Harrisons Principles of Internal Medicine Self-Assessment and Board Review 18th Ed.

SECTION II. Nutrition


II-1.  The answer is C. (Chap. 73) Carbohydrates comprise the greatest percentage of calories in the diet as they are the major fuel source for the brain and most tissues. The brain requires 100 g/d of glucose, with the rest of the body requiring about 50 g/d of glucose. Although glucose can be derived from proteolysis or fats, carbohydrates remain the primary energy source of the body and should comprise 45–55% of the total caloric intake. Fats should comprise no more than 30% of caloric intake, and proteins typically should comprise about 15%.

II-2.  The answer is B. (Chap. 73) Dietary reference intakes (DRIs) have supplanted the recommended daily allowances (RDAs) as the benchmark recommendations for determining nutrient intake in clinical practice. The RDAs outline the average intake that will meet the nutrient needs of nearly all healthy individuals of a specific age, life stage, sex, or physiologic condition. In contrast, the DRIs take a more comprehensive approach and also consider the estimated average requirement, adequate intake, and upper tolerable limit of intake. The estimated average intake is the amount of a nutrient estimated to meet the nutrient needs for half of the healthy individuals of a specific sex and age. Because this is a median value, it is generally not acceptable to set the estimated average intake as the benchmark for intake as, by definition, 50% of individuals would require more of the specific nutrient compared to this value. As stated above, the RDA is an estimated intake that would meet the nutrient needs of almost all healthy individuals and is defined as being two standard deviations above the estimated average requirement. Adequate intake is used in the place of RDAs when estimated average requirements are unable to be determined, thus preventing the calculation of an RDA. Adequate intake is determined based on observed or experimentally determined approximations of nutrient needs and is used for infants up to 1 year old, as well as for many minerals including calcium, manganese, chromium, and fluoride, among others. The tolerable upper limit of nutrient intake is the highest level of daily nutrient intake that is unlikely to cause adverse health effects. In many cases, there are insufficient data to determine a tolerable upper limit.

II-3.  The answer is B. (Chap. 73) For patients with stable weights, REE can be calculated if the gender, weight, and activity level are provided. For males, image, and for females, image, where w is weight in kilograms. The REE is then adjusted for activity level by multiplying by 1.2 for sedentary, 1.4 for moderately active, and 1.8 for very active individuals. Patient A has an REE of 2160 kcal/d. Patient B has an REE of 2880 kcal/d. For a given weight, a higher level of activity increases the REE more than a 20-kg change in weight at a given level of activity.

II-4.  The answer is C. (Chap. 73) The estimated average requirement (EAR) is the amount of a nutrient estimated to be adequate for half of the individuals of a specific age and sex. It is not useful clinically for estimating nutritional adequacy because it is a median requirement for a group: 50% of the individuals in a group fall below the requirement and 50% fall above it. A person taking the EAR of a vitamin has a 50% risk of inadequate intake. The recommended daily allowance (RDA) is defined statistically as two standard deviations above the EAR to ensure that the needs of most individuals are met. In this case the study used a dosage of two standard deviations above the EAR, which would be the RDA. Data on the tolerable upper limit of a vitamin are usually inadequate to establish a value for the upper limit of tolerability. The absence of a published tolerable upper limit does not imply that the risks are nonexistent.

II-5.  The answer is E. (Chap. 74) Deficiencies of many vitamins and minerals are rare in developed countries except in individuals with alcoholism or chronic illness. Alcoholism in general is associated with decreased intake of nutrients and may be associated with mal-absorption or impaired storage. Common vitamin deficiencies in those with alcoholism include thiamine and folate. Other vitamins that may be deficient in alcoholics are niacin, vitamin B6, vitamin C, and vitamin A. Vitamin B12 deficiency is uncommon as the vitamin is widely available in the food supply. It can be found in meats, nuts, and cereal grains, and in low levels in fruits and vegetables. Dietary deficiency of vitamin E does not occur, and deficiency is found only in individuals with prolonged fat malabsorption or genetic abnormalities of vitamin E metabolism or transport.

II-6.  The answer is E. (Chap. 74) Thiamine (vitamin B1) is a water-soluble vitamin found in yeast, organ meat, pork, legumes, whole grains, beef, and nuts. It is generally more common in those with rice-based diets as rice contains little thiamine. In Western diets, the most common cause of thiamine deficiency is alcoholism and chronic illness. Alcohol interferes with the absorption of thiamine and with the synthesis of thiamine pyrophosphate. When thiamine deficiency is possible, one must take care to replenish thiamine whenever carbohydrates are administered, as failure to do so can precipitate lactic acidosis. Thiamine deficiency in its earliest stages produces anorexia and nonspecific symptoms. Prolonged deficiency results in beriberi, which is often characterized as wet or dry. In patients with wet beriberi, cardiovascular symptoms predominate with findings including cardiomegaly, tachycardia, and high-output heart failure. In dry beriberi, the symptoms are primarily neurologic with symmetric peripheral sensory and motor neuropathy, and diminished reflexes. Alcoholics also commonly have central nervous system findings that are frequently underdiagnosed and are attributed to the alcoholism. Wernicke encephalopathy manifests as horizontal nystagmus, ophthalmoplegia, cerebellar ataxia, and mental impairment. When memory loss and confabulation are present, the syndrome is known as Wernicke-Korsakoff syndrome.

II-7.  The answer is B. (Chap. 74) Niacin (vitamin B3) has high bioavailability from beans, milk, meat, and eggs. Although the bioavailability from grains is lower, most flour is enriched with “free” niacin; thus deficiency of niacin is rare in Western diets. Niacin deficiency can be found in individuals with corn-based diets in some parts of China, Africa, and India; individuals with alcoholism; and individuals with genetic defects limiting the absorption of tryptophan. In addition, individuals with carcinoid syndrome are at increased risk of niacin deficiency because of an increased conversion of tryptophan to serotonin. Clinically, the syndrome of niacin deficiency is known as pellagra. Early symptoms of niacin deficiency are loss of appetite, generalized weakness, abdominal pain, and vomiting. Glossitis is characteristic of pellagra with a beefy red tongue. Pellagra also has many dermato-logic manifestations including a characteristic skin rash appearing on sun-exposed areas. The rash is scaling and erythematous. The rash often forms a ring around the neck. The four d’s of niacin deficiency—diarrhea, dermatitis, dementia, and death—are seen only in the most severe cases.

II-8.  The answer is E. (Chap. 74) Vitamin A, also known as retinol, is a fat-soluble vitamin that has biologically active metabolites, retinaldehyde, and retinoic acid, which are all important for good health. Collectively, these molecules are known as retinoids and are important for normal vision, cell growth and differentiation, and immunity. Vitamin A is found in its preformed state in liver, fish, and eggs, and it is often consumed as carotenoids from dark green and deeply colored fruits and vegetables. In developing countries, chronic vitamin A deficiency is endemic in many areas and is the most common cause of preventable blindness. In milder stages, vitamin A deficiency causes night blindness and conjunctival xerosis. This can progress to keratomalacia and blindness. Given the broad biologic functions of vitamin A, however, deficiency at any stage increases the risk of mortality from diarrhea, dysentery, measles, malaria, and respiratory disease. Vitamin A supplementation has been demonstrated to decrease childhood mortality by 23–34%.

II-9.  The answer is D. (Chap. 74) This patient has the classic perifollicular hemorrhagic rash of scurvy (vitamin C deficiency). In the United States, scurvy is primarily a disease of alcoholics and the elderly who consume less than 10 mg/d of vitamin C. In addition to nonspecific symptoms of fatigue, these patients also have impaired ability to form mature connective tissue and can bleed into various sites, including the skin and gingiva. A normal INR excludes symptomatic vitamin K deficiency. Thiamine, niacin, and folate deficiencies are also seen in patients with alcoholism. Thiamine deficiency may cause a peripheral neuropathy (beriberi). Folate deficiency causes macrocytic anemia and thrombocytopenia. Niacin deficiency causes pellagra, which is characterized by glossitis and a pigmented, scaling rash that may be particularly noticeable in sun-exposed areas.

II-10. The answer is B. (Chap. 74) High doses of vitamin E (>800 mg/d) may reduce platelet aggregation and interfere with vitamin K metabolism. Doses greater than 400 mg/d may increase mortality from any cause. Vitamin E excess is not related to an increased risk of venous thrombosis. Peripheral neuropathy and a pigmented retinopathy may be seen in vitamin E deficiency. Vitamin A deficiency is a cause of night blindness.

II-11. The answer is D. (Chap. 74) Hypozincemia is most commonly due to poor oral intake of zinc, although some medications can also inhibit zinc absorption (e.g., sodium valproate, penicillamine, ethambutol). Severe chronic zinc deficiency has been described among children from Middle Eastern countries as a cause of hypogonadism and dwarfism. Hypo-pigmented hair is also a part of this syndrome. Hypochromic anemia can be seen in a number of vitamin deficiency/excess disorders, including zinc toxicity and copper deficiency. Copper deficiency is also associated with dissecting aortic aneurysm. Hypoglycemia does not correlate with hypozincemia. Macrocytosis is associated with folate and vitamin B12 deficiency.

II-12. The answer is B. (Chap. 75) Marasmus and cachexia both represent forms of prolonged starvation with decreased energy intake. The primary difference between marasmus and cachexia is that the starvation in marasmus is related to decreased caloric intake, whereas in cachexia the poor energy is relative and is associated with a chronic inflammatory state. Other than the cause of malnutrition, marasmus and cachexia have common features when compared to kwashiorkor, or protein-calorie malnutrition. Marasmus and cachexia develop over a course of months to years, resulting in an individual who appears starved with a weight less than 80% for height. In addition, there is evidence of muscle and fat wasting with decreased triceps skinfold and midarm muscle circumference. On laboratory examination, there are often few abnormalities. The albumin may be low, but does not fall below 2.8 g/dL in uncomplicated cases. The only finding may be a low creatinine-to-height index when the 24-hour urine creatinine is low (<60%) for normal values based on height. Despite the starved appearance, individuals with marasmus or cachexia are immunocompetent and are able to respond reasonably well to short-term stresses. As this is a chronic illness, the approach to treatment should be cautious support of nutritional needs. Overly aggressive nutritional repletion can lead to overfeeding syndromes and life-threatening hypophosphatemia. The oral and enteral routes are the preferred methods for improving nutrition.

In contrast, kwashiorkor, or protein-calorie malnutrition (PCM), occurs acutely over the course of weeks. In developed countries, the most common of PCM is acute, life-threatening illness such as trauma or sepsis. Pathophysiologically, the stresses of the acute illness lead to increased protein and calorie needs at a time when intake is often limited. Early in the course of PCM, the patient usually looks well nourished, so a high index of suspicion is required. Signs of PCM include edema, poor wound healing, easy hair pluck-ability, and skin breakdown. In addition, severe PCM is reflected in low levels of albumin, transferrin, or iron-binding capacity. Cellular immune function is decreased, and lymphopenia may be seen. Aggressive nutritional support is required to reverse the disorder, although mortality remains high.

II-13. The answer is A. (Chap. 75) Several factors can help identify an individual who is at high risk of nutritional depletion upon hospital admission. The first factor to consider is the body mass index (BMI) and recent weight loss. If a patient is underweight (BMI <18.5 kg/m2) or has recently lost more than 10% of body weight, this would confer increased nutritional risk. Other general categories that increase nutritional risk include poor intake, excessive nutrient losses, hypermetabolic states, alcoholism, or medications that increase metabolic requirements. Poor oral intake can be related to current anorexia, food avoidance, or NPO status for more than 5 days, among others. Examples of excessive nutrient loss include malabsorption syndromes, enteric fistulae, draining wounds, or renal dialysis. Common hypermetabolic states are trauma, burns, sepsis, and prolonged febrile illness. The patient with anorexia in remission and a normal BMI would be least likely among these patients to have excessive nutritional risk.

II-14. The answer is B. (Chap. 75) A patient’s basal energy expenditure (BEE) can be calculated using the Harris-Benedict equation. The factors that are used for determining BEE are age, gender, height, and weight. The BEE for hospitalized patients is then adjusted by a factor of 1.1–1.4 depending on the severity of illness, with the highest values used for patients admitted with marked stress such as trauma or severe sepsis. The BEE serves as an estimate only. If it is important to have an exact calculation of energy expenditure, indirect calorimetry can be performed. Protein needs can also be calculated more definitively by the use of urine urea nitrogen (UUN) as an estimate of protein catabolism.

II-15. The answer is C. (Chap. 75) The two major types of protein energy malnutrition are marasmus and kwashiorkor; differentiating the two is extremely important in the malnourished patient because it directly affects the choice of therapy. This patient has marasmic kwashiorkor due to the impact of her anorexia nervosa, the acute stressor of the surgery, and the 10 days of starvation. This patient has chronic starvation (marasmus) as well as the major sine qua non of kwashiorkor (i.e., reduced levels of serum proteins). She is kwashiorkor predominant because of the acute starvation and the severely low levels of serum proteins. Vigorous nutritional therapy is indicated for kwashiorkor.

II-16. The answer is C. (Chap. 75) The energy stores in a healthy 70-kg man include approximately 15 kg as fat, 6 kg as protein, and 500 mg as glycogen. During the first day of a fast, most energy needs are met by consumption of liver glycogen. During longer fasting, resting energy expenditure will decrease by up to 25% (provided there is no ongoing inflammation). In the presence of water intake and no inflammation, a normal individual may fast for months. A well-nourished individual can tolerate approximately 7 days of starvation while experiencing a systemic response to inflammation. The hiker in this scenario has starved for 6 days and, except for mild acute renal failure, he has compensated well for his starvation. Greater than 10% weight loss in 6 months represents significant protein-calorie malnutrition. This person’s ferritin is only mildly elevated, although a true systemic response to inflammation (SRI) does increase the rate of lean tissue loss. Moreover, there are no other indicators that he is experiencing the systemic inflammatory response syndrome (SIRS). SRI often causes hyperglycemia, not hypoglycemia.

II-17. The answer is E. (Chap. 76) This patient would have at least a moderate systemic response to inflammation (SRI), as would be expected in the postoperative period. In such a situation, individuals benefit from adequate feeding by day 5–7. Picking the appropriate nutritional support should take into account the patient’s overall clinical course. Generally, the enteral route is preferred to promote the ongoing health and immunologic barrier function of the gut, as long as there are no contraindications. Parenteral nutrition alone is generally only indicated for prolonged ileus, obstruction, or hemorrhagic pancreatitis. As this patient has bowel sounds and evidence of ileostomy output, he is not exhibiting ileus at the present time. Thus, enteral nutrition would be used. Given his delirium and aspiration risk, he should not be initiated on an oral diet, and nasogastric feeding is also contraindicated, as it is associated with a higher aspiration risk. The preferred feeding method would be the use of a nasojejunal feeding tube placed post–ligament of Treitz.

II-18. The answer is D. (Chap. 76) When possible, at least a portion of the nutritional support given to a critically ill patient should be in the form of enteral nutrition. Use of the enteral route is particularly important for maintaining the overall health of the gastrointestinal tract. Seventy percent of the nutrients utilized by the bowel and its associated digestive organs are directly derived from food within the bowel lumen. Moreover, enteral feedings are important for maintaining the immunologic function of the gut as they stimulate the secretion of IgA and hormones to promote trophic activity of the gut. In addition, enteral feedings improve splanchnic blood flow and stimulate neuronal activity to prevent ischemia and ileus.

II-19. The answer is C. (Chap. 76) It is important to understand the thresholds of body mass index (BMI) that indicate malnutrition. Normal BMI ranges between 20 and 25 kg/m2, and a patient is considered underweight with likely moderate malnutrition at a BMI of 18.5 kg/m2. Severe malnutrition is expected with a BMI of less than 16 kg/m2. In men, a BMI of less than 13 kg/m2 is lethal, and in women, the lethal BMI is less than 11 kg/m2.

II-20. The answer is E. (Chap. 76) The two most common problems with the use of parenteral nutrition (PN) are fluid retention and hyperglycemia. The fluid retention is greater than would be expected by the volume of PN and is linked to the hyperglycemia. The dextrose provided by PN is hypertonic and stimulates greater insulin secretion than is generated by meal feeding. Insulin itself has antinatriuretic and antidiuretic properties that exacerbate fluid and sodium retention. Strategies to minimize fluid and sodium retention include providing both glucose and fat as energy sources and limiting sodium intake to less than 40 meq daily. In addition, it is best to initiate feeding with less than 200 g glucose/day to assess glucose tolerance. Regular insulin can be added to the PN formula to maintain glycemic control. In addition to providing insulin with the PN formula, additional subcutaneous insulin may be given based on a sliding scale every 6 hours with about two-thirds of the total dose given during a 24-hour period added to the PN formula the next day. In more severe cases, intensive insulin support with a separate infusion of insulin should be used. If a patient has known insulin-dependent diabetes mellitus, the dose of insulin required is usually twice the usual outpatient dosage.

II-21. The answer is D. (Chap. 75) Initiating enteral support is important in the critically ill, but does not come without complications. Tube malposition and aspiration are two of the most common complications of enteral feeding in the intensive care unit (ICU). Many patients in the ICU have delayed gastric emptying and also have alterations in mental status that increase the baseline risk of aspiration. This is further worsened in individuals who are intubated for mechanical ventilation. The act of suctioning alone induces coughing and gastric regurgitation. Endotracheal tubes are poor barriers to aspiration and may make aspiration worse by transiting across the vocal cords and epiglottis, two of the normal preventive mechanisms against aspiration. In the care of the ICU patient, measures should be taken to minimize the risk of aspiration. A primary measure is to keep the head of the bed elevated to more than 30°. In patients who are having difficulty tolerating full enteral nutrition, combining enteral and parenteral nutrition should be considered. Utilizing nurse-directed algorithms for formula advancement based on gastric residuals and patient tolerance is also important. Generally, feeding should not be held unless the residual is greater than 300 mL. Finally, the use of nasojejunal feeding tubes placed post–ligament of Treitz is a recent strategy to decrease the risk of aspiration. Neither nasogastric nor nasoduodenal tubes decrease the risk of aspiration.

II-22. The answer is C. (Chap. 77) In 2007-2008, the National Health and Nutrition Examination Surveys (NHANES) found that 68% of the adult population of the United States was overweight or obese [body mass index (BMI) >25 kg/m2]. Understanding the worsening of obesity in the United States requires understanding both the genetic and environmental factors that contribute to the development of obesity. It is clear that the rapid increase in obesity in the this county is far greater than can be attributed to changes in genetics. However, certain genetic factors certainly increase the risk of obesity. Obesity generally is inherited in a non-Mendelian pattern similar to that of height. Adopted children have BMIs more closely related to their biologic parents than their adopted parents. Likewise, monozygotic twins have BMIs more similar than dizygotic twins. Some of the genes that are known to play a role in the development of obesity include genes for leptin, proopiomelanocortin (POMC), and melanin-concentrating hormone, among others. Leptin is an important hormone in obesity. Produced by adipocytes, this hormone acts at the hypothalamus to decrease appetite and increase energy expenditure. In humans, mutations of the ob gene lead to decreased leptin production, and mutations of the db gene cause leptin resistance. The result of these mutations can be either decreased leptin production or resistance to leptin, which causes failure of the brain to recognize satiety. These mutations are generally associated with severe obesity beginning shortly after birth.

II-23. The answer is A. (Chap. 77) Several syndromes have been recognized as being associated with the development of obesity. Prader-Willi syndrome falls into a category of syndromes of obesity associated with mental retardation. Individuals with Prader-Willi syndrome are of short stature with small hands and feet. They exhibit hyperphagia, obesity, and neurodevelopmental delay in association with hypogonadotropic hypogonadism. Endocrine abnormalities or abnormalities of the hypothalamus are also commonly associated with obesity. Patients with Cushing’s syndrome have central obesity, hypertension, and glucose intolerance. Hypothyroidism is associated with obesity due to decreases in metabolic rate; however, it is a rare cause of obesity. Individuals with insulinoma often are obese, as they increase their caloric intake to try to prevent hypoglycemia episodes. Finally, individuals with hypothalamic dysfunction due to craniopharyngioma or other disorders lack the ability to respond to typical hormonal signals that indicate satiety, and therefore develop obesity. Acromegaly is not associated with obesity.

II-24. The answer is E. (Chap. 78) With over 60% of the U.S. population being overweight or obese, the primary care physician should be monitoring weight and BMI at every visit and making recommendations for weight loss to prevent long-term complications of obesity, including hypertension, hypercholesterolemia, and diabetes mellitus. Despite the very simple concept that energy output needs to be greater than caloric intake, it is very difficult for individuals to achieve and sustain weight loss. One initial factor that predisposes an individual to fail at attempts to lose weight is failure to understand what is a reasonable goal and time frame for weight loss. The initial target for weight loss should be about 10% over 6 months. In this patient, that would be an approximately 24- to 25-lb weight loss over 6 months. She would not realistically be able to achieve her prepregnancy weight of 70 kg for at least 18–24 months. Many individuals find diet therapy difficult to sustain for an extended period, especially when a specific and limited diet is prescribed. It is more important for the individual to think of the dietary changes that occur concurrently with weight loss as a lifestyle change. To achieve a weight loss of 0.5–1 kg weekly, caloric intake needs to decrease by about 500–1000 kcal daily. The specific dietary intervention to undertake depends on personal factors. Studies show that low-carbohydrate, high-protein diets (Atkins, South Beach, etc.) lead to greater weight loss, improved satiety, and decreased coronary disease risk factors in the short term, but at 12 months there is no difference among diets. Very low calorie diets (≤800 kcal/d) are a very aggressive form of dietary therapy with proprietary formulas. These diets are designed to cause weight loss of 13–23 kg over a 3- to 6-month period and should be utilized only in individuals with obesity and medical comorbidities for whom conservative approaches have failed. In combination with dietary changes, it should also be recommended that individuals begin an exercise program. Although exercise alone can lead to some weight loss, it should not be the only strategy for losing weight. The recommended amount of physical activity is 150 minutes of moderate-intensity activity or 75 minutes of high-intensity activity weekly. Pharmaco-therapy for obesity can be considered in individuals with a BMI greater than 30 kg/m2. However, options for pharmacotherapy are limited at the present time. Many new medications are undergoing clinical trials and may play a role in weight loss in the future. Bariatric surgery should not be considered unless conservative strategies for weight loss have failed.

II-25. The answer is D. (Chap. 78) Bariatric surgery should be considered for individuals who have a BMI of 40 kg/m2 or greater, or a BMI of 35.0 kg/m2 or greater if there are serious comorbid medical conditions including diabetes mellitus, hypertension, or hyper-cholesterolemia. Surgical weight loss therapy achieves weight loss through reducing the capability for calorie intake and may also cause malabsorption depending on the procedure chosen. There are two broad categories of weight loss procedures: restrictive and restrictive-malabsorptive. Restrictive surgeries decrease the size of the stomach to generate feelings of early satiety. The original procedure was the vertical-banded gastroplasty, but this procedure has been abandoned due to lack of effectiveness in long-term trials. It has been replaced by laparoscopic adjustable silicone gastric banding (LASGB). With this type of bariatric surgery, there is a subcutaneous reservoir into which saline can be injected or removed to change the size of the gastric opening. Restrictive-malabsorptive procedures include the Roux-en-Y gastric bypass, biliopancreatic diversion, and biliopancreatic diversion with duodenal switch. The Roux-en-Y procedure is the most common bypass procedure. The average weight loss following bariatric surgery is 30–35% of total body weight, and 60% of individuals are able to maintain this at 5 years. The restrictive-malabsorptive procedures achieve greater weight loss than restrictive procedures. Moreover, bariatric procedures lead to improvement in obesity-related comorbid conditions. The overall mortality rate from bariatric surgery is less than 1%, but increases with age and comorbid conditions. Approximately 5–15% of individuals develop stomal stenosis or marginal ulcers following the surgery that present as prolonged nausea and vomiting. Malabsorption does not occur following restrictive procedures. Individuals who have restrictive-malabsorptive procedures have an increased risk for micronutrient deficiency including vitamin B12, iron, folate, calcium, and vitamin D. Lifelong supplementation of these vitamins will be required.

II-26 and II-27. The answers are A and D, respectively. (Chap. 79) The patient in this scenario meets the criteria for the diagnosis of anorexia nervosa (AN). AN has a lifetime prevalence of about 1% in women. Although less common in males, the prevalence is rising in men as well. AN has a typical onset in late adolescence and young adulthood, although younger girls are being diagnosed as well. The etiology of AN is not known, although individuals with AN often have similar personality characteristics, with a tendency to more obsessional and perfectionist behavior. Patients with AN have an abnormal body image with an irrational fear of weight gain, despite being underweight. Weight loss is seen as a fulfilling accomplishment, and individuals with AN will have markedly decreased caloric intake and also excessive exercise. Despite this, those with AN will not complain of hunger. Although classically associated with bulimia nervosa, binge eating occurs in 25–50% of those with AN. As patients with AN become more obsessed with the eating disorder, they will become more socially isolated with an increased focus on exercise, dieting, and studying. Patients with AN often do not think they have a problem and only seek evaluation after pressure from family and friends. Amenorrhea is one of the diagnostic criteria. On physical examination, the patient will generally be underweight for height. Vital signs may show bradycardia and hypotension. Lanugo hair, acrocyanosis, and edema may be seen. Salivary gland enlargement may lead to a fullness of the face despite the overall starved appearance. On laboratory examination, anemia and leukopenia are common. The basic metabolic panel often demonstrates hyponatremia and hypokalemia with a metabolic alkalosis. BUN and creatinine may be slightly elevated despite the low muscle mass. Endocrine abnormalities are very common on laboratory examination and reflect hypothalamic dysfunction. Thyroid studies show a pattern characteristic of sick euthyroid syndrome [low thyroid-stimulating hormone (TSH), low T4, low T3, and elevated reverse T3]. Gonadotropin-releasing hormone (GnRH) secretion is very low and associated with low levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Given the generally stressed state of the body, however, serum and urine cortisol may be elevated.

The primary treatment of AN requires intensive psychotherapy under the care of an experienced psychologist or psychiatrist along with careful medical follow-up. The goal of treatment is to restore body weight to 90% of predicted body weight or higher. For patients with significant electrolyte abnormalities or body weight less than 75% predicted, inpatient treatment is recommended. Nutrition is primarily accomplished through oral feeding. The initial caloric intake goal is about 1200–1800 kcal/d with close follow-up to observe for evidence of refeeding syndrome. The weight gain goal is 1–2 kg weekly with advancement of caloric goal to 3000–4000 kcal/d. As many patients resist weight gain and lie about oral intake, supervised mealtimes are required in both inpatient and outpatient settings. As part of therapy, individuals must confront issues with body image. No psychotropic medications have been demonstrated to improve outcomes in AN. Appetite stimulants also have no role in the treatment of AN. Doxepin is a tricyclic antidepressant that has mild appetite-stimulating properties; however, it has not been trialed in AN and has side effects that include prolongation of the QT interval and should be avoided. The endocrine abnormalities do not have to be treated either, as these cortisol and thyroid hormone levels will correct with adequate nutrition. Patients should receive calcium and vitamin D supplementation, but estrogens have no benefit on bone density in underweight patients. Bisphosphonates can yield improvements in bone density, but the risks of therapy in young individuals are felt to outweigh the benefits.

II-28. The answer is C. (Chap. 79) Binge-eating disorder has a higher lifetime prevalence than bulimia nervosa or anorexia nervosa at about 4%. Although more men suffer from binge-eating disorder than other types of eating disorders, women with binge-eating disorder still outnumber men 2:1. Binge-eating disorder and bulimia nervosa share the common characteristic of episodes of eating a large amount of food in a short period of time with a feeling that the eating behavior is out of control. However, patients with binge-eating disorder do not exhibit inappropriate behaviors such as self-induced vomiting or the use of laxatives as a means to control the binge eating. Both binge-eating disorder and bulimia nervosa are associated with the presence of normal menstrual cycles in women. Individuals with binge-eating disorder are more likely to be obese and also have higher rates of anxiety and depression.

II-29. The answer is E. (Chap. 79) Based on the American Psychiatric Association’s practice guidelines, inpatient treatment or partial hospitalization is indicated for patients whose weight is less than 75% of expected for age and height, who have severe metabolic disturbances (e.g., electrolyte disturbances, bradycardia, hypotension), or who have serious concomitant psychiatric problems (e.g., suicidal ideation, substance abuse). There should be a low threshold for inpatient treatment if there has been rapid weight loss or if weight is less than 80% of expected. Amenorrhea, exaggeration of food intake, and fear of gaining weight are part of the diagnostic criteria for AN, and purging is not uncommon in this population. Weight restoration to 90% of predicted weight is the goal of nutritional therapy.

II-30. The answer is D. (Chap. 79) Approximately 25–50% of patients with anorexia nervosa (AN) recover fully with few physiologic or psychological sequelae. However, many patients have persistent difficulties with weight maintenance, depression, and eating disturbances. Approximately 5% of patients with AN die per decade, usually due to the physical effects of chronic starvation or from suicide. Virtually all of the physiologic derangements associated with AN will improve with weight gain. One exception is the loss of bone mass, which may not recover fully when AN occurs during adolescence (i.e., during peak bone mass formation). Psychological health also improves with successful treatment, although these patients remain at risk for depression, recurrence, and development of bulimia nervosa.

II-31. The answer is E. (Chap. 80) Involuntary weight loss (IWL) is a frequent finding in older individuals, affecting more than 25% of frail individuals older than 65 years. Clinically important weight loss is defined as a loss of more than 5% of body weight or more than 5 kg over the course of 6–12 months. In older individuals, weight loss is associated with hip fracture, pressure ulcers, decreased functional status, and death. There are many causes of IWL, with the most common categories being malignancy, chronic inflammatory or infectious disease, metabolic disorders, and psychiatric disorders. In older individuals, it is also important to consider neurologic disorders, including stroke leading to dysphagia, progressive vision loss, and dementia. IWL can be one of the earliest manifestations of Alzheimer’s disease. An under-recognized cause of IWL is lack of access to food or inability to pay for food. When evaluating an individual for IWL, a complete physical examination, including a dental examination, should be performed to assess for obvious physical causes that would lead to weight loss. Medications may also lead to changes in appetite or weight loss. Patients should undergo age-appropriate cancer screening. In older individuals, a Mini-Mental State Examination, Mini-Nutritional Assessment, and assessment of performance of activities of daily living may be helpful. It may also be useful to observe the patient’s eating. Depression in the elderly may also present with loss of appetite and should be assessed. Laboratory studies could include a complete blood count, comprehensive metabolic panel, thyroid function tests, and erythrocyte sedimentation rate and C-reactive protein. HIV testing is indicated if risk factors are identified.