Which one of the following features is not associated with Turner's syndrome?
Correct Answer E:
Primary, not secondary, amenorrhoea is seen in Turner's syndrome.
Turner's syndrome:
Turner's syndrome is a chromosomal disorder affecting around 1 in 2,500 females. It is caused by either the presence of only one sex chromosome (X) or a deletion of the short arm of one of the X chromosomes.
Turner's syndrome is denoted as 45,XO or 45,X.
Features:
There is also an increased incidence of autoimmune disease (especially autoimmune thyroiditis) and Crohn's disease.
A 68-year-old woman presents with lethargy and generalized aches. As part of a blood screen the following results are obtained:
What is the most likely cause of these blood results?
This question tests whether you have an understanding of the incidence of common disorders. All of the above may cause hypercalcaemia but cancer and primary hyperparathyroidism are the most common causes in this age group. A normal ESR (given her age) points towards a diagnosis of primary hyperparathyroidism.
Hypercalcaemia: causes:
The most common causes of hypercalcaemia are malignancy (bone metastases, myeloma, PTHrP from squamous cell lung cancer) and primary hyperparathyroidism.
Other causes include:
*Other causes of granulomas may lead to hypercalcaemia e.g. Tuberculosis and histoplasmosis.
**Usually normal in this condition but hypercalcaemia may occur with prolonged immobilization.
A study looks at whether a new oral treatment for patients with heart failure can prevent hospital admissions.
When reviewing the data how should it be decided if the test was statistically significant?
Correct Answer C:
The significance level of a test is defined as the probability of rejecting the null hypothesis when the null hypothesis is actually true (a Type I error). It is often represented by the Greek symbol alpha. A study is only statistically significant if the p-value reaches the significance level set before the study is started.
Popular levels of significance are 5% (0.05), 1% (0.01) and 0.1% (0.001).
Significance tests:
A null hypothesis (H0) states that two treatments are equally effective (and is hence negatively phrased). A significance test uses the sample data to assess how likely the null hypothesis is to be correct.
For example:
The alternative hypothesis (H1) is the opposite of the null hypothesis, i.e. There is a difference between the two treatments.
The p value is the probability of obtaining a result by chance at least as extreme as the one that was actually observed, assuming that the null hypothesis is true. It is therefore equal to the chance of making a type I error (see below).
Two types of errors may occur when testing the null hypothesis:
The power of a study is the probability of (correctly) rejecting the null hypothesis when it is false, i.e. the probability of detecting a statistically significant difference:
Which of the following statements is true regarding autosomal dominant inheritance?
Due to non-penetrance affected individuals do not always have affected parents.
Autosomal dominant: In autosomal dominant diseases:
Complicating factors:
Which one of the following statements regarding hypocalcaemia is incorrect?
Correct Answer D:
Hypocalcaemia: Trousseau's sign is more sensitive and specific than Chvostek's sign.
Hypocalcaemia: features:
As extracellular calcium concentrations are important for muscle and nerve function many of the features seen in hypocalcaemia seen a result of neuromuscular excitability.
Trousseau's sign:
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