Last Updated on November 14, 2025 by Ugurkan Demir

At Liv Hospital, we know that anemia is a condition where there are fewer red blood cells, hemoglobin, or hematocrit. This leads to less oxygen getting to tissues and organs. It can happen due to many reasons, like not enough nutrients, chronic diseases, or genetic problems.

It’s key to understand how anemia starts to diagnose and treat it correctly. We know how important it is to classify anemia correctly. This helps us find and fix the root cause and tell the different types apart..

Key Takeaways

• Anemia is a condition where the body has a lower-than-normal number of red blood cells or the red blood cells do not have enough hemoglobin.
• Understanding anemia pathogenesis is key to accurate diagnosis and effective treatment.
• Classifying anemia is vital to tackle its underlying causes.
• Liv Hospital offers expert insight into diagnosing and treating complex forms of anemia.
• Reduced oxygen delivery to tissues and organs is a big problem caused by anemia.

Understanding Anemia: Definition and Clinical Significance

Anemia is when your body has too few red blood cells or they don’t carry enough oxygen. This is because they lack hemoglobin, a key protein.

Anemia is marked by low levels of red blood cells, hemoglobin, or hematocrit. The World Health Organization sets specific levels for these. For men, it’s below 13 g/dL, and for women, it’s below 12 g/dL. These levels help doctors diagnose anemia and understand its effects.

Defining Anemia Through Decreased RBC, HGB, and HCT

Anemia is caused by low RBC, HGB, or HCT levels. It can happen for many reasons, like not making enough red blood cells or losing too many. Knowing these levels is key to treating anemia well.

Red Blood Cells (RBC) carry oxygen to all parts of the body. If there are fewer RBCs, tissues and organs don’t get enough oxygen.

Hemoglobin (HGB) is a protein in RBCs that carries oxygen. Low HGB means the body can’t deliver enough oxygen to tissues.

Hematocrit (HCT) shows how much of your blood is made up of RBCs. A low HCT means your body can’t carry enough oxygen.

Global Prevalence and Public Health Impact

Anemia affects about 25% of the world’s population. It leads to more illnesses, deaths, and costs for healthcare.

Some groups, like pregnant women and children, are more likely to have anemia. Knowing who is most affected helps in making better health plans.

Doctors can improve health by understanding anemia better. This can help lower its impact on public health worldwide.

The Fundamental Pathophysiology of Anemia

Anemia is a complex issue that affects how our bodies get oxygen. It happens when we don’t have enough red blood cells or hemoglobin. This makes it hard for our tissues to get the oxygen they need.

Reduced Oxygen-Carrying Capacity

Anemia means we have fewer red blood cells or less hemoglobin. This reduces our ability to carry oxygen. Without enough oxygen, our organs and tissues suffer. The more severe the anemia, the worse the symptoms.

Compensatory Mechanisms in Anemic States

When we don’t have enough oxygen, our body tries to fix it. It works harder to pump blood and gets oxygen to important areas. It also helps our tissues use oxygen better. These efforts help keep our bodies working right.

Clinical Manifestations of Tissue Hypoxia

Even with these fixes, anemia can cause problems. People might feel tired, weak, or short of breath. In serious cases, organs can fail. The symptoms depend on the cause, how fast it happens, and the person’s health.

Knowing these signs is key to treating anemia. Early detection helps doctors start the right treatment. This can make patients feel better and live better lives.

Anemia Pathogenesis: The Three Primary Mechanisms

Anemia’s cause lies in three main ways that affect red blood cells. Knowing these is key to treating anemia well.

Impaired Red Blood Cell Production (Erythropoiesis)

When red blood cells aren’t made right, it’s a big problem. This can happen for many reasons, like:

• Nutritional shortages (e.g., not enough iron, vitamin B12, or folate)
• Problems with the bone marrow (e.g., aplastic anemia, myelodysplastic syndromes)
• Long-term illnesses (e.g., chronic kidney disease, chronic infections)

These issues stop the body from making enough red blood cells, causing anemia. For example, iron deficiency anemia happens when the body can’t make enough hemoglobin because of iron lack.

Increased Red Blood Cell Destruction (Hemolysis)

When red blood cells break down too early, it’s called hemolysis. This can be caused by:

1. Genetic problems (e.g., sickle cell disease, thalassemia)
2. External factors like autoimmune diseases, infections, or certain medicines

Hemolytic anemia can cause jaundice, an enlarged spleen, and a higher chance of getting sick.

“Hemolysis is a critical mechanism underlying various anemias, and its diagnosis requires a thorough understanding of the underlying causes.”

Acute or Chronic Blood Loss (Hemorrhage)

Blood loss is another main reason for anemia. It can be sudden, like from an injury or surgery, or ongoing, like from menstrual issues or ulcers.

Long-term blood loss can lead to iron deficiency anemia. This is because the body’s iron stores get used up over time.

In summary, anemia comes from three main causes: not making enough red blood cells, breaking them down too fast, and losing blood. Knowing these causes helps us figure out what kind of anemia someone has and how to treat it.

Morphological Classification of Anemias

Anemias are sorted by the size and look of red blood cells. This is key to figuring out the cause and finding the right treatment. There are three main types: microcytic, normocytic, and macrocytic anemia.

Microcytic anemia means small red blood cells. It’s often caused by iron deficiency or thalassemia. In these cases, RBC, HGB, and HCT levels are usually low.

Normocytic anemia has red blood cells of normal size. It’s usually caused by acute blood loss, chronic disease, or bone marrow problems. Macrocytic anemia has large red blood cells. It’s often linked to a lack of vitamin B12 or folate, which doesn’t fit the normal anemia range.

Knowing how to classify anemias is vital for doctors. It helps them diagnose and treat anemia better. By looking at the size of red blood cells, doctors can find the cause and plan the right treatment.

FAQ

References

1. Gerber, G. F. (2024). Anemia Due to Excessive Bleeding. Merck Manuals. https://www.msdmanuals.com/home/blood-disorders/anemia/anemia-due-to-excessive-bleeding