A 37 year old woman presents to her GP with weight gain and menstrual irregularities. She has also noticed that her skin has started to bruise more easily. She has a past medical history of inflammatory bowel disease and has had a recent exacerbation of this. Otherwise, she is fit and well and works full-time as an engineer. She has no allergies and has had no previous surgeries.

Laboratory tests show low ACTH levels and elevated serum cortisol levels.

Which of the following is the most likely cause of her symptoms?

Options:
explanation: This patient has Cushing's syndrome. Nelson syndrome is a condition that can occur in patients with a history of Cushing's disease (typically due to a pituitary adenoma) who have undergone bilateral adrenalectomy as part of their treatment. After adrenalectomy, cortisol production ceases, and ACTH levels rise as the body attempts to stimulate the remaining pituitary tumour cells. As a result, the pituitary tumour can grow, leading to the characteristic features seen in Nelson syndrome: including weight gain, skin hyperpigmentation, menstrual irregularities, and other symptoms. This patient has had no previous surgeries, ruling out this option.
name: Nelson syndrome
label: e
answer: no
explanation: This is the correct answer. This patient has Cushing's syndrome. The most common cause of Cushing's syndrome is the long-term, high-dose use of glucocorticoids. Given the patient's history of inflammatory bowel disease, she may have been prescribed corticosteroids as part of her treatment, contributing to the development of Cushing syndrome.
name: Iatrogenic corticosteroid use
label: a
answer: yes
explanation: This patient has Cushing's syndrome. Adrenal carcinoma is a rare cancer of the adrenal cortex that can lead to excessive cortisol production. However, it usually presents with more severe and aggressive symptoms. Although it can be associated with Cushing's syndrome, the clinical presentation is often distinct and may include features like rapid weight gain, hypertension, and a palpable abdominal mass due to the tumour. In addition, adrenal carcinomas are relatively rare compared to other causes of Cushing's syndrome.
name: Adrenal carcinoma
label: c
answer: no
explanation: This patient has Cushing's syndrome. The patient's low ACTH levels suggest that the source of the excess cortisol is not an overproduction of ACTH due to a pituitary adenoma, the most common cause of Cushing's disease. In Cushing's disease, the pituitary tumour results in high ACTH levels, which, in turn, stimulate the adrenal glands to produce excess cortisol. However, in this scenario, the patient's ACTH levels are low, indicating a different cause for the elevated cortisol levels.
name: Pituitary adenoma
label: b
answer: no
explanation: This patient has Cushing's syndrome. The condition that involves many small cysts on the ovaries is polycystic ovary syndrome (PCOS). It is a common hormonal disorder in women that can cause menstrual irregularities and weight gain, like in this patient vignette, but it does not involve low ACTH levels, elevated cortisol levels, or easy bruising.
name: Many small cysts on the ovaries
label: d
answer: no

Correct answer: a