Anisocytosis in anemia syndrome
Changes in the complete blood count accompanied by morphological defects of erythrocytes are persistent. Anemia may develop very rapidly:
- Hemoglobin: drops to 70–80 g/L and lower within literally a few days.
- Erythrocytes: their count drops to $3.0 \times 10^{12}$/L and below.
- Cell morphology: microscopy clearly visualizes anisocytosis and poikilocytosis.
Simultaneously, changes in the white blood cell count may be observed: neutrophilic leukocytosis (up to $8.0–15.0 \times 10^9$/L, occasionally up to $20.0 \times 10^9$/L) against the background of a decreased proportion of lymphocytes and eosinophils (down to anoxemia/aneosinophilia). The erythrocyte sedimentation rate (ESR) can reach 60–80 mm/h even with mild leukocytosis. The appearance of immature neutrophil forms, myelocytes (left shift), and toxic granulation is regarded as an unfavorable prognostic sign.
Role in the differential diagnosis of jaundice
Assessment of erythrocyte size and shape is critical for the differential diagnosis of jaundice syndrome. The presence of anisocytosis and poikilocytosis against the background of decreased hemoglobin is a classic laboratory criterion for prehepatic (hemolytic) jaundice.
| Parameter | Hemolytic jaundice | Parenchymal jaundice |
|---|---|---|
| Erythrocytes and Hb | Decreased (anisocytosis, anemia) | Normal |
| Blood bilirubin | ↑ indirect (unconjugated) | ↑ direct and indirect |
| Liver enzymes | ALT, AST normal | ↑↑ pronounced cytolysis |
| Stool | Hypercholic (dark) | Hypocholic |
| Urine | ↑↑ urobilin, no bilirubin | Bilirubin present |
Unlike hemolysis, in parenchymal (viral hepatitis, leptospirosis) and obstructive jaundice, red blood cell morphology remains normal.
Anisocytosis in infectious processes (using malaria as an example)
One of the causes of the hemolytic component with pronounced anisocytosis is infections, particularly malaria (caused by Plasmodium vivax or Plasmodium malariae).
The disease begins with pronounced intoxication and initial fever lasting the first 6 days. Then, typical malaria paroxysms develop with alternating phases of chills, fever, and sweating, recurring every other day. The patient develops hepatosplenomegaly. Destruction of erythrocytes by plasmodia leads to the development of anemia with decreased hemoglobin, anisocytosis, and leukopenia by the end of the second or third week of the disease.
The diagnosis is confirmed by microscopy of a thick drop and blood smear. For example, upon detecting 100 parasites in 10 fields of view, the level of parasitemia is estimated at 5,000 per 1 µL. Treatment requires suppressive therapy with chloroquine and radical therapy with primaquine (a 14-day course).
Additional workup plan
Upon detecting anisocytosis and signs of hemolytic syndrome (scleral icterus, elevated ESR), the patient is prescribed a comprehensive diagnostic algorithm:
- CBC (repeat): thorough evaluation of erythrocyte count, shape, and size, reticulocyte and platelet counts, and leukocyte differential.
- Blood chemistry: bilirubin fractions (direct/indirect), AST, ALT, alkaline phosphatase, creatinine, urea, total protein, and serum iron (typically decreased in hemolysis).
- Urinalysis: screening for urobilin (its concentration sharply increases in hemolysis) and bile pigments.
- Specific diagnostics: serum ELISA for viral hepatitis markers, PCR for HBV DNA and HCV/HDV RNA to rule out viral etiology of liver injury.
- Imaging: ultrasound, CT, MRI, or MRCP are used when necessary to rule out obstructive jaundice.
Class and exam questions
What other morphological blood changes is anisocytosis frequently combined with?
In clinical practice, it is almost always detected simultaneously with poikilocytosis (variation in erythrocyte shape) against the background of a sharp drop in hemoglobin levels.
Which type of jaundice is characterized by the appearance of anisocytosis?
This is a pathognomonic sign of prehepatic (hemolytic) jaundice, which involves the active destruction of red blood cells.
How long after the onset of malaria do signs of anemia and anisocytosis appear in the blood?
The development of anemia syndrome and corresponding erythrocyte changes become characteristic by the end of the second or third week of the disease course.
What else to study on this topic
- Criteria and markers of parenchymal and obstructive jaundice
- Left shift of the leukocyte formula and toxic granulation of neutrophils
- Life cycle of Plasmodium vivax and Plasmodium malariae
- Regimens for prescribing chloroquine and primaquine in malaria
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