Welcome to NP Certification Q&A presented by Fitzgerald Health Education Associates. This podcast is for NP students studying to pass their NP certification exam. Getting to the correct test answers means breaking down the exam questions themselves. Leading NP expert Dr. Margaret Fitzgerald shares her knowledge and experience to help you dissect the anatomy of a test question so you can better understand how to arrive at the correct test answer. So, if you're ready, let's jump right in.
A 12-month-old is seen for well-child care. He's been walking solo since age 11 months, and now waves “bye bye,” searches for an item under a blanket, as well using “Mama” and “Dada” specifically. His physical exam is within normal limits. Laboratory evaluation reveals a mild microscopic hypochromic anemia with an elevated RDW. The NP considers which of the following two are the most likely contributing causes of this anemia?
And the correct answers are B. and C., Plumbism and Iron deficiency.
Where do you start? First, consider what kind of a question this is. Well, technically anemia is not a diagnosis, but rather a clinical syndrome of signs and symptoms attributable to an underlying cause. We're just going to kind of ignore that anemia is not a diagnosis, and we're going to call this a diagnosis question.
A bit of background information here. Iron deficiency anemia presents as a microcytic hypochromic anemia with an elevated RDW in the child, the adult, the elder, it matters not the age group. In the first year of life, the diet should be quite replete with iron, either from breastfeeding, with iron supplementation, or iron-fortified formula. As the child ages and the child gets into toddler years, and technically this little one's now a toddler because the little one is a year old, 12 months old, foods rich in iron should be offered, including iron-fortified cereals and a wide variety of protein and vegetable sources that are high in iron. However, in that first year of life, in this scenario, again, as a one-year-old, the little one does draw off of birth iron stores, and those are only as good as the mom's iron stores were during pregnancy. In other words, iron deficiency is not all that uncommon at age one year, even in otherwise well children.
If you recall, what makes up 90% of the red blood cells volume? It's hemoglobin, a combination of heme, which is largely iron-based, and globin, which is a protein. When there's not enough iron in a red blood cell, I'm going to say this one more time because no matter how old the person is, this isn't just a pediatric issue, but when there's not enough iron in a red blood cell, then the cell will be small, described as microcytic, and pale, described as hypochromic. The new cells will be even smaller and paler than the old cells as the anemia evolves. Hence, the RDW will be elevated. Clearly, iron deficiency is one of the considerations in this anemia.
But we're dealing with the toddler, so we have to keep in mind plumbism, also known as lead poisoning or lead toxicity. This condition remains a significant public health problem. Today, there are children in at least 4 billion U.S. households who are exposed to high levels of lead, largely through lead-based paint. There are approximately half a million children in the United States at any given time, age one through five, with lead levels that are above 5 micrograms per DL. The reference level, which the CDC considers that is a public health risk, and that efforts to prevent or mitigate exposure to lead should be initiated.
How does this happen? Well, ingested lead inactivates heme synthesis by inhibiting the insertion of iron into the protoporphyrin ring. This leads to the development of a microcytic hypochromic anemia with an elevated RDW. Some of the other issues to consider with lead toxicity is the lead can deposit in solid organs, the bones, and the nervous system. Long-term complications of lead poisoning include behavior or attention problems, poor academic performance, hearing challenges, kidney damage, reduced IQ, and slowed body growth.
Very high levels of lead like levels of lead of 40 or greater. And remember, anything greater than 5 is considered to be problematic, so, 40 is sky high. Very high levels of lead like that can result in vomiting, staggering gait, muscle weakness, seizures, or comas. But most children will present with rather low lead levels even when they achieve a diagnosis of plumbism, and they'll have few or no symptoms.
Periodic screening of all children is recommended, particularly between the ages of one and four years, usually done annually, regardless of where the child lives. Period. Why ages one through four? Because these are the prime lead poisoning years in early childhood. Overall, the amount of lead exposure in the environment for all ages is markedly reduced from where it was 40 to 50 plus years ago, owing to two major public health initiatives. One is gasoline at one time contained lead, and therefore when the gasoline burned in an internal combustion engine like a car or any other kind of motor that uses gasoline, the lead was liberated into the environment. And leaded gasoline has not been sold in the United States for a number of decades. That dramatically reduced lead that was in the air, and therefore all of us benefit from this public health initiative. The other is lead-based paint, which is the most common source of lead exposure in toddlers, such as with this child. Lead-based paint has not been sold in the United States since the late 1970s. However, children living in housing built prior to the late 1970s, and in particular prior to the late 1950s, still have significant lead exposure if there's not been lead mitigation in the housing.
I'm particularly sensitive to this since I practice in a community where a good deal of the housing stock was built prior to the 1970s. Why is then lead paint such a potent source of plumbism for toddlers? Think for a minute: these kids are walking, that's what we've been told in this question, and windowsills are at a perfect height for a toddler to chew on or pick up small pieces of lead paint if these are present in the environment. And if you're wondering why would a toddler eat a chip of paint? Apparently, lead-based paint has a slightly minty taste to it And toddlers, trust me, will eat just about anything. And that's why being vigilant to ingestion of non-food substances with toddlers is so key to discuss with parents. With that in mind, let's take a look at the question and the possible answer options.
Before we get into the possible answers, though, I want to point out to you the developmental assessment of this child, as reported is just spot on, hitting a number of milestones within appropriate parameters.
A 12-month-old is seen for a well-child care. He has been walking solo since age 11 months, now waves “bye bye,” searches for an item under a blanket, as well as using “Mama” and “Dada” specifically. His physical exam is within normal limits and laboratory evaluation reveals a mild microcytic hypochromic anemia with an elevated RDW. And the NP considers which of the following two are the most likely contributing causes of this anemia?
A. Vitamin B12 deficiency. Well, clearly this is incorrect. First, in the toddler years, B12 deficiency is nearly non-existent. You know, in our line of work, you hardly ever say never or always, but it's so close to never with B12 deficiency in childhood. Keep in mind dietary B12 deficiency at any age is quite uncommon. And what's the most common cause of B12 deficiency? This is, of course, pernicious anemia, which is the result of an autoimmune process where B12 transport is markedly decreased. Pernicious anemia is most often seen in older adults. And then, of course, it will present with a macrocytic normochromic anemia with an elevated RDW, and usually neuro findings like numb hands, numb feet, something like that. Keeping in mind what you already know about anemia, you should be able to eliminate B12 deficiency from the four choices pretty quickly.
B. Plumbism. This, of course, is one of the correct answers. On occasion, particularly with one of the certifying exams, you'll be asked a question where more than one choice is correct, but you'll always, always be told how many are correct. And we were advised here that two correct options follow. There are no all of the above or none of the above questions on any of the boards.
As mentioned, this child is prime time for plumbism, the toddler years. And we're being told that this little one has been walking for more than a month. Routine screening for plumbism in this age group is recommended. In a future podcast, I'll get into the treatment of iron deficiency and plumbism in the toddler years. Milder plumbism, as I mentioned, typically presents as a microcytic hypochromic anemia with an elevated RDW in a child who is otherwise well.
One last comment. Of course, on rare occasion, adults can present with plumbism. But invariably what this is, is it's traceable to an industrial exposure, particularly if lead mitigation practices are not in place as are required by OSHA.
C. Iron deficiency. This, of course, is the other correct answer for the reasons I've already outlined. Kids are more at risk for iron deficiency once they hit the toddler years. Iron deficiency, no matter what the cause, no matter what the age of the patient will present as a microcytic hypochromic anemia with an elevated RDW, since the body is circulating those small pale iron cells. The new cells are even more iron deficient than the existing cells until the anemia is treated. Hence the elevated RDW. Once the anemia is treated with iron deficiency and really all the other pathologic anemias, the abnormality in the RBC indices will result.
Key takeaway: As I've said countless times. Common conditions occur commonly. What are the two most common reasons for an otherwise well little one to present with a microcytic hypochromic anemia, with an elevated RDW? It'll be iron deficiency and plumbism. Keeping in mind who is most likely to have a given disease and how it would present is key to safe practice and to NP board success.
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