Good morning and welcome to your Tuesday dose of Your Daily Meds.
Bonus Review: What are some of the actions of gastric acid?
Answer: A few main ones -
* Activation of pepsinogens to produce pepsins
* Assists protein digestion (pepsins require low pH for activity)
* Kills ingested bacteria - helps prevent infection
* Inhibited gastrin secretion from antral G-cells (negative feedback loop)
* Increases secretion of bile and pancreatic juices
* Facilitates iron absorption in duodenum
Paeds:
A 4-year-old boy complains to his mother of acutely painful defaecation. The mother reports that there is spotting of blood on the toilet paper. Whish of the following is the most likely diagnosis?
* Meckel diverticulum
* Intussusception
* Anal fissure
* Henoch-Schönlein purpura
* Appendicitis
Have a think.
More scroll for more chat.
A Query:
Which of the following biochemical abnormalities is most likely in Cushing’s syndrome due to ectopic ACTH secretion?
* Elevated ACTH, elevated cortisol, reduced serum potassium
* Elevated ACTH, elevated cortisol, elevated serum potassium
* Elevated ACTH, reduced cortisol, reduced serum potassium
* Reduced ACTH, markedly elevated cortisol, reduced serum potassium
* Markedly elevated ACTH, reduced serum cortisol, reduced serum potassium
(Where ACTH = adrenocorticotrophic hormone)
Have a think.
More scroll for more chat.
Spots and Pain:
Anal fissure is the most common cause of painful rectal bleeding in this age group. It is often due to passage of a hard constipated stool.
Intussusception can occur acutely, it is more likely to be reported as colicky pain and the stool classically has the appearance of red currant jelly.
Meckel diverticula, when acute, are associated with central abdominal pain and can cause sufficient blood loss and result in haemodynamic instability, as opposed to spotting on the toilet paper.
Henoch-Schönlein purpura is also associated with intussusception and bloody stools (as opposed to spotting) and often presents with abdominal pain, vasculitic rash and joint pain and swelling.
Appendicitis classically presents as a central abdominal pain that localises to the right iliac fossa. It is associated with fever, nausea and vomiting and diarrhoea but is less likely to cause spotting.
Cushingoid:
Key to answering this question is understanding that Cushing’s syndrome is caused by excess activation of glucocorticoid receptors.
Most commonly, Cushing’s syndrome is iatrogenic due to exogenous administration of glucocorticoids.
Endogenous forms of Cushing’s syndrome are due to over-production of cortisol by the adrenal glands as a result of adrenal tumour, excess adrenocorticotrophic hormone (ACTH) secretion by a pituitary tumour (Cushing’s disease), or ectopic ACTH production by some other tumour.
In ACTH-secreting tumours, there is likely to be impaired negative feedback sensitivity to cortisol, unlike in ACTH-secreting pituitary tumours, which retain this sensitivity.
So patients would most likely exhibit elevated ACTH, elevated cortisol, reduced serum potassium.
This inappropriately elevated ACTH is associated with pigmentation changes, as it binds to melanocortin-1 receptors in skin melanocytes. The elevated cortisol can overcome the kidney’s capacity to inactivate cortisol, resulting in Hypokalaemic alkalosis, contributing to the myopathy and hyperglycaemia typical of Cushing’s syndrome.
Cast your mind back to awful feedback loops like this one:
Bonus: What is bile?
Answer in tomorrow’s dose.
Closing:
Thank you for taking your Meds and we will see you tomorrow for your MANE dose. As always, please contact us with any questions, concerns, tips or suggestions. Have a great day!
Luke.
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