Anemia in C3 Glomerulopathy (C3G): Causes, Symptoms, and Treatment

C3 glomerulopathy (C3G) is a rare, chronic kidney disease driven by overactivity in part of the immune system. As C3G damages the kidneys, anemia (a shortage of healthy red blood cells) can develop and affect your energy, stamina, and quality of life.

But C3G itself and even some of your medications can also cause fatigue, so it’s not always clear if anemia is contributing.

Find out which symptoms signal anemia when you have C3G, which tests doctors use to confirm it, and the best ways to treat it.

How Does C3G Cause Anemia?

“Healthy kidneys produce erythropoietin, a hormone that signals the bone marrow to make red blood cells,” says Darshika Chhabra, MD, the medical director and primary transplant nephrologist for the kidney transplant program at Advocate Christ Medical Center in Oak Lawn, Illinois.

“As C3G damages the kidneys over time, they may produce less erythropoietin, which can lead to anemia; this kind of anemia is called anemia of chronic disease or anemia of inflammation and is usually caused by a prolonged diseased state,” says Dr. Chhabra.

Doctors usually become more concerned as kidney function declines, although there is no single point when anemia suddenly develops. “Some people experience it earlier than others depending on the severity of their kidney disease and whether other factors are also contributing — with C3G, anemia is rarely caused by just one thing,” she says.

Other factors contributing to anemia can include:

• Chronic Inflammation Inflammation from C3G and chronic kidney disease can interfere with red blood cell production and make it harder for the body to use stored iron.
• Iron Deficiency or Blood Loss Iron is needed to make hemoglobin, the protein in red blood cells that carries oxygen. Poor iron absorption, gastrointestinal bleeding, frequent blood draws, and blood loss during dialysis can all deplete iron stores.

  [2]

• Low Vitamin B12 or Folate Poor appetite, low food intake, digestive problems, or a diet that has become too limited may make it harder to get enough of the nutrients needed to produce healthy red blood cells, says Antonette Hardie, RDN, a registered dietitian-nutritionist at the Ohio State University Wexner Medical Center in Columbus.
• Medication Effects Some medicines may lower blood cell counts, contribute to bleeding, or otherwise add to anemia, says Chhabra.

Recognizing the Signs and Symptoms of Anemia

Given all the possible contributing factors, simply having fatigue doesn’t mean you have anemia.

• Weakness or less stamina for work, exercise, errands, or household tasks
• Shortness of breath or dizziness during minor activities, such as showering or climbing stairs
• Pale skin, which may be especially noticeable inside the lower eyelids or around the nail beds
• Feeling unusually cold, particularly in your hands and feet
• A fluttering, pounding, or racing heartbeat

But even many of those symptoms can be caused by other issues. “Shortness of breath, dizziness, weakness, pale skin, and a racing heartbeat can also occur with heart, lung, or other medical conditions, which is why symptoms alone can’t confirm anemia,” says Chhabra.

Medical Treatments for Anemia in Kidney Disease

Because several causes may overlap, we don’t assume that everyone with C3G has the same type of anemia, says Chhabra. “Understanding what is driving it helps us choose the most appropriate treatment,” she says.

Reduced erythropoietin, inflammation, iron deficiency, and other factors can overlap, so some people need a combination of treatments.

Here are some common treatment options.

Iron Supplementation

“Iron helps when iron deficiency is the problem,” Chhabra says. Oral iron may be appropriate for a mild deficiency when it is well tolerated, although it can take time to restore iron levels and may cause constipation, nausea, or other digestive side effects.

Intravenous iron may be a better option for someone with more advanced kidney disease, poor iron absorption, difficulty tolerating pills, or iron levels that have not improved enough with oral treatment. “The decision is based on laboratory results, symptoms, overall health, and access to care,” she says.

Vitamin B12 or Folate

Erythropoiesis-Stimulating Agents

Erythropoiesis-stimulating agents (ESAs) are injections that act like the erythropoietin normally produced by the kidneys, prompting the bone marrow to make more red blood cells.

“Erythropoiesis-stimulating agents may be appropriate when anemia is related to chronic kidney disease and other treatable causes, such as iron deficiency, have already been addressed,” Chhabra says.

These medications stimulate the bone marrow to produce more red blood cells, which can improve symptoms of anemia and reduce the need for blood transfusions. “Patients receiving these medications require regular and close monitoring because raising hemoglobin too high can increase the risk of complications, including high blood pressure, blood clots, and stroke,” says Chhabra.

Treatment for C3G

“Treating the underlying disease can improve anemia, especially if kidney function stabilizes and inflammation decreases,” Chhabra says.

Complement inhibitors, immunosuppressants, and other C3G treatments may help by controlling inflammation and slowing further kidney damage.

“Some people notice an improvement in anemia within several weeks, while others improve more gradually over a few months,” says Chhabra. The timeline depends on how much kidney function remains and whether iron deficiency, blood loss, or another cause also needs treatment, she says.

Lifestyle Measures That Can Help

Lifestyle changes can support anemia treatment and make low energy easier to manage, but they can’t replace erythropoietin or correct every cause of anemia.

Work With a Renal Dietitian

Poor appetite, digestive symptoms, and dietary restrictions can make it difficult to get enough calories, iron, vitamin B12, folate, and other nutrients.

A renal dietitian can review your food intake and laboratory results, then tailor recommendations to your kidney function, other health conditions, and whether you receive dialysis.

“Small, frequent meals may be easier when appetite is low,” says Hardie. She recommends bringing recent laboratory results, a list of medications and supplements, and a food record to your appointment with a dietitian so they can identify possible nutrient or calorie gaps.

Keep Your Medical Team Updated

“Feeling tired should never become something you simply accept,” Chhabra says.

Let your healthcare team know if fatigue persists, worsens, or continues to limit daily activities. Mention shortness of breath, dizziness, palpitations, pale skin, appetite changes, possible bleeding, and any symptoms that began after a medication change.

Keep follow-up appointments and complete recommended blood tests so your doctor can see whether treatment is working.

Adjust Your Routine Without Blaming Yourself

Until the anemia improves, schedule more demanding activities during the part of the day when you have the most energy, take breaks before you become exhausted, and accept help with less important tasks.

Contact Your Healthcare Team

If fatigue is new, worsening, or making everyday activities more difficult, call your doctor. Chest pain, severe shortness of breath, fainting, or a racing heartbeat should be evaluated right away because these symptoms may signal a more serious problem, Chhabra says.