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Here are a few recent questions that have been submitted, and the responses given by our experts:
Course: MCEM Part A
Question:
To whom it may concern, just to question the answer and explanation about hypokalaemia and renin release (QID 109936). I was under the impression that low potassium would inhibit renin release. I thought renin would stimulate aldosterone release which causes sodium retention and increased potassium excretion. Therefore through negative feedback, I thought hypokalaemia would inhibit renin release (as further renin release would cause a further reduction in potassium levels). Would appreciate clarification.
Answer from Simon Bell MRCP, FCEM
Associate Professor of Emergency Medicine, Emergency Department, Poole Hospital NHS Foundation Trust, Dorset
“Here is data from pubmed
I think the question is correct as it stands:
Arch Mal Coeur Vaiss. 1984 Apr;77 Spec No:87-91.
[Effects of potassium on renin and aldosterone].
[Article in French]
Kotchen TA.
Abstract
The renin-aldosterone system contributes to the regulation of arterial pressure and to the maintenance of sodium and potassium balance. Alterations in plasma potassium concentration have opposite and independent effects on renin secretion by the kidney and on aldosterone secretion by the adrenal gland. Renin secretion tends to be inhibited by hyperkalemia and stimulated by potassium depletion. In contrast, increases of plasma potassium directly stimulate aldosterone secretion. This effect of potassium on aldosterone serves as a protective mechanism against the development of hyperkalemia. Conversely, hypokalemia inhibits aldosterone production. Small changes in plasma potassium have a greater effect on aldosterone than on renin secretion. In patients with essential hypertension, diuretic induced alterations in serum potassium concentrations may affect both renin and aldosterone secretion. We have observed that therapy with a thiazide diuretic results in a reduction of serum potassium and a greater increase in renin activity than therapy with the potassium-retaining diuretic, spironolactone, despite comparable natriuretic responses with both drugs. Conversely spironolactone therapy is associated with a greater increase in aldosterone production. The greater effect of thiazides on renin activity and the greater effect of spironolactone on aldosterone production may be related to the thiazide induced reduction of serum potassium and the spironolactone induced increases of serum potassium.
PMID: 6428366 [PubMed - indexed for MEDLINE]”
Question:
With regards to this question -during the cardiac cycle the following statements are true
c. The end-diastolic volume will be less if there is decreased compliance of the ventricular wall
Explanation
Feedback will be provided once you are at the last question in this group
Key B
A True
B False
Decreased compliance of myocardium surely causes reduced end-diastolic volume of the ventricles? I answered “true” to this and was marked wrongly.
Answer from Iain Beardsell MB ChB (Birm) FCEM, Consultant in Emergency Medicine, Southampton University Hospitals NHS Trust:
The comment is correct: at a given pressure if complinace decreases the EDV will also decrease.
Question:
beta-2 agonism results in increased rate and force of contractility
Key B
A True
B False
I was marked wrong in saying this phrase is true.
Answer from Iain Beardsell MB ChB (Birm) FCEM, Consultant in Emergency Medicine, Southampton University Hospitals NHS Trust:
Unlike Beta 1 receptors, beta 2 receptor have little effect on the heart and therefore do not effect heart rate or force of contractility
Course: MRCPsych Paper 1
Question: Regarding question QID: 69628:
“My CPN needlebottoms me every 28 days”. The answer is given as “Paragrammatism (Sims-159).” Sims defines paragrammatism as ‘when there are a mass of complicated clauses that make no sense in achieving the goal of thought’ and a ‘disorder of grammatical construction’. The grammar in the sentence is fine. The only abnormality is the word ‘needlebottoms’. I think this is a verbal paraphasia – described by Sims as ‘the loss of the appropriate word but the statements are still meaningful’ and gives an example of a chair being described as ‘a four-legged sit-up’. ‘Needlebottoms’ clearly means ‘gives me my depot’ and is still meaningful. Please could you clairfy this, thanks.
Answer from Dr Albert Michael
West Suffolk Hospital, Bury St. Edmunds
“Paragrammatism- Kleist introduced the term in 1916, paragrammatism to denote a disordered mode of expressing oneself that is characterized by confused and erroneous word order, syntactic structure and/or grammatical morphology. It is a synonym for paraphasia -a form of aphasia in which a person has lost the ability to speak correctly, substituting one word for another, and jumbling words and sentences unintelligibly. … Synonym: jargon, paragrammatism, paraphrasia, pseudoagrammatism. It is a disorder of grammatical construction.
References
Butterworth, Brian, Howard, David (1987): Paragrammatisms, in: Cognition 26, 1-37.
Schlenck, Klaus-J.rgen (1991): Paragrammatismus, in: Blanken, Gerhard (ed.): Einf.hrung in die linguistische Aphasiologie. Theorie und Praxis,Freiburg: HochschulVerlag, 199-229.”
Course: MRCP Part 1
Question:
Please could the Author clarify how they worked out the answer to the following question regarding number needed to treat.
40 out of 200 heroin misusers in the group treated with buprenorphine (Subutex) give up heroin and 4 out of 200 give up heroin in the control group. The numbers needed to treat (NNT) is
A. 5
B. 6
C. 10
D. 18
E. 36
Answer: B
1/18% = 5.56 or 6 people
Response from Dr. Una Coales:
Dr Una Coales BA (Hons) MD FRCSEd (General Surgery) FRCSEd (ENT) FRCGP DRCOG DFFP PGCertMedEd
ARR% = 40/200 x 100% minus 4/200 in the control group x 100% = 20%-2% = 8%
NNT = 1/ARR% = 1/18% = 5.56 or 6 people as one cannot have 5 people and 0.56 of a person.