MCQs In Nutrition

Q 1:

An 8-month-old infant presents with the primary complaint of irritability. He has been exclusively

breastfed since birth. His mother was not interested in providing any supplemental foods

because her milk supply has been adequate. Physical examination reveals a fussy infant who

has frontal bossing and whose weight and height are both at the 25th percentile. The infant

becomes irritable with movement of the left arm. Arm radiography reveals a humeral fracture

and bowing of both radii. Chest radiography demonstrates enlargement of the costochondral

junctions.

Of the following, the MOST likely diagnosis is

A. congenital syphilis

B. osteogenesis imperfecta

C. vitamin D-deficient rickets

D. vitamin D-resistant rickets

E. vitamin E deficiency

The Answer :

C

Explanation :

The clinical presentation and radiographic findings  described for the exclusively breastfed infant

in the vignette suggest vitamin D-deficient rickets.

Biochemical complications of vitamin D deficiency include reduced calcium and phosphorus absorption, increased parathyroid hormone secretion, and phosphaturia.

Congenital syphilis , vitamin Dresistant rickets, and osteogenesis imperfecta  all can present with skeletal

abnormalities, but these conditions are less common than vitamin D-deficient rickets and

typically have additional clinical findings.

 Vitamin E deficiency presents with neuropathy and hemolysis rather than skeletal abnormalities.

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Q 2 :

You are addressing a group of new mothers regarding infant feeding. One asks you when an

infant can be switched from formula to whole cow milk.

Of the following, you are MOST likely to respond that whole cow milk

A. can be introduced at 6 months of age if an infant has significant gastroesophageal reflux

B. can be given at 9 months of age if the infant is also taking a wide variety of supplemental

foods

C. may be given as a supplement at any age as long as the infant also receives human milk

D. should be avoided until 12 months of age because its iron content is absorbed poorly

E. should be avoided until 2 years of age because its caloric content is inadequate for optimal

growth

The Answer :

D

Explanation :

Iron-fortified formulas are the preferred nutrition for infants up to 12 months of age if a mother is

unable or chooses not to breastfeed. These formulas contain 10 to 12 mg/L of iron,

approximately 4% of which is absorbed by the infant.

 This amount of iron is sufficient to prevent iron deficiency in most term infants until 4 to 6 months of age. At this age, iron stores become depleted and supplemental foods, such as iron-fortified cereals, should be added.

The iron content of cow milk is approximately 0.5 mg/L, and although up to 10% of the iron is

absorbed, it is inadequate to prevent iron deficiency, even if iron-fortified foods are added.

In addition, cow milk may cause increased fecal blood loss in some infants, further exacerbating

iron deficiency.

 Cow milk also has a higher content of protein and electrolytes, such as sodium

and potassium, which results in a renal solute load that is too high for the infant kidney. For

these reasons, cow milk is not recommended until 12 months of age.

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Q 3:


A 3-month-old infant who has a history of renal dysplasia associated with obstructive uropathy has marked polyuria. He is breastfeeding and receiving supplemental cow milk-based formula. In an effort to reduce the high urine output, you consider reducing the renal solute load by changing feedings from the milk-based formula currently being used. Of the following, the MOST appropriate change is to

A. a hydrolyzed formula containing medium-chain triglycerides
B. a more concentrated (24-kcal) milk-based formula
C. human milk exclusively
D. soy milk-based formula
E. whole cow milk

Answer :

C


The infant described in the vignette has polyuria caused by a urinary concentrating defect.

 The concentrating defect is the result of tubular damage due to the obstructive uropathy.

The inability to concentrate the urine causes the kidneys to create an "excessive" volume of urine to excrete the solute load presented to them. One strategy to reduce polyuria is to reduce the solute burden placed on the kidneys.

Potential renal solute load is affected by intake of protein, sodium, potassium, chloride, and phosphorus.

The protein and phosphorus content are the most important variables when comparing infant feeding regimens.

Human milk possesses a lower potential renal solute load than cow milk or cow milk-based formulas. Accordingly, the most appropriate change in feeding for the infant in the vignette is to recommend that the mother stop cow milk formula supplementation and exclusively breastfeed.

If human milk is not available, a "low-solute" cow milk-based formula can be used. A low calcium phosphorus formula has the next lowest potential renal solute load compared with human milk.

Cow milk, soy milk-based formula, hydrolyzed formula with medium-chain triglycerides, and 24-
kcal milk-based formula all have greater renal solute loads than human milk.

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Q 4

A 6-year-old child who has chronic liver disease becomes disoriented and develops vomiting, nausea, and weakness. She is receiving fat-soluble vitamin replacement therapy. Evaluation reveals hypercalcemia, hypercalciuria, and osteopenia.

Of the following, the MOST likely cause of this girl's symptoms is:

A. hypervitaminosis A

B. hypervitaminosis D

C. vitamin A deficiency

D. vitamin E deficiency

E.  vitamin K deficiency

Answer :

B

Patients who have chronic liver and renal disease routinely receive supplemental fat-soluble vitamin therapy, including vitamin D. Excessive amounts of vitamin D result in signs and symptoms similar to those of idiopathic hypercalcemia, including hypotonia, anorexia, irritability, constipation or diarrhea, polydipsia, and polyuria. Hypercalcemia and hypercalcuria often are noted, as in the girl described in the vignette. Vomiting, poor growth, osteopenia, and hypertension also may develop. Prolonged ingestion of excessive vitamin D may result in renal damage due to nephrocalcinosis. Metastatic calcification of the heart, blood vessels, bronchi, and stomach also may occur.

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Q 5

A high school student wants to know why the American Academy of Pediatrics has recommended exclusive breastfeeding during the first 6 months of life and continuation through the second 6 months. Her research resources indicate that cow milk formula has 40% more protein than human milk.

Your discussion about the protein in human milk compared with cow milk formula is MOST likely to include information that mature human milk:

A. feeding results in higher serum concentrations of methionine

B. feeding results in higher serum concentrations of valine

C. has the same concentration of protein as cow milk-based formula

D. protein delays gastric emptying

E. whey proteins have more lactoferrin and secretory immunoglobulin A

Answer

E

There are differences in both the quantity and quality of protein content in human and cow milk. The protein concentration of mature human milk is 0.9 g/dL compared with 3.4 g/dL for cow milk and 1.5 g/dL for modified cow milk formulas that provide 20 kcal/oz. The protein content of human milk is 70% whey and 30% casein; cow milk contains 18% whey and 82% casein. The various modified cow milk formulas have whey contents that vary from 18% to 100%. The predominant whey protein of human milk is alpha lactalbumin and is beta lactoglobulin in cow milk. The whey proteins of human milk provide relatively greater amounts of lactoferrin, lysozyme, and secretory immunoglobulin A than are contained in cow milk formulas.

            The serum levels of methionine, phenylamine, threonine, and valine are higher in infants fed whey-dominant modified cow milk formulas compared with breastfed infants. There is no known adverse effect associated with these differences.

            The whey proteins, which are more plentiful in human milk, are digested more easily and promote gastric emptying.

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Q 6

A severely malnourished 10-year-old boy develops respiratory distress shortly after total parenteral nutrition with 20% dextrose is initiated. His fluid intake is appropriate for his weight and hydration syndrome.

Of the following, the MOST likely cause of his respiratory distress is:

A. excessive carbohydrate administration

B.  excessive lipid administration

C.  excessive protein administration

D.  inadequate bicarbonate administration

E.  inadequate calcium administration

Answer

A

Patients who require parenteral nutrition often are moderately or severely malnourished. Aggressive use of intravenous or enteral nutrition can result in mineral and metabolic abnormalities (hypophosphatemia, hypokalemia, hypoglycemia, hypomagnesemia, hypocalcemia) that lead to respiratory, neuromuscular, cardiac, and hematologic dysfunction, termed refeeding syndrome. In response to chronic undernutrition, there may be compensatory reductions in cardiac output, hemoglobin level, muscle mass, hepatic glycogen content, and renal concentrating ability. Refeeding syndrome occurs when energy substrates, particularly carbohydrate, are initiated in a catabolic patient. The resulting hyperinsulinemia stimulates intracellular uptake of glucose, potassium, phosphorus, and magnesium to support the proliferating body cell mass and hepatic glycogen synthesis.

            Excessive carbohydrate administration can result in respiratory failure, as noted for the boy in the vignette. If the amount of carbon dioxide produced during metabolism of the carbohydrate exceeds the ventilatory capacity, the Pco2 will increase, especially in patients who have underlying pulmonary disease. Water overload, which can result from salt and water retention following the increased insulin concentrations, also is associated with excessive carbohydrate administration. Increased metabolic rate and cardiac workload can lead to congestive heart failure, especially if the left ventricle has been thinned by malnutrition. Although excessive fluid administration can result in congestive heart failure in a malnourished patient, fluids alone do not cause the refeeding syndrome. Careful attention to fluid and calorie administration will help to prevent the refeeding syndrome. Using an alternate source of calories (fat), the metabolism of which produces less carbon dioxide, and supplementation with magnesium, potassium, and phosphorus also will decrease the likelihood of refeeding syndrome developing.

            On an equimolar basis, lipid metabolism produces less carbon dioxide than does carbohydrate and is, therefore, less likely to cause the respiratory failure associated with the refeeding syndrome. Although acidosis and hypocalcemia can develop in patients receiving parenteral nutrition, they are not associated with the development of respiratory failure in the absence of tetany. Excessive protein intake does not have any effect on respiratory function.