Pediatric Examination and Board Review (59 page)

6.
(E)
Familial intrinsic short stature. The most frequent causes of short stature in children are the genetic normal variants, including familial intrinsic short stature and constitutional delay of growth and puberty.

7.
(B)
Sedimentation rate, thyroid function tests. General screening tests of overall health including a CBC to rule out anemia, a comprehensive metabolic panel to rule out kidney or liver problems, and a sedimentation rate to rule out underlying inflammation are an important first step in detecting a medical cause of short stature. Hormonal causes of short stature include hypothyroidism, which can be ruled out with thyroid function tests, and growth hormone deficiency. Growth hormone is secreted in a pulsatile fashion; thus a random growth hormone level would not be helpful. Measurements of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) are often used to screen for growth hormone deficiency. Gonadotropin levels would not be helpful in a prepubertal 10-year-old child.

8.
(C)
Four to 6 months. A minimum interval of 4-6 months is typically needed for an accurate determination of growth velocity because seasonal variations in growth velocity have been reported. Although follow-up at 1 year would give the most accurate data on growth velocity, if this child had an attenuated growth pattern, valuable time would be lost in diagnosis and treatment of the growth disorder.

9.
(C)
The answer is 5-6.5 cm/year. Between the ages of 3 and 10 years, children tend to grow at a constant growth velocity, which averages 5 cm, or 2 inches, per year.

10.
(A)
On a scale equipped with a flexible height arm. The most reproducible way to measure children is using a wall-mounted stadiometer. In younger children, a supine stadiometer should be used that provides a stationary board at their head and a movable footboard. If a stadiometer is unavailable, the next best way to measure a child would be standing flat against a wall. The flexible height arm on a scale tends to be very unreliable.

11.
(D)
The answer is 5'10". A child’s genetic height potential can be estimated by calculating mid-parental height. For boys, 5 inches is added to the mother’s height and averaged with the father’s height, and for girls, 5 inches is subtracted from the father’s height and averaged with the mother’s height.

12.
(C)
Seven years of age. Typically between 3 and 10 years of age, children grow along a certain percentile for height. Any deviation from this percentile is a warning sign of a potential growth problem. During the first 3 years of life, it is not unusual for children to move upward or downward across growth channels toward their mid-parental height range. In addition, children who will go on to have constitutional delay of growth and puberty will often cross percentiles downward within the first 3 years of life. During puberty, children may again cross growth percentiles because the pubertal growth spurt of individuals is often out of phase. Thus a 13-year-old who has delayed puberty may cross percentiles downward even though he or she has a normal prepubertal growth rate.

13.
(B)
Growth rate from 3 to 10 years. Children with constitutional delay of growth and puberty and intrinsic short stature grow at normal rates between the ages of 3 and 10 years; thus growth velocity alone at these ages will not help differentiate among the causes of short stature. Children with constitutional delay in growth and puberty tend to fall off the normal growth curve between 0 and 3 years of age, grow slower than normal between the ages of 11 and 14 years because they are not yet in puberty, and end up at a normal stature as an adult. In contrast, children with intrinsic short stature tend to follow parallel but below the normal lines on the growth chart, and they end up shorter as adults. A bone age radiograph would help differentiate these two genetic variants.

14.
(E)
Decreased arm span. Arm span typically approximates height. Decreased arm span can be seen in conditions such as achondroplasia and hypochondroplasia, but it is not typically seen in growth hormone deficiency. Classic features of growth hormone deficiency include an attenuated growth pattern, short stature, hypoglycemia in infancy in cases of congenital growth hormone deficiency, delayed bone age, central distribution of body fat, and low IGF-1 levels.

15.
(B)
Pseudotumor cerebri. A potential adverse effect of growth hormone is fluid retention, which can lead to pseudotumor cerebri. This complication is typically reversed with a discontinuation of the growth hormone. Most children can be restarted on growth hormone at a lower dose without problems. Development of tumors in children without other predisposing factors has not been demonstrated.

16.
(C)
Hypothyroidism. Patients with constitutional delay of puberty and intrinsic short stature grow at a normal rate.

17.
(A)
Karyotype. Turner syndrome is the most common pathologic cause of short stature in girls. The incidence of Turner syndrome is approximately 1 in 2500 newborn girls. Turner syndrome is caused by the deletion of X chromosomal material. The most characteristic features of Turner syndrome are short stature and gonadal dysgenesis. In older girls, checking gonadotropin levels and estradiol is often used as a screen because these girls will have menopausal levels of gonadotropins and low estradiol as a result of primary ovarian failure.

18.
(E)
Right-sided cardiac anomalies. Left-sided cardiac anomalies such as coarctation of the aorta are more common in Turner syndrome; right-sided anomalies are more often seen in Noonan syndrome (in which patients present with a Turner-like phenotype but normal sex chromosomes). Other features of Turner syndrome include webbing of the neck, broad chest, widely spaced nipples, low posterior hairline, spooning of the nails, lymphedema, cubitus valgus, and renal anomalies, such as horseshoe kidney. Data have shown that growth hormone treatment increases growth velocity and final adult height in girls with Turner syndrome.

19.
(E)
Cushing syndrome. Children with Cushing syndrome present with short stature, excessive weight gain, and striae because of an increase in fragility of the skin as a result of excess cortisol.

20.
(D)
Excess exogenous corticosteroids. Supraphysiologic levels of exogenous steroids can attenuate growth and cause short stature and obesity in children. This contrasts with exogenous obesity in which children tend to be tall. Klinefelter syndrome is associated with tall stature. The most common cause of tall stature in a child is intrinsic familial tall stature.

S
UGGESTED
R
EADING

Botero D, Evliyaoglu O, Cohen LE. Hypopituitarism. In: Radovick S, MacGillivray MH, eds.
Pediatric Endocrinology
,
A Practical Clinical Guide
. Totowa, NJ: Humana Press; 2003:3-36.

Cuttler L, Rosenfield RL. Somatic growth and maturation. In: DeGroot LJ, Jameson JL, eds.
Endocrinology.
5th ed. Philadelphia, PA: WB Saunders; 2006:697-732.

Rosenfeld RG, Cohen P. Disorders of growth hormone/insulinlike growth factor secretion and action. In: Sperling MA, ed.
Pediatric Endocrinology.
3rd ed. Philadelphia, PA: WB Saunders; 2008:254-334.

CASE 38: AN 8
¹
/
₂
-YEAR-OLD WITH PUBERTAL DEVELOPMENT

An 8
¹
/
₂
-year-old patient is brought into your office because of concerns of early pubertal development. The mother noted the development of breast buds approximately 2 months before the visit. There is no report of pubic hair development or acne. The child is otherwise healthy and has been on no medications. On physical examination, the child is friendly and in no distress. Height and weight are at the 50th percentile. The child has Tanner stage 2 breast development and stage 1 pubic and axillary hair.

SELECT THE ONE BEST ANSWER

1.
If this child is a girl, the most likely diagnosis would be which of the following?

(A) gynecomastia

(B) precocious puberty

(C) normal puberty

(D) premature thelarche

(E) premature pubarche

2.
On physical examination of the girl, you note that her breast development is asymmetric. What would you do next?

(A) breast ultrasound

(B) breast biopsy

(C) consult a surgeon

(D) assure her that it is normal

(E) mammogram

3.
If this were a 6-year-old girl, which of the following would be the most important history to ask to help narrow your differential diagnosis?

(A) birth size

(B) developmental history

(C) birth history

(D) parental heights

(E) history of medications in the house

4.
If this child is an 8
¹
/
₂
-year-old girl who instead has Tanner stage 2 pubic hair development with Tanner stage 1 breast development, the most likely diagnosis would be which of the following?

(A) precocious puberty

(B) normal puberty

(C) premature thelarche

(D) premature pubarche

(E) congenital adrenal hyperplasia

5.
If this child were a boy with testicles measuring 2 cm in long diameter, the most likely diagnosis would be which of the following?

(A) precocious puberty

(B) pubertal gynecomastia