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Title: Endocrinology QOD review


1
Endocrinology QOD review
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

A
B
3
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
E
D
4
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
  1. Curve A
  2. Curve B
  3. Curve C
  4. Curve D
  5. Curve E

5
  • 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 SpecificationsKnow how to
    distinguish between familial short stature and
    other conditions
  • Recognize the signs of familial short stature

6
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.

7
Of the following, the BEST indicator that the boy
is following his genetic growth pattern is
  1. bone age radiograph normal for age
  2. his height at the 3rd percentile for age
  3. normal weight for height
  4. steady linear growth at 3 cm/year
  5. steady linear growth at 5 cm/year

8
  • 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.

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

10
Of the following, the factor that MOST strongly
suggests that the boy has constitutional growth
delay is that
  1. he has a normal sense of smell  
  2. he has Sexual Maturity Rating 3 pubic hair  
  3. he was small for gestational age  
  4. current weight is at the 50th percentile for age
     
  5. his mother reached menarche at 15 years of age

11
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.

12
Of the following, this girl is MOST likely to
have early menarche if the physical examination
reveals
  1. a body mass index gt the 85th percentile
  2. adult body odor
  3. breast tissue
  4. facial acne
  5. pubic hair

13
  • 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).

14
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.

15
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
    off-limits to the children
  5. shower immediately after applying the gel so that
    the preparation does not contaminate his children

16
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 SpecificationRecognize that
    testosterone creams used by parents can cause
    virilization in male or female children

17
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.

18
Of the following, the MOST typical electrolyte
pattern for primary adrenal insufficiency is

19
  • 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

20
(No Transcript)
21
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.

22
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

23
  • 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.

24
  • 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.

25
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).

26
Of the following, the MOST likely cause of this
child's thyroid enlargement is
  1. adolescent goiter
  2. chronic lymphocytic thyroiditis
  3. Graves disease
  4. iodine deficiency
  5. thyroid carcinoma

27
  • 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.

28
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.

29
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 malignant
  4. the biopsy offers a greater than 90 chance of
    determining whether a thyroid nodule is benign or
    malignant
  5. thyroid nodules in girls are more likely to be
    malignant than nodules in boys

30
  • 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 SpecificationKnow that a
    solitary thyroid nodule may be a sign of thyroid
    cancer

31
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.

32
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 normal

33
  • 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-lowerin
    g 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.

34
  • 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 glucoseVarious
    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.

35
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).

36
Of the following, the MOST useful additional
laboratory test is
  1. serum C-peptide assessment
  2. serum insulin assessment
  3. serum proinsulin assessment
  4. serum tryptophan synthetase assessment
  5. urine dipstick for ketones

37
  • 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.

38
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.

39
Of the following, the MOST likely cause of the
twitching is
  1. hypercalcemia
  2. hypocalcemia
  3. hypomagnesemia
  4. hypophosphatemia
  5. vitamin D deficiency

40
  • 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.Ameri
    can Board of Pediatrics Content Specification(s)
  • Recognize the signs and symptoms of hypocalcemia

41
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.

42
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

43
  • 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

44
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.

45
Of the following, the MOST appropriate next step
is
  1. blood test for free thyroxine TSH
  2. CT scan of the neck region
  3. MRI of the neck region
  4. oncology consultation
  5. surgery consultation

46
  • 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

47
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.

48
Of the following, the MOST appropriate action for
them is to
  1. administer an additional dose of glargine insulin
    immediately and follow this with frequent sips of
    glucose-containing fluids
  2. administer sugar-containing fluids but no
    ultrashort-acting insulin until he stops vomiting
  3. offer one glass of water every 2 hours even if he
    is vomiting
  4. provide only regular insulin in a small dose
    every 4 to 6 hours as long as his blood glucose
    remains gt200 mg/dL he can tolerate solid foods
  5. 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

49
  • 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

50
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).

51
Of the following, the additional laboratory study
that is MOST likely to yield abnormal results for
this boy is a
  1. complete blood count
  2. high-density lipoprotein cholesterol
  3. serum creatinine
  4. serum free thyroxine
  5. urine microalbumin

52
  • 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

53
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.

54
Of the following, the MOST likely abnormal
laboratory finding is the serum concentration of
  1. bilirubin
  2. calcium
  3. creatinine
  4. potassium
  5. total protein

55
  • 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

56
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.

57
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
    subcutaneously
  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

58
  • 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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