What is the significance of a low ferritin level of 5 ng/mL in a 33-year-old female with a history of iron deficiency anemia, not currently on iron supplementation medication?

Differential Diagnosis for a 33-year-old Female with Iron Deficiency

Single Most Likely Diagnosis

• Iron Deficiency Anemia due to Menstrual Blood Loss: This is the most likely diagnosis given the patient's history of iron deficiency and low ferritin level, which is a common condition in premenopausal women due to regular menstrual blood loss.

Other Likely Diagnoses

• Dietary Iron Deficiency: Inadequate dietary iron intake can lead to iron deficiency, especially in individuals with increased iron requirements or those following a vegetarian or vegan diet.
• Gastrointestinal Blood Loss: Conditions such as ulcers, gastritis, or inflammatory bowel disease can cause chronic blood loss, leading to iron deficiency.
• Pregnancy or Lactation: Increased iron demands during pregnancy or lactation can lead to iron deficiency if not adequately supplemented.

Do Not Miss Diagnoses

• Celiac Disease: An autoimmune disorder that can cause malabsorption of iron and other nutrients, leading to iron deficiency. It's crucial to consider this diagnosis to avoid long-term complications.
• Colon Cancer or Other Malignancies: Although less common, iron deficiency can be a presenting sign of colon cancer or other malignancies, especially in older adults, but it should not be overlooked in younger individuals.
• Inherited Disorders (e.g., Hereditary Hemochromatosis): While more commonly associated with iron overload, some genetic disorders can lead to iron deficiency or affect iron metabolism.

Rare Diagnoses

• Gastric Bypass Surgery or Other Malabsorptive Conditions: Certain surgical procedures or conditions that affect the gastrointestinal tract can lead to iron malabsorption and deficiency.
• Chronic Diseases (e.g., Rheumatoid Arthritis, Chronic Kidney Disease): Some chronic conditions can lead to iron deficiency due to inflammation, blood loss, or decreased iron absorption.
• Parasitic Infections (e.g., Hookworm): Infections with certain parasites can cause chronic blood loss and lead to iron deficiency, particularly in individuals from or traveling to endemic areas.