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Flashcards in Clinical Correlates 10 Nutrition Deck (49):
1

___ ___ is characterized by self-induced weight loss. Individuals frequently affected include young, affluent, white women, who despite an emaciated appearance, often claim to be ‘‘fat.’’ It is partially a behavioral problem; those afflicted are obsessed with losing weight.

Anorexia nervosa

2

Essential amino acids
a. ___ amino acids cannot be synthesized in the body and are required in the diet: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
b. Only a small amount of ___ is required in the diet; however, larger amounts are required for growth (e.g., children, pregnant women, people recovering from injuries).
c. ___ can be synthesized in limited amounts and is required in the diet for growth.

Nine
histidine
Arginine

3

___ commonly occurs in children in developing countries where the diet, adequate in calories, is low in protein. A deficiency of dietary protein causes a decrease in protein synthesis and eventually inhibits regeneration of intestinal epithelial cells, further compounded by malabsorption. ___ and a distended abdomen are often observed.

Kwashiorkor
Hepatomegaly

4

___ results from a diet deficient in both protein and calories. Persistent starvation ultimately results in death.

Marasmus

5

water soluble vitamin deficiencies
Thiamine B1

Clinical Consequence of Vitamin Deficiency

Beriberi: high-output heart failure (wet beriberi) and peripheral neuropathy (dry beriberi).

Wernicke-Korsakoff syndrome: deficiency in chronic alcoholics manifesting with ataxia, ophthalmoplegia, confusion, and confabulation

6

water soluble vitamin deficiencies
Riboflavin B2

Clinical Consequence of Vitamin Deficiency

Rare deficiency because grain and cereal products are fortified with riboflavin. Deficiency is associated with atrophy of the tongue (glossitis), fissures of the corner of the mouth (cheilosis), dermatitis, and corneal ulceration.

7

water soluble vitamin deficiencies
Niacin B3

Clinical Consequence of Vitamin Deficiency

Deficiency results in pellagra, characterized by diarrhea, dementia, and dermatitis. Deficiency can result from the antituberculoid medication isoniazid, Hartnup disease, or carcinoid syndrome.

8

water soluble vitamin deficiencies
Pyridoxine B6

Clinical Consequence of Vitamin Deficiency

Most severe symptoms due to the requirement for decarboxylating glutamic acid to the inhibitory neurotransmitter GABA, resulting in seizures. Deficiency can be associated with isoniazid or penicillamine use.

9

water soluble vitamin deficiencies
Biotin

Clinical Consequence of Vitamin Deficiency

Deficiency is rare because biotin is synthesized by gastrointestinal bacteria, although deficiency may be associated with long-term antibiotic use. Deficiency is also associated with the consumption of raw eggs, containing avidin, that binds and inhibits absorption of biotin.

10

water soluble vitamin deficiencies
Cobalamin B12

Clinical Consequence of Vitamin Deficiency

Deficiency associated with lack of intrinsic factor, produced by parietal cells of the stomach. Deficiency results in a block in purine and thymidine biosynthesis, resulting in megaloblastic anemia and subacute combined degeneration of the spinal cord. It also causes a functional deficiency of folate.

11

water soluble vitamin deficiencies
Folate

Clinical Consequence of Vitamin Deficiency

Lack of folate results in impaired thymidine monophosphate (dTMP) synthesis, with arrest of DNA synthesis in rapidly dividing cells, like hematopoietic cells, resulting in megaloblastic anemia. Pregnant patients require more folate; deficiency results in neurotubule defects, such as spina bifida, in the developing fetus.

12

water soluble vitamin deficiencies
Vitamin C

Clinical Consequence of Vitamin Deficiency

Deficiency can result in scurvy, which is characterized by easy bruising, muscular fatigue, soft swollen gums, hemorrhage, and anemia.

13

Biochemical Function
Thiamine B1

Cofactor for pyruvate and a-ketoglutarate dehydrogenase

14

Biochemical Function
Riboflavin B2

Precursor to the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)

15

Biochemical Function
Niacin B3

Required for the production of NAD+ and NADP+ as well as numerous

16

Biochemical Function
Pyridoxine B6

Required for several transaminase and decarboxylation reactions

17

Biochemical Function
Biotin

Required for some carboxylation reactions

18

Biochemical Function
Cobalamin B12

Required by methylmalonyl CoA mutase and methionine synthase

19

Biochemical Function
Folate

Reduced by dihydrofolate reductase to tetrahydrofolate (THF), which functions as a one-carbon donor in many biosynthetic pathways

20

Biochemical Function
Vitamin C

Hydroxylation of proline residues in collagen and aids in iron absorption

21

Lipid Soluble Vitamin Deficiencies
Deficiency results in night blindness, dry eyes leading to corneal damage, and urinary stones

Vitamin A

22

Lipid Soluble Vitamin Deficiencies

Rickets in children results in defective bone ineralization
with a ‘‘squared’’ head, chest deformity, spine abnormalities, and bowing of the legs. In adults, osteomalacia can occur, with weakening of bone and increased incidence of fracture.

Vitamin D

23

Lipid Soluble Vitamin Deficiencies

Rare; however, lack of vitamin E can contribute to the development of atherosclerosis and cardiovascular disease.

Vitamin E

24

Lipid Soluble Vitamin Deficiencies

Deficiency is seen in newborns because vitamin K is produced by the yet undeveloped gastrointestinal flora, resulting in hemorrhage and bleeding diathesis. The blood thinner warfarin, used to treat blood clots, antagonizes the vitamin’s actions.

Vitamin K

25

Biochemical Function

Required for growth and differentiation; required for the production of the light-absorbing vision protein rhodopsin

Vitamin A

26

Biochemical Function

Regulation of gene expression for the absorption of calcium from the gastrointestinal tract

Vitamin D

27

Biochemical Function

Functions as an antioxidant and free radical scavenger

Vitamin E

28

Biochemical Function

Required for the g-carboxylation of coagulation factors II, VII, IX, and X

Vitamin K

29

A normal person refers to a 70-kg individual with a fuel reserve of 30% by weight. The increased reserve of the obese individual is mostly fat. Complete fasts indicate one can live without food, but with water, for about 60 days (theoretically, a 70-kg person has 21 kg of fuel reserve, divided as 15 kg of fat and 6 kg of protein. This approximates 165,840 calories of energy. The daily metabolic need of such a person is about 2620 calories per day, for a survival time of 63 days). Death ensues when ___ ___ (e.g., from brain, heart) start to
be used for energy.

essential proteins

30

Important Mineral Deficiency
Copper

Deficiency results in muscle weakness, neurologic defects, and abnormal collagen cross-linking.

31

Important Mineral Deficiency
Iodine

Deficiency results in goiter and hypothyroidism; uncommon with the advent of iodized salt.

32

Important Mineral Deficiency
Iron

Deficiency results in defective hemoglobin production and developing hypochromic, microcytic anemia.

33

Important Mineral Deficiency
Selenium

Deficiency results in cardiomyopathy (Keshan disease).

34

Important Mineral Deficiency
Zinc

Deficiency results in growth retardation and impaired
wound healing.

35

Copper
Biochemical Function

Component of many oxidases in oxidative metabolism, neurotransmitter synthesis, and collagen synthesis

36

Iodine
Biochemical Function

Essential component of thyroid hormone

37

Iron
Biochemical Function

Essential component of hemoglobin as well as other metalloenzymes

38

Selenium
Biochemical Function

Component of glutathione peroxidase

39

Zinc
Biochemical Function

Component of many oxidases

40

Patients with severe liver disease cannot detoxify __ and thus develop hepatic ____ from the accumulation of ____. ___ is used to treat this condition and reduces ammonia by either increasing bacterial assimilation of ammonia or reducing deamination of nitrogenous compounds.

ammonia
encephalopathy
ammonia in the CNS
Lactulose

41

_____ are common diagnostic markers of liver damage found in serum. The cytosolic alanine aminotransferase (ALT) and aspartate aminotransferase
(AST) are released from dying cells upon insult.

Transaminases

42

The BUN is a widely used measure of the kidney’s functional ability to excrete the ___ waste produced by the body.

nitrogenous

43

EPO, produced by recombinant DNA technology, is used in the management of ___ resulting from kidney failure, hemolytic anemia, or anemia associated with chemotherapy. It is also a blood doping agent in endurance sports such as cycling, rowing, and long-distance running.

anemia

44

5. A 57-year-old alcoholic man with chronic pancreatitis is admitted to the hospital for treatment. The absorption of which one of the following vitamins may be affected with pancreatitis?
(A) Vitamin B12 (cobalamin)
(B) Folic acid
(C) Vitamin B2 (riboflavin)
(D) Vitamin B6 (pyridoxine)
(E) Vitamin D

E. Although alcoholics are often malnourished with various nutrient deficiencies, pancreatitis will affect the role of the exocrine pancreas in the absorption of fat-soluble vitamins. Vitamin D is the only vitamin listed that is fat soluble; the other vitamins listed are water soluble.
With the lack of pancreatic lipase dietary fat cannot be digested, and the fat-soluble vitamins cannot be released from the lipids. The vitamins thus pass through the intestine, nonabsorbed. The other fat-soluble vitamins are vitamins E, K, and A.

45

6. A 54-year-old Native American living on an Indian reservation in southwest Arizona is brought into the clinic by a family member. They are concerned because of impaired memory, diarrhea, and a rash on the face, neck, and dorsum of the hands. Which vitamin deficiency
do these symptoms represent?
(A) Niacin
(B) Cobalamin
(C) Folic acid
(D) Vitamin C
(E) Vitamin E

A. The patient presents with the classic presentation of pellagra, or niacin deficiency, with diarrhea, dementia, and dermatitis. Niacin is synthesized from the essential amino acid tryptophan, which is particularly deficient in corn-based diets. However, niacin is still required in the diet because the amount of niacin derived from tryptophan is insufficient for daily needs. A cobalamin deficiency (vitamin B12) will lead to megaloblastic anemia along with methylmalonic acidemia. Folic acid deficiency often manifests with megaloblastic anemia. Vitamin C deficiency results in scurvy. Vitamin E deficiency is rare and can result in neurologic symptoms.

46

7. A 32-year-old woman presents to the physician with extreme fatigue and vague neurologic complaints. On examination, it is found that she has decreased positional and vibrational sense, and her complete blood count reveals a megaloblastic anemia. She relates a history of gastric resection 4 years ago for severe stomach ulcers. Which vitamin deficiency does this represent?
(A) Vitamin C
(B) Vitamin D
(C) Vitamin K
(D) Vitamin B12
(E) Folate

D. Both folate and vitamin B12 deficiency lead to a megaloblastic anemia secondary to a reduction in DNA synthesis. Only vitamin B12 deficiency causes neurologic dysfunction associated with damage to the dorsal spinal columns. The history of gastric resection is consistent with a deficiency of intrinsic factor required for reabsorption of vitamin B12 in the terminal ileum. Vitamin C, D, and K deficiencies will not lead to megaloblastic anemia.

47

8. A 75-year-old chronic alcoholic man presents to the emergency room after being found unconscious on the floor of his home. On examination, he is found to have a distended abdomen consistent with ascites.Which of the following functions of the liver has been compromised to lead to the finding of abdominal ascites?
(A) Lipid metabolism
(B) Albumin synthesis
(C) Estrogen metabolism
(D) Alcohol detoxification
(E) Decreased production of coagulation factors

B. Cirrhosis results in several complications, including ascites, caused by decreased oncotic pressure causing extravasation of intravascular fluid. Albumin is the primary protein that maintains oncotic pressure within the vessels. Albumin is synthesized by the liver, and in malnourished or chronic disease states, such as chronic alcoholism, the liver synthesizes reduced levels of albumin, and hypoalbuminemia results. Decreased production of coagulation factors leads to bleeding problems, not ascites production. Ascites production is not due to problems in lipid metabolism, estrogen metabolism, or alcohol detoxification.

48

9. A 45-year-old alcoholic man walks into the emergency room with a clumsy, wide-based gait and appears confused. He has pronounced nystagmus, and laboratory tests are significant for a metabolic acidosis and a serum blood alcohol level of 0.13. This patient should most probably be treated with IV fluids containing
which of the following?
(A) Thiamine
(B) Riboflavin
(C) Niacin
(D) Pantothenic acid
(E) Biotin

A. Wernicke encephalopathy, with the classic triad of ataxia, confusion, and ophthalmoplegia (and nystagmus), is due to thiamine deficiency. Thiamine is an essential coenzyme in carbohydrate metabolism, including the pentose-phosphate pathway (transketolase) and the TCA cycle (pyruvate dehydrogenase and a-ketoglutarate dehydrogenase). Riboflavin deficiency is possible in malnourished alcoholics, causing cheilosis, glossitis, and corneal changes. Niacin deficiency causes diarrhea, dementia, and dermatitis. Deficiencies of pantothenic acid and biotin are rare, although a biotin deficiency will lead to hypoglycemia and mild ketosis.

49

10. A fourth-year medical student does an international rotation in Sub-Saharan Africa. While immunizing children against polio, he sees hundreds of malnourished children in refugee camps with bloated-appearing abdomens. He learns that they are severely protein deficient because they are fed a diet of cornmeal that is provided by international relief agencies. These children likely suffer from which of the following?
(A) Marasmus
(B) Anorexia nervosa
(C) Bulimia
(D) Kwashiorkor
(E) Cachexia

D. Protein deficiency (but not overall calorie deficiency), as in kwashiorkor, results in a deficiency of visceral proteins, including those in the blood that normally provide oncotic pressure to retain fluid within vessels. As such, patients with kwashiorkor have abdominal bloating secondary to edema. Marasmus is a deficiency of calories and protein; the children in this question are presumably receiving carbohydrate calories through the cornmeal. Anorexia nervosa and bulimia are disorders of self-induced weight loss that are found mostly in developed countries. Cachexia is weight loss associated with cancer.