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• Restless Legs Syndrome: An irresistible urge to move the legs, often accompanied by uncomfortable sensations.
• Glossitis: Swelling and soreness of the tongue.
• Poor Appetite: Especially in more severe cases.
• Irritability: Due to fatigue and overall discomfort.

2. Explain the laboratory findings in John Doe’s case and how they support the diagnosis of iron deficiency anemia.

John Doe’s laboratory findings strongly support the diagnosis of iron deficiency anemia:

• Hemoglobin (Hb): 9.5 g/dL (Normal range: 13.5-17.5 g/dL)
  • John’s hemoglobin level is significantly low. Hemoglobin is the protein in red blood cells that carries oxygen, and low levels directly indicate anemia.
• Hematocrit (Hct): 29% (Normal range: 40-50%)
  • Hematocrit represents the percentage of red blood cells in the total blood volume. John’s low hematocrit further confirms the reduced number of red blood cells, consistent with anemia.
• Mean Corpuscular Volume (MCV): 75 fL (Normal range: 80-100 fL)
  • John’s MCV is below the normal range, indicating that his red blood cells are microcytic (smaller than normal). This is a hallmark feature of iron deficiency anemia because iron is crucial for synthesizing heme, a component of hemoglobin, and without enough iron, the red blood cells cannot properly mature and remain small.
• Serum Iron: 25 mcg/dL (Normal range: 60-170 mcg/dL)
  • John’s serum iron level is very low. This directly measures the amount of iron circulating in the blood. A low level points to a depleted iron supply.
• Total Iron Binding Capacity (TIBC): 400 mcg/dL (Normal range: 250-450 mcg/dL)
  • John’s TIBC is at the higher end of the normal range, indicating that his body is trying to compensate for low iron by increasing its capacity to bind and transport any available iron. In iron deficiency anemia, the body’s iron stores are low, so it upregulates transferrin (the protein that binds iron), leading to an increased TIBC, showing it has many “empty seats” to pick up iron.
• Ferritin: 10 ng/mL (Normal range: 30-400 ng/mL)
  • John’s ferritin level is significantly low. Ferritin is the primary protein that stores iron in the body. A low ferritin level is the most sensitive and specific indicator of depleted iron stores, confirming iron deficiency.

In summary, the low hemoglobin and hematocrit confirm anemia, the low MCV points to microcytic red blood cells, and the triad of low serum iron, high TIBC (or high-normal trying to compensate), and critically low ferritin collectively confirms that the anemia is specifically due to iron deficiency.

3. What are the potential causes of iron deficiency anemia in adults, and how would you approach further investigations in this patient?

The potential causes of iron deficiency anemia in adults generally fall into three categories:

1. Chronic Blood Loss (Most Common Cause in Adults):
   • Gastrointestinal (GI) Bleeding: This is the most common cause in adult males and post-menopausal women. Sources include:
     • Peptic Ulcers: Gastric or duodenal ulcers.
     • Esophagitis/Gastritis: Inflammation of the esophagus or stomach.
     • Colon Polyps or Cancer: Growths in the large intestine.
     • Diverticulosis: Small pouches in the digestive tract that can bleed.
     • Inflammatory Bowel Disease (IBD): Crohn’s disease or ulcerative colitis.
     • Angiodysplasia: Abnormal blood vessels in the GI tract.
     • Medications: Chronic use of NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) like ibuprofen, or aspirin, can cause GI irritation and bleeding.
   • Menstrual Blood Loss: Heavy or prolonged menstrual periods (menorrhagia) are a very common cause in pre-menopausal women.
   • Urinary Tract Bleeding: Less common, but chronic bleeding from the kidneys or bladder.
   • Frequent Blood Donations: Can deplete iron stores over time.
2. Inadequate Iron Intake or Absorption:
   • Dietary Deficiency: Insufficient intake of iron-rich foods (e.g., vegetarians/vegans who don’t adequately supplement or combine foods).
   • Malabsorption Syndromes: Conditions that impair nutrient absorption in the small intestine, such as:
     •