Drug-induced immune hemolytic anemia

Alternative names

Immune hemolytic anemia secondary to drugs; Anemia - immune hemolytic - secondary to drugs

Definition

Drug-induced immune hemolytic anemia is an acquired form of hemolytic anemia caused by interaction of certain drugs with the immune system. The result is the production of antibodies against the red blood cells and premature red blood cell destruction.

Causes, incidence, and risk factors

Drug-induced immune hemolytic anemia occurs when certain drugs start an immune reaction against red blood cells. In some instances, the drugs interact with the red blood cell membrane, causing the cell to become antigenic. This means the body identifies these cells as not belonging to the body. Antibodies form against the red blood cells. The antibodies attach to red blood cells and result in their premature destruction. This condition is rare in children.

Drugs that can cause immune hemolytic anemia include the following:

• Penicillin and its derivatives
  
• Cephalosporins
  
• Levodopa
  
• Methyldopa
  
• Quinidine
  
• Some anti-inflammatory drugs
  

There are many other rarer causes of drug-induced hemolytic anemia. Drug-induced hemolytic anemia is most often associated with G6PD deficiency. However, G6PD deficiency and hemolysis is due to oxidative stress in the red cell, not an autoimmune phenomenon.

Symptoms

• Fatigue
  
• Pale color
  
• Shortness of breath
  
• Rapid heart rate
  
• Yellow skin color (jaundice)
  
• Dark urine
  

Signs and tests
A physical examination may show an enlarged spleen. Other tests may indicate drug-induced immune hemolytic anemia.

• A direct Coombs' test is positive.
  
• An indirect Coombs' test is positive if the offending drug is added to the test.
  
• Indirect bilirubin levels are elevated.
  
• Serum haptoglobin may be low.
  
• Hemoglobin may be present in the urine.
  
• Hemosiderin may be present in the urine.
  
• Urine and fecal urobilinogen are increased.