Merck Manual

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More About Some Causes of Anemia

More About Some Causes of Anemia

Cause

Mechanism

Treatment

Comments

An enlarged spleen traps and destroys abnormal red blood cells.

The disorder that caused the spleen to enlarge is treated.

Sometimes the spleen must be removed surgically.

Extremely large spleens cause abdominal pain and a feeling of fullness after eating a small amount of food.

Often, an enlarged spleen also traps platelets and white blood cells, thus reducing their number in the bloodstream.

Mechanical damage to red blood cells

Abnormalities in blood vessels (such as an aneurysm), an artificial or damaged heart valve, can break normal red blood cells apart.

The cause of the damage is identified and corrected.

Red blood cells are destroyed in the blood vessels.

The immune system destroys red blood cells.

Hemoglobin from these damaged cells is concentrated in urine during the night, resulting in dark, reddish urine in the morning.

Eculizumab, a drug that blocks the complement system, helps relieve symptoms.

People with blood clots may need to take an anticoagulant.

People may have severe stomach cramps and clotting in the large veins of the abdomen and legs.

Symptoms often occur in episodes (paroxysmally).

Hereditary spherocytosis

Red blood cells become misshapen and rigid, getting trapped and destroyed in the spleen.

Treatment is usually not needed, but severe anemia may require removal of the spleen.

This hereditary disorder can also cause bone abnormalities, such as a tower-shaped skull.

This disorder can sometimes cause gallstones.

Hereditary elliptocytosis

Red blood cells are oval or elliptical in shape rather than the normal disk shape.

Severe anemia may require removal of the spleen.

The anemia is usually mild and requires no treatment.

Red blood cell enzyme abnormalities

Glucose-6-phosphate dehydrogenase (G6PD) deficiency: The G6PD enzyme is missing from red blood cell membranes, making cells more fragile.

Pyruvate kinase (PK) deficiency, which is usually present at birth (congenital), also makes red blood cells more fragile.

In G6PD deficiency, anemia can be prevented by avoiding things that trigger it, such as drugs.

In PK deficiency, some people may benefit from removal of the spleen.

G6PD deficiency is a hereditary disorder that almost always affects males.

About 10% of black males and a smaller percentage of white people of Mediterranean origin have G6PD deficiency.

Pyruvate kinase deficiency is rare.

Other red blood cell membrane abnormalities

stomatocytosis (where the cell membrane has an abnormal 'slit'), which can be inherited or can develop during life (acquired), or in rare cases of low phosphate levels in the blood.

For acquired stomatocytosis, avoid triggers (such as alcohol)

For inherited stomatocytosis, sometimes removal of the spleen

For people with low phosphorus levels in the blood, phosphate supplements

The anemia is usually mild and requires no treatment.