60) HYPERPARATHYROIDISM CAUSES

[Editor]

a) Hypercalcaemia
b) hyperphosphataemia
c) increased urinary phosphate excretion
d) increased urinary calcium excretion
e) characteristic eye changes

[Editor]

TFTTF

Hyperparathyroidism results in hyperclacaemia. This would lead to an increase calcium loss in the urine. PTH stimulates phosphate excretion. Hypophosphataemia and hyperphosphaturia would be expected. Characteristic eye changes are present with certain thyroid pathologies not parathyroid pathology.

d. is F
PTH increases renal calcium reabsorption (A-Z)

d is T due ^ filtration of Ca, ganong

Stem d

I have always thought that the art to answering negatively market mcq\'s is not about the questions that you know to be correct but the questions that you find ambiguous. Some of the stems are not always 100% correct.This would be too easy for the college. Instead some of the questions are deliberately misleading.

They need these questions as marker questions. These questions commonly appear from one paper to another and are used to distinguish between the good and bad candidates.

When i published this mcq i wasn\'t sure what the correct answer should be . It depends what came first. The chicken or the egg.
Lets look at the known facts

Hyperparathyroidism is due to an increasd level of PTH. This in turn leads to an increased calcium absorption from the gut,bone and kidney. This hence results in hypercalcaemia. If this were the conclusion that the examiners wanted then the answer would be False.
However there are compensatory mechanisms in physiology that tend to maintain the equilibrium.
Due to an increased calcium load to the glomerulus the renal filtrate contains a high concentration of calcium ions. This saturates the reabsorptive mechanisms that are present and hence calcium appears in the urine. this is a simliar mechanism to that of glycosuria in pregnancy.

If i were sitting this question in the exam ( which i wont because i\'ve already passed it) i would have 2 options.
Option 1: Get the rather round (but nice) chap who sits at the front of the exam hall to get off his chair, get short of breath and come and explain to you what the question is really asking.

Option 2:Leave it blank. This defines a good candidate who has the knowledge and insight not to fall into the trap.

However If i had to bet the house on it i would answer as i have origionally.