aHUS and Fatigue

Brian Murphy, Ph.D. avatar

by Brian Murphy, Ph.D. |

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People with atypical hemolytic uremic syndrome (aHUS) may experience fatigue — extended periods of exhaustion or low energy — that can take a toll on health. Here is some information about how fatigue is related to aHUS and possible treatments to help manage it.

What is aHUS?

In patients with aHUS, the body’s complement system, a series of related proteins that help label foreign invaders for the immune system to attack, becomes overly active. This causes the immune system to mistakenly attack the lining of blood vessels, causing the formation of blood clots in the capillaries.

These blood clots in turn cause thrombotic microangiopathy (TMA) and can block or limit blood flow to certain tissues and organs. Partial blockages of the capillaries also can lead to the rupture of red blood cells as they attempt to squeeze through the blockage. The loss of red blood cells can lead to anemia, while blood clots also can reduce the number of available platelets in the blood. This can cause patients to be more prone to bruising and bleeding.

Since the kidneys, brain, eyes, and several other organs contain many small blood vessels, TMA can lead to damage to these organs.

Fatigue in aHUS patients

Fatigue is experienced by many people with aHUS. One study used data from the Global aHUS Registry to record patients’ levels of fatigue using the functional assessment of chronic illness therapy (FACIT) fatigue scale. The scale contains 13 questions that determine self-reported levels of fatigue and its impact on patients’ quality of life. The scores go from 0 to 52, with higher scores connoting better health status. The general population averages a score of 43.5. The study found that the average score among 521 adults with aHUS was 34.7. This number was much lower for patients on dialysis (25.8) and those experiencing TMA (32.5), indicating that these conditions may make fatigue worse.

The most likely cause of increased fatigue in patients with aHUS, especially those with more severe symptoms, is the anemia caused by the ruptured red blood cells. Anemia results in the tissues of the body not getting enough oxygen, which impairs their ability to function. The condition increases in patients with TMA and can be worse in those with chronic kidney disease.

Healthy kidneys secrete a hormone called erythropoietin (EPO), which stimulates the bone marrow to create more red blood cells. When the kidneys become damaged, as in aHUS, they do not produce as much EPO. This leads to the body producing fewer red blood cells.

The stress of living with a chronic illness and disturbed sleep also can contribute to fatigue in people with aHUS.

Treatments to manage fatigue

Significant improvements in FACIT-Fatigue scores were found in people with aHUS who started taking eculizumab (brand name Soliris), according to another study that made use of the Global aHUS Registry. Indeed, the average patient’s score before treatment was 29.0. It increased to 41.0 after treatment.

Several lifestyle changes also may help reduce fatigue, including eating healthier foods such as fruits and vegetables. Eating such foods can increase nutrients your body may be lacking. In addition, make sure you are drinking plenty of water as dehydration also can lead to fatigue. If you have kidney disease, check with your physician how much water you should consume.

Quitting smoking, reducing alcohol consumption, and avoiding recreational drug use also can reduce fatigue.

Patients experiencing fatigue should consult with their physician to make sure there aren’t other underlying causes for fatigue. Healthcare professionals may be able to adjust medications to boost a patient’s energy levels and regulate sleep patterns.


Last updated: Oct. 26, 2020


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