Endocrinology QOD review

Endocrinology QOD review
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
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
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
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
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.
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
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
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.
Question 3
• A 14-year-old boy is
worried because he is
so much smaller than
his peers. You review
his previous growth
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
5. his mother reached menarche at 15 years
of age
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.
Of the following, this girl is MOST likely to
have early menarche if the physical
examination reveals
1. a body mass index > the 85th percentile
2. adult body odor
3. breast tissue
4. facial acne
5. pubic hair
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).
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 2year-old daughter and 4-year-old son
adversely and wonders how best to
protect them.
Of the following, the BEST advice is for the
father to
1. allow the gel to dry on the skin, get dressed,
and wash his hands with soap and water
before touching the children
2. clean his hands & the area of application with
an alcohol-containing cleanser before
touching the children
3. have limited contact with the girl, but the boy
should not experience any harmful effects
4. make the room in which he applies the gel offlimits to the children
5. shower immediately after applying the gel so
that the preparation does not contaminate his
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
American Board of Pediatrics Content Specification:
Recognize that testosterone creams used by parents can cause
virilization in male or female children
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
Of the following, the MOST typical
electrolyte pattern for primary adrenal
insufficiency is
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
American Board of Pediatrics Content Specification:
Know how to use laboratory tests effectively for the diagnosis of Addison
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.
Of the following, the MOST appropriate
action is to
1. arrange for blood tests and a urine culture at a
local laboratory on Monday morning
2. arrange for her daughter to be seen as an
outpatient on Sunday
3. reassure her and ask her to bring her daughter to
the office on Monday
4. reassure her and ask her to come to the office if
the symptoms persist for several days
5. tell her to bring her daughter to the local hospital
emergency department immediately
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.
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.
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).
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
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
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.
Of the following, the MOST appropriate information
to share with the family is that
1. all thyroid nodules in boys should be removed
because they have a higher risk of malignancy than
nodules in girls
2. no further follow-up is necessary if the pathology
report suggests a benign thyroid adenoma
3. there is a 50% chance that the thyroid nodule will be
4. the biopsy offers a greater than 90% chance of
determining whether a thyroid nodule is benign or
5. thyroid nodules in girls are more likely to be malignant
than nodules in boys
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. Calcitoninsecreting 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
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
Of the following, you are MOST likely to advise the
resident that this child's risk of developing
metabolic syndrome
1. can be predicted by a determination of
hemoglobin A1c values
2. is close to that of the general population
because there is no family history of
hyperlipidemia or systemic hypertension
3. is reduced if he begins to develop a
healthy lifestyle as a child
4. is the same as the general population if
cholesterol-lowering agents are started,
even without lifestyle changes
5. is the same as the general population if
his fasting lipid profile is currently
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
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
Elevated triglycerides
Low high-density lipoprotein (HDL) cholesterol
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 assessme
urine dipstick for ketones
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
vitamin D deficiency
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
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.
Of the following, the MOST helpful
diagnostic laboratory blood test is
measurement of
1. androstenedione
2. dehydroepiandrosterone sulfate
3. electrolytes
4. 17-hydroxyprogesterone
5. testosterone
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
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 17hydroxyprogesterone.
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
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
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 glucosecontaining 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
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
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 electrolytecontaining 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
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
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 highdensity 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
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
1. bilirubin
2. calcium
3. creatinine
4. potassium
5. total protein
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
1. administer 4 units of ultrashort-acting
insulin subcutaneously using an insulin
pen or syringe and needle and repeat
every 2 to 3 hours
2. administer 20 units of glargine insulin
3. continue the insulin pump at its usual
infusion rate
4. give the boy hard candy and orange juice
as tolerated every hour
5. try to get the police or emergency vehicle
to his house and transport his son to the
hospital for intravenous rehydration and
insulin therapy
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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