Approach to precocious puberty: Clinical sciences

Puberty refers to the transition phase between childhood and adulthood, during which an individual develops secondary sexual characteristics and becomes capable of reproduction. Precocious puberty is defined as pubertal development before age 8 in biological females and age 9 in biological males. Most isolated signs of early puberty are variants of normal, but an evaluation for precocious puberty is indicated when pubertal development and linear growth proceed rapidly. Precocious puberty can be divided into two main categories: central and peripheral precocious puberty.

Now, let’s talk about what to do if your patient is presenting with chief concerns suggesting precocious puberty. First, perform a focused history and physical examination, including Tanner staging, and measure weight and height.

Here’s a high-yield fact! Puberty begins with activation of the hypothalamic-pituitary-gonadal or HPG axis, which is when the hypothalamus releases gonadotropin-releasing hormone or GnRH that stimulates the anterior pituitary gland to secrete gonadotropin hormones called luteinizing and follicle-stimulating hormones, or LH and FSH for short. These hormones then travel through the bloodstream to the gonads, where they stimulate the production of sex hormones like estradiol and testosterone! This process of gonadal activation, growth and maturation is also known as gonadarche. On the other hand, adrenarche is associated with adrenal gland maturation and increased adrenal hormone production, leading to the development of signs like axillary and pubic hair! In other words, adrenarche is independent of the HPG axis, so to determine the true onset of puberty, you should always look for signs of gonadarche, not adrenarche.

Okay, first, let’s focus on benign variants of early puberty, starting with benign isolated premature adrenarche. These patients can be biological females under age 8 or biological males under age 9. The physical exam reveals normal linear growth velocity with no signs of virilization in combination with apocrine odor and occasionally, acne. Next, let’s take a look at Tanner staging, also known as the sexual maturity rating, which classifies secondary sex changes that individuals go through in puberty! These individuals will have stage 1 of breast or testicular development and stage 2 of pubic hair development! With these findings, you can diagnose benign isolated premature adrenarche.

Next up is prepubertal vaginal bleeding. In this case, your patient will be a biological female under the age of 8 who presents with episodic vaginal bleeding. The physical exam reveals normal linear growth velocity with no evidence of trauma, foreign body, or vaginal mass on the vaginal exam. Finally, they’ll have stage 1 of breast and pubic hair development. With these findings, diagnose prepubertal vaginal bleeding. Be sure to thoroughly assess any child who presents with vaginal bleeding for assault or abuse!

Here’s a clinical pearl! There are many other benign variants of early puberty, such as isolated pubic hair of infancy and mini puberty, which is pubertal development that begins during the first few months of life and resolves within a year as the HPG axis matures.

Now, let’s take a look at findings that are suggestive of precocious puberty. Keep in mind that the age of normative pubertal development may vary by race and ethnicity. Generally speaking though, in biological females, the history will reveal breast development before 8 years of age, while in biological males will have testicular enlargement before 9 years of age. Next, the physical exam might reveal axillary hair and apocrine odor, with stage 2 or higher of breast or testicular development, and stage 2 or higher of pubic hair development.

With these findings, you should consider precocious puberty, so your next step is to order a left-hand X-ray to assess your patient’s bone age. Once you assess bone age, look for red flags that suggest a pathologic cause of early pubertal development. These include increased height velocity, advanced bone age on X-ray, signs of both gonadarche and adrenarche, and rapid pubertal progression.

If you identify no red flags, consider a benign variant of early puberty called benign isolated premature thelarche. These patients are biologically female and under the age of 8, with early breast development and no symptoms of adrenarche. If the physical examination confirms Tanner stage 2 or 3 breast development and stage 1 pubic hair development, the diagnosis is benign isolated premature thelarche. This idiopathic and self-limited condition is especially common in biological females under 2 years of age. Most patients can be monitored every 6 months to ensure that their linear growth rate remains normal and that there’s no evidence of rapid pubertal progression.

Here’s a clinical pearl! When a patient appears to have early breast development, but the exam reveals fatty tissue without underlying firm glandular breast tissue, you can diagnose lipomastia. This is a benign condition associated with obesity and does not represent true thelarche. On the other hand, the development of glandular breast tissue in a biologically male patient is called gynecomastia. During puberty, gynecomastia is often normal, but prior to puberty, it requires further investigation.

Now, let’s go back and take a look at patients presenting with one or more red flags. In this case, diagnose true precocious puberty and assess the function of the HPG axis by ordering additional labs, including LH, FSH, as well as estradiol in biological females, and testosterone in biological males.

If the LH, FSH, and estradiol or testosterone results are in the pubertal range, this is consistent with HPG axis activation and central precocious puberty. The next step is to assess the patient for indications for an MRI of the brain. These include biological females under the age of 6 years, all biological males under 9 years, and the presence of neurologic signs or symptoms, such as headaches or impaired vision.

If any of the indications for MRI are present, your next step is to order imaging of the brain and pituitary gland. The presence of an intracranial mass in the hypothalamic or pituitary region is suggestive of a CNS tumor. The most common cause of precocious puberty is hypothalamic hamartoma, while other less common causes include glial cell and germ cell tumors. Keep in mind that subarachnoid cysts, hydrocephalus, cranial irradiation, and severe head trauma could also cause this type of precocious puberty!