Anaemia & Kidney Failure

Anaemia is a well-known medical term generally associated with “less blood” in the body. It is also, an inevitable complication in the course of every Chronic Kidney Disease (CKD) and Kidney Failure journey.

But do you really understand what Anaemia is? Why does that occur in CKD in the first place? And is there a way you could report to your doctor about it on time? Sure there is. Learn all this, and more, below.



Anaemia or Anemia (whichever way you like to spell it!) is the fancy medical term for an abnormal decrease in our Red Blood Cell (RBC) numbers below the normal range. Broadly speaking, this could happen in conditions that present with:

■ A defect in “the red blood cell production system”

■ Massive blood loss over a short time period (Example: An injury)

■ Minute but sustained blood loss over several years

■ Injury and premature death of Red blood cells




First a bit of a brief preface.

Red Blood Cells (RBCs) act as “Transporters” within our body. One of their chief functions is to ferry life-saving Oxygen from Lungs to each of our tissues  & deliver Oxygen there. RBCs do so with the help of a special protein called Hemoglobin found within each of them. In short, RBCs provide our tissues with the critical “fuel” that they need for survival & to carry out day-to-day activities.

In Anaemia (from all causes), there is a shortage of Red Blood Corpuscle (RBC) production for varied root cause-specific reasons. Low RBC count implies a fall in total Hemoglobin levels in the body. As mentioned above, this means an unfortunate compromise in our efficient Oxygen Transport system within our body. As a result, tissues face “fuel-shortage” over time and end up getting malnourished.

The Heart senses this situation and tries to help by pumping faster than normal to transport more blood (RBCs) to tissues at a time. While it’s very kind of our Heart to be that thoughtful, this arrangement is only momentarily beneficial before it tires out our heart and makes us feel “out of breath” easily. At this point, healthy Kidneys jump into action by producing more of Erythropoietin — the RBC-forming hormone. This hormone signals our body to generate more RBCs (containing Hemoglobin) such that the oxygen shortage to tissues can be alleviated.



Chronic kidney disease (CKD) brings about a gradual but permanent loss of kidney function over the years. Anaemia is an inevitable, unavoidable complication in the course of every Chronic Kidney Disease and Kidney Failure journey. It is also one of the important reasons that contribute to all members of Club CKD feeling “easily drained-out of energy” even with low activity levels.



Anemia in CKD is the result of a complex co-ordination of a number of mechanisms that act in tandem to reduce overall red blood cell count. The image below summarises these mechanisms. We will be briefly discussing these ahead.

Anemia in CKD Mechanisms




In good health, special cells lining the tiny filtration tubes in Kidneys produce a hormone called Erythropoietin (pronounced Eri-throw-poy-tin). This hormone is essential for signaling our bone marrow (within bones in our limbs) to produce NEW red blood cells (RBCs) containing a fresh stock of Hemoglobin protein within each of them. These RBCs then transport Oxygen to different tissues – facilitated by Hemoglobin within them.

When chronic kidney disease sets-in, these Erythropoietin producing cells in the kidneys begin to suffer permanent scarring (fibrosis). Such damage prevents the production of the RBC-forming hormone in quantities adequate for generating new red blood cells.

When such scarring in CKD affects the diseased kidneys to an extent that overall kidney function reduces below 50% of normal, Erythropoietin production falls low enough for RBC numbers to drop below the normal healthy lower limit of 4.5 million RBCs per deciliter of blood. Fall in RBC numbers implies a reduction in overall Hemoglobin content in the body.

As per the Kidney Disease: Improving Global Outcome (KDIGO) guidelines, Haemoglobin levels below 13g/dL in males & 12 g/dL in females can be considered Anaemia. (1)

The resulting low Hemoglobin content directly puts an adverse impact on our in-house Oxygen transport & delivery system. Consequently, all organs begin to suffer from the lack of adequate Oxygen, most notably, our heart & nerves. These malnourished organs try to “voice” their concerns to us through an entire set of Symptoms (discussed below). It is these symptoms that in return help your medical team decide if they should test you for Anaemia or not.



Chronic Kidney Disease patients tend to have an overall poor nutritional status. This reflects on body iron stores over time. Iron is an essential component of the oxygen-carrying protein — Hemoglobin housed within RBCs. In fact, the “iron core” is what makes Hemoglobin capable of carrying Oxygen across the body. Poor Iron stores translate as low Hemoglobin content in each red blood cell (RBC) and hence an overall defect in Oxygen supply to organs across the body. This leads to symptoms of Anemia.



The immune system processes (inflammation) that go on within the body at the onset of CKD can interfere with proper utilization of existing Iron stores in the body. This again translates as the scenario as explained above and propels symptoms of Anaemia.



CKD causes our delicate kidney filters to gradually get scarred and lose their ability to conserve enough Calcium in our blood as they otherwise do. As a result, blood calcium levels start to fall. In response to this, the Parathyroid glands situated in our neck end-up releasing Parathyroid Hormone (PTH) rapidly, in order to “mobilize” calcium from bones to blood.

The high PTH level in blood in-turn aberrantly promotes the release of substances that cause the bone marrow to get fibrosed. This makes the marrow lose its usual ability to produce enough RBCs & hence, anaemia.



As CKD progresses, blood levels of Folic Acid and Vitamin B12 also tend to fall. These nutrients are necessary for new Red Blood Cells to make the oxygen-carrying protein — Hemoglobin. Hence, their low levels produce RBCs with less Hemoglobin than normal & compromise with the Oxygen-carrying capacity of the blood. This further worsens symptoms of Anaemia.




In advanced Chronic Kidney Disease, the blood levels of cellular waste products such as Urea begins to rise incessantly. This condition is called  “Uremia”. Your medical team monitors this rise with a blood test called Blood Urea Nitrogen (BUN).

When Blood Urea levels rise, it turns the watery part of the blood (outside of blood cells) much thicker in consistency than usual water levels within the Red Blood Cells. Science has found, that water always has a tendency to move towards thicker consistencies to “restore fluid balance”. Going by this dictum, in CKD patients with Uremia, water from within RBCs tens to move outwards into the fluid part of the blood in an attempt to “reduce the sudden thickness”. As a result, red blood cells end up getting shrunk or “crenated”.


Anaemia CKD Echinocyte


This makes these RBCs inadequate for oxygen transport in addition to resulting in their premature death. This is an important contributor to worsening Anemia in CKD.



#  Anaemia BLOOD LOSS

The subset of CKD patients who also have Hematuria suffer a sustained loss of Red Blood Cells (RBCs) in significant numbers via Urine, throughout their CKD journey. This is an unavoidable contributor of Anaemia during CKD. Further, blood loss in patients undergoing hemodialysis is also a prominent reason for the worsening of Anaemia in CKD. (3)




The presence of other conditions along with Chronic Kidney Disease such as Pregnancy (Iron deficiency), Thyroid hormone disturbances (RBC formation defect) or certain Auto-immune Disorders (premature RBC death) can severely impact red blood cell numbers.




The signs and symptoms of anaemia in someone with CKD directly relate to the organs that get affected the earliest – the Heart & Nerves. These symptoms may include: –

  • weakness
  • fatigue, or feeling tired
  • headaches
  • problems with concentration
  • paleness
  • dizziness
  • Pica (the urge to eat or chew on non-food substances such as Chalk, Mud or Metal)
  • difficulty breathing or shortness of breath
  • chest pain

Anyone having difficulty breathing or with shortness of breath or Chest Pain should seek immediate medical care.

Knowing these symptoms, and the reason why Anaemia causes these to develop can help you report to your doctor on time. Understanding how Anaemia in CKD works, YOU:- 

Save yourself from taking “supplements” that are unlikely to benefit you.

Understand why Anaemia presents with a specific set of symptoms only.

Learn to proactively recognize those symptoms

Can be in legitimate control of your own CKD journey.

It’s always nice to NOT be clueless about what’s next isn’t it? To avoid Apprehension of the Unknown?

Then TRY & UNDERSTAND THE BARE BASICS. That’s the mantra.

Take care all of you.



Now that you understand the basics of Anaemia in CKD, the logical extension to this article is about how your medical team diagnoses it & the various treatment approaches adopted.

To understand that, keep a tab of this space for our next article in The Anaemia Series.



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