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OVERVIEW
This page is dedicated to organizing various examples of standardized exam questions whose answer is congenital adrenal hyperplasia (CAH). While this may seem a odd practice, it is useful to see multiple examples of how CAH will be characterized on standardized exams (namely the boards and the shelf exams). This page is not meant to be used as a tradition question bank (as all of the answers will be the same), however seeing the classic “test” characterization for a disease is quite valuable.
KEY CHARACTERISTICS OF THIS CONDITION (ON EXAMS)
When it comes to standardized exams, each condition has its own “code” marked by key buzzwords, lab findings, clues, etc. If you are well versed in this code you will be able to more quickly identify the condition that is being discussed, and get the right answer on the exam you are taking. Below is the “code” for CAH.
Chief Complaints:
Clinical Workup:
- Clitoral enlargement/ambiguous genitalia may be noted on a physical exam
QUESTION EXAMPLES
Question # 1
A 16 year old female comes to the physician for evaluation of excess hair. She is a runner and says that she keeps “very active”. She has used multiple creams and makeup products over the last year, but is still very self conscious regarding her facial hair. She has had irregular menstrual cycles since she began menarche at the age of 12. He last menstrual period was 4 weeks ago. The patient’s BMI is 21 mg/m², blood pressure is 125/70 mm Hg, and pulse is 80/min. Her physical exam confirms that she has hirsutism. She has normal external femal genitalia, and the rest of her exam is unremarkable. A urine pregnancy test is negative. Laboratory results for this patent are listed below:
- Serum LH: 20 IU/L (0.5-15 IU/L)
- Serum FSH: 10 IU/L (1-9 IU/L)
- 17-hydroxyprogesterone: 365 ng/mL (Normal < 15 ng/mL)**
- Serum testosterone: 85 ng/mL (Normal 20-75 ng/dL)
- Serum dehydroepiandrosterone sulfate (DHEA-S): 395 µg/mL (Normal 75-370 µg/dL)
The patient’s serum glucose and electrolytes are unremarkable. What is the most likely diagnosis?
Explanation # 1
Increased 17-hydroxyprogesterone = CAH
Question # 2
A 14 year old female is brought to the clinic by her father for a routine exam. Her vital signs are as follows: temperature of 98.2°F, blood pressure of 155/92 mm Hg, pulse of 70/min, and respirations of 17/min. A physical exam is notable for an absence of secondary sexual characteristics and a pelvic exam reveals the presence of a blind vagina. Lab studies are notable for hypokalemia and low eleves of both testosterone and estradiol. Karyotyping of the patent revels that she has both X and Y chromosomes. What is the most likely diagnosis in this paint?
Explanation # 2
Question # 3
Explanation # 3
TESTABLE FACTS ABOUT THIS CONDITION (BEYOND ITS IDENTIFICATION)
Many questions on standardized exams go beyond simply recognizing the underlying condition. Often there are specific testable facts regarding some aspect of the disease’s pathophysiology/management/clinical implications that are commonly asked. Some of these are listed below:
- Causes are various enzyme deficiencies that relate to the synthesis of adrenal hormones:
- 21-hydroxylase deficiency: most common deficiency. Leads to accumulation of 17-hydroxyprogesterone.
- 17-alpha-hydroxylase deficiency: rare cause. Females will appear phenotypically normal at birth. Males will appear to be females (but lack internal genitalia).
- Inheritance pattern: autosomal recessive
Page Updated: 10.15.2016