5 Complications of Hemodialysis

Hemodialysis is a life-saving intervention when the kidneys are no longer functioning—but one that can cause significant side effects and complications. Many of the problems are related to the creation of dialysis access through which blood is removed from the body and cleaned in a dialysis machine. Other complications are caused by the imbalance of fluids and electrolytes in the body and the impact that has on blood pressure and heart function.

Preventing complications of hemodialysis requires careful management on the part of your nephrologist (kidney specialist), the dialysis team, and you as the patient. Knowing the causes and symptoms can ensure that treatment is delivered quickly if a complication occurs, further extending your life, health, and well-being.

Hemodialysis is the most common form of dialysis in the United States. It involves removing blood from an access point in a vein, then cleaning the blood of toxins and excess fluids before returning it to the body.

Hemodialysis is meant to replicate the function of the kidneys, but it is an inexact science. If the speed of the procedure is too aggressive, or the individual being treated doesn't adhere to the proper dietary or fluid restrictions, the homeostasis (balance) of the body chemistry can be thrown off, causing side effects and complications.

The creation of an artificial access point in the body also poses a risk in that the closed vascular system is now open. Infection is the most common concern but not the only one.

Here are just a few of the complications that a nephrologist will watch out for (and try to prevent) if you are on hemodialysis:

Hypotension is the medical term used to describe low blood pressure. This is a common occurrence during hemodialysis in which the dose and speed of the procedure can cause the too-rapid removal of fluids from the blood. By doing so, the internal pressure in the blood vessels will invariably drop, sometimes precipitously. This can cause symptoms such as:

• Abdominal discomfort
• Yawning or sighing
• Nausea
• Vomiting
• Muscle cramps
• Restlessness
• Anxiety
• Dizziness or fainting
• Clammy skin
• Blurred vision

Adhering to the recommended fluid restrictions can help. By limiting your fluid intake, the amount being extracted during dialysis will be decreased and any drop in blood pressure will be minimized.

Hemodialysis not only removes toxins and excess fluid from the body, but also many of the electrolytes that the body needs to function. In most cases, this won't pose a concern if you adhere to the proper diet.

However, if you have diabetes or take angiotensin-receptor blockers (ARBs), even adherence to the diet may not be enough to prevent a condition known as hypokalemia.

Hypokalemia is abnormally low potassium in the blood. Potassium is one of the most important electrolytes that the body uses to regulate fluid balance, muscle contractions, and nerve signals. When potassium levels drop excessively, it can affect all of these functions, causing:

• Fatigue
• Weakness
• Constipation
• Muscle cramping
• Heart palpitations

If hypokalemia is extreme—defined as levels below 2.5 millimoles per liter (mmol/l)—it can cause potentially serious complications including the breakdown of muscle tissue, ileus (lazy bowels), cardiac arrhythmia (irregular heart rate), respiratory failure, paralysis, and atrial or ventricular fibrillation.

Other electrolytes can be affected by hemodialysis and lead to conditions such as hypocalcemia (low calcium), hyponatremia (low sodium), and hypermagnesemia (high magnesium). Each is concerning and can affect the body in different ways:

• Hypocalcemia can cause weakness, calciphylaxis (calcium deposits in blood vessels and the skin), and life-threatening arrhythmia.
• Hyponatremia can cause fatigue, mental changes, and seizures. 
• Hypermagnesemia can impair nerve signals to the muscle, causing muscle weakness and the loss of reflexes.

The imbalance of electrolytes coupled with persistent hypotension can also contribute to the development of neuropathy (pins-and-needles sensations), a condition common in people on dialysis.

The regular monitoring of blood chemistry and adverse symptoms can detect and treat these imbalances before they become serious.

Infection is an omnipresent risk in people undergoing hemodialysis. The creation of dialysis access provides bacteria and other microorganisms the opportunity to enter the bloodstream. If an infection were to occur, symptoms would typically include:

• Local swelling, redness, warmth, and pain
• Flatulence (the accumulation of pus beneath the skin)
• Fever and/or chills

Antibiotics are typically used to treat the infection. Heparin, a type of blood thinner, may be used to prevent blood clots and limb ischemia. Maintaining optimal hygiene and sanitary practices can significantly reduce the risk of infection.

Fluid overload, also known as hypervolemia, occurs when the kidneys are no longer able to remove enough fluid from the body. If the dialysis machine is not calibrated correctly, hypervolemia may persist despite treatment.

Symptoms of hypervolemia include:

• Headache
• Abdominal cramping and bloating
• Shortness of breath
• Swelling of the feet, ankles, wrist, and face
• High blood pressure
• Weight gain

Adhering to fluid restrictions and tracking your fluid intake can significantly reduce the risk of hypervolemia.

If left untreated, hypervolemia can lead to heart problems, including congestive heart failure, cardiac arrhythmia, and cardiomegaly (enlargement of the heart).

Dialysis disequilibrium syndrome (DDS) is an uncommon neurological condition that typically affects people who have just started hemodialysis. It is believed to be the body's response to a procedure it considers abnormal, resulting in the reason of inflammatory cytokines and other inflammatory chemicals that cause the brain to swell (cerebral edema).

Symptoms of DDS include:

• Weakness
• Dizziness
• Nausea and vomiting
• Headache
• Muscle cramps
• Changes in behavior or mental status

This is usually a short-lasting complication that will resolve as the body adapts to treatment. Intravenous saline is sometimes used to raise blood pressure along with an injection of mannitol (a diuretic) to relieve swelling and pressure around the brain.