Iron deficiency and iron deficiency anemia (pediatrics): Clinical sciences

Iron deficiency is a condition that occurs when the body lacks sufficient iron for normal growth, development, and production of enough healthy red blood cells. Iron plays a vital role in the production of hemoglobin, which is the protein responsible for carrying oxygen in red blood cells. Consequently, when iron levels are low, the body is unable to produce an adequate amount of hemoglobin, leading to impaired red blood cell production. You can differentiate between iron deficiency without anemia and iron-deficiency anemia by examining your patient’s laboratory results.

Now, if a pediatric patient presents with a chief concern suggestive of iron deficiency or iron-deficiency anemia, first, you should obtain a focused history and physical examination. The history typically reveals vague symptoms like fatigue, lightheadedness, low muscular endurance, and palpitations, which manifest as a compensatory response to inadequate tissue oxygen supply.

Caregivers may also report behavior changes, such as poor concentration or irritability, as well as pica, which is the compulsive consumption of non-nutritive substances like dirt or ice. Finally, keep in mind iron deficiency risk factors, like heavy menstrual bleeding, exposure to lead, certain chronic conditions, low dietary iron intake, and active participation in athletics. Additionally, the physical exam might reveal tachycardia and tachypnea. You may also notice pallor, which is most often visible in the conjunctivae, lips, and nail beds. Other common findings include brittle nails and koilonychia, characterized by nails that are concave or spoon-shaped. Finally, you might notice glossitis, which is a smooth and glossy tongue, as well as angular stomatitis, which refers to inflammation and cracking at the corners of the mouth.

Now, here’s a clinical pearl to keep in mind! Certain medications can potentially result in iron deficiency, such as nonsteroidal anti-inflammatory drugs or NSAIDs, which can increase the risk of peptic ulcers and subsequent bleeding; and proton pump inhibitors or PPIs, which can reduce absorption of iron. So, if your patient has been using these medications, this should increase your suspicion of iron deficiency.

At this point, you should suspect iron deficiency, so your next step is to check labs. First, to identify anemia, you’ll need to order a CBC, which includes a hemoglobin level, as well as red blood indices, such as the mean corpuscular volume, or MCV. You should also order labs to check your patient’s iron status. These include the reticulocyte hemoglobin concentration; serum ferritin, which is a sensitive indicator of the body’s iron stores; transferrin saturation or TSAT, which is the percentage of occupied iron-binding sites on transferrin; and the total iron-binding capacity, or TIBC, which measures the blood’s ability to attach to iron and transport it throughout the body.

Here’s a high yield fact to keep in mind! Serum iron concentration is often not obtained in pediatrics, especially because it does not necessarily help with differentiating iron deficiency without anemia from iron deficiency anemia. Even so, keep in mind that serum iron concentration is often normal in iron deficiency without anemia, and low in iron deficiency anemia.

Now, let’s move on and discuss the lab results you’d expect to see in iron deficiency without anemia. In this case, the CBC will reveal normal hemoglobin values for your patient’s age and biological sex, and a normal MCV. On the flip side, reticulocyte hemoglobin concentration, serum ferritin, and transferrin saturation will be low; while the total iron-binding capacity will be normal. With these findings, you can diagnose iron deficiency without anemia.

Now, here’s a clinical pearl to keep in mind! Serum ferritin is a sensitive measure of the body’s iron stores, but because it’s also an acute phase reactant, it can be elevated in some chronic conditions, even in the setting of iron deficiency. If your patient has a chronic illness, and their serum ferritin level is in the normal range, you should still consider iron deficiency. Look at the TSAT, and if it’s below 20%, diagnose iron deficiency, in addition to anemia of chronic disease.