PATH - Macrocytic (MCV > 100 fL) anemia

Question 1

Megaloblastic anemia

Answer 1

Impaired DNA synthesis–>maturation of nucleus of precursor cells in bone marrow delayed relative to maturation of cytoplasm.

-RBC macrocytosis
-hypersegmented
neutrophils
-glossitis

Question 2

Folate deficiency

Answer 2

Megaloblastic anemia

INC homocysteine
normal methylmalonic acid

*No neurologic symptoms (vs B12 deficiency).

Causes: malnutrition (alcoholics), malabsorption, drugs (methotrexate,
trimethoprim, phenytoin),  requirement (hemolytic anemia, pregnancy)

Question 3

Vitamin B12 (cobalamin) deficiency

Answer 3

Megaloblastic anemia

INC homocysteine
INC methylmalonic acid

**Neurologic symptoms

diagnosed with the *Schilling test

Causes: insufficient intake (veganism), malabsorption (Crohn disease), pernicious
anemia, Diphyllobothrium latum (fish tapeworm), gastrectomy

Question 4

Orotic aciduria

Answer 4

Megaloblastic anemia

Autosomal recessive

Presents in *children as
failure to thrive, developmental delay, and
megaloblastic anemia refractory to folate
and B12.

INC Orotic acid in urine

Question 5

Diamond-Blackfan-Blackman anemia

Answer 5

Megaloblastic anemia

Rapid-onset anemia within *1st year of life due to intrinsic defect in *erythroid progenitor cells

INC % HbF (but DEC total Hb)

Short stature, craniofacial abnormalities, and upper extremity malformations (triphalangeal thumbs)

Question 6

Nonmegaloblastic anemia

Answer 6

Macrocytic anemia in which DNA synthesis is *unimpaired.

Causes: alcoholism, liver disease

RBC macrocytosis *without hypersegmented
neutrophils