Chapter 22: Hemolytic Anemia Resulting from a Chemical or Physical Agent

Hemolysis can be mainly intravascular (i.e., hypotonic lysis or heat damage) or predominantly extravascular (i.e., arsine gas and oxygen).

Certain drugs can induce hemolysis in individuals with abnormalities of erythrocytic enzymes, such as glucose-6-phosphate dehydrogenase, or with an unstable hemoglobin (see Chaps. 15 and 18). Such drugs can also cause hemolysis in normal individuals if given in sufficiently large doses.

Other drugs induce hemolytic anemia through an immunologic mechanism (see Chap. 26).

The drugs and chemicals discussed here cause hemolysis by other mechanisms.

Arsine gas is formed in many industrial processes.

Inhalation of arsine gas can lead to severe anemia and jaundice.

Lead poisoning in children usually is a result of ingestion of lead paint flakes or chewing lead-painted objects. In adults, it usually is the result of industrial exposure.

Lead intoxication leads to anemia largely caused by inhibition of heme synthesis. There is also a modest decrease in red cell life span.

Lead also inhibits pyrimidine 5'-nucleotidase (see Chap. 15), which may be responsible for the basophilic stippling of red cells found in lead poisoning. Basophilic stippling may be fine or coarse and is most likely found in polychromatophilic cells.

The anemia is usually mild in adults but may be severe in children. Red cells are normocytic and slightly hypochromic.

Ringed sideroblasts are frequently found in the marrow.

Hemolytic anemia may be induced by high levels of copper in patients hemodialyzed with fluid contaminated by copper tubing, or in patients with Wilson disease.

Wilson disease may present or be called to medical attention by a hemolytic anemia, often having spherocytes and Heinz bodies as a result of copper injury to red cells. The presence of liver disease with a hemolytic anemia should raise the question of Wilson disease. (See Table 22–1 for laboratory findings in Wilson disease.)

The hemolysis is probably caused by inhibition of several erythrocyte enzymes.

Ingestion of sodium or potassium chlorate, or contamination of dialysis fluid with chloramines, can cause oxidative damage with formation of Heinz bodies and methemoglobin and with development of hemolytic anemia.

Other drugs and chemicals that can cause hemolytic anemia are listed in Table 22–2.

Water administered intravenously, inhaled in near-drowning, or gaining access to the circulation during irrigation procedures can cause hemolysis.

Hemolytic anemia has developed in patients receiving hyperbaric oxygenation and in astronauts exposed to 100 percent oxygen.

Severe hemolysis may occur in some patients following bites by bees, wasps, spiders, or scorpions.

Snake bites are only rarely a cause of hemolysis.

Patients with extensive burns may develop severe hemolytic anemia, apparently as a result of direct damage to the red cells by heat.

Blood films of many burned patients show spherocytes and fragmentation, and the osmotic fragility may be increased.

Neocytolysis, the selective destruction of young red cells is a phenomenon unique to microgravity and is associated with a rapid decrease in erythropoietin levels.

Experienced by astronauts after space flight even in the presence of normal ambient oxygen concentration or in people rapidly descending from high altitude to sea level.

Radiolabeling studies of erythrocytes indicated that the anemia was caused by selective hemolysis of young erythrocytes less than 12 days old.