Derick Mussen Preventive Healthcare

Normochromic Hemolytic Anemias

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Hemolytic anemias result from a shortened erythrocyte life span with insufficient compensation from increased erythrocyte production (Table 24).

H Usually, hematopoiesis in the bone marrow is increased in compensation, and, depending on the course of the disease, may make up for the accelerated cell degradation for all or some of the time by recycling the iron as it becomes free.

Accordingly, counts of the young, newly emerged erythrocytes (reticulocytes) are always raised, and usually sporadic normoblasts are found. Anemia proper often becomes apparent only in a "crisis" with acute, accelerated cell degradation, and reticulocyte counts increased up to more than 500%.

A common cellular phenomenon after extended duration of hemolytic anemia is the manifestation of macrocytic hypochromic disorders (p. 150), because the chronic elevation of hematopoietic activity can exhaust the endogenous folic acid reserves (pernicious anemia).

Bone marrow analysis shows both relative and absolute increases in erythropoietic activity: among the red cell precursors, in acute severe hemolysis the more immature forms often predominate more than in normal bone marrow, and in chronic hemolysis the maturer forms do (orthochromatic normoblasts). In addition, the normoblasts in hemolytic bone marrow often are markedly clustered (Fig.48), whereas in normal bone marrow they are more evenly dispersed (Fig. 18).

Consistently elevated "young" erythrocytes (reticulocytes) suggest hemolysis a

Fig. 48 Hemolytic anemia. a and b Newly formed erythrocytes appear as large, polychromatic erythrocytes (1) after Pappenheim staining (a); supravital staining (b) reveals spot-like precipitates (reticulocyte = 2). Thrombocyte (3). c Bone marrow cells in hemolytic anemia at low magnification: increased hematopoiesis with cell clusters. Orthochromatic erythroblasts predominate. A basophilic erythro-blast shows loosened nuclear structure (arrow), a sign of secondary folic acid deficiency.

Fig. 48 Hemolytic anemia. a and b Newly formed erythrocytes appear as large, polychromatic erythrocytes (1) after Pappenheim staining (a); supravital staining (b) reveals spot-like precipitates (reticulocyte = 2). Thrombocyte (3). c Bone marrow cells in hemolytic anemia at low magnification: increased hematopoiesis with cell clusters. Orthochromatic erythroblasts predominate. A basophilic erythro-blast shows loosened nuclear structure (arrow), a sign of secondary folic acid deficiency.

Table 24 Causes of the most common hemolytic anemias

		Special morphological	Further advanced
		features of erythrocytes	diagnostics
Causes within the erythrocytes (corpuscular hemolyses)
>	Hereditary
	• Membrane abnormalities
	- Spherocytosis (see p. 144)	- Small spherocytes	Osmotic resistance
	- Elliptocytosis	- Elliptocytes
	• Hemoglobin abnormalities
	- Thalassemia (see p. 138)	- Target cells	Hemoglobin electro-
	- Sickle cell anemia (see	- Sickle cells	phoresis
	p. 144)
	- Other rare hemoglobin-
	related disorders
	• Enzyme defects
	- Glucose-6-phosphate	- Possibly Heinz bodies	Enzyme tests
	dehydrogenase	- Macrocytes
	- Pyruvate kinase and
	many others
>	Acquired
	• Paroxysmal nocturnal		Sucrose hemolysis
	hemoglobinuria		test, absence of CD 55
			(DAF) and CD 59
	• Zieve syndrome	- Foam cells in the bone	MIRL(membrane
		marrow	inhibitor of reactive
			lysis)
Causes outside the erythrocytes (extracorpuscular hemolyses)
>	Biosynthesis of antibodies
	• Isoantibodies (fetal erythro		Rh serology
	blastosis, transfusion events)
	• Warm autoantibodies		Coombs test
	• Cold autoantibodies	- Autoagglutination	Coombs test,
			Cold agglutination
			titer
	• Chemical-allergic antibodies
	(e. g., cephalosporin, methyl-
	dopa)
>	Physical or chemical noxae	- Partially Heinz bodies
	(e. g., after burns, heart valve
	replacement; heavymetal
	exposure, animal- or plant-
	derived poisons)
>	Microangiopathic hemolysis in	- Schizocytes, fragmen-	Thrombocytes |
	hemolytic-uremic syndrome,	tocytes(see p. 143)	Liver, kidney
	thrombotic-thrombocytopenic
	purpura, bone marrow carci-
	noses
>	Infection-related noxae (e. g.	- For malaria pathogen	Demonstration of
	influenza, salmonella infection,	(seep. 158)	pathogen
	malaria)
>	Hypersplenism, e. g. lymphatic		Cause of
	system disease, infections with		splenomegaly
	splenomegaly, portal hyperten-
	sion

Distribution pattern and shape of erythrocytes can be relevant in the diagnosis of hemolysis a b

Fig. 49 Autoagglutination and fragmentocytes. a Clumps of erythrocytes. If this is the picture in all regions of the smear, an artifact is unlikely and serogenic (au-to)agglutination should be suspected (in this case due to cryoagglutinins in myco-plasmic pneumonia). Thrombocytes are found between the agglutinated erythrocytes. b and c Conspicuous half-moon and egg-shell-shaped erythrocytes: frag-mentocytosis in microangiopathic hemolytic anemia. Fragmentocytes (1), target cell (2), and echinocytes (3) (this last has no diagnostic relevance).

Fig. 49 Autoagglutination and fragmentocytes. a Clumps of erythrocytes. If this is the picture in all regions of the smear, an artifact is unlikely and serogenic (au-to)agglutination should be suspected (in this case due to cryoagglutinins in myco-plasmic pneumonia). Thrombocytes are found between the agglutinated erythrocytes. b and c Conspicuous half-moon and egg-shell-shaped erythrocytes: frag-mentocytosis in microangiopathic hemolytic anemia. Fragmentocytes (1), target cell (2), and echinocytes (3) (this last has no diagnostic relevance).

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