Nutritional Assessment

Question 1

Copper deficiency is associated with

1: leukocytosis.
2: macrocytic anemia.
3: microcytic hypochromic anemia.
4: erythrocytosis.

Answer 1

3: microcytic hypochromic anemia.

Patients on long-term parenteral nutrition have developed anemia, leukopenia, neutropenia and skeletal abnormalities. Deficiencies of iron or copper result in microcytic hypochromic anemia (small red blood cells that are pale in color due to decreased heme pigment). Deficiencies of B12 or folate result in macrocytic anemia (large red blood cells). Other symptoms of copper deficiency include: sensory ataxia, lower extremity spasticity, parathesis in extremities, leukopenia, neutropenia, hypercholesterolemia, increased erythrocyte turnover, decreased ceruloplasmin and erythrocyte copper/zinc superoxide dismutase (SOD), abnormal EKG patterns, myeloneuropathy.

Question 2

A patient receiving PN has high ileostomy output. Which of the following changes to the PN prescription is most appropriate to recommend?

1: increase sodium and increase fluid volume.
2: decrease water and decrease sodium.
3: increase sodium and decrease protein.
4: decrease sodium and increase fluid volume.

Answer 2

1: increase sodium and increase fluid volume.

Patients with high ileostomy or small bowel fistula output are at increased risk for water and electrolyte losses. The sodium content of ileostomy output can be as high as 120 mEq/liter. Hyponatremia can result when fluid replacement does not contain adequate sodium to correct for ileostomy losses.

Question 3

Which of the following is a clinical characteristic of acute disease or injury related severe malnutrition?

1: Moderate depletion of body fat
2: Mild fluid accumulation
3: Mild depletion of muscle mass
4: 10% weight loss in 6 months

Answer 3

1: Moderate depletion of body fat

Clinical characteristics to diagnose malnutrition of acute or injury-related disease are weight loss of > 2% in 1 week, > 5% in 1 month, > 7.5% in 3 months, energy intake of < 50% for > 5 days, moderate depletion of body fat, moderate depletion of muscle mass, and moderate to severe fluid accumulation. Grip strength is not recommended in intensive care units.

Question 4

Which of the following is most suggestive of malnutrition?

1: 10th percentile of tricep skinfold thickness
2: Voluntary body mass index change from 30 to 25 over 6 months
3: Involuntary weight loss of 10% usual body weight over six months
4: Albumin decrease from 4.0 to 3.5

Answer 4

3: Involuntary weight loss of 10% usual body weight over six months

Tricep skinfold thickness below the 5th percentile is abnormal in hospitalized patients. Tricep skinfold may be falsely elevated with edema, and may not be reliable in obese patients. Recent involuntary weight loss of 10% of usual body weight over 6 months detects obese and non-obese patients at risk for malnutrition. Voluntary weight loss from a BMI of 30 (obese) to a BMI of 25 (normal) does not reflect malnutrition. Albumin may be altered by conditions not related to nutritional factors.

Question 5

When conducting a nutrition focused physical exam (NFPE), which of the following is an indicator of severe muscle loss?

1: Hollowing depression of the temporalis muscle
2: Rounded curves at the arm and shoulder
3: Slightly depressed interosseous muscle
4: Somewhat prominent iliac crest

Answer 5

1: Hollowing depression of the temporalis muscle

Muscle loss in a patient with severe malnutrition can be identified when conducting an NFPE. The temporalis muscle will have a hollowing, scooping depression. The clavicle and acromion bone region/deltoid muscle will appear square with very prominent bones. The interosseous muscle on the dorsal hand will appear depressed between the thumb and forefinger. A prominent iliac crest pertains to subcutaneous fat loss, not muscle loss.

Question 6

Which of the following is common in both acute illness or injury-related and social or environmental related malnutrition?

1: Ketosis
2: Hypoglycemia
3: Lipolysis
4: Hypermetabolism

Answer 6

3: Lipolysis

Catabolism of endogenous substrate including fat stored in adipose tissue (lipolysis) is common in both forms of malnutrition. Hypoglycemia and ketosis are characteristic of starvation. Hypermetabolism and hyperglycemia are characteristic of stress-related malnutrition.

Question 7

Which of the following nutrition tools includes evaluating subcutaneous fat and muscle wasting at multiple body sites to determine nutrition status?

1: Nutritional risk index (NRI)
2: Nutrition Risk in Critically Ill (NUTRIC)
3: Subjective Global Assessment (SGA)
4: Nutrition Risk Score (NRS-2002)

Answer 7

3: Subjective Global Assessment (SGA)

The SGA is a nutrition assessment tool using five historical (weight history, dietary intake, gastrointestinal symptoms, functional status, and metabolic demand) and three components focusing on physical examination (fat depletion, muscle wasting, and nutrition related edema). The data are subjectively weighted to classify the patient as well nourished, moderately malnourished, or severely malnourished. The SGA has been found to be a good predictor of complications in patients undergoing gastrointestinal surgery, liver transplantation, and dialysis. For critically ill patients, the SGA may have limited use. ASPEN and the Society of Critical Care Medicine recommend the use of the NRS-2002 or the NUTRIC tool to determine nutrition risk in this patient population. The NRS-2002 includes unintentional weight loss, BMI, disease severity, impaired general condition and age > 70. The NUTRIC score includes APACHE II score, SOFA (with or without IL-6), number of comorbidities and days from hospital to ICU admission. The NRI uses serum albumin and the ratio of current weight to usual weight.

Question 8

The subjective global assessment (SGA) uses which of the following to evaluate the nutritional status of patients?

1: Dietary intake, delayed hypersensitivity skin testing, and weight history
2: Weight history, dietary intake, and gastrointestinal symptoms
3: Laboratory indices, weight history, and gastrointestinal symptoms
4: Arm anthropometry, dietary intake, and laboratory indices

Answer 8

2: Weight history, dietary intake, and gastrointestinal symptoms

The SGA has been applied successfully as a method of assessing nutritional status in a variety of patient populations. The SGA is a nutrition assessment tool using five historical (weight history, dietary intake, gastrointestinal symptoms, functional status, and metabolic demand) and three components focusing on physical examination (fat depletion, muscle wasting, and nutrition related edema).

Question 9

Which of the following has been reported to be a significant independent predictor of morbidity and mortality in critically ill patients?

1: Albumin
2: Prealbumin
3: Transferrin
4: Retinol-binding protein

Answer 9

1: Albumin

Albumin is a negative acute phase protein. Levels decrease in response to stress and hypoalbuminemia is more a reflection of the degree of stress resulting from disease, injury and inflammation than nutritional status. Hypoalbuminemia has been associated with increased short-term mortality, length of hospital stay and complications and to correlate strongly with 30-day mortality.

Question 10

A previously well-nourished patient with persistent fever is admitted to the hospital. Laboratory tests reveal: albumin, 2.1 g/dL; C-reactive protein, 30 mg/L; serum calcium of 7.2 mg/dL. Which of the following is the most likely etiology of hypoalbuminemia?

1: Caloric deficiency
2: Protein deficiency
3: Hypocalcemia
4: Inflammatory response

Answer 10

4: Inflammatory response

Albumin may decrease during inflammation and hypervolemia. Even though it is a good predictive indicator of clinical outcome, it does not always reflect nutritional status. Elevated C-reactive protein reflects an inflammatory status, which may be the reason for hypoalbuminemia. Positive acute phase protein concentrations such as C-reactive protein increase during inflammation, whereas negative acute phase protein concentrations such as albumin and pre-albumin decrease during inflammation. Although there is a causal relationship between hypoalbuminemia and hypocalcemia, a low serum calcium does not cause a low serum albumin.

Question 11

Which of the following compromises the reliability of urinary urea nitrogen to calculate nitrogen balance?

1: Protein intake <0.5 g/kg/day
2: Creatinine clearance <50 mL/min
3: Diuresis >2.5 L
4: Fecal nitrogen >1g

Answer 11

2: Creatinine clearance <50 mL/min

Urine urea nitrogen is used primarily to monitor protein intake during nutrition support. Urine is usually collected for a 24-hour period in order to quantify the amount of urinary urea nitrogen. Compromised renal function, as indicated by a creatinine clearance <50 mL/min, low urine output, and muscle atrophy can alter urinary urea nitrogen, resulting in unreliable results.

Question 12

Which of the following has been shown to reduce plasma homocysteine concentrations?

1: Folic acid
2: Vitamin E
3: L-carnitine
4: Ascorbic acid

Answer 12

1: Folic acid

Hyperhomocysteinemia has been linked to an increased risk for coronary artherosclerosis. Studies have shown that folic acid, vitamin B6, and vitamin B12 supplementation can reduce plasma homocysteine concentrations. It is not known whether hyperhomocysteinemia is a causative factor of artherosclerosis or simply a marker of vascular disease.

Question 13

Which of the following is the most appropriate fluid requirement for a healthy 78-year old adult?

1: 20 ml fluid/kg/day
2: 25 ml fluid/kg/day
3: 35 ml fluid/kg/day
4: 45 ml fluid/kg/day

Answer 13

2: 25 ml fluid/kg/day

The fluid requirements for healthy adults are 35ml/kg for adults age 18-55, 30ml/kg for adults age 55-75, 25ml/kg for adults older than 75 years, and less than 25ml/kg when fluid restriction is indicated.

Question 14

Which of the following enzymes initiates the digestive process of carbohydrates in the mouth?

1: Lipase
2: Lactase
3: Maltase
4: Amylase

Answer 14

4: Amylase

The salivary gland releases an enzyme called alpha amylase that initiates hydrolysis of carbohydrate when food enters the mouth. The degree of hydrolysis depends on the time that food is chewed and the nature of the food that enters the stomach. Lipase is an enzyme released from the pancreas that is important in the digestion of fat. Both lactase and maltase are located in the brush border cells of the small intestine and are important in intraluminal carbohydrate digestion.

Question 15

Iron is primarily absorbed in the

1: stomach.
2: colon.
3: ileum.
4: jejunum.

Answer 15

4: jejunum.

Iron is absorbed primarily in the duodenum and jejunum in the ferrous state rather than the ferric state. The ferric form of iron is insoluble in aqueous solutions and, therefore, not absorbed. Gastric acid is very important in maintaining dietary iron in the ferrous state.

Question 16

Which of the following amino acids is most crucial in small intestinal structure and function?

1: Alanine
2: Leucine
3: Aspartate
4: Glutamine

Answer 16

4: Glutamine

While all amino acids are important in metabolism, glutamine is a key fuel for the small intestine. Glutamine is essential for small intestinal structure and function. It could be useful to supplement glutamine to patients who are suffering trauma or receiving parenteral nutrition.

Question 17

In persons with phenylketonuria(PKU), tyrosine becomes an essential amino acid due to

1: an increase in the tyrosine hydroxylase enzyme.
2: a deficiency in the phenylalanine hydroxylase enzyme.
3: an increase in the phenylalanine hydroxylase enzyme.
4: a decrease in the tyrosine hydroxylase enzyme.

Answer 17

2: a deficiency in the phenylalanine hydroxylase enzyme.

PKU is an inborn error of phenylalanine metabolism caused by a deficiency of the hepatic enzyme phenylalanine hydroxylase (PAH). PAH catalyzes the hydroxylation of phenylalanine to tyrosine. In the absence of PAH, phenylalanine levels become extremely high and tyrosine becomes deficient. Treatment with a phenylalanine-free diet and tyrosine supplementation is used for chronic management.

Question 18

Which of the following are examples of conditionally essential amino acids?

1: Leucine and Isoleucine
2: Phenylalanine and Valine
3: Glutamine and Arginine
4: Histidine and Glutamate

Answer 18

3: Glutamine and Arginine

Conditionally essential amino acids are synthesized from other amino acids under normal conditions but require a dietary source in order to meet increased needs caused by metabolic stress. For example, arginine becomes conditionally essential for wound healing. Conditionally essential amino acids include: arginine, cysteine, glutamine, glycine, proline and tyrosine.

Question 19

An NPO post-operative patient has been on 2-in-1 parenteral nutrition (PN) for three weeks. He develops a diffuse scaly dermatitis, hair loss, anemia and thrombocytopenia. Which of the following is the probable cause?

1: He has not been receiving lipid injectible emulsion (ILE) for three weeks.
2: He has been receiving trace elements 3 times per week due to a national shortage.
3: He is receiving 20 kcal/kg per day from PN because of hyperglycemia.
4: He has PN related cholestasis and is experiencing fat malabsorption.

Answer 19

1: He has not been receiving lipid injectible emulsion (ILE) for three weeks.

Provision of fat free PN for three weeks has resulted in essential fatty acid deficiency (EFAD). EFAD usually results after 4 week of fat free PN, although signs of deficiency can be seen as early as 10-20 days in adults although deficiency can occur more rapidly in infants and children. Signs of EFAD include scaly dermatitis, alopecia, thrombocytopenia, anemia and impaired wound healing. Provision of 4-10% of total calories from soy or soy/safflower ILE should be sufficient to prevent essential fatty acid deficiency. Trace elements deficiencies need to be monitored in the light of shortages. Using ASPEN guidelines should reduce the risk. Hypocaloric PN actually may benefit patient on fat free PN as it is thought that EFA are released as a result of lipolysis of endogenous fat stores in response to reduction in insulin levels. Cholestasis is usually associated with high ILE doses.

Question 20

Which of the following IV fluids most closely resemble jejunal and ileal electrolyte content?

1: Lactated Ringer’s
2: 0.9% sodium chloride
3: 0.45% sodium chloride
4: D5 0.45% sodium chloride

Answer 20

1: Lactated Ringer’s

The electrolyte content of gastrointestinal secretions changes according to their location along the GI tract. The composition of jejunal and ileal fluids is listed below. Jejunum: Sodium = 95-120 mEq/L; Potassium = 5-15 mEq/L; Chloride = 80-130 mEq/L; Bicarbonate = 10-20 mEq/L. Ileum: Sodium = 110-130 mEq/L; Potassium = 10-20 mEq/L; Chloride = 90-110 mEq/L; Bicarbonate = 20-30 mEq/L. Lactated Ringer’s most closely resembles these values. IV electrolyte content is as follows: Lactated Ringer’s: Glucose = 0; Sodium = 130 mEq/L; Chloride = 109 mEq/L; Potassium = 4 mEq/L; Lactate = 28 mEq/L; Calcium = 2.7 mEq/L. Normal saline (0.9% Sodium Chloride) contains only: Sodium - 154 mEq/L and Chloride 154 mEq/L. ½ Normal saline (0.45% Sodium Chloride) contains only: Sodium = 77 mEq/L and Chloride = 77 mEq/L. D5 0.45% Sodium Chloride contains: Glucose = 50 grams/L; Sodium = 77 mEq/L; Chloride = 77 mEq/L.

Question 21

All of the following are clinical symptoms of syndrome of inappropriate antidiuretic hormone (SIADH) EXCEPT

1: increased urinary output.
2: increased urinary sodium.
3: hyponatremia.
4: increased urinary osmolality.

Answer 21

1: increased urinary output.

SIADH is one of the most common causes of hyponatremia. It is a disorder of sodium and water balance caused by the inappropriate release of antidiuretic hormone (ADH). The result is an increased in total body water which causes a dilutional hyponatremia. Increased sodium concentrations and osmolality are seen in the urine due to excessive water reabsorption. To compensate for expansion of extracellular fluid, aldosterone secretion is inhibited while atrial natriuretic peptide (ANP) increases. These compensative responses serve to maintain euvolemia, but at the same time further worsen hyponatremia. Due to the fact that not all afflicted patients show elevated circulating levels of ADH, the expression “syndrome of inappropriate antiduresis” has been determined to be more accurate.

Question 22

A 45 year old patient with chronic corticosteroid use has a suspected vitamin A deficiency. Supplementation of vitamin A (3,000-15,000/day) should usually be given for a maximum of

1: 30 days.
2: 7 days.
3: 90 days.
4: 14 days.

Answer 22

2: 7 days.

Vitamin A has multiple functions in wound healing including cellular differentiation, enhancement of epithelialization and collagen synthesis. A wide dosage range of 3000 to 15,000 RAE/d orally for 7 days has been recommended to counteract the inhibitory effects that steroids have on collagen synthesis and connective tissue repair. Oral administration of 3,000 to 4,500 RAE/d is recommended to enhance wound healing with concurrent corticosteroid therapy.

Question 23

A patient with alcoholism is admitted with small bowel obstruction and is started on PN providing 400 grams of dextrose. If, after 3 days, the patient develops mental status changes it is most likely due to a deficiency of

1: pyridoxine.
2: thiamin.
3: cyanocobalamin.
4: niacin.

Answer 23

2: thiamin.

Alcohol-related thiamin deficiency often presents as Wernicke’s encephalopathy, which can present as mental status changes, confusion, nystagmus, gait ataxia, and polyneuritis. Alcoholic or malnourished patients may require thiamin supplementation. Thiamin plays an essential role in glucose metabolism. The glucose loads associated with parenteral nutrition increases the metabolic demand for thiamin.

Question 24

Lactic acidosis can be a result of which vitamin deficiency?

1: Folic acid
2: Vitamin E
3: Thiamin
4: Vitamin C

Answer 24

3: Thiamin

Thiamin is necessary for the metabolism of glucose, specifically, the conversion of pyruvate to acetyl CoA. In the absence of thiamin, the resultant inhibition of pyruvate dehydrogenase drives carbohydrate metabolism toward lactic acid fermentation, resulting in a build-up of lactic acid. Untreated thiamin deficiency can result in fatal lactic acidosis.

Question 25

In addition to aggressive refeeding, which of the following places a patient at high risk for hypophosphatemia?

1: Diabetic ketoacidosis(DKA)
2: Tumor lysis syndrome
3: Vitamin D deficiency
4: Acute kidney injury(AKI)

Answer 25

1: Diabetic ketoacidosis(DKA)

Patients at risk for hypophosphatemia include malnourished patients who are at rish for refeeding syndrome, patients with DKA, chronic alcoholism, respiratory and metabolic alkalosis, critical illness and Fanconi syndrome. Insulin is an anabolic hormone that drives potassium and phosphorus into cells and results in serum depletion. In DKA substantial phosphorous is lost in urine as a result of osmotic diuresis associated with hyperglycemia. Tumor lysis syndrome can result in high serum phosphorus levels. Vitamin D deficiency is associated with hypocalcemia, osteomalacia, osteoporosis. AKI can lead to high phosphorus levels as a result of decreased excretion.

Question 26

The risk of metastatic calcification in soft tissues begins to increase when the product of serum calcium and phosphorus exceeds

1: 25.
2: 55.
3: 75.
4: 95.

Answer 26

2: 55.

A primary complication of hyperphosphatemia is soft tissue and vascular calcification. Calcification occurs when the product of serum calcium and phosphorus exceeds 55 mg2/dL2. Additional symptoms of hyperphosphatemia include secondary hyperparathyroidism and renal osteodystrophy.

Question 27

Zinc deficiency is most commonly associated with

1: diarrhea.
2: carotenemia.
3: coagulopathy disorder.
4: cholestasis.

Answer 27

1: diarrhea.

The overall biochemical functions of zinc can be categorized as catalytic, structural and/or regulatory in nature. Additional zinc is recommended in patients with additional losses from thermal injury, excessive GI losses such as diarrhea, decubitus ulcers and high output fistulas.

Question 28

Copper toxicity is associated with

1: liver disease.
2: kidney disease requiring hemodialysis.
3: aggressive zinc supplementation.
4: lung disease.

Answer 28

1: liver disease.

Copper toxicity can cause severe nausea, diarrhea, and vomiting. More serious manifestations with acute or more chronic toxic ingestion or Wilson’s disease include coma, hepatic necrosis, liver failure, renal failure, vascular collapse, and death. Since about 80% of copper is excreted in the bile, patients who have liver disease should be monitored and supplementation reduced or eliminated. Hemodialysis increases copper losses. Enteral zinc supplementation can compete with copper for absorption.

Question 29

Hepatic encephalopathy is most likely to be improved by which of the following trace elements?

1: Selenium
2: Copper
3: Zinc
4: Chromium

Answer 29

3: Zinc

An altered zinc metabolism with zinc deficiency and decreased serum zinc is noted in most forms of clinical liver disease, especially acute liver disease. Zinc may also be effective in the treatment of HE. The preliminary results of a small RCT in patients with cirrhosis, elevated ammonia levels, and low serum zinc levels showed that, compared to no supplementation, zinc supplementation of total 150 mg/d for 3 months was effective in reducing blood ammonia levels.

Question 30

Which of the following best describes the utility of aluminum in parenteral solutions?

1: Potentiates the action of insulin
2: Has no known biologic function
3: Decreases the incidence of bone fractures
4: Is necessary for normal erythropoiesis

Answer 30

2: Has no known biologic function

Aluminum has not been shown to have any biologic function but is present as a contaminant in many PN components. Toxicity occurs upon accumulation and can result in abnormalities of hematopoietic, bone, and neurologic functions. Complications of aluminum intake are best avoided by minimizing the use of aluminum-containing agents such as antacids, sucralfate, etc. Aluminum toxicity is treated with deferoxamine, an agent that chelates aluminum.

Question 31

Which of the following can result in an invalid indirect calorimetry (IC) measurement?

1: Ascites
2: Chest tube leak
3: Hemodynamic stability
4: Inspired oxygen (FiO2) less than 20%

Answer 31

2: Chest tube leak

There are several absolute contraindications for IC. Again, recalling that IC is a respiratory measurement that under proper conditions is equivalent to metabolism, any factor that violates these conditions is a contraindication to IC. Examples include air leaks; extracorporeal membrane oxygenation; hemodialysis; Fi02 > 60 in mechanically ventilated patients; and for spontaneously breathing patients - reliance on supplemental oxygen, inability to cooperate with measurement, and claustrophobia or anxiety about the measurement). Furthermore, if RMR is the desired value to be measured (and it usually is), then any factor that prevents the patient from being at rest or cooperating with the device operator is also a contraindication.

Question 32

How should a critically ill patient’s energy delivery be modified in response to resting energy expenditure (REE) measured by indirect calorimetry?

1: Reduced by 10% if respiratory quotient exceeds 1.0.
2: Increased by a stress factor of 1.2-1.5 for sepsis or trauma.
3: Adjusted by a thermogenesis factor for enterally fed patients.
4: Used as the caloric target without addition of stress or activity factors.

Answer 32

4: Used as the caloric target without addition of stress or activity factors.

REE measured under steady state conditions closely approximates true 24-hour energy expenditure. The addition of a stress or activity factor may not be necessary and could result in overfeeding. If a patient is measured while fasting or if feedings are intermittently provided, it is reasonable to allow an additional 5% factor to account for thermogenesis.

Question 33

A respiratory quotient (RQ) of 0.87 most likely suggests

1: primarily fat oxidation.
2: mixed substrate utilization.
3: primarily carbohydrate oxidation.
4: primarily protein oxidation.

Answer 33

2: mixed substrate utilization.

RQ = CO2 produced/O2 consumed. An RQ <0.7 or >1.0 may result from hypoventilation or hyperventilation. While there are several metabolic causes for an RQ < 0.7 or > 1.0, traditional interpretation of RQ is as follows: RQ of 0.71 is primarily fat oxidation, 0.82 is primarily protein oxidation, 0.85 suggests mixed substrate utilization, and 1.0 is carbohydrate oxidation.

Question 34

Which of the following predictive equations has demonstrated the greatest accuracy in estimating actual resting metabolic rate in healthy obese and nonobese adults?

1: Harris-Benedict equation
2: Ireton-Jones equation
3: Penn State equation
4: Mifflin-St. Jeor equation

Answer 34

4: Mifflin-St. Jeor equation

The Mifflin-St. Jeor equations, when using actual body weight have demonstrated the greatest accuracy with healthy obese and non-obese people when compared to the Harris-Benedict equation. The Ireton-Jones and Penn State equations were developed to estimate energy requirements in critically ill patients, not healthy adults. The Mifflin-St. Jeor equations are as follows: For males: actual body weight in kg x 9.99 plus height in cm x 6.25 minus age in years x 4.92 plus 5. For females: actual body weight in kg x 9.99 plus height in cm x 6.25 minus age in years x 4.92 minus 161.

Question 35

Cheilosis is a physical symptom associated with a deficiency of

1: vitamin D.
2: folic acid.
3: riboflavin.
4: vitamin C.

Answer 35

3: riboflavin.

Cheilosis, cracking of the corners of the mouth, is observed with a deficiency of riboflavin. Other symptoms of riboflavin deficiency include: hyperemia and edema of pharyngeal and oral mucosa, angular stomatitis, and glossitis (magenta tongue). Vitamin D deficiency is most often characterized by a loss of bone density. A classic feature of folic acid deficiency is megaloblastic or macrocytic anemia. A deficiency in Vitamin C can lead to scurvy.

Question 36

Malnutrition is most common in which form of inflammatory bowel disease?

1: Crohn’s disease
2: Ulcerative colitis
3: Microscopic colitis
4: Collagenous colitis

Answer 36

1: Crohn’s disease

Since Crohn’s disease usually involves the small intestine, malnutrition and micronutrient deficiencies are much more common than with ulcerative, microscopic, or collagenous colitis. Depending on severity of disease, weight loss has been reported in 20% to 85% of those with Crohn’s disease. Also reported is that 65-75% of inpatients and more than 50% of outpatients with Crohn’s disease experience significant weight loss. Possible mechanisms for malnutrition in Crohn’s disease include malabsorption from diseased small bowel mucosa, increased nutrient requirements from active inflammation, and reduced oral food intake due to abdominal discomfort and diarrhea.

Question 37

A patient with end stage liver disease with refractory ascites awaiting liver transplantation is on PN due to intolerance to tube feeding. His sodium is 124 mEq/L. In addition to fluid restriction, which of the following changes to his PN prescription is most appropriate to recommend?

1: Supplement sodium, provide 2.5g protein/kg per day
2: Restrict sodium , provide 0.5 g protein/kg per day
3: Restrict sodium, provide 1.5 g protein/kg per day
4: Supplement sodium, provide 1.0 g protein/kg per day

Answer 37

3: Restrict sodium, provide 1.5 g protein/kg per day

Appropriate treatment for ascites includes fluid and sodium restriction. Protein intake should be 1.0 – 1.5 g/kg/d for patients with cirrhosis. While optimum nutrition support may not be possible, use of maximally concentrated solutions provides the best opportunity to avoid further salt and fluid overload while providing necessary substrate for anabolism.

Question 38

Arginine supplementation should be used most cautiously in which of the following patients?

1: Short bowel patients
2: Cirrhotic patients
3: Septic shock patients
4: Immunocompromised patients

Answer 38

3: Septic shock patients

Arginine, which increases the production of nitric oxide, has been shown to have positive effects on recovery from trauma and surgery through its effect on blood flow, immune function, wound healing, and organ failure. In conditions of pronounced vasodilation, as in septic shock, the production of nitric oxide would be expected to exacerbate hemodynamic instability. Increased mortality and morbidity in this population has been demonstrated in some studies.

Question 39

What is the approximate normal length of small intestine in adults?

1: 150-200 cm
2: 300-600 cm
3: 700-900 cm
4: 1000-1200 cm

Answer 39

2: 300-600 cm

The normal length of the small intestine in adults ranges from 300-600 cm. Factors such as bowel length, specific segment of the small bowel that has been resected, residual disease in the remaining intestine, absence of colon and/or ileocecal valve, and prior gastric resection will have an impact on the absorptive function of the bowel. When the small bowel is <120 cm to an end jejunostomy or ileostomy, parenteral nutrition and hydration will likely be needed. The presence of an ileocecal valve and colon significantly improves fluid and electrolyte absorption as well as uptake of short-chain fatty acids and may allow survival without PN with as little as 60 cm of small bowel.

Question 40

What is the primary fuel of the colonocytes?

1: Medium chain fatty acids
2: Glucose
3: Glutamine
4: Short chain fatty acids

Answer 40

4: Short chain fatty acids

Short chain fatty acids (SCFA) are the primary fuel product for colonic cells. In general, dietary fiber is considered to be an intact, plant-based carbohydrate that is nondigestible by humans. It is, however digestible by intestinal microbes through the process of fermentation yielding SCFAs such as acetate, butyrate, and propionate which serve as fuel for the colonocytes. SCFAs are significant sources of energy, contributing up to 10% of the daily calorie requirement and may provide up to 1000 kcal/day in patients with short bowel syndrome.

Question 41

Dietary fat is predominately absorbed in what part of the gastrointestinal tract?

1: Ileum and colon
2: Stomach and duodenum
3: Distal jejunum and ileum
4: Duodenum and proximal jejunum

Answer 41

4: Duodenum and proximal jejunum

Dietary fat is absorbed in the proximal small bowel. Lingual lipase released in the mouth and gastric lipase produced in the stomach have a limited role in fat digestion in healthy adults. Bile acids secreted by the liver as well as lipase and colipase produced by the pancreas aid in the micellar solubilization and absorption of dietary fat.

Question 42

Gastrectomy patients are at risk for a deficiency of which vitamin?

1: B12
2: Folic Acid
3: Thiamine
4: B6

Answer 42

1: B12

A gastrectomy is the total or partial removal of the stomach. Parietal cells in the stomach are responsible for producing intrinsic factor, which under normal circumstances binds with vitamin B12 and aids in the absorption of B12 in the small bowel. When the stomach is resected, there is no longer adequate intrinsic factor to bind with B12, and thus a deficiency may result.

Question 43

Which of the following areas of the gastrointestinal tract has the LEAST impact on nutrient absorption and intestinal adaptation following significant intestinal resection?

1: Colon
2: Ileum
3: Jejunum
4: Ileocecal valve

Answer 43

3: Jejunum

Resections of the proximal bowel, including the duodenum and proximal jejunum, are generally better tolerated because of ileal compensation and adaptation. In general, ileal resection is poorly tolerated because adaptive hyperplasia in the remaining jejunum is limited. The ileocecal valve slows intestinal transit allowing for greater absorption of nutrients. The colon has critical roles in fluid and nutrient absorption. Therefore, patients lacking a colon are at greater risk of dehydration. Furthermore, the colon is capable of salvaging calories through anaerobic bacterial fermentation of undigested carbohydrates into absorbable short-chain fatty acids (SCFAs).

Question 44

Which of the following is associated with adaptation to starvation?

1: Increased glycogenesis
2: Increased lipid oxidation
3: Increased gluconeogenesis
4: Increased glucose oxidation

Answer 44

2: Increased lipid oxidation

During fasting, fuel oxidation gradually shifts from carbohydrates to mainly lipids as oxidative source. Lipolysis increases strongly and provides the body with fatty acids. As a consequence of increased fatty acid oxidation, terminal glucose oxidation is decreased. Endogenous glucose production by gluconeogenesis provides the body with sufficient glucose for glucose-dependent processes. Glucose is still used for glycogen synthesis but to a lesser degree.

Question 45

How much fluid per day is required to maintain fluid balance in an average healthy adult?

1: 10-20 mL/kg/day
2: 25-35 mL/kg/day
3: 45-55 mL/kg/day
4: 60-70 mL/kg/day

Answer 45

2: 25-35 mL/kg/day

Water intake is derived primarily from the diet, whereas various sources of water losses contribute to total fluid output. In most cases, sensible losses from the gastrointestinal tract and kidneys account for the majority of fluid loss. Insensible losses from the lungs and skin can contribute up to 1L per day. Fluid gains should be in balance with fluid losses over a period of several days.

Question 46

Valproic acid has been shown to induce a deficiency in which of the following nutrients?

1: Chromium
2: Carnitine
3: Leucine
4: Vitamin D

Answer 46

2: Carnitine

Valproic acid, an antiepileptic drug, has been shown to induce carnitine deficiency. Carnitine is involved in the metabolism of fatty acids and is an essential cofactor in the proper metabolism of valproic acid and ammonia elimination. Valproic acid depletes hepatic carnitine stores by forming valproylcarnitine, which inhibits the carnitine transported on the plasma membrane. Fatty acids cannot be metabolized due to lack of carnitine, resulting in chronic fatty liver. Consider carnitine replacement in patients with coma, elevated ammonia concentration, hepatotoxicity or a valproate concentration above 450 mcg/mL. Fatalities have been reported in untreated carnitine deficiency.

Question 47

Methotrexate acts by interfering with the normal intracellular metabolism of which of the following nutrients?

1: Thiamin
2: Folate
3: Copper
4: Pyridoxine

Answer 47

2: Folate

The chemotherapeutic drug methotrexate is a folate analogue that became available in the early 1950s. Methotrexate is structurally similar to folate. It competitively inhibits dihydrofolate reductase, an enzyme that catalyses the converstion of dihydrofolate to tetrahydrofolate, a cofactor in the synthesis of purine nucleotides and thymidylate. Therefore, Methotrexate impairs malignant growth by interfering with DNA synthesis, repair and cellular replication.

Question 48

What vitamin absorption is most likely to be impaired with chronic use of proton pump inhibitor therapy?

1: Vitamin B3
2: Vitamin B1
3: Vitamin B6
4: Vitamin B12

Answer 48

4: Vitamin B12

Gastric acid facilitates the proteolytic process that releases vitamin B12 from the proteins in foods. This free vitamin B12 then binds to R-proteins in the stomach and intrinsic factor in order to be absorbed in the terminal ileum. Proton pump inhibitors decrease gastric acidity and may interfere with the absorption of protein-bound dietary vitamin B12. Long term use (>3 years) of proton pump inhibitors may cause a fall in circulating levels of vitamin B12. Absorption of crystalline vitamin B12, the form utilized in vitamin supplements and fortified foods, is not affected by gastric acid.