A 15-year-old boy is brought to the office by his parents due to concerns about his pubertal development. The patient says, "I am the only one of my friends whose voice has not changed and who does not have any body hair. I'm tired of being called 'weak' in gym class." The patient has been fatigued lately, which he attributes to staying up late talking with friends; he otherwise feels well. He has had no recent headaches, vomiting, or vision changes. The patient has a good appetite and eats a well-varied diet. His father is 178 cm (5 ft 10 in) and his mother is 160 cm (5 ft 3 in) . Blood pressure is 116/70 mm Hg and pulse is 78/min. Weight and height are at the 15th and 3rd percentiles, respectively, unchanged from his last visit 12 months ago. The patient's height has increased 4.5 cm (1.8 in) since then. Physical examination shows a well-appearing, quiet adolescent with no dysmorphic features. The thyroid is palpable and not enlarged. There is no gynecomastia. Cardiopulmonary examination is normal. The testes are soft and measure 2 mL (Tanner stage I) . The phallus is normal in length. There is no axillary or pubic hair. The rest of the physical examination is normal. Bone age x-ray is consistent with age 13. Item 1 of 2
Which of the following is the most likely diagnosis in this patient?

Question

Quizplus · Accepted Answer

Explanation: 11ec2b69_bfd0_9115_8f63_074fc782dcd3_MD0005_00 Puberty is considered delayed if no secondary sexual characteristics (typically testicular enlargement [>4 mL] or breast development) are present by age 14 in boys or age 12 in girls. This patient with short stature but normal growth velocity (4-6 cm/yr) most likely has constitutional delay of puberty. A family history of "late bloomers" would support this diagnosis; however, this history is not present in every case. In contrast to familial short stature, in which short stature and normal growth velocity are accompanied by a normal bone age, constitutional delay is associated with a delayed bone age on x-ray of the wrist, as seen in this patient (Choice C). Height and pubertal development typically correlate more closely with bone age than with chronological age. On follow-up, patients with constitutional delay of puberty often demonstrate an onset of puberty similar to that of family members, and reaching the midparental adult height is expected following the pubertal growth spurt. (Choice B) Although a pituitary tumor (eg, craniopharyngioma) can interrupt normal hormonal regulation required for pubertal development, patients frequently have headache and loss of peripheral vision due to the mass. This patient has no features of an intracranial mass. (Choice D) Hypothyroidism may cause pubertal delay, short stature, and fatigue; however, decreased growth velocity would be expected. In addition, fatigue is more commonly related to poor sleep habits in adolescents without other findings of metabolic slowing (eg, weight gain, bradycardia, constipation) or thyromegaly. (Choice E) Kallmann syndrome is characterized by anosmia and hypogonadotropic hypogonadism. Affected males often have cryptorchidism and a micropenis. It is far less common than constitutional delay and is unlikely in this patient without anosmia. Educational objective: Constitutional delay is characterized by delayed development of secondary sexual characteristics in conjunction with delayed bone age, short stature but normal growth velocity, and a family history of "late bloomers." References: Normal and abnormal puberty. (http://www.ncbi.nlm.nih.gov/pubmed/25905253)

A 15-Year-Old Boy Is Brought to the Office by His