Endocrinology QOD review

Endocrinology QOD review
1

Of the following growth curves, the one MOST likely to be associated with familial short stature in a boy who had a birth weight of 3.3 kg is A B 2

Of the following growth curves, the one MOST likely to be associated with familial short stature in a boy who had a birth weight of 3.3 kg is C D E 3

Curve A Curve B Curve C Curve D Curve E
Of the following growth curves, the one MOST likely to be associated with familial short stature in a boy who had a birth weight of 3.3 kg is Curve A Curve B Curve C Curve D Curve E 15

Children who are born relatively large but are destined to have short stature as adults because they come from short families (familial short stature) generally show a shift in growth percentiles so that by the time they are 2 years of age, they are growing at a steady rate and their height percentile is appropriate for their family. They mature at a normal time and achieve short normal adult stature after reaching full maturation, as in growth chart A. Some affected children have idiopathic short stature and some may have a known single gene mutation leading to short stature. Growth charts B, C, and D show the progress of children who have growth attenuation or arrest occurring or persisting past the second year. Such children likely have serious underlying illnesses interfering with linear growth. An examination of weight for age might be helpful in assessing the cause of the growth attenuation. For example, a child who has celiac disease would be underweight and often experience weight loss before slowing in growth, while a child who has hypothyroidism would have a normal weight or be overweight for age, but have marked growth attenuation. Growth chart E shows a continuation of growth with a growth spurt after other boys have reached adult height. A period of slowdown or attenuation in growth rate is documented just before the pubertal growth spurt, which may be relatively prolonged if puberty is late. This pattern is seen in delayed adolescence, and it can be associated with relative short stature during childhood and a normal adult height. American Board of Pediatrics Content Specifications: Know how to distinguish between familial short stature and other conditions Recognize the signs of familial short stature 5

Question 2 The parents of a 3-year-old boy are concerned because he is the same size as 2-year-old children in his preschool playgroup. Both of the parents are healthy. The father is 5 ft 3 in (160.0 cm) in height and the mother is 4 ft 10 in (147.3 cm) in height. They recognize that their child may be short because they are not tall, but they want to be sure that there is no other problem. 6

bone age radiograph normal for age
Of the following, the BEST indicator that the boy is following his genetic growth pattern is bone age radiograph normal for age his height at the 3rd percentile for age normal weight for height steady linear growth at 3 cm/year steady linear growth at 5 cm/year 15

Familial short stature is a diagnosis of exclusion that is defined by the presence of short parents and an otherwise normal short child. It often is called idiopathic short stature because familial short stature may have known etiologies. Eventually, genetic diagnoses should be determined to explain all the differences in height among families, but at present, except for relatively unusual short stature conditions, scientists do not have the capacity to make a genetic diagnosis. Children who have familial short stature reach a specific growth centile in the first 2 years after birth, which they then follow in the normal manner until reaching adult height. At age 3, a growth rate of 5 cm/year is considered normal, whereas a growth rate of 3 cm/year is more than 3 standard deviations below the mean for growth rate for age and more suggestive of an organic disorder causing short stature. Prediction of adult height is based upon the reading of bone age radiographs after the age of 6 or 7 years. Before that time, bone age height predictions are not useful; height predictions can best be made by assessment of midparental height. Height at the 3rd percentile is a good sign that a child will have a reasonably normal height as an adult, but does not give information about age at puberty, which can limit or extend the period of active growth because of early or late epiphyseal fusion. A child who has normal weight for height is less likely to have an underlying serious organic disorder to explain short stature, but this finding in itself offers little prognostically. The best predictor is continued good growth for age. 8

Question 3 A 14-year-old boy is worried because he is so much smaller than his peers. You review his previous growth records 9

he has a normal sense of smell
Of the following, the factor that MOST strongly suggests that the boy has constitutional growth delay is that he has a normal sense of smell he has Sexual Maturity Rating 3 pubic hair he was small for gestational age current weight is at the 50th percentile for age his mother reached menarche at 15 years of age 15

Question 4 A mother brings in her 7-year-old daughter because she is worried that the little girl will go through puberty too early. The woman tells you that she reached menarche at 9 years of age, and this was a difficult experience. The child's father, on the other hand, had his growth spurt at the end of high school. 11

a body mass index > the 85th percentile adult body odor
Of the following, this girl is MOST likely to have early menarche if the physical examination reveals a body mass index > the 85th percentile adult body odor breast tissue facial acne pubic hair 15

Age at puberty has a heritable component
Age at puberty has a heritable component. In some families, the inheritance may be autosomal dominant; in others, it seems polygenic. A 7-year-old girl whose mother reached menarche at an early age and whose father was delayed in puberty, as described in the vignette, could have either early or late puberty. However, early menarche at, for example, 9 years of age, would be associated with some signs of breast development (thelarche) by 7 years of age. Higher body mass index is associated with early puberty in girls, but not in boys. Adult body odor, pubic hair, and acne are all signs of adrenal puberty (adrenarche or pubarche). This occurs more or less independently of gonadal puberty, which, in girls, is identified clinically by the beginning of breast budding (thelarche). 13

Question 5 An anxious mother tells you that following pituitary surgery, her husband has started using a testosterone gel applied to the skin on his abdomen daily. She has read that this medication might affect her 2-year-old daughter and 4-year-old son adversely and wonders how best to protect them. 14

Of the following, the BEST advice is for the father to
allow the gel to dry on the skin, get dressed, and wash his hands with soap and water before touching the children clean his hands & the area of application with an alcohol-containing cleanser before touching the children have limited contact with the girl, but the boy should not experience any harmful effects make the room in which he applies the gel off-limits to the children shower immediately after applying the gel so that the preparation does not contaminate his children 15

Answer A Testosterone gels applied to the skin to maintain normal testosterone concentrations in men who have hypogonadism have been reported to cause virilization in family members if used incorrectly. After applying the gel to an area of skin that will be covered with clothing, the user should wash the hands with soap and water to remove any residual testosterone. An individual using the preparation should wait 5 to 6 hours before showering to allow full cutaneous absorption. If direct skin-to-skin contact with another individual is anticipated, the area of application should be washed thoroughly. Soap and water or alcohol will remove the testosterone from the skin. Unless the testosterone gel has been applied to room surfaces and another individual comes into contact with the surfaces, there is no need to limit room access. Both boys and girls can develop masculinization after exposure to testosterone gels, so no children should have inappropriate exposure to these potent medications. American Board of Pediatrics Content Specification: Recognize that testosterone creams used by parents can cause virilization in male or female children 16

Question 6 A 12-year-old boy who has chronic lymphocytic thyroiditis presents to the emergency department with a 1-week history of nausea, vomiting, and muscle pains. On physical examination, the child is dehydrated, has a blood pressure of 80/40 mm Hg and a heart rate of 110 beats/min, and appears tanned even though it is November and he lives in Minnesota. You suspect adrenal insufficiency (Addison disease) and order laboratory tests for serum cortisol and adrenocorticotropic hormone as well as serum and urine electrolytes. 17

Of the following, the MOST typical electrolyte pattern for primary adrenal insufficiency is
15

American Board of Pediatrics Content Specification:
Children who have primary adrenal insufficiency (Addison disease) are unable to retain sodium and excrete potassium because of aldosterone deficiency. They have low concentrations of cortisol and high concentrations of circulating adrenocorticotrophic hormone (ACTH). They become dehydrated and break down muscle tissue, developing hyponatremia, hyperkalemia, an elevated blood urea nitrogen, and acidosis. Their urine electrolytes (increased sodium and decreased potassium) reflect the aldosterone deficiency. Children who have ACTH deficiency (ie, secondary adrenal insufficiency) also manifest the effects of cortisol deficiency: weight loss, nausea, and inability to maintain blood pressure. They often have hyponatremia because the low intravascular volume resulting from cortisol deficiency leads to release of vasopressin. Because they can release aldosterone, they do not develop hyperkalemia. They also do not develop hyperpigmentation. American Board of Pediatrics Content Specification: Know how to use laboratory tests effectively for the diagnosis of Addison disease 19

Question 7 You are covering your group's pediatric practice over the weekend. A mother calls you at 3 PM Saturday afternoon to tell you that her 9-year-old daughter wet the bed the night before, although she has not been enuretic since she was a toddler. She is tired and has been napping on and off all day. She also has been very thirsty for about a week, with increased thirst in the past day. The mother says she looked these symptoms up on the Internet and is worried that her daughter could have diabetes. On questioning, she reports that she has not noticed weight loss, and the girl's appetite has been normal. A maternal great grandmother developed diabetes when she was 75 years old. 21

Of the following, the MOST appropriate action is to
arrange for blood tests and a urine culture at a local laboratory on Monday morning arrange for her daughter to be seen as an outpatient on Sunday reassure her and ask her to bring her daughter to the office on Monday reassure her and ask her to come to the office if the symptoms persist for several days tell her to bring her daughter to the local hospital emergency department immediately 15

More than 50% of children who have type 1 diabetes mellitus diagnosed in the United States are identified because of early symptoms and do not present initially in diabetic ketoacidosis. Early diagnosis is essential to preventing the serious consequences of uncompensated type 1 diabetes. Increased public awareness of the symptoms of diabetes can decrease further the number of children who present with diabetic ketoacidosis. Most children who have type 1 diabetes do not have an affected family member. Initial symptoms of the disease are reflective of insulin deficiency, hyperglycemia, and glycosuria and include weight loss with increased appetite and thirst. Polyuria as a result of glycosuria may manifest as frequent nocturnal urination or as secondary enuresis. Anorexia, continued insatiable thirst, nausea, and vomiting are late manifestations of uncompensated diabetes associated with developing ketoacidosis. Coma and eventual death is the outcome of untreated severe hyperosmolar dehydration and acidosis. 23

The early diagnosis of diabetes can be particularly difficult in young children who still are in diapers and receive much of their nutrition in liquid form. Frequency of urination cannot be used as a marker of hydration in vomiting children who have diabetes because urination reflects the marked glycosuria and osmotic diuresis, not hydration status. Symptoms of type 1 diabetes can worsen rapidly, and diabetic ketoacidosis can develop within hours. Therefore, if diabetes is suspected, as suggested by the symptoms described for the girl in the vignette, the child's blood and urine should be checked for glucose and ketones without delay. If glucose values are elevated, appropriate laboratory studies to define severity should be obtained, and the child should be treated promptly. 24

Question 8 During the health supervision visit for a 14-year-old girl, you note that her thyroid gland is symmetric, somewhat firmer than normal, and about twice normal size. Thyroid testing shows a free thyroxine value of 1.3 ng/dL (16.7 pmol/L) (normal, 0.9 to 1.8 ng/dL [11.6 to 23.2 pmol/L]) and a thyroid-stimulating hormone value of 2.4 mIU/L (normal, 0.5 to 5.0 mIU/L). 25

chronic lymphocytic thyroiditis Graves disease iodine deficiency
Of the following, the MOST likely cause of this child's thyroid enlargement is adolescent goiter chronic lymphocytic thyroiditis Graves disease iodine deficiency thyroid carcinoma 15

The girl described in the vignette has a symmetrically enlarged, firm thyroid gland sometimes referred to as a goiter. The most common cause of thyroid enlargement in adolescents is chronic lymphocytic thyroiditis, or Hashimoto thyroiditis. This autoimmune disorder can be diagnosed in most cases by measuring concentrations of antithyroid antibodies such as those directed against thyroperoxidase (antimicrosomal or anti-TPO antibodies) or against thyroglobulin (antithyroglobulin antibodies). Abnormal thyroid function is not required to have chronic lymphocytic thyroiditis, although many people who have this disorder develop hypothyroidism. The thyroid may enlarge during periods of rapid growth of adolescence (ie, adolescent goiter) or increased need for thyroid hormone, as during pregnancy, but it does not develop the firm consistency seen with chronic lymphocytic thyroiditis. The girl described in the vignette has normal thyroid hormone and thyroid-stimulating hormone (TSH) values, indicating that she could not have active Graves disease, which is autoimmune hyperthyroidism. Iodine deficiency causes thyroid enlargement and elevated TSH concentrations, but such deficiency is very uncommon in the United States, unless the child eats a very restricted iodine-deficient diet. Thyroid cancer is rare in children and adolescents and usually presents as a nodule within the thyroid or with cervical lymphadenopathy rather than symmetric, smooth, firm thyroid enlargement. 27

Question 9 You are examining a 9-year-old boy who has a soft, but distinctly palpable 2-cm nodule on the left lobe of his thyroid. It moves with swallowing. You arrange for thyroid fine-needle aspiration biopsy with ultrasonographic guidance. 28

Of the following, the MOST appropriate information to share with the family is that
all thyroid nodules in boys should be removed because they have a higher risk of malignancy than nodules in girls no further follow-up is necessary if the pathology report suggests a benign thyroid adenoma there is a 50% chance that the thyroid nodule will be malignant the biopsy offers a greater than 90% chance of determining whether a thyroid nodule is benign or malignant thyroid nodules in girls are more likely to be malignant than nodules in boys 15

Thyroid fine-needle aspiration (FNA) biopsy, usually conducted under ultrasonographic guidance, has revolutionized the management of thyroid nodules in adults. Depending on the series, almost all malignancies are identified by aspiration biopsy (more than 95%), although some malignancies cannot be diagnosed easily on FNA smear, and an area of malignancy may be missed in a complex nodule. Nodules may be simple and cystic, simple and composed of follicular or papillary tissue, or complex and composed of some areas that are cystic and other areas with follicular or components. Calcitonin-secreting medullary carcinoma of the thyroid also may present as a nodule and is most worrisome because of its resistance to therapy. Less than 10% of thyroid cancers in children are medullary carcinomas. The risk of malignancy in an adult who has a thyroid nodule is less than 15%. Because most thyroid carcinomas progress slowly, watchful waiting and careful observation after biopsy may be all that is needed in the average adult. The results of FNA seem similar in children, but the greater likelihood of a malignant lesion (a little less than 25%) and the longer life span of children make many endocrinologists uncomfortable with observational management after a negative biopsy. The risk of malignancy is higher in boys who have thyroid nodules, but the general risk still is slightly less than 25% of all nodules in children. Any nodule that is not removed should be monitored because an area of malignancy in a complex nodule could have been missed. American Board of Pediatrics Content Specification: Know that a solitary thyroid nodule may be a sign of thyroid cancer 30

Question 10 During your examination of a 7-year-old boy at his health supervision visit, conducted with a pediatric resident, you determine that his weight is greater than the 97th percentile for age. His mother is obese, his father has type 2 diabetes mellitus, and one grandfather died of a myocardial infarction at 51 years of age. You counsel the family about improvements they can make in the boy's diet and level of exercise.

can be predicted by a determination of hemoglobin A1c values
Of the following, you are MOST likely to advise the resident that this child's risk of developing metabolic syndrome can be predicted by a determination of hemoglobin A1c values is close to that of the general population because there is no family history of hyperlipidemia or systemic hypertension is reduced if he begins to develop a healthy lifestyle as a child is the same as the general population if cholesterol-lowering agents are started, even without lifestyle changes is the same as the general population if his fasting lipid profile is currently normal 15

The findings on physical examination combined with the family history for the boy described in the vignette suggest that he is at risk of metabolic syndrome, a combination of medical disorders that increase the risk of developing cardiovascular disease and diabetes. Metabolic syndrome affects one in five people, the prevalence increases with age, and some studies estimate the prevalence in the United States to be up to 25% of the population. Metabolic syndrome also is known as metabolic syndrome X, syndrome X, and insulin resistance syndrome. The term "metabolic syndrome" dates back to at least the late 1950s but came into common usage in the late 1970s to describe various associations of risk factors with diabetes. The term "metabolic syndrome" for associations of obesity, diabetes mellitus, hyperlipoproteinemia, and hyperuricemia describes the additive effects of risk factors on atherosclerosis. The terms "metabolic syndrome," "insulin resistance syndrome," and "syndrome X" now are used specifically to define a constellation of abnormalities that is associated with increased risk for the development of type 2 diabetes and atherosclerotic vascular disease (eg, heart disease and stroke). Very little is known about the development of metabolic syndrome in children, and the term is not used in pediatrics. However, clinicians are becoming increasingly cognizant of the risk factors in the pediatric population, which include obesity, family predisposition to early cardiovascular disease, systemic hypertension, type 2 diabetes, and an unhealthy dietary and exercise-related lifestyle. Criteria have been determined for treating childhood hyperlipidemia, with the first line of therapy being diet modification and exercise programs. Adoption of such lifestyle changes in childhood can reduce the risk of developing metabolic syndrome. Cholesterol-lowering agents never are used in the absence of concomitant recommendations for institution of lifestyle changes. Although an elevated hemoglobin A1c value does predict diabetes, data are insufficient in the pediatric population to make predictions regarding the use of this value alone to predict risk for the eventual development of the metabolic syndrome. The same holds for fasting lipid profiles: an abnormal panel predicts the development of hyperlipidemia during adulthood but does not predict the development of the metabolic syndrome. A normal fasting lipid profile does not reduce this risk. The risk for the development of metabolic syndrome does not require the presence of all components of the definition. The absence of several risk factors (ie, family history of hyperlipidemia/hypertension) does not reduce this child's risk to that of the normal population because of the presence of other risk factors.

The exact mechanisms of the complex pathways of metabolic syndrome are not yet completely known. Most patients are older, obese, sedentary, and have a degree of insulin resistance. Stress also can be a contributing factor. The most important factors are: obesity, genetic predisposition, aging, and sedentary lifestyle (ie, low physical activity and excess caloric intake). There is debate regarding whether obesity or insulin resistance is the cause of the metabolic syndrome or if they are consequences of a more far-reaching metabolic derangement. A number of markers of systemic inflammation, including C-reactive protein, often are increased, as are fibrinogen, interleukin-6, tumor necrosis factor-alpha, and others. Central adiposity is a key feature of the syndrome. However, despite the importance of obesity, patients who are of normal weight also may be insulin-resistant and have the syndrome. The metabolic syndrome affects 44% of the United States population older than age 50, and a greater percentage of women older than age 50 have the syndrome than do men. It is estimated that 75% of patients who have type 2 diabetes have the metabolic syndrome. With appropriate cardiac rehabilitation and changes in lifestyle (eg, nutrition, physical activity, weight reduction, and, in some cases, medications), the prevalence of the syndrome can be reduced. The International Diabetes Federation consensus worldwide definition of the metabolic syndrome (2006) includes central obesity (defined by waist circumference), AND any two of the following: Elevated triglycerides Low high-density lipoprotein (HDL) cholesterol Hypertension Elevated fasting plasma glucose Various strategies have been proposed to prevent the development of metabolic syndrome, including increased physical activity (such as walking 30 minutes every day) and a healthy, reduced-calorie diet. However, these measures are effective in only a minority of people, primarily due to a lack of compliance. Drug treatment frequently is required. Diuretics and angiotensin-converting enzyme inhibitors may be used to treat hypertension. Cholesterol drugs may be used to lower low-density lipoprotein cholesterol and triglyceride concentrations, if they are elevated, and to raise HDL concentrations, if they are low. Use of drugs that decrease insulin resistance such as metformin is controversial; this treatment is not approved by the United States Food and Drug Administration. Cardiovascular exercise has been shown to be therapeutic in approximately 30% of cases. The most probable benefit is reduction in triglyceride concentrations, but fasting plasma glucose and insulin resistance in most patients did not improve.

Question 11 A 3-year-old boy is brought to the emergency department by emergency medical services after being found unresponsive and twitching by his parents. The emergency medical technicians determined that the boy's blood glucose was 25 mg/dL (1.4 mmol/L) on the scene and started an intravenous infusion with dextrose. When you see him in the emergency department, he is beginning to awaken and recognize his parents. Repeat blood glucose measures 73 mg/dL (4.1 mmol/L).

Of the following, the MOST useful additional laboratory test is
serum C-peptide assessment serum insulin assessment serum proinsulin assessment serum tryptophan synthetase assessment urine dipstick for ketones 15

It is important to determine the cause of childhood hypoglycemia, as described for the boy in the vignette, because management varies, depending upon the cause of the episode. The most common cause of hypoglycemia in early childhood is ketotic hypoglycemia, which seems to result from an imbalance between glucose utilization and production through hepatic, and to a lesser extent, renal glycogenolysis and gluconeogenesis. It commonly manifests as fasting hypoglycemia noted in the morning hours after sleep that has followed poor food intake the day before. Affected children often are thin and have decreased muscle and fat mass. This disorder should not persist beyond the age of 7 or 8 years because hepatic glucose production capacity from glucose precursors produced from muscle and fat should meet fasting glucose needs of the brain and other obligate glucose-using tissues after that time. Measurement of a "critical" blood sample at the time of hypoglycemia may help to determine if hyperinsulinism is the cause of low blood glucose concentrations. Measurement of serum insulin and C-peptide can determine whether insulin values are elevated at the time of hypoglycemia. If C-peptide is not elevated when insulin values are high, the hyperinsulinism likely is from an insulin medication vial and, therefore, free of the C-peptide released from the pancreatic beta cell in equimolar amounts with insulin. Proinsulin also is released from the beta cell but in relatively small amounts compared with insulin. In some rare disorders of insulin cleavage, proinsulin is released in relatively larger amounts compared with insulin. Once hypoglycemia has been treated, as it has been for this boy, measurement of insulin and related compounds are not useful diagnostic tests. Because insulin suppresses ketogenesis, the finding of a large amount of acetoacetate (ketones) in a dipstick urine sample shortly after hypoglycemia strongly suggests that insulin excess is not the cause of hypoglycemia and supports the diagnosis of ketotic hypoglycemia. However, small amounts of ketones have been found in the urine of some children who have documented hyperinsulinism. Other disorders that involve an inability to use ketones or ineffective metabolism of carbohydrate may lead to hypoglycemia with ketonuria. Examples include endocrine deficiency disorders, some glycogen storage diseases, defects in gluconeogenesis, and organic acidurias. Tryptophan synthetase is an enzyme found in plants and bacteria, but not in animals, that catalyzes the final step in the synthesis of tryptophan. Tryptophan is an essential amino acid that cannot be synthesized by humans.

Question 12 A 9-month-old girl is brought to the emergency department by her middle eastern immigrant parents, who have observed an episode of twitching of her extremities. On physical examination, the infant has prominent wrists and ankles and an open fontanelle. The parents tell you through an interpreter that she is exclusively breastfed and neither she nor her mother takes vitamins. You note that the mother is partially veiled.

Of the following, the MOST likely cause of the twitching is
hypercalcemia hypocalcemia hypomagnesemia hypophosphatemia vitamin D deficiency 15

The child described in the vignette has clinical signs of rickets, and her mother is protected from sunlight by veiling. Neither mother nor child takes supplemental vitamins. Therefore, the child likely has vitamin D deficiency as a result of poor stores at birth and continued poor vitamin D intake and production. However, vitamin D deficiency alone does not cause the twitching reported for the girl. Twitching is a sign of hypocalcemia caused by vitamin D deficiency. Hypocalcemia induces neuromuscular irritability that can manifest as a positive Chvostek sign, carpopedal spasm, or a positive Trousseau sign. Approximately 10% of individuals who have normal calcium concentrations have positive Chvostek signs. A positive Trousseau sign is induced by the tissue hypoxia caused by a tight blood pressure cuff and causes enough discomfort that this test rarely is performed when a laboratory assessment of calcium is so easily confirmatory. Severe hypocalcemia induces paresthesias (oral, finger, and toe tingling), twitching, and seizures. Hypocalcemia also can lead to diarrhea. One of the most common causes of hypocalcemia is vitamin D deficiency rickets, either when it is very severe or during the initial phases of recovery when calcium is being taken up rapidly by healing bone. Hypercalcemia can cause slowed mentation, stupor, constipation, polyuria, renal calculi, and extreme thirst but does not cause twitching. Hypomagnesemia may cause neuromuscular irritability similar to that seen in hypocalcemia but is much less common and is accompanied by nausea and loss of appetite. Magnesium interferes with release of stored parathyroid hormone and, therefore, can cause hypocalcemia. The signs and history typical for vitamin D deficiency rickets reported for this girl make this less probable. Hypophosphatemia causes muscle weakness and changes in mental status. It also may be seen in rickets but is not associated with neuromuscular irritability. American Board of Pediatrics Content Specification(s): Recognize the signs and symptoms of hypocalcemia

Question13 You are seeing a 6-year-old girl for a health supervision visit. On physical examination, you note Sexual Maturity Rating (SMR) 3 pubic hair and SMR 1 breast tissue. You noted no pubic hair last year. She has had a growth spurt in the past 2 years and is presently at the 75th percentile for height . Her weight is at the 50th percentile for age. Her blood pressure is 90/60 mm Hg. The remainder of her evaluation is within normal parameters except for possible clitoromegaly. The radiologist interprets a bone age radiograph as 8 years.

dehydroepiandrosterone sulfate electrolytes 17-hydroxyprogesterone
Of the following, the MOST helpful diagnostic laboratory blood test is measurement of androstenedione dehydroepiandrosterone sulfate electrolytes 17-hydroxyprogesterone testosterone 15

The girl described in the vignette has an advanced bone age, rapid growth rate over 2 years, pubic hair, and clitoromegaly. The most likely explanation for these findings in a girl is congenital adrenal hyperplasia (CAH). Because the degree and the timing of onset of virilization in children who have CAH depends upon the degree of enzyme activity of the most severely affected of the two inherited cyp21 genes, there is a spectrum of presentations in this disorder. The presentations can range from almost complete enzyme deficiency resulting in masculinization of female fetuses and the rapid development of a salt-losing crisis to very mild virilization of adult females, which may be confused with polycystic ovary syndrome in adult women. Within this spectrum, children have been classified as having classic salt-losing CAH, non-salt-losing, and nonclassic CAH identified at various ages to adulthood. The incidence of classic CAH in the United States is about 1 in 14,000, but the incidence of later-onset forms is reported to be 1 in 100 to 1 in 1,000 among whites, in whom it is more common than other racial groups. Classic CAH most commonly results from 21-hydroxylase deficiency (95%). More than 70% of children present with a salt-losing crisis within the first several weeks after birth. Girls who have this condition exhibit masculinization of genital development at birth (Item C122). Some children can produce enough mineralocorticoid (aldosterone) (non-salt losers) and, therefore, are identified only because of masculinization of genital development in baby girls and isosexual precocity in boys. Children who have the classic form of CAH usually are identified via prenatal screening for 17-hydroxyprogesterone. The diagnosis of CAH resulting from 21-hydroxylase deficiency (the most common type) is based on the finding of an elevated 17-hydroxyprogesterone concentration in response to an adrenocorticotrophic hormone stimulus or in a first morning specimen, when adrenal steroid release is at its highest. Dehydroepiandrosterone sulfate concentrations are elevated to pubertal ranges in CAH, but such findings also are seen in children who have premature pubarche. Although androstenedione may be elevated in children who have CAH, such a finding is not diagnostic. Because most children have greater elevations in 17-hydroxyprogesterone, the end product just before the enzymatic block in adrenal biosynthesis, this is taken as the gold standard for diagnosing 21-hydroxylase deficiency, although evaluation of other steroid precursors or genetic analysis is necessary for confirmation. Serum electrolyte values are abnormal in decompensated classic CAH associated with aldosterone deficiency. In this situation, low serum sodium and elevated serum potassium values might be expected, but electrolyte abnormalities are not found in late-onset CAH. The testosterone value is somewhat elevated in late-onset CAH, but this finding is not diagnostic. American Board of Pediatrics Content Specification(s): Recognize the signs and symptoms of congenital adrenal hyperplasia Know the laboratory evaluation of congenital adrenal hyperplasia

Question 14 A mother brings her 3-year-old daughter to your office for evaluation of a lump in the child's neck. On physical examination, you note a 1x1.5-cm ovoid mass that seems to move with swallowing and is centrally located just above the thyroid . It is not red, inflamed, or painful, but it is firm.

Of the following, the MOST appropriate next step is
blood test for free thyroxine & TSH CT scan of the neck region MRI of the neck region oncology consultation surgery consultation 15

An ovoid mass that moves with swallowing and is centrally located just above the thyroid almost always is a thyroglossal cyst. Such cysts result when a tract is left during embryologic descent of the thyroid anlage from the base of the tongue. They generally are not associated with hypothyroidism, and, therefore, assessment of free thyroxine and thyroid-stimulating hormone is not necessary. Occasionally, the thyroid itself is located within a cyst, and extirpative surgery renders an individual hypothyroid. Ultrasonography or a radioactive scan using technetium often is used to confirm the location of the thyroid before surgery, but computed tomography scan or magnetic resonance imaging is unnecessary. Surgical removal of the mass usually is indicated, particularly if there have been episodes of infection. Oncology consultation is unnecessary, although occasional papillary carcinomas have been reported in these cysts. American Board of Pediatrics Content Specification(s): Recognize a thyroglossal duct cyst

Question 15 The family of a 4-year-old boy with diabetes calls at 11 AM to tell you that the boy has an acute vomiting illness just like his brother. It lasted for 12 hours in his brother. He has not been sick since the onset of diabetes 6 months ago, and the family wants to verify how to handle sick days. He normally receives glargine insulin every evening and a small amount of an ultrashort-acting insulin based on his blood glucose measurement and planned carbohydrate intake before every meal. He received his glargine insulin dose last night but has not been able to keep down any food since 8 AM. The family is planning to check his blood glucose every 2 hours and urine or blood ketones every 2 to 4 hours and will try to get him to eat and drink. They understand that if he continues to vomit, he will require evaluation.

Of the following, the MOST appropriate action for them is to
administer an additional dose of glargine insulin immediately and follow this with frequent sips of glucose-containing fluids administer sugar-containing fluids but no ultrashort-acting insulin until he stops vomiting offer one glass of water every 2 hours even if he is vomiting provide only regular insulin in a small dose every 4 to 6 hours as long as his blood glucose remains >200 mg/dL & he can tolerate solid foods provide small amounts of his normal short-acting insulin every 2 to 3 hours as long as his blood glucose is greater than 100 mg/dL (5.6 mmol/L) and he can consume clear sugar-containing liquids 15

Children who have diabetes and receive a long-acting insulin regimen such as glargine insulin to cover basal insulin needs and an ultrashort-acting insulin such as insulin lispro or aspart usually are protected from ketoacidosis during periods when they cannot eat because they have sufficient basal insulin administered once daily. If the dose is correct, it will not cause hypoglycemia during periods of food deprivation. However, illness itself may induce insulin resistance, necessitating insulin supplementation. Because the action of ultrashort-acting insulins generally begins about 10 to 15 minutes after administration, peaks at 1 hour, and lasts no longer than 3 to 4 hours, supplementing with small amounts of this insulin every 2 to 3 hours if glucose is greater than 100 mg/dL (5.6 mmol/L) for the boy described in the vignette is reasonable. If he can take sips of carbohydrate- and electrolyte-containing fluids, he should remain free from significant ketosis and can be managed with oral rehydration and ultrashort-acting insulin every 2 to 3 hours. Glargine insulin should not be used as an acute supplement because its action is spread over 24 hours. Insulin can be administered, even to a child who is vomiting, as long as blood glucose concentrations are elevated. The dosing should be based on whether the child can take carbohydrates orally. Providing plain water alone to a child who has diabetes and is vomiting will result in electrolyte depletion. Regular insulin can be provided every 4 to 6 hours to treat hyperglycemia, but the time course of action is slower and less predictable than that of the shorter-acting insulins. Also, use of regular insulin is more likely to lead to prolonged hypoglycemia in a child who no longer can consume carbohydrates orally. Because this child is vomiting, oral rehydration rather than supplying solid food is a reasonable response. American Board of Pediatrics Content Specification(s): Know how to manage sick days in diabetic patients

Question 16 You are seeing a 16-year-old boy for the first time. He complains that he is always thirsty and has been getting up to go to the bathroom two or three times a night for the past few weeks. On physical examination, he has a body mass index of 35 kg/m2 with a central weight distribution, acanthosis nigricans of the neck and axillae, and a blood pressure of 150/90 mm Hg. He is at Sexual Maturity Rating 5 puberty. He says that he has always been big-boned and he likes to eat. His mother and father both have diabetes. His mother had a mild stroke 2 years ago, but is now "getting around OK." His blood glucose measures 273 mg/dL (15.2 mmol/L).

high-density lipoprotein cholesterol serum creatinine
Of the following, the additional laboratory study that is MOST likely to yield abnormal results for this boy is a complete blood count high-density lipoprotein cholesterol serum creatinine serum free thyroxine urine microalbumin 15

The long-term complications of type 2 diabetes include macrovascular disease leading to myocardial infarction, stroke, and peripheral vascular disease; neuropathy; proteinuria; renal failure; and retinopathy. The young man described in the vignette likely has type 2 diabetes, like his parents, and given his body mass index and findings on physical examination, he also has metabolic syndrome. His hypertension puts him at increased risk for stroke, like his mother. However, at this point, the most likely additional abnormal laboratory finding would be low high-density lipoprotein (HDL) and high low-density lipoprotein cholesterol values related to his metabolic syndrome. The macrovascular complications of diabetes can become apparent relatively early in the course of type 2 diabetes in adolescents and young people. His complete blood count result is likely to be normal, and he is unlikely to have sufficiently severe renal disease to have an abnormal serum creatinine reading. His thyroid function should be normal. Approximately 10% of individuals who have diabetes mellitus type 1 develop chronic lymphocytic thyroiditis, but this is not common in type 2 diabetes. Of note, many obese people have slight elevations in thyroid-stimulating hormone (TSH) concentrations, which have been attributed to "TSH resistance" of unknown cause. The boy might have an elevated urine microalbumin reading because of his weight and his poor diabetes control, but low HDL cholesterol values are much more likely to be found at the time of diagnosis. American Board of Pediatrics Content Specification(s): Recognize the long-term complications of type 2 diabetes Recognize that complications of type 2 diabetes may be present at diagnosis

Question17 A previously healthy 11-year-old boy has developed nocturnal enuresis. He does not have glycosuria, and a serum glucose concentration is in the normal range. A urinalysis reveals no evidence of infection.

Of the following, the MOST likely abnormal laboratory finding is the serum concentration of
bilirubin calcium creatinine potassium total protein 15

The acute occurrence of nocturnal enuresis in a child who has no urinary tract infection, such as the boy described in the vignette, often is a sign of polyuria. The causes of polyuria include development of diabetes mellitus, renal disease, diabetes insipidus, hyperthyroidism, hypercalcemia, and hypomagnesemia. This boy does not have an abnormal glucose concentration and has no evidence of kidney infection. Hypercalcemia is more common in a previously healthy boy than is hypomagnesemia. It may be the first sign of hyperparathyroidism or perhaps vitamin D toxicity. Other symptoms of hypercalcemia can include altered mental status, nausea, vomiting, and coma. Hypomagnesemia usually is related to severe magnesium losses from the gastrointestinal tract or kidneys and is associated with other chronic illness or with congenital genetic magnesium loss. Hypokalemia might lead to muscle weakness or problems with cardiac contractility; hyperkalemia could affect myocardial function. Hypokalemia can affect renal concentrating ability and might lead to nocturnal enuresis, but few disorders acutely lead to hypokalemia in an 11-year-old child. Bilirubin values do not influence renal concentration. An elevated creatinine could reflect severe renal disease, but polyuria is a fairly late marker of this disorder. The total protein in the serum does not influence urine volume. American Board of Pediatrics Content Specification(s): Recognize the signs and symptoms of hypercalcemia

Question 18 On January 13, the father of one of your patients calls to tell you that the tubing on his son's insulin pump became dislodged during the night. The 75-lb 10-year-old boy has had diabetes for 2 years. According to the father, the boy is feeling nauseated and has a blood glucose of 450 mg/dL (25.0 mmol/L) with large ketones in the urine. The father has replaced the infusion set, which now seems to be working well, but his driveway was snowed in overnight and he does not think he will be able to get out of the house for at least 4 to 6 hours. You tell him to try to give his son sips of ice cold water as well as saltine crackers as tolerated for the next few hours and check his blood glucose and urine ketones every 2 hours.

Of the following, the MOST appropriate additional suggestion for the father is to
administer 4 units of ultrashort-acting insulin subcutaneously using an insulin pen or syringe and needle and repeat every 2 to 3 hours administer 20 units of glargine insulin subcutaneously continue the insulin pump at its usual infusion rate give the boy hard candy and orange juice as tolerated every hour try to get the police or emergency vehicle to his house and transport his son to the hospital for intravenous rehydration and insulin therapy 15

Failure of insulin pump therapy is becoming a leading cause of recurrent diabetic ketoacidosis (DKA), as described for the boy in the vignette. DKA develops about 6 hours after the failure of infusion of an ultrashort-acting insulin because there is no depot supply of insulin. The boy in the vignette has early DKA and will not have access to direct medical care for some hours. However, his family has the materials on hand to treat him and help him through this crisis. Although his insulin pump appears to be working and infusing well, this is not a certainty. Therefore, he should receive insulin by a more direct route. Four units of ultrashort-acting insulin administered via an insulin pen or syringe and needle every 2 to 3 hours represents approximately 0.1 unit/kg per dose, which is a relatively low dose of insulin for the treatment of DKA but should be sufficient because the boy will continue to receive his maintenance insulin through his pump. If his blood glucose value does not decrease by about 75 to 100 mg/dL per hour on this regimen, the insulin dose could be increased. Glargine insulin lasts for 24 hours but is released so slowly that it cannot treat DKA. It can be used for backup if a pump is not working properly but never should be administered as a pumped insulin. The insulin pump should be continued at its usual infusion rate, but this is not sufficient to treat the DKA. Because this boy has hyperglycemia and is not yet able to metabolize glucose because of insulin deficiency, he does not need hard candy and orange juice. Getting an emergency vehicle to the boy's home to transport him to the hospital appears to be difficult in this circumstance, but subcutaneous insulin administration has been as effective as intravenous insulin in the management of DKA. American Board of Pediatrics Content Specification(s): Plan the management of a child who has mild to moderate diabetic ketoacidosis

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