A 30-year-old woman who is investigated for obesity, hirsutism and oligo-menorrhoea is diagnosed as having polycystic ovarian syndrome (PCOS) following an ultrasound scan. She is hoping to start a family and her doctor starts metformin to try and improve her fertility.
What is the mechanism of action of metformin in PCOS?
Correct Answer C: The majority of patients with polycystic ovarian syndrome have a degree of insulin resistance which in turn can lead to complicated changes in the hypothalamic-pituitary-ovarian axis.
Polycystic ovarian syndrome: management: Polycystic ovarian syndrome (PCOS) is a complex condition of ovarian dysfunction thought to affect between 5- 20% of women of reproductive age. Management is complicated and problem based partly because the aetiology of PCOS is not fully understood. Both hyperinsulinaemia and high levels of luteinizing hormone are seen in PCOS and there appears to be some overlap with the metabolic syndrome.
General:
Hirsutism and acne:
Infertility:
*work by occupying hypothalamic oestrogen receptors without activating them. This interferes with the binding of oestradiol and thus prevents negative feedback inhibition of FSH secretion.
A 40-year-old woman complains of feeling tired all the time and putting on weight. On examination a diffuse, nontender goitre is noted. Blood tests are ordered:
What is the most likely diagnosis?
Correct Answer D: Hashimoto's thyroiditis = hypothyroidism + goitre + anti-TPO.
This patient has Hashimoto's thyroiditis, as evidenced by the hypothyroidism, goitre and anti-thyroid peroxidase antibodies. De Quervain's thyroiditis typically causes a painful goitre and a raised ESR. Around 90% of patients with Grave's disease have anti-TSH receptor stimulating antibodies.
Hashimoto's thyroiditis: Hashimoto's thyroiditis is an autoimmune disorder of the thyroid gland. It is typically associated with hypothyroidism although there may be a transient thyrotoxicosis in the acute phase. It is 10 times more common in women.
Features:
A 24-year-old woman is found to have a blood pressure of 170/100 mmHg during a routine medical check. She is well and clinical examination is unremarkable. Blood tests show:
Which one of the following investigations is most likely to be diagnostic?
Correct Answer C: Conn's syndrome is the likely diagnosis - a renin:aldosterone ratio would be an appropriate first-line investigation.
A normal clinical examination makes a diagnosis of Cushing's syndrome less likely.
Primary hyperaldosteronism: Primary hyperaldosteronism was previously thought to be most commonly caused by an adrenal adenoma, termed Conn's syndrome. However, recent studies have shown that bilateral idiopathic adrenal hyperplasia is the cause in up to 70% of cases. Differentiating between the two is important as this determines treatment. Adrenal carcinoma is an extremely rare cause of primary hyperaldosteronism.
Investigations:
Management:
*please note that some of these notes have been copied to Wikipedia, and not vice-versa
A 49-year-old man with type 2 diabetes mellitus is reviewed. Despite weight loss and therapy with metformin and gliclazide his last HbA1c is 7.2%.
Which one of the following factors would suggest that the patient may benefit from a meglitinide?
Correct Answer D: Meglitinides - stimulate insulin release - good for erratic lifestyle.
Meglitinides stimulate insulin release and are particularly useful for post-prandial hyperglycaemia or an erratic eating schedule, as patients take them shortly before meals.
Diabetes mellitus: management of type 2: NICE updated its guidance on the management of type 2 diabetes mellitus (T2DM) in 2009. Key points are listed below:
Dietary advice:
HbA1c:
Blood pressure:
The NICE treatment algorithm has become much more complicated following the introduction of new therapies for type 2 diabetes. We suggest reviewing this using the link provided. Below is a very selected group of points from the algorithm:
Starting insulin:
Other risk factor modification:
*many local protocols now recommend starting metformin upon diagnosis.
Which of the following statements is true regarding the pathophysiology of diabetes mellitus?
Correct Answer A: Type 1 diabetes mellitus is caused by autoimmune destruction of the Beta-cells of the pancreas. Identical twins show a genetic concordance of 40%. It is associated with HLA-DR3 and DR4. It is inherited in a polygenic fashion.
Type 2 diabetes mellitus is thought to be caused by a relative deficiency of insulin and the phenomenon of insulin resistance. Age, obesity and ethnicity are important aetiological factors. There is almost 100% concordance in identical twins and no HLA associations. Haemochromatosis is an example of secondary diabetes.
Diabetes: pathophysiology: Type 1 DM:
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