Iron Deficiency Anemia

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Introduction:

Iron is a mineral. Most of the iron in the body is found in the hemoglobin of red blood cells and in the myoglobin of muscle cells. Iron is needed for transporting oxygen and carbon dioxide. It also has other important roles in the body. In people with iron deficiency anemia, the red blood cells can’t carry enough oxygen to the body because they don’t have enough iron. People with this condition often feel very tired.

Iron helps red blood cells deliver oxygen from the lungs to cells all over the body. Once the oxygen is delivered, iron then helps red blood cells carry carbon dioxide waste back to the lungs to be exhaled. Iron also plays a role in many important chemical reactions in the body.

Incidence:

Over 10% of Western urban populations are iron deficient though not all are anemic. In many other parts of the world, the incidence is still higher. Iron deficiency anemia is particularly common in women of child bearing age.

Causes:

1- Poor diet:

Foods rich in iron include:

  • Red meat.
  • Beef liver.
  • Poultry.
  • Seafood.
  • Beans.
  • Dark green leafy vegetables, such as spinach.
  • Dried fruit, such as raisins and apricots.
  • Iron-fortified cereals, breads, and pastas.

2- Malabsorption of iron:

  • Following stomach surgery (rapid transit).
  • Lack of stomach HCL acid (achlorhydria): stomach acidity is required for absorption of iron.
  • Coeliac disease.

3- Blood loss:

This may be via heavy menstruation or bleeding from the bowel or urinary system.

Clinical Features: 

  • General features of anemia: tiredness, shortness of breath on effort, dizziness, and headaches.
  • Angular stomatitis and atrophic glossitis.
  • Brittle spoon-shaped nails (koilonychia).
  • Brittle sparse hair.
  • Pruritis vulvae (itching around female private parts).
  • Rarely a posterior cricoid web may develop (Plummer-Vinson syndrome).

Angular Stomatitis     atrophic glossitis  koilonychia    Koilonychia-2

Investigations:

FBC (Full Blood Count) and Blood Film:

  • Microcytosis (small red cells – MCV <78fl) appears first and progresses as anemia develops.
  • Hypochromia (red cells contain less hemoglobin).
  • Anisocytosis (variation in red cell size).
  • Poikilocytosis (variation in red cell shape).
  • Pencil cells are characteristic.
  • White cell count and platelet count are usually normal, however, platelet count may rise if the cause of the iron deficiency is blood loss.
iron deficiency anemia

Note the small red cells containing a narrow rim of hemoglobin at the periphery. Compare to the scattered, fully hemoglobinized cells derived from a recent blood transfusion given to the patient.

Biochemistry:

  • Serum iron is low (normal range: 10-30 umol/L).
  • Total Iron Binding Capacity (TIBC) is high normal or raised (normal range: 40-70 umol/L).
  • The % Iron Saturation (Transferrin Saturation) is usually <10% (serum iron/TIBC).
  • Serum Ferritin is reduced (usually < 10 ug/dL), although it may be misleadingly higher if there is a coexistent inflammation, infection or malignancy.

Once iron deficiency is diagnosed the underlying cause MUST BE ESTABLISHED by thorough history taking, physical examination, and relevant further investigations like upper and lower Gastrointestinal endoscopy (OGD & Colonoscopy) if GI blood loss or Coeliac disease are suspected; ultrasound scan of the uterus to out rule fibroids if menorrhagia is the likely cause of the iron deficiency anemia is also warranted.

IT IS NOT ENOUGH TO REPLACE THE DEFICIENT IRON … IN ALL CASES, THE CAUSE OF THE IRON DEFICIENCY SHOULD BE IDENTIFIED! IRON DEFICIENCY ANEMIA COULD BE THE FIRST PRESENTING SIGN OF BOWEL CANCER IN THE ELDERLY!

Treatment:

Oral iron:

Oral iron is given to correct the anemia and then replete the body stores (3-6 months).

Administer orally between meals (e.g., 2 hours before or 1 hour after a meal).

Ferrous sulfate 200mg three times daily is cheap and effective though the dose must be reduced in patients who experience side-effects!

Ferrous fumarate capsules (Galfer) 210 mg once or twice daily is also effective.

Oral iron may cause Gastrointestinal disturbances e.g. constipation, diarrhea, stomach discomfort and feeling sick. Some patients are intolerant of oral iron and parenteral iron may be considered if the anemia is severe.

For patients who have difficulty tolerating oral iron supplements, administer smaller, more frequent doses; start with a lower dose and increase slowly to the target dose; try a different form or preparation, or take with or after meals or at bedtime.

Iron-drug interactions of clinical significance may occur in many patients and involve a large number of therapies. Concurrent ingestion of iron causes marked decreases in the bioavailability of a number of drugs e.g. tetracycline, tetracycline derivatives (doxycycline, methacycline and oxytetracycline), penicillamine, methyldopa, levodopa, carbidopa and ciprofloxacin. The major mechanism of these drug interactions is the formation of iron-drug complexes (chelation or binding of iron by the involved drug). A large number of other important and commonly used drugs such as thyroxine, captopril and folic acid have been demonstrated to form stable complexes with iron.

Parenteral iron:

This should only be used if oral iron cannot be tolerated or if negative iron balance persists.

There are many available preparations which can be given as an intravenous iron infusion in the hospital like Injectafer, CosmoFer, Monofer, and Venofer. Parenteral iron should only be administered under strict medical supervision.

References:

Hillman RS, et al. (2011). Iron-deficiency anemia. In RS Hillman et al., eds., Hematology in Clinical Practice, 5th ed., pp. 53-64. New York: McGraw-Hill.

Means RT (2012). Red blood cell function and disorders of iron metabolism. In EG Nabel, ed., ACP Medicine, section 15, chap. 21. Hamilton, ON: BC Decker.

Polk RE, Healy DP, Sahai J et al. Effect of ferrous sulfate and multivitamins with zinc on absorption of ciprofloxacin in normal volunteers. Antimicrob Agents Chemother. 1989; 33:1841-4.

Summary
Iron Deficiency Anemia
Article Name
Iron Deficiency Anemia
Description
In people with iron deficiency anemia, the red blood cells can't carry enough oxygen to the body because they don't have enough iron.
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askhematologist.com
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