Wednesday, December 22, 2010

Clinical Case: A Young Obese Woman With Irregular Menses Presents With Acne And Hirsutism

Clinical Vignette: A 20-year-old Caucasian woman was referred with persistent severe acne and hirsutism. Her menses were infrequent, irregular and heavy. She was on no medication and used barrier methods of contraception. Her mother also had irregular menses. On examination, she was obese, had moderately severe acne, greasy skin, and excessive amounts of body hair in a male pattern distribution. The distribution of her obesity was uniform. Her visual fields were normal. There were no other abnormalities on examination or urinalysis.
Results of investigations were as follows:

Plasma luteinizing hormone 20 IU/L (normal range 3–8)
Plasma follicle stimulating hormone 6 IU/L (normal range 2–8)
Plasma prolactin 423 IU/L (normal range <600)
Plasma thyroxine 98 nmol/L (normal range 70–140)
Plasma testosterone 11 nmol/L (normal range 1–3)
Dehydroepiandrosterone sulphate(DHAS) 6 μmol/L (normal range 3–7)
Urinary 17-oxosteroids 39 μmol/L (normal range 14–59)

1 What is the diagnosis?
(a) Congenital adrenal hyperplasia
(b) Anabolic steroids
(c) Pituitary adenoma
(d) Polycystic ovary syndrome
(e) Cushing’s syndrome

2 How would you confirm this?
(a) MRI pituitary
(b) 24-hour urinary cortisol
(c) Pelvic ultrasound scan
(d) CT abdomen and pelvis
(e) LH suppression test

1 (d)
2 (c)
A young obese woman with irregular menses presents with acne and hirsutism. There is a family history of this problem and she has raised LH and testosterone.
Differential diagnosis
Another USMLE and MRCP favourite clinical vignette...
If hirsutism is not associated with menstrual irregularities you are unlikely to find an underlying cause. This woman does have menstrual irregularity. However, there are specific reasons to exclude most of the differential diagnoses. Her corticosteroid production is normal (DHAS and 17-oxysteroids) which make adrenal causes unlikely.
Similarly, there are no other clinical features of pituitary disease, making acromegaly unlikely, Cushing’s is excluded by the clinical clue of the uniform distribution of the obesity, and the thyroxine level is normal. She is on no medication and there are no features of systemic disease.
The cause is likely to be ovarian. A malignant disease is very rare and unlikely, whereas polycystic ovary syndrome (Stein–Leventhal syndrome) is common – it is the cause of 80 per cent of all cases of oligomenorrhoea and 25 per cent cases of amenorrhoea. It is classically associated with greasy skin and acne as well as obesity and a family history is common. Levels of LH are raised, FSH normal or low, and testosterone/DHAD at the upper limit of normal or raised. It can be confirmed with a pelvic ultrasound scan; a CT is unnecessary and has a high radiation dose.
Excess androgens cause the hirsutism and masculinization and excess oestrogens inhibit FSH and stimulate LH, leading to failure of ovulation.