Question

Anemia Case Study

A 50 year old white woman had seen her physician and reported having no energy and feeling tired all the time. She also reported experiencing mild pain in the abdominal region. The physician ordered a routine CBC.

WBC: 4,500/ul

RBC: 1.76 x 10⁶/ul

Hb: 6.2 g/dl

HCT: 22%

MCV: 129.4 fl

MCHC: 32 g/dl

The peripheral blood smear demonstrated abnormalities of erythrocytes and leukocytes. On receipt of the laboratory data, the physician ordered the following additional tests: vitamin B12 and folate assays, reticulocyte count, serum iron and TIBC, serum bilirubin, and serum LD. A fecal examination for occult blood was additionally ordered with the following results:

Vitamin B12: 121 pmol/L (decreased)

Folate: normal

Retic count: 0.4%

Serum iron and TIBC: normal

Serum bilirubin: 1.8 mg/dl

Serum LD: >3,000 units (significantly increased)

Occult blood: negative

Questions:

1. What category of anemia is suggested by the hematological findings in this case?

2. What specific kind of anemia can be diagnosed based on the laboratory findings?

3. What is the etiology and physiological process in this anemia?

4. What is the characteristic WBC seen in this anemia that helps with the diagnosis?

5. What is the most likely cause of this anemia based on the laboratory findings?

Answer 1

1. The category of anemia suggested by the hematological findings in this case is Normochromic , macrocytic anemia ( normal MCHC , high MCV ) .

2. The specific kind of anemia that can be diagnosed based on the laboratory findings is Megaloblastic anemia .

3. Etiology :-

- vitamin B12 deficiency

- folate deficiency

- combination of both

- drug induced

Physiologicalprocess :-

Megaloblastic bone marrow is hyperactive:

• stimulated by EPO active on erythroid stem cells; CFU-E's are increased in numbers but are abnormal since their descendants are defective

• megaloblasts are likely to die during maturation, so ratio of young erythroid cells in bone marrow is higher than normal--> ineffective erythropoiesis

• cells fail to mature properly, and die in bone marrow (RBCs fiat to enter circulation)

Mature megaloblastic erythrocytes:

• have abnormal shapes and variable sizes

• MCV is higher than normal (recall these are often synonymous with macrocytic anemias)

• normal amount of hemoglobin (MCHC)

• shorter RBC lifespan due to random destruction

• reduced reticulocyte count due to destruction of fragile megaloblastic erythroid precursor cells

• accumulation of giant metamyelocytes (and band cells)--> hypersegmented neutrophils

- giant megakaryocytic may also be present; all other myeloid precursors are larger than normal

4. White blood cell (WBC) and platelet counts may be decreased in primary marrow disturbances. Hypersegmented neutrophils and macro-ovalocytes strongly suggest megaloblastic anemia.