Review Question - QID 108623

This patient with delayed menarche and a webbed neck most likely has Turner syndrome (TS). Patients with TS undergo premature ovarian insufficiency, often even before they reach adolescence, which is associated with low anti-Mullerian hormone levels.

TS is caused by the loss of an X chromosome in a female resulting in a genetic karyotype of (45, XO). TS patients will present with primary amenorrhea, short stature, and urinary tract infections as well as pyelonephritis due to renal malformations. A physical exam will reveal a “shield chest", widely spaced nipples, and a webbed neck. Other possible findings include cystic hygroma, carpal and pedal edema, bicuspid aortic valve, and aortic coarctation. TS patients are also at an increased risk of dyslipidemia, hyperglycemia, atherosclerosis, and coronary artery disease. Although there is a range of ovarian function in these patients, “streak ovaries” are the classic finding and result in premature ovarian insufficiency with primary amenorrhea. Due to their low estrogen state, patients may also not undergo thelarche. Adrenarche, however, is unaffected because the adrenal functions are preserved. Treatment is with growth hormone, estrogen, and progesterone replacement.

Figure/Illustration A is a clinical photograph showing a patient with a webbed neck (red circles) that is classically associated with Turner syndrome. This appearance is due to the presence of underlying cystic hygroma lesions.

Viuff and Gravholt present evidence regarding fertility in patients with Turner syndrome. They discuss how patients often have primary amenorrhea and low anti-Mullerian hormone levels. They recommend using oocyte donation as an option for these patients.

Incorrect Answers:
Answer 1: Elevated creatinine levels can be seen in patients with acute or chronic renal insufficiency. Horseshoe kidneys are commonly seen in TS and may be asymptomatic or associated with increased UTIs and risk of pyelonephritis. However, pyelonephritis that was appropriately treated is unlikely to cause a permanently elevated creatinine.

Answer 3: Low fasting glucose level is unlikely to be present in this patient, as women with TS are at increased risk of developing insulin resistance and type 2 diabetes mellitus. TS patients are also more likely to develop dyslipidemia and cardiovascular disease, possibly due to the loss of estrogen’s protective effects on the cardiovascular system. Frequent screening for metabolic syndrome and early intervention is important for these patients.

Answer 4: Low follicle-stimulating hormone (FSH) levels can be seen in hypothalamic insufficiency as FSH release from the anterior pituitary relies on signaling by gonadotropin-releasing hormone pulses from the hypothalamus. This could result in amenorrhea, but this patient’s presentation is more consistent with TS. In the context of premature ovarian insufficiency, ovarian production of estrogen would be low and therefore FSH levels would be elevated due to lack of feedback inhibition.

Answer 5: Low growth hormone (GH) levels is seen in growth hormone deficiency. This condition can be congenital, typically due to mutations in growth hormone-releasing hormone receptors. It can also result from acquired pituitary insufficiency. Patients typically have short stature as well as delayed motor milestones and late puberty. Although TS patients usually have short stature and GH can be administered to stimulate growth, there is no actual GH deficiency in this condition.

Bullet Summary:
Turner syndrome is caused by loss of an X chromosome in female patients and presents with short stature, webbed neck, shield chest, horseshoe kidney, biscuspid aortic valve, and premature ovarian insufficiency.