Nutritional Diseases

CASE 1: Pregnancy and Iron Deficiency

Clinical History:

A 22-year-old woman is in the 2nd trimester of her first pregnancy (G1 P0). An ultrasound performed at 18 weeks gestation showed a normal male fetus with no apparent abnormalities. She has felt progressively more tired and weak as the weeks have passed, however. She delivers a 2400 gm infant at 38 weeks gestation. The Apgar scores are 6 at 1 minute and 8 at 5 minutes. The baby has a pale color. Both baby and mother continue to appear pale and somewhat listless at well-baby checkups in the ensuing 3 months.

A CBC is ordered on the mother and shows:
WBC count8500/uL
Hgb9.8 g/dL
MCV70 fL
Platelet count481,000/uL

  1. How do you interpret the CBC?

  2. The WBC count and platelet count are normal. The Hgb and Hct indicate anemia of a moderate degree. The low MCV indicates that this is a microcytic anemia. Examination of her peripheral blood smear will show hypochromasia (pale red blood cells with an increased zone of central pallor) and microcytosis (small red blood cells). The platelet count is often high.

  3. What is the most likely cause for these findings?

  4. The microcytic anemia is characteristic for an iron deficiency anemia. Iron deficiency is the most prevalent dietary deficiency in the world. Persons at greatest risk are women in reproductive years (with menstrual blood loss), pregnant women, and children. Iron is an integral component of heme, which together with globin chains forms hemoglobin. Less iron available to make heme means downsizing with less hemoglobin packaged into each RBC, so RBCs are smaller.

  5. What other laboratory tests can you do to confirm the diagnosis?

  6. The CBC data are solid, and without a history of additional problems it is unlikely that further testing will change your diagnosis. If you were to confirm the diagnosis of iron deficiency, the cheapest method would be a serum iron with iron binding capacity. A serum ferritin will also indicate iron stores. In this case, typical values would be:

    • Serum iron 20 micrograms/dL (30 - 160 for females)

    • TIBC 500 micrograms/dL (240 - 450)

    • Ferritin 6 ng/mL (7 - 75 for females)

    Note the low serum iron and high iron binding capacity, with very low % saturation (4%). Note the low serum ferritin. These findings are consistent with iron deficiency.

    If you wanted to waste resources, you could do a bone marrow biopsy and show diminished iron stores, which is the most definitive test.

  7. What are the dietary sources to alleviate this problem?

  8. Iron is most abundant in heme, and heme is found in red meat. For vegetarians, there is spinach (Popeye's favorite). Non-heme iron is found primarily in fruits, vegetables, dried beans, nuts and grain products. Absorption of iron from non-heme foods can be increased by a good source of vitamin C (ascorbic acid) such as oranges, grapefruits, tomatoes, and broccoli.

  9. What pharmacologic therapy is available to treat this condition?

  10. Intramuscular injections of iron (iron dextran complex) are rarely used. Pharmaceutical products with iron (iron alone or more likely iron supplemented vitamins) are available, but one must be careful with their use. The standard tablets have 25 to 50 mg of iron. It is possible to overdose on iron. The body has no mechanism for ridding itself of excess iron. Just 25 tablets of 25 mg each can produce severe toxicity in a small child. 3 gm of iron is lethal to a 2-year-old child.