Content:
Iron deficiency anemia is a form of microcytic hypochromic anemia, representing the most prevalent nutritional disorder.
◉ Introduction
Iron deficiency anemia is the most common cause of anemia worldwide.
Iron is an important molecule in hemoglobin formation which then carry oxygen to all tissues in our body. Iron deficiency anemia happens when iron deficiency is severe enough to diminish erythropoiesis.
As a result of iron deficiency and lack of oxygen that reach our tissues patient may have symptoms such as shortness of breath, fatigue and palpitations.
◉ Pathogenesis
Iron is an important molecule for vitals in all organisms. Because it is necessary for several metabolic activities, such as oxygen transport, DNA synthesis, and electron transport.
The body carefully regulates iron balance to make sure that enough iron is absorbed to substitute for iron losses.
Iron deficiency anemia occur when there's insufficient iron due to blood loss or decreased iron intake these conditions decrease iron available for hemoglobin synthesis as a result impaired erythropoiesis and production of microcytic hypochromic erythrocytes.
◉ Causes of iron deficiency anemia
There are many factors that contribute to iron deficiency anemia including dietary causes, blood loss and many other causes.
1- Insufficient intake
Decreased iron intake may result from many causes such as:
- Eating disorders as anorexia nervosa, bulimia and pica.
- Self-imposed dietary restrictions as vegan diet or food insecurity.
2- Decreased iron absorption
Malabsorption of iron is a common cause of iron deficiency which may result from many conditions as:
- Gastrointestinal disease: celiac disease, chron's disease, ulcerative colitis, or infection by helicobacter pylori.
- Surgical resection of gastrointestinal tract and bariatric surgery.
- Excess calcium intake.
- Endurance training or exercise: these types of exercises cause loss of iron in athletes through gastrointestinal tract and breakdown of red blood cells (RBCs).
3- Increased iron demand
- Pregnancy and lactation.
- Increased growth: in infant, children and adolescents there's more need for iron to improve tissues growth.
4- Blood loss
- Gastrointestinal bleeding (ulcers, gastritis, colorectal cancer)
- Heavy menstrual bleeding
- Frequent blood donation
◉ Symptoms and signs of iron deficiency anemia
Symptoms of iron deficiency anemia vary from severe to mild depending on the degree of anemia. People with mild anemia may be asymptomatic, but if it is severe, symptoms such as tiredness or angina may develop.
Patients with iron deficiency anemia may complain of the following symptoms:
- Easy fatiguability and intolerance to hard work as patient fell that he gets tired more than usual.
- Headache
- Dizziness
- Palpitations
- Shortness of breath or chest pain.
- Poor memory and poor concentration.
- Cold intolerance: patient unable to tolerate with cold weather.
- Pallor: patient have pale skin (pallor is the most important sign of iron deficiency anemia it does not develop unless hemoglobin is 7-8gm/dl).
- Pounding or whooshing in ear.
- Craving for ice or clay(pica) especially in children with iron deficiency anemia.
On examination:
- Delayed growth in infants and cognitive impairment.
- Pallor in mucous membrane (for example in: conjunctiva, in palmar crease, and in inner lip).
- Spoon like nails(koilonychia).
- Glossitis (smooth tongue): develop due to atrophy of lingual papillae.
- Angular stomatitis: it's a fissure at angle of mouth.
- In untreated severe cases patient may develop splenomegaly.
◉ How is iron deficiency anemia diagnosed?
Diagnosis of iron deficiency anemia depends on obtaining a detailed medical and family history from the patient, as well as assessing the clinical picture presented, with characteristic findings in blood tests. Additionally, the patient should be evaluated for underlying causes that may contribute to iron deficiency anemia.
1- Complete blood count (CBC):
- Low Mean corpuscular volume (MCV).
- Low hemoglobin (Hb) and hematocrit (Htc).
- Low mean corpuscular hemoglobin concentration (MCHC).
- Red blood cell distribution width (RDW): higher than normal range.
- In most cases there's elevated platelet count, especially in patients who are bleeding.
2- Peripheral blooms smear:
- Microcytic hypo-chromic red blood cells.
- Anisocytosis and poilkilocytosis.
- Target cells.
3- Iron studies:
- Serum ferritin (it's a measure of total body iron stores) decreased.
- Serum iron: decreased.
- Transferrin saturation: decreased.
- Total iron binding capacity (TIBC): increased.
4- The Simple Mean Corpuscular Hemoglobin/Red Blood Cells Index, or Mentzer Index, helps differentiate between two causes of microcytic hypochromic anemia. Essentially, this test distinguishes between iron deficiency anemia and thalassemia minor.
- If index > 15 this suggest iron deficiency anemia (IDA).
- If index < 11 this suggest thalassemia minor.
5- Hemoglobin electrophoresis: this is definitive test to rule out thalassemia minor.
6- Fecal occult blood test: this test done to detect blood in stool as anemia may be due to lower gastrointestinal bleeding.
7- Bone Marrow aspiration: this is the standard test for establishing iron deficiency anemia.
8- Upper endoscopy and colonoscopy: these are imaging modalities made to detect abnormalities in gastrointestinal tract as bleeding or disease affect iron absorption.
9- Urine analysis: to detect hemoglobin or blood in urine.
◉ Treatment of iron deficiency anemia
Treatment of iron deficiency anemia requires a doctor to identify the cause and address it. However, even after treating the underlying cause, patients may still need to take medical iron supplements until the deficiency is corrected. In cases where the causes of iron deficiency anemia are not identified, iron supplements may still be recommended.
Increasing iron intake through diet:
Patients should include meat, poultry, fish, leafy green vegetables, and legumes in their diet.
Medical iron:
- Most people require 150-200mg/day of elemental iron (typically 2-5mg/kg per day).
- Vitamin C (ascorbic acid) improves the absorption of iron.
- If a patient takes antacids, they should take iron tablets 2 hours before or 4 hours after taking antacids.
Parenteral iron:
In some cases, doctors may prescribe parenteral iron for patients who have difficulties absorbing iron due to gastrointestinal diseases or those with severe iron deficiency or chronic blood loss. This may also be recommended for patients receiving supplemental erythropoietin or those unable to tolerate oral iron. Preparations of intravenous iron include:
- Iron dextran
- Iron sucrose
- Ferric gluconate
Red Blood Cell transfusion:
Given to actively bleeding patients or those with severe iron deficiency anemia.
◉ Conclusion
In conclusion, there are numerous causes leading to iron deficiency anemia. The management plan is determined based on the specific cause and symptoms of anemia.