Right 2

Question 1

The average energy intake is

Answer 1

~2600 kcal/d for American
men and ~1800 kcal/d for American women, though these estimates
vary with body size and activity level.

Question 2

Formulas for roughly estimating
REE are useful in assessing the energy needs of an individual whose
weight is stable. Thus,

Answer 2

for males, REE = 900 + 10m, and for females,

REE = 700 + 7m, where is m mass in kilograms

Question 3

The calculated REE

is then adjusted for physical activity level by multiplying by

Answer 3

1.2 for

sedentary, 1.4 for moderately active, or 1.8 for very active individuals.

Question 4

The nine essential

amino acids are

Answer 4

histidine, isoleucine, leucine, lysine, methionine/

cystine, phenylalanine/tyrosine, threonine, tryptophan, and valine

Question 5

For adults, the recommended dietary allowance (RDA) for protein

Answer 5

is ~0.6 g/kg desirable body mass per day, assuming that energy needs
are met and that the protein is of relatively high biologic value. Current
recommendations for a healthy diet call for at least 10–14% of calories
from protein

Question 6

Fats are a concentrated source of energy and
constitute, on average, 34% of calories in U.S. diets. However, for
optimal health, fat intake should total

Answer 6

no more than 30% of calories.
Saturated fat and trans fat should be limited to <10% of calories and
polyunsaturated fats to <10% of calories, with monounsaturated fats
accounting for the remainder of fat intake

Question 7

least 45–55% of total

calories should be derived from carbohydrates. The brain requires

Answer 7

~100 g of glucose per day for fuel; other tissues use about 50 g/d. Some
tissues (e.g., brain and red blood cells) rely on glucose supplied either
exogenously or from muscle proteolysis. Over time, adaptations in
carbohydrate needs are possible during hypocaloric states. Like fat
(9 kcal/g), carbohydrate (4 kcal/g), and protein (4 kcal/g), alcohol
(ethanol) provides energy (7 kcal/g)

Question 8

For adults, 1–1.5 mL of water per kilocalorie of energy expenditure
is sufficient under usual conditions to allow for normal variations
in physical activity, sweating, and solute load of the diet.

Answer 8

Water
losses include 50–100 mL/d in the feces; 500–1000 mL/d by evaporation
or exhalation; and, depending on the renal solute load, ≥1000
mL/d in the urine. I

Question 9

Fever increases water losses by

~200 mL/d per °C; diarrheal losses vary but may be as great as

Answer 9

5 L/d

in severe diarrhea.

Question 10

When renal function is normal and solute
intakes are adequate, the kidneys can adjust to increased water intake
by excreting up to

Answer 10

18 L of excess water per day

Question 11

Increased water needs during pregnancy are ~30 mL/d.

Answer 11

During lactation, milk production increases daily water requirements
so that ~1000 mL of additional water is needed, or 1 mL for each milliliter
of milk produced

Question 12

benchmark recommendations regarding

nutrient intakes have been developed to guide clinical practice.

Answer 12

These
quantitative estimates of nutrient intakes are collectively referred to
as the dietary reference intakes (DRIs

Question 13

Thiamine deficiency is therefore

more common in cultures that rely heavily on a

Answer 13

rice-based diet.
Tea, coffee (regular and decaffeinated), raw fish, and shellfish contain
thiaminases, which can destroy the vitamin

drinking large
amounts of tea or coffee can theoretically lower thiamine body stores.

Question 14

In Western countries, the primary causes of

thiamine deficiency are alcoholism and chronic illnesses such as cancer.

Answer 14

Alcohol interferes directly with the absorption of thiamine and
with the synthesis of thiamine pyrophosphate, and it increases urinary
excretion. Thiamine should always be replenished when a patient with
alcoholism is being refed, as carbohydrate repletion without adequate
thiamine can precipitate acute thiamine deficiency with lactic acidosis

Question 15

Wet beriberi presents primarily
with cardiovascular symptoms that are due to impaired myocardial
energy metabolism and dysautonomia

Answer 15

; it can occur after 3 months
of a thiamine-deficient diet. Patients present with an enlarged heart,
tachycardia, high-output congestive heart failure, peripheral edema

Question 16

dry beriberi present with a symmetric
peripheral neuropathy of the motor and sensory systems, with
diminished reflexes.

Answer 16

The neuropathy affects the legs most markedly,

and patients have difficulty rising from a squatting position

Question 17

Alcoholic patients with chronic thiamine deficiency also may have
central nervous system (CNS) manifestations known as

Answer 17

Wernicke’s
encephalopathy, which consists of horizontal nystagmus, ophthalmoplegia
(due to weakness of one or more extraocular muscles),
cerebellar ataxia, and mental impairment (Chap. 467). When there
is an additional loss of memory and a confabulatory psychosis, the
syndrome is known as Wernicke-Korsakoff syndrome. Despite the
typical clinical picture and history, Wernicke-Korsakoff syndrome is
underdiagnosed.

Question 18

The laboratory diagnosis of thiamine deficiency usually is made by
a functional enzymatic assay of transketolase activity measured before
and after the addition of thiamine pyrophosphate.

Answer 18

A >25% stimulation
in response to the addition of thiamine pyrophosphate (i.e., an activity
coefficient of 1.25) is interpreted as abnormal.

Question 19

In acute thiamine deficiency with either cardiovascular or neurologic signs,

Answer 19

200 mg of thiamine three times daily should be given intravenously
until there is no further improvement in acute symptoms;
oral thiamine (10 mg/d) should subsequently be given until recovery
is complete.

Question 20

niacin refers to nicotinic acid and nicotinamide and their
biologically active derivatives. Nicotinic acid and nicotinamide serve
as precursors of two coenzymes,

Answer 20

nicotinamide adenine dinucleotide
(NAD) and NAD phosphate (NADP), which are important in numerous
oxidation and reduction reactions in the body.

Question 21

Niacin deficiency causes

Answer 21

pellagra, which is found
mostly among people eating corn-based diets in parts of China,
Africa, and India.

Pellagra in North America is found mainly
among alcoholics; among patients with congenital defects of intestinal
and kidney absorption of tryptophan (Hartnup disease

Bright red glossitis then ensues and is
followed by a characteristic skin rash that is pigmented and scaling,
particularly in skin areas exposed to sunlight. This rash is known as
Casal’s necklace because it forms a ring around the neck

Question 22

The primary
manifestations of this syndrome are sometimes referred to as “the
four D’s”:

Answer 22

dermatitis, diarrhea, and dementia leading to death.

Question 23

Treatment of pellagra consists of oral supplementation with

Answer 23

100– 200 mg of nicotinamide or nicotinic acid three times daily for 5 days.
High doses of nicotinic acid (2 g/d in a time-release form) are used
for the treatment of elevated cholesterol and triglyceride levels and/
or low high-density lipoprotein cholesterol levels

Question 24

is also important for connective tissue
metabolism and cross-linking (proline hydroxylation), and it is a component
of many drug-metabolizing enzyme systems, particularly the
mixed-function oxidase systems.

Answer 24

Vitamin C

Question 25

Administration of vitamin C (200 mg/d) improves the symptoms | of scurvy within several days.

Answer 25

High-dose vitamin C supplementation (e.g., 1–2 g/d) may slightly decrease the symptoms and duration of upper respiratory tract infections.

Question 26

Vitamin C supplementation has also | been reported to be useful in

Answer 26

Chédiak-Higashi syndrome (Chap. 80) | and osteogenesis imperfecta

Question 27

Taking g of vitamin C in a single dose may result in abdominal pain, diarrhea, and nausea. Since vitamin C may be metabolized to oxalate, it is feared that chronic high-dose vitamin C supplementation could result in an increased prevalence of kidney stones. However, except in patients with preexisting renal disease, this association has not been borne out in several trials

Answer 27

>2

Question 28

is a water-soluble vitamin that plays a role in gene expression, gluconeogenesis, and fatty acid synthesis and serves as a CO2 carrier on the surface of both cytosolic and mitochondrial carboxylase enzymes.

Answer 28

Biotin

Question 29

is believed to have caused the “burning feet syndrome” seen in prisoners of war during World War II.

Answer 29

Pantothenic acid deficiency

Question 30

is a precursor for acetylcholine, phospholipids, and betaine. Choline is necessary for the structural integrity of cell membranes, cholinergic neurotransmission, lipid and cholesterol metabolism, methyl-group metabolism, and transmembrane signaling

Answer 30

Choline

Question 31

Retinaldehyde (11-cis) is the essential form of vitamin A that is required for normal vision, whereas

Answer 31

retinoic acid is necessary for normal morphogenesis, | growth, and cell differentiation.

Question 32

is the most prevalent carotenoid | with provitamin A activity in the food supply

Answer 32

β-Carotene

Question 33

VIt A deficiency This condition includes milder stages of night blindness and conjunctival xerosis (dryness) with Bitot’s spots (white patches of keratinized epithelium appearing on the sclera) as well as rare, potentially blinding corneal ulceration and necrosis.

Answer 33

Keratomalacia (softening of the cornea) leads | to corneal scarring

Question 34

Any stage of xerophthalmia should be treated with

Answer 34

60 mg (or RAE) of vitamin A in oily solution, usually contained in a soft-gel capsule. The same dose is repeated 1 and 14 days later. Doses should be reduced by half for patients 6–11 months of age. Mothers with night blindness or Bitot’s spots should be given vitamin A orally–either 3 mg daily or 7.5 mg twice a week for 3 months

Question 35

Infants 6–11 months of age should | receive 30 mg vitamin A;

Answer 35

children 12–59 months of age, 60 mg. For reasons that are not clear, vitamin A supplementation has not proven useful in high-risk settings for preventing morbidity or death among infants 1–5 months of age.

Question 36

vit a toxicity

Answer 36

``` Acute toxicity is manifested by increased intracranial pressure, vertigo, diplopia, bulging fontanels (in children), seizures, and exfoliative dermatitis ```

Question 37

represents the classic disease of vitamin D deficiency. Signs of deficiency are muscle soreness, weakness, and bone pain. Some of these effects are independent of calcium intake.

Answer 37

Rickets

Question 38

There are two natural forms of vitamin K:

Answer 38

vitamin K1, also known as phylloquinone, from vegetable and animal sources, and vitamin K2, or menaquinone, which is synthesized by bacterial flora and found in hepatic tissue. Phylloquinone can be converted to menaquinone in some organs.

Question 39

Vitamin K is required for the posttranslational carboxylation of glutamic acid,

Answer 39

which is necessary for calcium binding to γ-carboxylated proteins such as prothrombin (factor II); factors VII, IX, and X; protein C; protein S; and proteins found in bone (osteocalcin) and vascular smooth muscle (e.g., matrix Gla protein).

Question 40

Vitamin K is found in

Answer 40

green leafy vegetables such as kale and spinach, and appreciable amounts are also present in margarine and liver. Vitamin K is present in vegetable oils; olive, canola, and soybean oils are particularly rich sources

Question 41

The symptoms of vitamin K deficiency are due to hemorrhage;

Answer 41

newborns are particularly susceptible because of low fat stores, low breast milk levels of vitamin K, relative sterility of the infantile intestinal tract, liver immaturity, and poor placental transport. Intracranial bleeding as well as gastrointestinal and skin bleeding can occur in vitamin K–deficient infants 1–7 days after birth. Thus, vitamin K (0.5–1 mg IM) is given prophylactically at delivery.

Question 42

Vitamin K deficiency

Answer 42

is treated with a parenteral dose of 10 mg. For patients with chronic malabsorption, 1–2 mg/d should be given orally or 1–2 mg per week can be taken parenterally

Question 43

is an integral component of many metalloenzymes in the body; it is involved in the synthesis and stabilization of proteins, DNA, and RNA and plays a structural role in ribosomes and membranes

Answer 43

Zinc

Question 44

mild chronic zinc deficiency can cause stunted growth in children, decreased taste sensation (hypogeusia), and impaired immune function. Severe chronic zinc deficiency has been described as a cause of hypogonadism and dwarfism in several Middle Eastern countries. In these children, hypopigmented hair is also part of the syndrome.

Answer 44

Acrodermatitis enteropathica is a rare autosomal recessive disorder characterized by abnormalities in zinc absorption.

Question 45

Zinc (20 mg/d until recovery) may be an effective adjunctive

Answer 45

therapeutic strategy for diarrheal disease and pneumonia in children ≥ 6 months of age.

Question 46

is an X-linked metabolic disturbance of copper metabolism characterized by mental retardation, hypocupremia, and decreased circulating ceruloplasmin

Answer 46

Menkes kinky hair syndrome

Question 47

The diagnosis of is usually based on low serum levels of copper (<65 μg/dL) and low ceruloplasmin levels (<20 mg/ dL).

Answer 47

copper deficiency

Question 48

Serum levels of copper may be elevated

Answer 48

in pregnancy or stress conditions since ceruloplasmin is an acute-phase reactant and 90% of circulating copper is bound to ceruloplasmin.

Question 49

is an endemic cardiomyopathy found in children and young women residing in regions of China where dietary intake of selenium is low (<20 μg/d).

Answer 49

Keshan disease

Question 50

Malnutrition can arise from primary or secondary causes, resulting in the former case from inadequate or poor-quality food intake and in the latter case from

Answer 50

diseases that alter food intake or nutrient | requirements, metabolism, or absorption.

Question 51

Primary malnutrition occurs mainly in developing countries and under conditions of political unrest, war, or famine.

Answer 51

Secondary malnutrition, the main form encountered in industrialized countries, was largely unrecognized until the early 1970s, when it was appreciated that persons with adequate food supplies can become malnourished as a result of acute or chronic diseases that alter nutrient intake or metabolism, particularly diseases that cause acute or chronic inflammation

Question 52

Marasmus is the end result of | a long-term deficit of dietary energy, whereas kwashiorkor

Answer 52

has been | understood to result from a protein-poor diet

Question 53

is a state in which virtually all available body fat stores have been exhausted due to starvation without systemic inflammation

Answer 53

Marasmus (starvation–related malnutrition)

Question 54

is a state that involves substantial loss of lean body mass | in the presence of chronic systemic inflammation

Answer 54

Cachexia (chronic disease–related | malnutrition)

Question 55

Acute ↓ energy and protein intake with substantial systemic inflammation

Answer 55

Kwashiorkor (Acute Disease– or Injury– Related Malnutrition)

Question 56

kwashiorkor

Answer 56

The major sine qua non is severe reduction of levels of serum proteins such as albumin (<2.8 g/dL) and transferrin (<150 mg/dL) or of iron-binding capacity (<200 μg/dL). Cellular immune function is depressed, as reflected by lymphopenia (<1500 lymphocytes/μL in adults and older children) and lack of response to skin test antigens (anergy

Question 57

After ~10 days of total starvation, an unstressed individual loses about 12–18 g of protein per day (equivalent to ~60 g of muscle tissue or ~2–3 g of nitrogen). I

Answer 57

In contrast, in injury and sepsis, protein breakdown accelerates in proportion to the degree of stress, reaching 30–60 g/d after elective surgery, 60–90 g/d with infection, 100–130 g/d with severe sepsis or skeletal trauma, and >175 g/d with major burns or head injuries

Question 58

is the only fuel that can be utilized by hypoxemic tissues (anaerobic glycolysis), white blood cells, and newly generated fibroblasts.

Answer 58

Glucose

Question 59

remains prevalent, causing | goiter, hypothyroidism, and cretinism.

Answer 59

Iodine deficiency

Question 60

is endemic in many populations, producing growth retardation, hypogonadism, and dermatoses and impairing wound healing

Answer 60

Zinc deficiency

Question 61

Nutritional Deficiency: The High-Risk Patient

Answer 61

Underweight (body mass index <18.5) and/or recent loss of ≥10% of usual body mass Poor intake: anorexia, food avoidance (e.g., psychiatric condition), or NPOa status for more than ~5 days Protracted nutrient losses: malabsorption, enteric fistulas, draining abscesses or wounds, renal dialysis Hypermetabolic states: sepsis, protracted fever, extensive trauma or burns Alcohol abuse or use of drugs with antinutrient or catabolic properties: glucocorticoids, antimetabolites (e.g., methotrexate), immunosuppressants, antitumor agents Impoverishment, isolation, advanced age

Question 62

BMI values <18.5 are | considered underweight;

Answer 62

<17, significantly underweight; and <16, severely wasted. Values of 18.5–24.9 are normal; 25–29.9, overweight; and ≥30, obese.

Question 63

The triceps is a convenient site that is generally | representative of the body’s overall fat level.

Answer 63

A thickness <3 mm | suggests virtually complete exhaustion of fat stores

Question 64

(the half-life of serum albumin is

Answer 64

~21 days, whereas those of prealbumin and retinol-binding protein are ~2 days and ~12 h, respectively), some of these proteins

Question 65

Multiplying by 1.1–1.4 yields a range 10–40% above basal that estimates the 24-h energy expenditure of the majority of patients.

Answer 65

The lower value (1.1) is used for patients without | evidence of significant physiologic stress; the higher value (1.4) is

Question 66

can also be useful in patients who have difficulty weaning from a ventilator and whose energy needs therefore should not be exceeded to avoid excessive CO2 production. Patients at the extremes of weight (e.g., obese persons) and/or age are good candidates as well, because the Harris-Benedict equations were developed from measurements in adults with roughly normal body weights

Answer 66

Indirect calorimetry

Question 67

2.8–3.5 g/dL: Protein depletion or systemic inflammation

Answer 67

<2.8 g/dL: Possible acute malnutrition or severe | inflammation

Question 68

Body Mass Index (BMI), Muscle Mass, and Protein Energy Malnutrition (PEM)

Answer 68

``` >30 Normal Obese 25–29.9 Normal Overweight 20–24.9 Normal Normal >18.5 Decreased PEM despite adequate or excessive adipose tissue store >18.5 Decreased Moderate PEM <16 Decreased Severe PEM <13 Decreased Lethal in men <11 Decreased Lethal in women ```

Question 69

is the provision of liquid formula meals through a tube | placed into the gut.

Answer 69

Enteral SNS

Question 70

is the direct infusion of complete mixtures of crystalline amino acids, dextrose, triglyceride emulsions, and micronutrients into the bloodstream through a central venous catheter or (rarely in adults) via a peripheral vein.

Answer 70

Parenteral SNS

Question 71

The chief disadvantage of tube feeding in acute illness is | intolerance due to gastric retention, risk of vomiting, or diarrhea.

Answer 71

The presence of severe coagulopathy is a relative contraindication to the insertion of a feeding tube. In adults, parenteral nutrition (PN) almost always requires aseptic insertion of a central venous catheter with a dedicated port.

Question 72

A previously well-nourished person can tolerate whereas the degree of tolerance to prolonged starvation is much less in patients whose skeletal muscle mass is already reduced, whether from PEM, from the muscle atrophy of old age (sarcopenia), or from muscle atrophy due to neuromuscular disease.

Answer 72

~7 days of starvation without harm, even in the | presence of a moderate systemic response to inflammation (SRI),

Question 73

In general, unintentional weight loss of >10% during the previous 6 months or a weight-to-height ratio that is <90% of standard, when associated with physiologic impairment, crudely predicts that the patient has moderate PEM.

Answer 73

Weight loss | >20% of usual or <80% of standard makes severe PEM more likely

Question 74

is a negative acute-phase protein and hence a | marker of the SRI.

Answer 74

Serum albumin

Question 75

A major disadvantage of enteral SNS is that the amounts of protein and calories provided to critically ill patients commonly fail to reach target goals within the first

Answer 75

7–14 days after SNS is initiated. This problem is compounded by the lack of enteral products that allow the provision of the recommended protein target of 1.5–2.0 g/kg without simultaneously inducing potentially harmful caloric overfeeding.

Question 76

The bowel and its associated digestive organs derivesecretion of gastrointestinal hormones that stimulate gut trophic activity

Answer 76

70% of their required nutrients directly from nutritional substrates absorbed from the intestinal lumen. Enteral feeding also supports gut function by stimulating splanchnic blood flow, neuronal activity, IgA antibody release, and

Question 77

In renal disease, except for brief periods, protein intakes should approach the required level for normal adults of at least

Answer 77

0.8 g/kg and should aim for 1.2 g/kg as long as severe azotemia does not occur Patients with severe renal failure who require SNS need concurrent renal replacement therapy.

Question 78

In hepatic failure, protein intakes of

Answer 78

1.2–1.4 g/kg (up to 1.5 g/kg) should be provided as long as encephalopathy due to protein intolerance does not occur. In the presence of protein intolerance, formulas containing 33–50% branched-chain amino acids are available and can be provided at the 1.2- to 1.4-g/kg level

Question 79

Cardiac patients and many other severely stressed patients often benefit from fluid and sodium restriction

Answer 79

to 1000 mL of PN formula and | 5–20 meq of sodium per day.

Question 80

Normal adults require

Answer 80

~30 mL of fluid/kg of body weight from all sources each day as well as the replacement of abnormal losses such as those caused by diuretic therapy, nasogastric tube drainage, wound output, high rates of perspiration (which can be several liters per day during periods of extreme heat), and diarrhea/ostomy losses.

Question 81

Fluid restriction may be necessary in | patients with fluid overload.

Answer 81

Total fluid input can usually be limited to 1200 mL/d as long as urine is the only significant source of fluid output. In severe fluid overload, a 1-L central vein PN solution of 7% crystalline amino acids (70 g) and 21% dextrose (210 g) can temporarily provide an acceptable amount of glucose and protein substrate in the absence of significant catabolic stress

Question 82

For normally nourished, | healthy individuals, the total energy expenditure is

Answer 82

~30–35 kcal/kg.

Question 83

Critical illness increases resting energy expenditure, but this increase is significant only in initially well-nourished individuals with a robust SRI who experience, for example, severe multiple trauma, extensive burns, sepsis, sustained high fever, or closed head injury. In these situations, total energy expenditure can reach

Answer 83

40–45 kcal/kg

Question 84

The chronically starved patient with adapted PEM has a reduced energy expenditure and is inactive, with a usual total energy expenditure of

Answer 84

~20–25 kcal/kg.

Question 85

SNS is at least as effective as 100% for the first

Answer 85

10 days of critical illness, actual measurement of energy expenditure generally is not necessary in the early period of SNS

Question 86

Insulin resistance due to the SRI is associated with

Answer 86

increased gluconeogenesis and reduced peripheral glucose utilization, with resulting hyperglycemia. Hyperglycemia is aggravated by excessive exogenous carbohydrate administration from SNS.

Question 87

Hypocaloric nutrition, with provision of

Answer 87

~1000 kcal and 70 g protein per day for up to 10 days, requires less fluid and reduces the likelihood of poor glycemic control, although a higher protein intake would be optimal. During the second week of SNS, energy and protein provision can be advanced to 20–25 kcal/kg and 1.5 g/kg per day, respectively, as metabolic conditions permit

Question 88

The daily protein recommendation for healthy adults is

Answer 88

0.8 g/kg, but body proteins are replenished faster with 1.5 g/kg in patients with PEM, and net protein catabolism is reduced in critically ill patients when 1.5–2.0 g/kg is provided.

Question 89

In patients who are not critically ill but who require SNS in the acute-care setting, at least

Answer 89

1 g of protein/ kg is recommended, and larger amounts up to 1.5 g/kg are appropriate when volume, renal, and hepatic tolerances allow.

Question 90

Iron is a highly reactive catalyst of oxidative reactions and thus is not included in PN mixtures. The parenteral iron requirement is normally

Answer 90

only ~1 mg/d.

Question 91

Peripheral PN may be enhanced by

Answer 91

small amounts of heparin (1000 U/L) and co-infusion with parenteral fat to reduce osmolarity, but volume constraints still limit the value of this therapy, especially in critical illness

Question 92

The subclavian approach is best tolerated by the patient and is the easiest to dress.

Answer 92

The jugular approach is less likely to cause a pneumothorax. Femoral vein catheterization is strongly discouraged because of the risk of catheter infection

Question 93

to the daily parenteral formula for hospitalized patients with temporary catheters reduces the risk of fibrin sheath formation and catheter infection.

Answer 93

The addition of 6000 U of heparin

Question 94

The most common problems caused by parenteral SNS | are fluid overload and hyperglycemia (Table 98e-7).

Answer 94

Hypertonic dextrose stimulates a much higher insulin level than meal feeding. Because insulin is a potent antinatriuretic and antidiuretic hormone hyperinsulinemia leads to sodium and fluid retention

Question 95

Infections of the central access catheter rarely occur in the

Answer 95

first 72 h. Fever during this period is usually attributable to infection elsewhere or another cause. Fever that develops during parenteral SNS can be addressed by checking the catheter site and, if the site looks clean, exchanging the catheter over a wire, with cultures taken through the catheter and at the catheter tip

Question 96

If cultures are positive for more pathogenic bacteria or for fungi like Candida albicans, it is generally best to replace the catheter at a new site.

Answer 96

Whether antibiotic treatment is required is a clinical decision, but C. albicans grown from the blood culture in a patient receiving PN should always be treated with an antifungal drug because the consequences of failure to treat can be dire.