Complications of Hemodialysis

Hemodialysis is a form of treatment given to patients with kidney failure where blood is taken from a patient's body through a dialysis access and cleaned in a dialysis machine. This dialysis machine acts as an artificial kidney, and tries to replicate what a normal human kidney would do. Toxins are removed, excess fluid is extracted, and clean blood is returned to the patient.

Hemodialysis is just one of the different kinds of dialysis treatments but is the most common modality of treating kidney failure, at least in the United States. It is typically required when kidney function declines to the point where the patient starts to develop clinical features of kidney failure, called uremia, which is seen in conjunction with abnormal kidney function tests (elevated creatinine and a low GFR). In order to dialyze the patient, a dialysis access is required.

This article is an overview of selected complications that might occur in a patient on hemodialysis, with a more detailed discussion specifically about cramps, one of the most common complications that can occur when patients are receiving dialysis. However, this is not an all-inclusive list by any measure.

These include:

• Nausea
• Itching
• Headaches
• Back pain
• Chest pain
• Vomiting
• Fever
• Muscle cramps

Multiple mechanisms are responsible for these changes. The dose and aggression of dialysis are important factors. For instance, back pain is often seen in conjunction with rapid fluid removal at dialysis. Fever, on the other hand, could occur from infections, but could also just be an allergic reaction to the dialyzer. Chest pain at dialysis needs to be taken seriously and could occur because of drops in blood pressure (causing a drop in blood supply to the heart, also known as myocardial ischemia), and more rarely from air getting into the circulation, or air embolism. There are alarms programmed to go off on most modern dialysis machines should anything like this be detected.

Some of these complications can occur together, especially when the patient has just been started on dialysis, and this is referred to as dialysis disequilibrium syndrome.

One of the most common dialysis-related complication, cramps are more likely to develop when hemodialysis is aggressive; that is when a lot of toxins and fluid are removed from the patient in a short span of time during dialysis. It is therefore not just about the amount of fluid removed, it's also about how quickly it is removed. In other words, a patient might have just 2 liters of fluid removed during her dialysis treatment (not an unusual amount), however, if this amount was removed over a span of just one hour, it could still cause debilitating cramps.

Cramps tend to hit patients who see a high weight gain between dialysis treatments (inter-dialytic weight gain, or IDWG) more frequently. For people already on dialysis, you might be familiar with the term "dry weight." Prior to starting your dialysis treatment the dialysis staff will weigh you, and calculate how much weight you gained since the previous dialysis treatment when you left (dry weight). The difference between your current weight and the dry weight is the amount of fluid that will often end up being removed. The higher this amount, the more likely that cramps will develop  Hence, a common advice given to dialysis patients is to not gain an inordinate amount of weight between dialysis treatments. Therefore, dialysis patients are expected to watch how much they eat or drink in between treatments.

What the patient can do: Keep inter-dialytic weight gain low by watching fluid intake

What the dialysis staff can do: Reduce the rate/amount of fluid removal during dialysis treatment. Rate reduction can be achieved by prolonging the dialysis treatment, so even though the total amount of fluid removed might be the same, the amount of fluid removed per hour is still lower. The body typically will have a better chance of adapting to the fluid shifts and less likely to cramp. Dry weight could be readjusted in some cases.

There is some evidence that vitamin E and medications like gabapentin might help with cramps associated with dialysis, and could be tried in patients who cramp very frequently.  A drug called quinine used to be used for this as well, but is no longer recommended by the FDA given its toxicity.