What are the causes of IDA?

Causes of iron deficiency anemia include:

Blood loss

Blood contains iron within red blood cells. If you lose blood, you lose some iron. Women with heavy periods are at risk of iron deficiency anemia because they lose blood during menstruation. Slow, chronic blood loss within the body — such as from a peptic ulcer, a hiatal hernia, a colon polyp or colorectal cancer — can cause iron deficiency anemia. Gastrointestinal bleeding can result from regular use of some over-the-counter pain relievers, especially aspirin.

Acute blood loss

Causes of acute blood loss include trauma, surgery, peripartum haemorrhage, haematemesis and haemoptysis. plasma volume is replaced within 1 to 3 days of the acute blood loss but it can take several weeks for the red cell mass, and therefore hemoglobin to be replenished.

Chronic blood loss

The most common causes of chronic blood loss are gastrointestinal lesions and menorrhagia. The consequences are those of iron deficiency 

A lack of iron in your diet

Your body regularly gets iron from the foods you eat. If you consume too little iron, over time your body can become iron deficient. Examples of iron-rich foods include meat, eggs, leafy green vegetables and iron-fortified foods. For proper growth and development, infants and children need iron from their diets, too.

An inability to absorb iron

Iron from food is absorbed into your bloodstream in your small intestine. An intestinal disorder, such as celiac disease, which affects your intestine's ability to absorb nutrients from digested food, can lead to iron deficiency anemia. If part of your small intestine has been bypassed or removed surgically, that may affect your ability to absorb iron and other nutrients.

Pregnancy

Without iron supplementation, iron deficiency anemia occurs in many pregnant women because their iron stores need to serve their own increased blood volume as well as be a source of hemoglobin for the growing fetus.

Parasitic infection

The most important cause of iron deficiency anemia is parasitic infection caused by hookworms, whipworms, and roundworms, in which intestinal bleeding caused by the worms can lead to undetected blood loss in the stool. These are especially important problems in growing children.

Chronic renal disease

Chronic renal disease (decrease in or a complete loss of renal mass), or bilateral nephrectomy can lead to decrease production of EPO, resulting in anemia. Renal cell carcinomas can produce excess EPO, resulting in an erythrocytosis.

Recombinant EPO, produced in animal cells, is currently used for:

• Anemia due to renal failure
• Autologous blood transfusions
• After chemotherapy or bone marrow transplantation
• Anemia of chronic disease

Table showing various types of anemia and lab workup:

Disease	Ferritin	Transferrin sat.	Iron	TIBC
Acute blood loss	normal	Low	low	normal
Chronic blood loss	low	low	low	increased
Hemolytic anemia	increased	increased	increased	low
Iron deficiency	low	low	low	increased
Pregnancy	low	low	low	increased
Acute inflammation	increased	increased	normal	low
Hemochromatosis	increased	increased	increased	low
Chronic diseases	increased	low	low	low
Liver diseases (necrosis)	increased	increased	increased	increased
Estrogen therapy	Normal	Low	Increased	Increased

TIBC = total iron-binding capacity.
Transferrin sat. = Transferrin saturation.

Type of anemia	Ferritin level
Male, anemia of chronic diseases	<100 ng/mL
Female, anemia of chronic diseases	<20 ng/mL
Iron deficiency anemia	<10 ng/mL
Iron overload	>220 ng/mL

 

The Increased Ferritin Level Is Seen In:

• Ferritin levels may increase with age in males and postmenopausal females.
• A marked increase was seen in iron overload e.g Hemochromatosis, and certain liver diseases.
• Slightly increased seen in acute leukemia.
• Inflammatory diseases like pulmonary infections, osteomyelitis, chronic UTI.
• Rheumatoid arthritis, SLE.
• Certain chronic liver diseases.
• Acute myeloblastic and Lymphoblastic leukemia.
• Hodgkin’s lymphoma and breast cancers.
• It may be seen in viral hepatitis or following toxic injury to the liver. In that case, ferritin is released from the damaged liver cells.

The Decreased Ferritin Level Is Seen In:

• Iron deficiency anemia when ferritin level is <10 ng/ml.
• Heavy menstrual bleeding.
• Persistent bleeding of GIT.
• Poor absorption by the GIT.

In haemolytic anemia, red cells have shortened lifespan because they are destroyed at an accelerated rate. This increased red-cell destruction leads to anemia, which stimulates increase EPO production, leading to compensatory erythropoiesis. The clinical features of haemolytic anemias result from the increased red cell destruction and the compensatory increase in red cell production.