A 45-year-old woman is investigated for weight gain. She had had been unwell for around four months and described a combination of symptoms including depression, facial male-pattern hair growth and reduced libido. During the work-up she was found to be hypertensive with a blood pressure of 170/100 mmHg.
Which one of the following tests is most likely to be diagnostic?
Correct Answer D: The overnight dexamethasone suppression test is the best test to diagnosis Cushing's syndrome.
This patient has Cushing's syndrome as evidenced by the weight gain, hirsutism, depression and hypertension.
Polycystic ovarian syndrome may give some of these features but would not cause such an elevated blood pressure.
Cushing's syndrome: investigations:
Investigations are divided into confirming Cushing's syndrome and then localizing the lesion. A hypokalaemic metabolic alkalosis may be seen, along with impaired glucose tolerance. Ectopic ACTH secretion (e.g. secondary to small cell lung cancer) is characteristically associated with very low potassium levels. An insulin stress test is used to differentiate between true Cushing's and pseudo-Cushing's.
Tests to confirm Cushing's syndrome: The two most commonly used tests are:
Localization tests:
The first-line localization is 9am and midnight plasma ACTH (and cortisol) levels. If ACTH is suppressed then a non-ACTH dependent cause is likely such as an adrenal adenoma.
High-dose dexamethasone suppression test:
CRH stimulation:
Petrosal sinus sampling of ACTH may be needed to differentiate between pituitary and ectopic ACTH secretion.
A 36-year-old woman presents with feeling tired and cold all the time. On examination a firm, nontender goitre is noted. Blood tests reveal the following:
What is the most likely diagnosis?
Correct Answer E: Hashimoto's thyroiditis = hypothyroidism + goitre + anti-TPO.
The combination of a goitre with hypothyroidism points to a diagnosis of Hashimoto's. De Quervain's thyroiditis typically causes a painful goitre.
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 71-year-old woman with a history of type 2 diabetes mellitus presents with lethargy and polyuria. A diagnosis of hyperosmolar hyperglycaemic state is considered.
Which one of the following findings would be least consistent with this diagnosis?
Correct Answer C: A trace of ketones may be found in hyperosmolar hyperglycaemic state. Serum osmolality is typically > 320 mosmol/kg.
Hyperosmolar hyperglycaemic state:
The American Diabetes Association criteria for the diagnosis of hyperosmolar hyperglycaemic state (HHS) is as follows:
In patients with suspected insulinoma, which one of the following is considered the best investigation?
Correct Answer E: Insulinoma is diagnosed with supervised prolonged fasting.
Insulinoma: An insulinoma is a neuroendocrine tumour deriving mainly from pancreatic Islets of Langerhans cells.
Basics:
Diagnosis:
Management:
A 54-year-old woman presents to the Emergency Department with confusion and fever. She has a past history of thyrotoxicosis previously treated with radioiodine therapy. On examination she has a pulse of 120/min regular, blood pressure 150/90 mmHg, temperature of 39.1ºC and a respiratory rate of 18/min. Examination of the cardiorespiratory system is unremarkable and urine dipstick is clear. Blood results showed the following:
Which one of the following does not have a role in the subsequent management?
Correct Answer D: There is no indication for giving bicarbonate in this scenario.
Thyroid storm:
Thyroid storm is a rare but life-threatening complication of thyrotoxicosis. It is typically seen in patients with established thyrotoxicosis and is rarely seen as the presenting feature. Iatrogenic thyroxine excess does not usually result in thyroid storm.
Clinical features include:
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