At Hassenfeld Children’s Hospital at NYU Langone, our endocrinologists diagnose disorders of puberty.
Signs of puberty can include acne, body odor, growth spurts, and underarm and pubic hair growth. In girls, breast development and menstruation begin during puberty. Most girls experience their first menstrual period within two years of the start of puberty. Boys experience the growth of the testicles and penis, facial hair growth, and a lowering of the voice.
Puberty typically starts between ages 8 and 14 in girls and ages 9 and 14 in boys. It can take two to five years for a child’s body to complete puberty.
In both boys and girls, glands in the brain trigger puberty by releasing hormones, including gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH). In girls, these hormones signal the ovaries to begin producing the female sex hormone estrogen and to release eggs. They also cause reproductive organs, such as the uterus, to mature. In boys, these hormones signal the testicles to begin producing the male sex hormone testosterone and sperm.
Problems with the production of these hormones can lead to disorders of puberty, including precocious, or early, puberty and delayed puberty.
The causes of puberty disorders are mostly unknown, but can include malnutrition, noncancerous or cancerous brain tumors, diabetes, excessive exercise, eating disorders such as anorexia or bulimia, chemotherapy or radiation treatments for cancer, trauma to the head, and genetic conditions that cause missing or additional chromosomes. Obesity may cause early puberty in girls and delayed puberty in boys.
A specialist at Hassenfeld Children’s Hospital obtains a detailed medical history to determine the timing of your child’s physical milestones, dietary information, and, in girls, menstruation history. Your child’s doctor asks about family history because girls and boys tend to begin puberty at the same age as the parent of the same gender.
Next, the doctor performs a physical exam to check for signs of puberty. These may include the growth of pubic and underarm hair. Girls who have begun puberty may have breast buds, which are small, firm lumps beneath the nipple and areola. In boys, increased testicle and penis size may be observed.
Your child’s doctor may recommend one or more tests, the results of which can help to make an accurate diagnosis.
A bone age X-ray can help doctors evaluate whether your child’s bones are maturing at a rate that is consistent with his or her age.
In this test, a technician takes an X-ray of the bones and growth plates in the left hand and wrist. These images are then compared to those of other children of the same age and gender to determine whether your child is growing too quickly or too slowly.
Your child’s doctor may recommend blood testing to measure levels of hormones that affect the start of puberty. These include thyroid hormones, LH, FSH, prolactin, and human chorionic gonadotropin. Other blood tests include an adrenal profile, which measures levels of hormones that affect reproductive development, including cortisol, estradiol, and testosterone.
Your child’s doctor may order a GnRH stimulation test to measure how your child’s body reacts to changes in hormone levels that affect puberty.
During this test, blood samples are taken before and after an injection of leuprolide. This medication inhibits the body’s release of GnRH, a hormone that signals the ovaries and testicles to produce reproductive hormones. GnRH is released by a gland in the brain called the hypothalamus, which signals the pituitary gland to release FSH and LH, hormones that are important for the functioning of the ovaries and testicles.
In this test, a thin intravenous (IV) catheter is inserted into an arm or a leg. Blood is drawn to allow doctors to determine baseline GnRH levels in the body. Next, leuprolide is injected just under the skin of the arm. Because GnRH levels tend to fluctuate, additional blood samples are drawn at 15 minute intervals for an hour. These samples are tested in a laboratory to determine the level of GnRH after each injection. Your child’s doctor interprets the results.
Parents are encouraged to remain with their children for the duration of this test, which is performed while the child sits in a comfortable chair in a quiet area.
Sometimes, noncancerous and cancerous tumors on or near glands in the brain, trauma to the head, or chemotherapy and radiation treatment for cancer can cause puberty disorders. Your child’s doctor may order an MRI to evaluate the brain.
In an MRI, magnetic fields and radio waves are used to create computerized, three-dimensional images of the brain. Before the scan, a contrast agent may be injected into a vein in the arm to enhance the images.
Girls with puberty disorders may have a pelvic ultrasound to help the doctor evaluate the size of the ovaries and the length of the uterus. Girls with precocious puberty typically have measurements that are above normal for their age. This test can also identify cysts or tumors on or near the ovaries or an increase in the size of the ovaries.
During a pelvic ultrasound, the doctor places a device called a transducer on the abdomen. This emits sound waves to produce images of the ovaries and uterus on a monitor.
Mutations in genes can cause extra or missing chromosomes that lead to disorders of puberty. Your child’s doctor may recommend a blood test called karyotyping, which helps doctors identify the number and configuration of chromosomes. This can help them diagnose pituitary and neuroendocrine disorders that affect puberty.
Children with delayed puberty can sometimes experience bone loss, causing bones to be brittle and more likely to fracture. Your child’s doctor may order a bone density test. Called a dual energy X-ray absorptiometry, or DEXA, scan, this test determines if delayed puberty has led to bone loss.
During this test, your child lies on a table while a device positioned above determines the bone mineral density of your child’s hip and spine. Your child’s results are compared with the average bone densities of the hips and spines of healthy adolescents of the same age, gender, and ethnicity. The test takes about 20 minutes.
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