Pediatric Endocrine Disorders

A 7-year-old girl is brought to the pediatrician by her father, who recently noticed that she is developing breasts and has experienced a rapid increase in height over the past year. Vital signs are within normal limits for her age. Physical examination reveals Tanner stage 3 breast development and Tanner stage 2 pubic hair. No axillary hair or acne is noted, and the neurological examination is unremarkable. The physician suspects an early onset of puberty. Arrange the following steps in the most appropriate chronological sequence for the diagnostic evaluation and management of this patient's condition.

A $15$-month-old boy is brought to the pediatric clinic for a routine well-child visit. His mother is concerned because he is not yet walking independently and his vocabulary consists of only a single word. He was born at $39$ weeks gestation without perinatal complications, and newborn screening was reported as normal. A review of his growth chart demonstrates that his length has decreased from the $50$ th percentile at $6$ months of age to the $5$ th percentile currently, while his weight has remained steady along the $45$ th percentile. Vital signs include a temperature of $36.8^\circ\text{C}$ ($98.2^\circ\text{F}$), heart rate of $88$/min, and respiratory rate of $22$/min. Physical examination reveals an infant with a persistently open and large anterior fontanelle, generalized hypotonia, and delayed relaxation of the deep tendon reflexes. Laboratory evaluation shows:

Thyroid-stimulating hormone (TSH): $2.1\ \mu\text{U/mL}$ (Normal: $0.5-5.0\ \mu\text{U/mL}$)
Free thyroxine (T4): $0.4\ \text{ng/dL}$ (Normal: $0.9-2.4\ \text{ng/dL}$)

Which of the following is the most appropriate next step in the evaluation of this patient?

Review the following hormonal and clinical profiles of pediatric and adolescent patients presenting with disorders of steroidogenesis. Correlate each specific laboratory and physical presentation with the most accurate underlying enzyme deficiency or clinical syndrome.

An 11-year-old boy is brought to the emergency department by his parents after he fainted during a soccer game. Over the past three months, he has experienced worsening fatigue, unexplained weight loss, and recurrent episodes of vague abdominal pain and nausea. His parents mention that he has developed an intense craving for salty foods. On physical examination, his temperature is $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$), blood pressure is $82/50\text{ mmHg}$ while supine and drops to $68/40\text{ mmHg}$ upon standing, and pulse is $115\text{/min}$. He appears lethargic. There is noticeable darkening of the skin, particularly over the palmar creases, elbows, knees, and buccal mucosa.

Initial laboratory evaluation reveals:
Serum sodium: $128\text{ mEq/L}$
Serum potassium: $6.1\text{ mEq/L}$
Serum chloride: $95\text{ mEq/L}$
Serum bicarbonate: $16\text{ mEq/L}$
Blood urea nitrogen: $26\text{ mg/dL}$
Serum creatinine: $0.9\text{ mg/dL}$
Serum glucose: $58\text{ mg/dL}$

Which of the following pairs of baseline hormone levels is most likely to be present in this patient prior to any intervention?

A 9-year-old boy is evaluated in the pediatric endocrinology clinic for new-onset severe polyuria, polydipsia, and nocturia over the past month. He is otherwise healthy, and a recent comprehensive metabolic panel and hemoglobin A1c were within normal limits, ruling out diabetes mellitus. The physician suspects diabetes insipidus and admits the patient to the hospital for a water deprivation test. Arrange the following steps in the correct chronological sequence for performing this diagnostic test.

Match each pediatric patient's clinical and laboratory presentation to the most likely underlying endocrine disorder.

During a scheduled health maintenance visit, the parents of an $8$-year-old girl express concern about her recent rapid growth and the development of severe facial acne. Over the past eight months, she has required frequent shoe size changes, and her height has crossed from the $50$ th to the $90$ th percentile. The parents also report the onset of adult-type body odor and the appearance of dark, coarse pubic hair. She has not developed any breast tissue and has not had vaginal bleeding. On physical examination, her blood pressure is $102/64 \text{ mm Hg}$ and heart rate is $82/\text{min}$. Genitourinary examination reveals Tanner stage $3$ pubic hair and mild clitoromegaly. There are no palpable abdominal or pelvic masses. A radiograph of the left hand and wrist demonstrates a skeletal bone age of $11$ years. Which of the following is the most appropriate next step in the evaluation of this patient?