Snapshot A 15-year-old girl presents to her primary care physician due to lack of breast development, which is causing her emotional distress. She denies any headache, vision changes, or focal motor or sensory deficits. Physical examination is notable for a short stature and shield chest. Bone age appears to be that of a 12-year-old girl. Serum testing is remarkable for an elevated FSH and LH with decreased serum estradiol and karyotyping demonstrates 45,XO. (Turner syndrome) Introduction Overview in girls the absence of breast development by 12 years of age in boys the absence of testicular enlargment by 14 years of age causes of delayed puberty can be divided into primary hypogonadism Turner syndrome (45,XO) Klinefelter syndrome (47,XXY) gonadal injury from chemotherapy or radiation therapy autoimmune or postinfectious cryptorchidism impaired testosterone biosynthesis secondary hypogonadism constitutional delayed of puberty the most common cause of delayed puberty believed to be secondary to a functional defect in the production of gonadotropin-releasing hormone (GnRH) patients may have a family history of "late bloomers" isolated GnRH deficiency Kallmann snydrome presents with anosmia or hyposmia poor nutrition (e.g., anorexia nervosa) hypothyroidism excessive exercise chronic illnesses (e.g., inflammatory bowel disease) hypothalamic or pituitary disease (e.g., hemochromatosis, malformations, and malignancy) Epidemiology Risk factors family history of delayed puberty poor nutrition excessive exercises chronic illness (e.g., inflammatory bowel disease) ETIOLOGY Pathogenesis primary hypogonadism hypergonadotrophic hypogonadism gonadal failure, inability to synthesize sex hormones, or respond to sex steroids secondary hypogonadism hypogonadotrophic hypogonadism functional malnutrition excessive exercise chronic illness (e.g., inflammatory bowel disease) persistent impaired hypothalamic-pituitary-gonadal axis secondary to pathology at the level of the hypothalamus or the pituitary Presentation Symptoms depends on the underlying cause e.g., patients with a large prolactinoma may experience headache and visual field deficits Physical exam in boys lack of testicular enlargement (testicular volume of < 4 mL) by age 14 in girls lack of breast buds by age 12 lack of acne, facial hair, or pubic hair may be a sign of adrenarche rather than true puberty Imaging Radiography indication initial imaging study in the workup of delayed puberty performed on the left hand and wrist determines if the patient's age matches the bone age MRI of the brain with gadolinium indication patients with delayed puberty and neurologic symptoms (e.g., headache and vision changes) Studies Labs serum initial studies follicle-stimulating hormone (FSH) and luteinizing hormone (LH) testosterone (in men) estradiol (girls) thyroid-stimulating hormone (TSH) and free thyroxine (T4) prolactin Treatment Treatment should directed at the underlying cause, for example bromocriptine in patients with prolactinoma weight gain in patients with anorexia nervosa watchful monitoring Complications Lower self-esteem due to teasing in school Increased risk of fracture secondary to decreased bone mineral density Prognosis the height of boys or girls with constitutional delay of puberty may be slightly lower than their genetic potential