CushieBlog

INTRODUCTION

Cushing disease (CD) is caused by endogenous overproduction of glucocorticoids due to hypersecretion of adrenocorticotropic hormone (ACTH) by a pituitary adenoma. CD in pregnancy is very rare, and when it occurs, it is considered a high-risk pregnancy with many potential adverse outcomes for both the mother and fetus.¹ Infertility is common in CD due to cortisol and androgen excess leading to hypogonadotropic hypogonadism.¹ Due to the rarity of CD in pregnancy, there is little guidance in terms of treatment for this patient population. Similar to non-pregnant patients, the first-line treatment is transsphenoidal pituitary adenoma resection, with medical therapy as a second-line treatment option. This report presents a CASE that highlights the use of metyrapone, a steroidogenesis inhibitor, as a sole therapy in cases where surgery is deemed to be high risk and unlikely curative due to location of the tumor.

CASE REPORT

A 34-year-old woman with a past medical history of hypertension and infertility for six years presented to endocrinology for evaluation. Aside from difficulty conceiving, her only complaints were nausea and easy bruising. On exam she did not have clinical features of CD –abdominal violaceous striae, moon facies or a dorsocervical fat pad were absent. Her laboratory results revealed an elevated prolactin level (50-60ng/mL, reference range 1.4-24), an elevated ACTH level (61 pg/mL, reference range 0-46), and low FSH and LH levels (1.7mIU/mL and 1.76mIU/mL, respectively). Further testing demonstrated an elevated urinary free cortisol level (UFC) (290μg/24 hour, reference range 6-42) and her cortisol failed to suppress on a 1mg dexamethasone suppression test (cortisol 12.4μg/dL). Magnetic resonance imaging (MRI) of the pituitary with and without contrast showed a T2 hyperintense, hypoenhancing lesion within the right side of the sella touching the right cavernous internal carotid artery measuring 8x8x9 mm consistent with a pituitary adenoma (Figure 1).

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Figure 1. Caption: T1 weighted post gadolinium coronal image of the pituitary gland with a small hypoenhancing lesion within the right side of the sella.

After the presumed diagnosis of CD was made, she was referred to neurosurgery for transsphenoidal resection of the adenoma, which she underwent a few months later. Intra-operatively, a white friable tumor was found, and otherwise the surgery was uneventful. Three months later, however, she was found to have a persistent 8x8x9mm hypoenhancing lesion extending laterally over the right cavernous carotid artery on MRI. The mass approximated but did not contact the right intracranial optic nerve. The pathology from resected tissue was consistent with normal pituitary tissue with staining for growth hormone (80%), ACTH (30%), prolactin (40%), follicle stimulating hormone (5%), luteinizing hormone (40%) and thyroid stimulating hormone (15%), proving the surgery to have been unsuccessful.

Twelve weeks post-operatively, the patient discovered she was pregnant. At 12 weeks gestation, her UFC was 768μg/24h and two midnight salivary cortisol levels were elevated at 0.175 and 0.625μg/dL (reference <0.010-0.090). She was experiencing easy bruising and taking labetalol 400 mg twice daily for hypertension. She had gained 10 pounds by 12 weeks gestation.

A second transsphenoidal surgery during pregnancy was deemed high risk, with a high likelihood of residual disease due to the proximity of the tumor to the right carotid artery. The decision was made to treat the patient medically with metyrapone which was started at 250 mg twice per day at 12 weeks gestation and was eventually uptitrated based on UFC levels every 3-4 weeks (goal of <150μg /24h) to 1000 mg three times per day by the time of delivery with an eventual UFC level of 120μg/24h (Figure 2) . Morning ACTH and serum cortisol levels were monitored for potential adrenal insufficiency.

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Figure 2. Caption: This figure depicts the patient’s 24 hour urinary cortisol levels over time as well as the titration of metyrapone dosage in mg/day.

Her hypertension was well controlled throughout pregnancy on labetalol with the addition of nifedipine XL 30mg daily in the second trimester. She remained normokalemic with potassium ranging from 3.8-4.1mEq/L. She was diagnosed with gestational diabetes at 24 weeks by an abnormal two-step oral glucose tolerance test, which was diet-controlled. The patient was induced at 37 weeks gestation due to cervical insufficiency with cerclage in place, and was given stress dose steroids along with metyrapone. She delivered a healthy baby boy vaginally without complications. His Apgar scores were 9 and 9 and he weighed 6 pounds and 5 ounces. At the time of delivery and one week later, the baby’s cortisol levels were normal (6 μg/dL, normal 4-20), without evidence of adrenal insufficiency.

The patient’s metyrapone dose was reduced to 500mg three times a day after pregnancy and her 2 month postpartum 24 hour UFC was 42μg/24hr. The patient stopped the metyrapone on her own four months later and her UFC was found to be elevated at 272ug/24hr (normal 6-42μg/24hr). An MRI one year postpartum revealed a 10x10x9 mm adenoma in the right sella with some suprasellar extension without compression of the optic chiasm, but with abutment of the right carotid artery. Due to the persistently elevated cortisol, large size of the tumor, and potential for cure, especially if followed by radiation therapy, a second transsphenoidal surgery was recommended. However, due to the COVID-19 pandemic the patient underwent a delayed surgery 1.5 years postpartum. The pathology was consistent with a pituitary adenoma that stained strongly and diffusely for ACTH and synaptophysin, only. Her postoperative day 2 cortisol was 1.1μg/dL (reference range 6.7-22.6) and hydrocortisone 20mg in the morning and 10mg in the afternoon was started. She remains on hydrocortisone replacement and went on to conceive again, one month after her second surgery.

DISCUSSION

We describe a patient with pre-existing CD who became pregnant and was managed successfully with metyrapone throughout her pregnancy.

Although CD is rare in pregnancy, it can occur, and poses risks to both the mother and fetus.^1,2 Potential maternal complications include hypertension, preeclampsia, diabetes, fractures and more uncommonly, cardiac failure, psychiatric disorders, infection and maternal death.^1,2 There is also increased fetal morbidity including prematurity, intrauterine growth retardation and less commonly CD can lead to stillbirth, spontaneous abortion, intrauterine death and hypoadrenalism.^1,2

It is, therefore, imperative that these patients receive prompt care to control cortisol levels. The treatment of CD in pregnancy is challenging as there are no large research trials studying the efficacy and safety of medications in CD during pregnancy. Pituitary surgery is first-line recommendation and should be done late in the first trimester or in the second trimester to prevent spontaneous pregnancy loss.³ In this CASE, however, it was felt that a second surgery would be high-risk given the proximity of the tumor to the right carotid artery and possibly not curative, and thus surgery was not a feasible option. She was therefore successfully managed with medical therapy with metyrapone alone throughout her pregnancy.

Metyrapone use in pregnancy has been previously reported in the literature and has been shown to be effective in reducing cortisol levels.^4,5,6 Although not approved for use in pregnancy, this steroidogenesis inhibitor is the most commonly used medication to treat Cushing’s syndrome in pregnant women.^3,5 Due to metyrapone’s inhibition of 11-beta-hydroxylase, there is a buildup of steroidogenesis precursors such as 11-deoxycorticosterone, which can worsen hypertension, increase frequency of preeclampsia, and cause hypokalemia.³ Metyrapone also leads to elevation of adrenal androgens, which in conjunction with accumulation of 11-deoxycorticosterone, can cause hirsutism and virilization. ⁸

Though the use of Cabergoline has been reported in cases with Cushing disease during pregnancy, no long term safety data is available regarding it effects on pregnancy as well as the fetus. Moreover, studies assessing the effect of cabergoline in persistent or recurrent CD show a response rate of 20-30% only in cases with mild hypercortisolism. ⁹

There is no consensus on how to medically treat patients with CD during pregnancy. We chose a goal UFC of <150μg/24 hours because of the physiological rise of cortisol to two to three times the upper limit of normal during pregnancy.^3,7 During pregnancy, there is an increase in corticotropin-releasing hormone from the placenta, which is identical in structure to the hypothalamic form.⁷ This leads to increased levels of ACTH which stimulates the maternal adrenal glands to become slightly hypertrophic and accounts for the rise in serum cortisol levels in pregnancy.⁷ Corticosteroid-binding globulin also increases in pregnancy, along with serum free cortisol, leading to urinary free cortisol increasing to 3-fold the normal range.⁷ We therefore aimed to keep our patient’s urinary free cortisol approximately 3 times the upper limit of normal on our assay, to maintain normal cortisol levels for pregnancy.

Close surveillance of patients is required for worsening hypertension, hypokalemia, and potential adrenal insufficiency.³ Although no fetal adverse events from metyrapone have been reported, the medication does cross the placenta, leading to the potential for fetal adrenal insufficiency, and long-term effects are unknown.³

CONCLUSION

This CASE demonstrates the successful use of metyrapone alone to treat CD throughout pregnancy resulting in the birth of a healthy baby without adrenal insufficiency. These cases are particularly challenging given the lack of FDA-approved therapies and the lack of consensus on directing titration of medications and the duration of therapy.

Uncited reference

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