ABIM Exam Prep: How to Work Up Hirsutism
Hirsutism is excessive androgen-dependent body or facial hair that is present in females. Six main causes of hirsutism that can be tested on the ABIM Internal Medicine Board Exam include:
- Idiopathic hirsutism
- Polycystic Ovarian Syndrome (PCOS)
- Ovarian cancer
- Cushing’s disease
- Adrenal carcinoma
- Congenital adrenal hyperplasia (CAH)
Idiopathic hirsutism is a diagnosis of exclusion (when all of the above causes of hirsutism have been ruled out).
Basically, hirsutism workup is broken down into conditions with high testosterone level or high 17 OH steroid (DHEA-S) levels. First we will discuss the conditions with high testosterone levels:
High testosterone level conditions that cause hirsutism:
- PCOS
- Ovarian cancer
Patients with PCOS will have high testosterone levels but will also have an LH:FSH ratio that is elevated (usually more than 3:1).
Ovarian cancer will have extremely high testosterone levels. The diagnosis of ovarian cancer can be made by doing a trans-vaginal ultrasound or CT scan of the abdomen and pelvis to look for an ovarian mass.
High 17 OH steroid (DHEA-S) levels that causes hirsutism:
- Cushing’s disease
- Adrenal carcinoma
- Congenital adrenal hyperplasia (CAH)
With Adrenal carcinoma, the problem lies in the adrenal gland. This obviously will lead to increased DHEA-S levels. There will also be increased cortisol levels in patients with adrenal carcinoma. The increased cortisol from the adrenal carcinoma will have a negative feedback on the anterior pituitary, which will lead to a suppressed ACTH level.
With CAH, the main enzyme that is deficient is 21 beta hydroxylase. With this enzyme being deficient, production of cortisol is decreased. Since cortisol level is decreased, the negative feedback mechanism to the anterior pituitary will be to have increased ACTH levels. Obviously DHEA-S levels will be elevated. Additionally, patients with CAH will have elevated 17 OH progesterone levels.
High yield fact to remember for the ABIM Internal Medicine Board Exam: Adrenal adenoma does NOT produce elevated DHEA-S levels; therefore, it is NOT a cause of hirsutism. It, however, does share some similar properties of adrenal carcinoma and some similar properties of CAH. Like adrenal carcinoma, adrenal adenoma will have increased cortisol levels and a suppressed ACTH level due to the negative feedback to the anterior pituitary. Like CAH, adrenal adenoma will have elevated 17 OH progesterone levels.
This is the basic workup of hirsutism that is required to know for the ABIM Internal Medicine Board Exam.
Here it is now displayed in table form:
