicillin can trigger GN in people with an underlying kidney dysfunction.

Treatment depends on the underlying cause and may include:

  • Termination of the suspected drug if the cause is believed to be drug-related.
  • Corticosteroids, a man-made hormone that can suppress the overall immune response and alleviate inflammation.
  • Lasix to increase urine output taken with a calcium supplement to prevent excessive calcium loss.
  • Potassium-reducing drug like Kayexalate (sodium polystyrene sulfonate) to prevent hyperkalemia (high potassium) common with GN.
  • Plasmapheresis, a procedure in which your plasma (the fluid part of your blood) is removed and replaced with fluids or donated plasma that do not contain inflammatory proteins.
  • The restriction of protein, salt, and potassium from your diet, especially if the GN is chronic.

Acute Tubular Necrosis

Acute tubular necrosis (ATN) is a condition in which the tubules of the kidney begin to die from the lack of oxygen. Common causes include low blood pressure and nephrotoxic drugs (drugs toxic to the kidneys).

Many of the same approaches used for GN will be applied here, including:

  • Termination of suspected nephrotoxic drug
  • Lasix
  • Vasopressor medications
  • Potassium-reducing drugs
  • Restriction of protein, salt, and potassium
  • Hemodialysis in severe cases

Acute Interstitial Nephritis

Acute interstitial nephritis (AIN) is the swelling of the tissue in between the kidney tubules, often caused by a drug allergy or autoimmune disease.

Over 100 medications are associated with allergy-triggered AIN. Of the autoimmune causes, lupus (a disease in which the immune system may attack its own kidney tissues) remains the prime suspect. Some infections can cause AIN, as well.

Treatment of AIN is primarily focused on the termination of the suspected drug and the restriction of potassium, salt, and protein during recovery. Corticosteroids appear to provide little relief but may be used if the termination of the drug is unable to restore normal kidney function.

Postrenal ARF Treatment

Postrenal ARF is caused by an obstruction of the urinary tract, which includes the kidneys, bladder, prostate, and urethra. Common causes include an enlarged prostatekidney stonesbladder stones, or cancer of the kidneysbladder, or prostate.

The aim of treatment would be to normalize the urine flow while the underlying cause of the impairment. Postrenal ARF requires immediate treatment to either remove or bypass the obstruction before any permanent damage to the kidneys can occur.

This may involve:

  • Extracorporeal shock wave lithotripsy (ESWL) which uses sound waves to break up kidney or bladder stones.
  • A urinary catheter or stent to reroute the urinary flow around the obstruction whatever the underlying cause.
  • Drainage of the kidneys using a type of catheter, known as percutaneous nephrostomy tube, which is inserted through the skin.

Most people will regain normal kidney function if the condition is promptly reversed. If left untreated, the excessive pressure exerted on the kidneys, as well as the build-up of waste, can lead to kidney damage, sometimes permanent.

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