A 16 year old teenager presents to his GP surgery with concerns about his short stature. He is self-conscious because all his friends in school are taller than him and have a deeper voice.

Upon examination, testicular volume using an orchidometer is 3ml. There is no evidence of facial or body hair growth. Laboratory tests are ordered, including hormone panels to assess his growth hormone, thyroid function, and sex hormone level.

Which of the following blood results are most likely to confirm the diagnosis?

Options:
explanation: This is the correct answer. This vignette describes a boy who has delayed puberty. A testicular volume of <4ml, in addition to the absence of facial or body hair, reveals that this boy is still in the prepubertal stage. In males, LH stimulates the Leydig cells in the testes to produce testosterone. Low LH levels suggest a lack of stimulation of the testes, leading to reduced testosterone production. Similarly, low FSH levels indicate inadequate stimulation of the testes and reduced sperm production. This is known as hypogonadotropic hypogonadism.
name: Low luteinizing hormone (LH), low follicle-stimulating hormone (FSH), low testosterone
label: a
answer: yes
explanation: This vignette describes a boy who has delayed puberty. A testicular volume of <4ml, in addition to the absence of facial or body hair, reveals that this boy is still in the prepubertal stage. In males, LH stimulates the Leydig cells in the testes to produce testosterone. Low LH levels suggest a lack of stimulation of the testes, leading to reduced testosterone production. Similarly, low FSH levels indicate inadequate stimulation of the testes and reduced sperm production. This is known as hypogonadotropic hypogonadism. We would therefore expect low LH, low FSH and low testosterone.
name: High luteinizing hormone (LH), low follicle-stimulating hormone (FSH), high testosterone
label: c
answer: no
explanation: This vignette describes a boy who has delayed puberty. A testicular volume of <4ml, in addition to the absence of facial or body hair, reveals that this boy is still in the prepubertal stage. In males, LH stimulates the Leydig cells in the testes to produce testosterone. Low LH levels suggest a lack of stimulation of the testes, leading to reduced testosterone production. Similarly, low FSH levels indicate inadequate stimulation of the testes and reduced sperm production. This is known as hypogonadotropic hypogonadism. We would therefore expect low LH, low FSH and low testosterone.
name: High luteinizing hormone (LH), low follicle-stimulating hormone (FSH), low testosterone
label: e
answer: no
explanation: This vignette describes a boy who has delayed puberty. A testicular volume of <4ml, in addition to the absence of facial or body hair, reveals that this boy is still in the prepubertal stage. In males, LH stimulates the Leydig cells in the testes to produce testosterone. Low LH levels suggest a lack of stimulation of the testes, leading to reduced testosterone production. Similarly, low FSH levels indicate inadequate stimulation of the testes and reduced sperm production. This is known as hypogonadotropic hypogonadism. High LH, high FSH, and low testosterone would represent hypergonadotropic hypogonadism, commonly seen in Klinefelter Syndrome and chemotherapy patients.
name: High luteinizing hormone (LH), high follicle-stimulating hormone (FSH), low testosterone
label: b
answer: no
explanation: This vignette describes a boy who has delayed puberty. A testicular volume of <4ml, in addition to the absence of facial or body hair, reveals that this boy is still in the prepubertal stage. In males, LH stimulates the Leydig cells in the testes to produce testosterone. Low LH levels suggest a lack of stimulation of the testes, leading to reduced testosterone production. Similarly, low FSH levels indicate inadequate stimulation of the testes and reduced sperm production. This is known as hypogonadotropic hypogonadism. We would therefore expect low LH, low FSH and low testosterone.
name: Low luteinizing hormone (LH), high follicle-stimulating hormone (FSH), low testosterone
label: d
answer: no

Correct answer: a