Q 1
A
14-year-old girl has a 3-month history of a progressively enlarging mass in the
left thyroid lobe. She has developed hoarseness over the past 2 weeks. Physical
examination reveals a 3 cm firm mass in the left upper lobe of the thyroid
gland. There is no associated adenopathy.
Of
the following, the MOST helpful test for establishing the diagnosis is:
A. fine-needle
aspiration biopsy of the thyroid gland
B. measurement
of the thyroid-stimulating hormone level
C. measurement
of the thyroxin level
D. radionuclide
scan of the thyroid gland
E. ultrasonography
of the thyroid gland
Answer
A
Answer
A
Most
thyroid nodules present as painless masses near the midline of the lower neck.
The time of onset; rate of growth; and presence of pain, hoarseness, and
dysphagia as well as systemic symptoms of hypo- and hyperthyroidism are
important to identify. Prior radiation exposure significantly increases the
likelihood of malignancy. There may be an increased risk of malignancy in
certain illnesses, such as iodine deficiency, Hashimoto thyroiditis, and Grave
disease. Familial syndromes such as Pendred or Gardner syndromes as well as
multiple endocrine neoplasia (MEN) 2A and 2B clearly increase the risk of
thyroid carcinoma. Prophylactic thyroidectomy is recommended for children who have
high-risk syndromes.
Physical
examination should include assessment for vocal cord mobility and cervical
lymphadenopathy as well as for size and characteristics of the thyroid nodule.
Although
measurements of thyroid functions, including thyroid-stimulating hormone levels
and thyroxin levels, should be obtained, these are rarely abnormal in
asymptomatic individuals and do not differentiate benign from malignant
lesions. Chest radiography and lateral neck films usually appear normal, but
may show radiopaque psammoma bodies in papillary carcinomas. Thyroid gland
scintigraphy (thyroid scan) usually is performed with technetium 99 or iodine
123. The degree of isotope concentration differentiates a cold nodule from a
hot nodule.
Ultrasonography
can be useful for differentiating a solid from a cystic mass and for evaluating
for multiple nodules such as a multinodular goiter. Cystic lesions, however,
may be malignant.
Fine-needle
aspiration (FNA) biopsy is considered by most authors to be the diagnostic
procedure of choice for assessing solitary thyroid nodules. Based on results of
FNA, an experienced cytopathologist can segregate nodules accurately into
negative, nondiagnostic, or probable malignant categories. The overall
diagnostic accuracy of FNA cytology is approximately 90%. Because of this high
diagnostic accuracy, thyroid scans and ultrasonography are usually not
necessary.
Total
thyroidectomy is not recommended unless high-risk malignancy is diagnosed
definitively. Hemithyroidectomy occasionally is recommended for biopsy if FNA
cytology results are equivocal and usually is recommended for definitive
diagnosis of positive FNA cytology.
----
Q2
----
Q2
A
16-year-old otherwise healthy girl presents for evaluation of primary
amenorrhea. Physical examination reveals a height of 55.5 in (140 cm), weight
of 110 lb (50 kg), no breast tissue, and Sexual Maturity Rating (Tanner) stage
3 pubic hair development. Her mother's height is 68 in (173 cm), and her
father's height is 70 in (178 cm).
Of
the following, the MOST likely diagnosis is:
A. androgen
insensitivity (testicular feminization) syndrome
B. constitutional
delay of growth and development
C. familial
short stature
D. imperforate
hymen
E. Turner
syndrome
Answer
E
Answer
E
The
girl in the vignette has primary amenorrhea, defined as the absence of menses
by age 14 years in a patient who has no secondary sexual characteristics (eg,
breast development) or by 16 years when such characteristics are present. She
has short stature, normal weight, absent breast tissue (suggesting an absence
of ovarian estrogen), and normal pubic hair (confirming the presence of adrenal
androgens). These clinical findings are characteristic of gonadal dysgenesis
caused by Turner syndrome. Gonadal dysgenesis is the most common cause of
primary amenorrhea, and Turner syndrome is the most common cause of gonadal
dysgenesis.
The most common cause of pubertal delay is
constitutional delay of growth and development, which often is familial and
occurs more commonly in boys. Height, pubertal development, and bone age are
delayed by 2 to 4 years. Unlike the girl in the vignette, the appearance of
sexual hair and breast development are delayed in patients who have constitutional
delay. Individuals who have familial short stature do not experience pubertal
delay and have a compatible family history. Finally, although an imperforate
hymen is one cause of primary amenorrhea, affected patients have
normal pubertal progression and are of normal height
---
Individuals
who have androgen insensitivity (testicular feminization) syndrome are
chromosomally male (XY genotype) and have male gonads that produce normal
amounts of testosterone. However, because the androgen receptors do not
function normally, male external genitalia do not develop and, in contrast to
the patient in the vignette, pubic and axillary hair are sparse. Affected
individuals have normal stature and breast development.
---
During
the health supervision visit of a 14-year-old female, you find that her thyroid
gland is firm, nontender, symmetrically enlarged, mobile, and has a granular
texture. The thyroxine level is 5.2 mcg/dL (normal, 5.6 to 11.7 mcg/dL) and the
thyroid-stimulating hormone level is 17.5 mIU/mL (normal, 0.2 to 7.6 mIU/mL).
Of
the following, the MOST likely diagnosis is:
A. acute
suppurative thyroiditis
B. Graves
disease
C. Hashimoto
thyroiditis
D. simple
colloid goiter
E. solitary
thyroid nodule
Answer
C
Answer
C
The
girl presented in the vignette has a goiter, borderline low thyroxine (T4)
concentration, and elevated thyroid-stimulating hormone (TSH) concentration,
suggesting hypothyroidism. Hashimoto thyroiditis, also known as chronic
lymphocytic thyroiditis, is the most common cause of goiter in
the pediatric age group. It is an autoimmune disorder in which lymphocytes and
plasma cells infiltrate the thyroid gland, resulting in enlargement and damage
to thyroid cells through cytotoxic mechanisms. Most patients present with
either a euthyroid goiter or hypothyroidism without goiter; transient
hyperthyroidism occurs occasionally.
In
patients who have a goiter, T4 and TSH are measured to identify possible
hypothyroidism. If signs of hyperthyroidism are present, a triiodothyronine
(T3) measurement also is obtained. Although most patients who have Hashimoto
thyroiditis have circulating thyroid antibodies (eg, antithyroglobulin,
antimicrosomal antibody [thyroid peroxidase]), these antibodies are not
specific for the disease. In the rare case of diagnostic uncertainty, Hashimoto
thyroiditis can be confirmed by fine-needle biopsy.
The
natural history of Hashimoto thyroiditis is variable; many individuals remain
euthyroid for years, while others develop hypothyroidism. Occasionally there
may be spontaneous recovery. Patients who have a euthyroid goiter sometimes are
treated with thyroid hormone to reduce the size of the gland. Those who have
evidence of hypothyroidism or an elevated TSH concentration require thyroid
replacement.
Acute
suppurative thyroiditis is an uncommon disorder caused by infection with
Streptococcus pyogenes, S pneumoniae, or Staphylococcus aureus. Patients
present with the abrupt onset of anterior neck pain, fever, and toxicity.
Physical examination reveals marked tenderness to palpation of the anterior
neck and swelling that is nonmobile and sometimes fluctuant.
Although
patients who have Graves disease have thyroid enlargement, they exhibit
symptoms and signs of hyperthyroidism, including weight loss, deteriorating
school performance, poor concentration, nervousness, heat intolerance,
tachycardia, tremor, or exophthalmos. The serum T4 and T3 concentrations are
elevated, and TSH is suppressed.
A
simple colloid goiter generally presents as diffuse enlargement of the thyroid
gland in a patient who is clinically euthyroid. Results of thyroid function
tests are normal, and thyroid antibodies are absent.
A
solitary thyroid nodule is a discrete, localized enlargement of the thyroid
gland. It must be distinguished from a diffusely enlarged gland and nonthyroid
masses such as lymph nodes and dermoid cysts. Because a solitary thyroid nodule
may be malignant, all affected patients should be referred to a pediatric
endocrinologist for additional evaluation. Thyroid function tests should be
performed, but results usually are normal. Ultrasonography may be useful in the
diagnosis of nodules.
--------------------------
Q 3
--------------------------
Q 3
A
12-year-old girl is at the 5th percentile for height. She is an otherwise
healthy child. The bone age is greater than two standard deviations below the
chronologic age.
Of
the following, the MOST likely cause of this patient's short stature is:
A. constitutional
growth delay
B. genetic
short stature
C. growth
hormone deficiency
D. hypothyroidism
E. ulcerative
colitis
Answer
A
Answer
A
Assessment
of bone age is useful in the diagnosis and treatment of growth disorders. The
most frequently used method for assessing bone age, developed by Greulich and
Pyle, compares radiographs of the patient’s left hand and wrist with established
standards. The criteria for defining a certain bone age vary by gender and
race, and separate tables are used for males and females. In general, females
have more advanced skeletal maturity than males of the same age. In addition,
African-American children have more advanced skeletal maturity than Caucasian
children.
A
comparison of bone age with chronologic age allows for assessment of the growth
rate. During adolescence, those whose bone ages are advanced relative to their
chronologic ages are considered early developers; those who have bone ages that
are delayed relative to their chronologic ages are late developers.
The
child described in the vignette most likely has constitutional growth delay.
Affected children grow normally in early infancy, but then their growth rate
declines. Typically, such children lag 2 to 4 years behind their peers in
height age, bone age, and sexual development. Frequently, similar growth
patterns can be documented in parents, siblings, and other family members. Most
children who have constitutional growth delay attain normal adult heights when
their growth is complete.
Genetic
short stature is a common cause of short stature. Affected children usually
have a height at or below the 3rd percentile, but bone age is comparable to
chronologic age, and growth rate is normal.
Short
stature due to hypothyroidism is accompanied by other symptoms, such as
constipation, dry skin, cold intolerance, and puffiness (myxedema). Laboratory
evaluation reveals elevated thyroid-stimulating hormone and low thyroxine
levels. Determination of bone age documents a delay in bone maturation.
Ulcerative
colitis can retard growth and may delay bone development. Many affected
children experience poor growth for several years before the onset of the classic
symptoms of diarrhea and bloody stools.
Growth
hormone deficiency is a relatively rare cause of short stature that should be
considered if other conditions have been excluded. Affected children are often
chubby, and boys may have small genitalia. Hypoglycemia may be present. It is
associated with a significant delay in bone age compared with chronologic age.
The diagnosis can be confirmed by inadequate release of growth hormone
following stimulation with arginine or insulin.
---------
Q 4
---------
Q 4
You
are asked to evaluate an otherwise healthy 17-year-old girl for primary
amenorrhea. Her mother and sister began menstruating at age 12. She takes no
medications and denies any history of headaches, galactorrhea, nausea, or
vomiting. Thelarche occurred at age 13. Her breasts and genitalia are Sexual
Maturity Rating (Tanner) stage 5. The bimanual examination reveals a blind
vaginal pouch.
Of
the following, the study MOST likely to confirm the diagnosis is:
A. computed
tomography of the head
B. computed
tomography of the pelvis
C. serum
estradiol level
D. serum
karyotype
E. serum
prolactin level
Answer
D
Answer
B
-----------------------
Q 6
Answer
D
Most
teens have menarche within 2 to 2.5 years after thelarche or within 1 year of
attaining full physical maturity. The presence of primary amenorrhea and normal
secondary sexual characteristics at age 17 in the otherwise healthy adolescent
girl described in the vignette warrant further evaluation.
There
are numerous causes of primary amenorrhea, but not all need to be considered in
a patient who has mature secondary sexual characteristics. Although her
external genitalia are phenotypically female, the presence of a blind vaginal
pouch is most consistent with the diagnosis of male pseudohermaphroditism. A
serum karyotype will confirm this diagnosis.
Complete
testicular feminization is the most common cause of male pseudohermaphroditism
(phenotypic female who has 46,XY karyotype and with testes) and results from
androgen insensitivity. Not all affected individuals present with ambiguous
genitalia because the spectrum of sensitivity is broad. If the receptor to
androgens is nonfunctional or absent, the external genitalia will be those of a
normal female. The diagnosis is usually delayed until the absence of menses
brings the adolescent to medical attention. Internal female genitalia do not
form because the müllerian ducts regress under the effects of müllerian
inhibiting factor produced by occult male gonads located in the abdomen.
However, low levels of gonadal and adrenal estrogens, unopposed by androgens,
allow breast development to occur in affected individuals.
Signs
and symptoms of male pseudohermaphroditism are variable, depending on the
etiology. As described previously, the phenotypic female may present with
primary amenorrhea or an infant may have ambiguous genitalia noted at birth.
The otherwise healthy teenager who has androgen insensitivity may have sparse
axillary and pubic hair, normal breast development, and a blind vaginal pouch
with absence of the ovaries, uterus, and fallopian tubes. Testes and normal
male levels of testosterone are present.
Because
the adolescent described in the vignette does not have a central cause of
amenorrhea, computed tomography of the head is unnecessary. Furthermore,
magnetic resonance imaging is the study of choice to visualize the pituitary
gland. Computed tomography of the pelvis may confirm the absence of internal
female genitalia, but will not make the diagnosis. A serum estradiol level is
unnecessary in the adolescent who has mature breast development. A serum
prolactin level is also not indicated because the primary amenorrhea clearly
stems from abnormal genital anatomy.
------
Q 5
------
Q 5
An
18-month-old infant is seen because the mother is concerned that his legs are
bowed. The infant was breastfed until 14 months of age. The mother states that
her grandfather was very short.
Of
the following, laboratory tests are MOST likely to reveal:
A. high
circulating parathyroid hormone concentrations
B. inadequate
reabsorption of phosphate by the kidney
C. inadequate
stimulation of bone resorption by parathyroid hormone
D. low
conversion of vitamin D to 25-hydroxylase vitamin D
E. poor
gastrointestinal absorption of phosphate
Answer
B
Any
child who has hypophosphatemia requires a thorough evaluation because phosphate
is essential for energy production and for bone growth and development. The
kidney plays a major role in maintaining therapeutic levels of serum phosphate
by reabsorbing about 85% to 90% of the filtered phosphate during the first few
years of life.
Ricketsis a general term used to describe bony malformation due to any abnormality in the production or excretion of calcium and
phosphate. Any child who has clinical evidence of growth retardation or rickets
in the presence of a low serum phosphate level should have serum levels of
calcium, parathyroid hormone (PTH), 25-hydroxyvitamin D, and 1,25
dihydroxyvitamin D (1,25(OH)2D) measured. These values will provide clues to
the etiology of the growth failure.
The
most common form of inherited rickets is X-linked hypophosphatemic rickets
(X-hyp). Children who have this disorder develop hypophosphatemia due to renal
wasting of phosphate. The precise mechanism (transport protein abnormality) has
not yet been elucidated. Regardless, there is high urinary excretion of
phosphate and simultaneous low serum phosphate concentrations. The leak most
likely occurs in the renal proximal tubule. Serum calcium and PTH levels are
normal. Furthermore, serum 1,25(OH)2D levels are also “normal.” It has been
suggested that part of the problem in X-hyp may be due to inadequate
stimulation of 1,25(OH)2D synthesis in the kidney in the face of low serum
phosphate. Given that one role of 1,25(OH)2D is to stimulate reabsorption of
phosphate in the gastrointestinal tract, a compensatory increase in its levels
in children who have low serum phosphate levels is expected. Thus, the
abnormality in X-hyp appears to be inadequate reabsorption of phosphate by the
renal proximal tubule in combination with inappropriate levels of 1,25(OH)2D
synthesis by the kidney.
-----------------------
Q 6
A
12-year-old girl presents with a history of palpitations, problems with
sleeping, and recent weight loss despite increased appetite. Significant
findings on physical examination include tachycardia, mild exophthalmos, a
palpable thyroid, and a tremor.
Of
the following, the MOST appropriate initial treatment for this child is:
A. observation
and re-evaluation
B. oral
methimazole
C. oral
thyroxine
D. thyroid
ablation with I131
E. thyroidectomy
Answer
B
Answer
B
Therapy
for hyperthyroidism includes medical treatment, ablation with I131, and
surgery. The most appropriate initial treatment is oral therapy
with methimazole, carbimazole, or propylthiouracil. Methimazole
often is preferred because maintenance doses can be administered once daily.
Minor complications of medical therapy include pruritus, fever, rash, and
urticaria. Suppressive medical therapy is recommended for at least 12 to 24
months before the drug gradually is discontinued.
----------------
Q 7
----------------
Q 7
A
6-year-old girl who has type 1 diabetes presents with a 2-day history of fever,
malaise, and diarrhea. She is well hydrated, and findings on physical
examination are normal. The urine is positive for ketones, and the blood
glucose level is 14.4 mmol/L (260 mg/dL). Electrolyte levels, including
bicarbonate, are normal.
In
addition to providing supplemental insulin as needed, the MOST appropriate
management of this patient is to:
A. hospitalize
her immediately
B. instruct
her to check her blood glucose once a day
C. instruct
her to check her urine for ketones once a day
D. instruct
her to decrease her total caloric intake
E. instruct
her to drink large amounts of sugar-free liquids
Answer
E
Children who have diabetes need to be monitored closely during an intercurrent illness. The primary goal for management of diabetes during an illness is to prevent the occurrence of hypoglycemia and diabetic ketoacidosis and the need for hospitalization. When diabetic children are sick, they almost always require some extra insulin in addition to their routine dose. Supplemental insulin often can be administered as a dose of subcutaneous regular insulin equivalent to approximately 10% of the total daily dose; this may be repeated every 2 to 4 hours until ketosis is cleared.
monitoring of blood glucose values.
Drinking large amounts of sugar-free liquids
should help prevent dehydration. Young children should ingest approximately 3
to 6 oz/hr; adolescents should drink 6 to 8 oz/hr. In addition, maintaining or
increasing total caloric intake should speed recovery. If a child cannot
tolerate liquids, and vomiting persists, he or she may need to be evaluated in
an emergency department or admitted to a hospital for administration of
intravenous fluids and glucose and careful monitoring of electrolytes. Parents
should be instructed to seek medical assistance if the child has signs or
symptoms of severe dehydration, persistent vomiting or diarrhea, severe
abdominal pain, or any respiratory difficulties
-------------------------
Q 8
E
Children who have diabetes need to be monitored closely during an intercurrent illness. The primary goal for management of diabetes during an illness is to prevent the occurrence of hypoglycemia and diabetic ketoacidosis and the need for hospitalization. When diabetic children are sick, they almost always require some extra insulin in addition to their routine dose. Supplemental insulin often can be administered as a dose of subcutaneous regular insulin equivalent to approximately 10% of the total daily dose; this may be repeated every 2 to 4 hours until ketosis is cleared.
monitoring of blood glucose values.
It
is recommended that children who have diabetes ideally check blood glucose
levels every 4 to 6 hours on sick days. In addition, checking urine for ketones
every 4 to 6 hours on sick days will alert children if they begin to spill
ketones in their urine, indicating ketoacidosis. Ketones indicate insulin
deficiency or stress-related insulin resistance with inadequate compensation
using extra insulin.
-------------------------
Q 8
A
newborn whose birthweight was 1,100 g and estimated gestational age at birth
was 30 weeks is receiving mechanical ventilation, intravenous nutrition, and
antibiotic therapy for suspected sepsis at 10 days of postnatal life. Results
from routine screening for thyroid function reveal a low serum total thyroxine
(T4) concentration and a low serum thyroid-stimulating hormone (TSH)
concentration.
Of
the following, the MOST accurate statement regarding thyroid function in this
infant is that:
A. hypothalamic-pituitary-thyroid
immaturity is largely hypothalamic in origin
B. hypothyroxinemia
of prematurity warrants brief thyroid replacement therapy
C. nonthyroidal
illness decreases the serum concentration of reverse triiodothyronine
D. thyroid
hormone surge immediately following birth is absent
E. topical application of iodine-containing
antiseptics is a common cause of primary
Answer
A
The
principal cause of hypothyroxinemia of prematurity is immaturity of the
hypothalamic portion of the hypothalamus-pituitary-thyroid axis.
The resulting
lack of endogenous production of the hypothalamic hormone,
thyrotropin-releasing hormone (TRH), leads to a low serum concentration of both
thyroid-stimulating hormone (TSH) and thyroxine (T4), as reported for the
infant in the vignette. In preterm infants, exogenous administration of TRH
causes a prompt increase in serum concentration of TSH and a secondary increase
in serum concentration of T4, which suggests that both the pituitary and the
thyroid glands are normally responsive to the hypothalamic hormone.
-------------------------
Q 9
You are caring for a 12-year-old boy who has been receiving 125 mcg/d of thyroxine for
treatment of congenital hypothyroidism. He has been growing well and doing well in school. His
thyroxine and thyroid-stimulating hormone (TSH) values have been normal and stable for the
past year. At this visit, you measure a free thyroxine (fT4) concentration of 2.5 ng/dL (32.3
pmol/L) (normal, 0.8 to 2.0 ng/dL [10.3 to 25.7 pmol/L]) and a TSH concentration of 12.6 mIU/L
(12.6 mU/L) (normal, 0.5 to 5.0 mIU/L [0.5 to 5.0 mU/L]).
Of the following, the MOST likely reason for these abnormal laboratory study results is
A. patient nonadherance with therapy
B. pubertal thyroid hormone resistance
C. pubertal TSH resistance
D. resetting of normal TSH concentrations due to in utero hypothyroidism
E. substitution of generic thyroxine by pharmacy
Answer
A
The child described in the vignette has an elevation in both his free thyroxine (fT4) and thyroidstimulating
hormone (TSH) values. The most common reason for these findings in an individual
taking thyroid hormone is medication mismanagement. Although it is reasonable to take a double
dose of medication if the thyroxine was forgotten the day before, both the TSH and the fT4 are
likely to be elevated for up to 7 days because of discordance between thyroxine administration
and TSH suppression. Because medication mismanagement is so common, TSH alone never
should be used to monitor the need for changes in thyroxine dosage.
-----------------------
Q 10:
You are discussing treatment choices with the family of a 13-year-old girl in whom you have just
diagnosed hyperthyroidism. You include antithyroid drug therapy, surgery, and radioactive iodine
treatment in your discussion. They choose antithyroid drug therapy with methimazole for initial
therapy.
Of the following, the MOST likely adverse effect of this therapy is
A. agranulocytosis
B. cholestatic jaundice
C. headache
D. hematuria
E. rash
Answer
E
The most common adverse effects of the thionamide antithyroid drugs such as methimazole and propylthiouracil are rashes, arthritis, and arthralgias, which are considered minor complications. Headache is not a common adverse effect of these agents.
More severe complications are relatively rare and include hepatitis. Liver involvement with methimazole is
reversible, but propylthiouracil-induced hepatitis may result in liver failure. Neutropenia may be
seen with either methimazole or propylthiouracil. It is important to obtain a baseline white blood
cell count before starting therapy because thyrotoxicosis itself may be associated with
neutropenia. Agranulocytosis is a rare complication, usually occurring in older individuals within
the first few months of therapy, and sometimes is irreversible. It may be dose-dependent.
Hematuria is an unusual complication of therapy with these drugs and results from systemic
vasculitis. Vasculitis is more common with propylthiouracil and rarely reported with methimazole
-------------------------
Q 9
You are caring for a 12-year-old boy who has been receiving 125 mcg/d of thyroxine for
treatment of congenital hypothyroidism. He has been growing well and doing well in school. His
thyroxine and thyroid-stimulating hormone (TSH) values have been normal and stable for the
past year. At this visit, you measure a free thyroxine (fT4) concentration of 2.5 ng/dL (32.3
pmol/L) (normal, 0.8 to 2.0 ng/dL [10.3 to 25.7 pmol/L]) and a TSH concentration of 12.6 mIU/L
(12.6 mU/L) (normal, 0.5 to 5.0 mIU/L [0.5 to 5.0 mU/L]).
Of the following, the MOST likely reason for these abnormal laboratory study results is
A. patient nonadherance with therapy
B. pubertal thyroid hormone resistance
C. pubertal TSH resistance
D. resetting of normal TSH concentrations due to in utero hypothyroidism
E. substitution of generic thyroxine by pharmacy
Answer
A
The child described in the vignette has an elevation in both his free thyroxine (fT4) and thyroidstimulating
hormone (TSH) values. The most common reason for these findings in an individual
taking thyroid hormone is medication mismanagement. Although it is reasonable to take a double
dose of medication if the thyroxine was forgotten the day before, both the TSH and the fT4 are
likely to be elevated for up to 7 days because of discordance between thyroxine administration
and TSH suppression. Because medication mismanagement is so common, TSH alone never
should be used to monitor the need for changes in thyroxine dosage.
-----------------------
Q 10:
You are discussing treatment choices with the family of a 13-year-old girl in whom you have just
diagnosed hyperthyroidism. You include antithyroid drug therapy, surgery, and radioactive iodine
treatment in your discussion. They choose antithyroid drug therapy with methimazole for initial
therapy.
Of the following, the MOST likely adverse effect of this therapy is
A. agranulocytosis
B. cholestatic jaundice
C. headache
D. hematuria
E. rash
Answer
E
The most common adverse effects of the thionamide antithyroid drugs such as methimazole and propylthiouracil are rashes, arthritis, and arthralgias, which are considered minor complications. Headache is not a common adverse effect of these agents.
More severe complications are relatively rare and include hepatitis. Liver involvement with methimazole is
reversible, but propylthiouracil-induced hepatitis may result in liver failure. Neutropenia may be
seen with either methimazole or propylthiouracil. It is important to obtain a baseline white blood
cell count before starting therapy because thyrotoxicosis itself may be associated with
neutropenia. Agranulocytosis is a rare complication, usually occurring in older individuals within
the first few months of therapy, and sometimes is irreversible. It may be dose-dependent.
Hematuria is an unusual complication of therapy with these drugs and results from systemic
vasculitis. Vasculitis is more common with propylthiouracil and rarely reported with methimazole
