A 2-week-old girl is admitted to the hospital for dehydration and vomiting. She had an uncomplicated vaginal delivery at home and did not undergo newborn screening. Breastfeeding has been difficult due to the newborn's lethargy and frequent vomiting. The mother has no medical problems, took no medications during the pregnancy, and had normal prenatal laboratory results. Family history is significant for a brother who died at age 1 month from severe dehydration several years ago. The newborn has a 2-year-old sister who is healthy. Vital signs show hypotension and tachycardia. Examination shows a sunken fontanelle and ambiguous genitalia. The rest of the examination is unremarkable. Abdominal x-ray, abdominal ultrasound, and upper gastrointestinal studies are normal. Karyotype analysis is pending. Serum chemistry results are as follows: Karyotype analysis shows 46,XX female. Laboratory results would most likely show elevation of which of the following hormones?

Question

A 2-week-old girl is admitted to the hospital for dehydration and vomiting.  She had an uncomplicated vaginal delivery at home and did not undergo newborn screening.  Breastfeeding has been difficult due to the newborn's lethargy and frequent vomiting.  The mother has no medical problems, took no medications during the pregnancy, and had normal prenatal laboratory results.  Family history is significant for a brother who died at age 1 month from severe dehydration several years ago.  The newborn has a 2-year-old sister who is healthy.  Vital signs show hypotension and tachycardia.  Examination shows a sunken fontanelle and ambiguous genitalia.  The rest of the examination is unremarkable.  Abdominal x-ray, abdominal ultrasound, and upper gastrointestinal studies are normal.  Karyotype analysis is pending.  Serum chemistry results are as follows:  Karyotype analysis shows 46,XX female.  Laboratory results would most likely show elevation of which of the following hormones?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bead_6e02_8f63_1bd48ca3256e_MD0005_00 Marked elevation of 17-hydroxyprogesterone, a substrate of 21-hydroxylase, confirms the diagnosis with 21-hydroxylase deficiency. High testosterone levels are responsible for virilization of external female genitalia. Aldosterone and cortisol levels are abnormally low. (Choices A and B) 11-deoxycorticosterone and 11-deoxycortisol are elevated in 11-hydroxylase deficiency, causing hypertension, hypernatremia, and hypokalemia, in contrast to 21-hydroxylase deficiency. This diagnosis is unlikely as this patient is hypotensive, hyponatremic, and hyperkalemic. (Choice D) Total cholesterol levels are not affected by 21-hydroxylase deficiency. However, its metabolites, including testosterone, progesterone, and 17-hydroxyprogesterone, are elevated. (Choice E) Galactose levels are high in galactosemia but not in 21-hydroxylase deficiency. Educational objective: A diagnosis of 21-hydroxylase deficiency is confirmed by excessive levels of 17-hydroxyprogesterone. Aldosterone and cortisol levels are abnormally low. References: Congenital adrenal hyperplasia due to 21 hydroxylase deficiency: from birth to adulthood. (http://www.ncbi.nlm.nih.gov/pubmed/23044877) Congenital adrenal hyperplasia: issues in diagnosis and treatment in children. (http://www.ncbi.nlm.nih.gov/pubmed/24254335)

A 2-Week-Old Girl Is Admitted to the Hospital for Dehydration