Zinc deficiency and protein-energy malnutrition: Pathology review

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A 2 year old girl, named Addae, is brought to the pediatric clinic for a well-child visit.

She was adopted from Ghana a month ago, and her new parents tell you that they’ve noticed dark patches of flaky skin all over her body.

Physical examination reveals erythematous plaques on her face, axilla, and groin skin folds, as well as prominent rounded cheeks and a distended abdomen.

You also notice that both her feet and ankles are swollen, and when you press for a few seconds, a pit remains.

Finally, upon palpation of the abdomen, the liver appears enlarged.

You decide to run some blood tests, which reveal that Addae has decreased serum levels of albumin.

Based on the history and initial presentation, Addae seems to have some form of malnutrition, which results from not getting enough nutrients from the diet.

For your exams, two important conditions associated with malnutrition include zinc deficiency, meaning there’s not enough zinc to meet the body requirements, as well as protein-energy malnutrition, which refers to a lack of energy due to the inadequate intake of protein or total calories, and has two major forms: Kwashiorkor and marasmus.

Okay, let’s begin with zinc deficiency.

Zinc is a mineral that’s found mostly in poultry, oysters, and fish.

Normally, it is mainly absorbed in the duodenum and jejunum, and gets transferred via the portal circulation to the liver, where it gets stored.

So, for your test, note that the liver is the main organ involved in maintaining systemic zinc homeostasis.

Now, zinc is essential for the function of hundreds of different enzymes.

In addition, zinc is necessary for the formation of specific transcription factors motifs, known as zinc fingers, that bind DNA and regulate the expression of various genes.


Zinc deficiency is mainly caused by inadequate dietary consumption or a defect in intestinal absorption, like celiac disease and acrodermatitis enteropathica, and it's commonly associated with alcoholic cirrhosis. Symptoms include impaired wound healing, alopecia, immune dysfunction, dysgeusia, anosmia, and male hypogonadism. Protein-energy malnutrition is most common in resource-deprived regions and includes Kwashiorkor and marasmus. Kwashiorkor is due to inadequate protein intake with normal or increased calorie intake and presents in children between 6 months and 3 years of age with lethargy, poor appetite, susceptibility to infections, bilateral pitting edema, moon faces, mild muscle wasting, distended abdomen with an enlarged fatty liver, hair loss, and dermatitis.

Marasmus is due to inadequate calorie intake from all macronutrients and presents in infants under the age of 1 with restlessness or irritability, voracious appetite, susceptibility to infections, an emaciated appearance, profound muscle wasting, and dry and wrinkled skin. However, with marasmus, the abdomen is typically flat, and there is no edema or hepatomegaly. Blood tests in both Kwashiorkor and marasmus may show electrolyte disturbances, like hypophosphatemia, hypomagnesemia, and hypokalemia, as well as anemia and lymphocytopenia. But what sets them apart is that Kwashiorkor also has hypoalbuminemia, while in marasmus, serum albumin is normal or slightly decreased.


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