A study is designed to see whether the degree of chest pain is linked to the troponin I value for patients admitted following a myocardial infarction. The pain is assessed using a scale of 1-10, with 10 representing the worst pain that the patient has ever experienced.
Which one of the following significance tests is it most appropriate to use to investigate this link?
Correct Answer C:
This scenario looks at whether the values are correlated. As the data is non-parametric, particularly the observation based pain scale, Spearman's rank correlation coefficient should be used.
Significance tests: types:
The type of significance test used depends on whether the data is parametric (something which can be measured, usually normally distributed) or non-parametric.
Parametric tests:
Non-parametric tests:
Paired data refers to data obtained from a single group of patients, e.g. Measurement before and after an intervention. Unpaired data comes from two different groups of patients, e.g. Comparing response to different interventions in two groups.
Which one of the following types of oral steroid has the least amount of mineralocorticoid activity?
This is clinically relevant as there are some situations where it is important to combine high glucocorticoid (antiinflammatory) activity with minimal mineralocorticoid (fluid-retention) effects. A good example is the use of dexamethasone for patients with raised intracranial pressure secondary to brain tumours.
Corticosteroids:
Corticosteroids are amongst the most commonly prescribed therapies in clinical practice. They are used both systemically (oral or intravenous) or locally (skin creams, inhalers, eye drops, intra articular). They augment and in some cases replace the natural glucocorticoid and mineralocorticoid activity of endogenous steroids.
The relative glucocorticoid and mineralocorticoid activity of commonly used steroids is shown below:
Side-effects:
The side-effects of corticosteroids are numerous and represent the single greatest limitation on their usage. Sideeffects are more common with systemic and prolonged therapy.
Glucocorticoid side-effects:
Mineralocorticoid side-effects:
Selected points on the use of corticosteroids:
What chemical mediator is mainly responsible for the tissue oedema seen in patients in hereditary angioedema?
Correct Answer D:
Hereditary angioedema:
Hereditary angioedema is an autosomal dominant condition associated with low plasma levels of the C1 inhibitor (C1-INH) protein. C1-INH is a multifunctional serine protease inhibitor - the probable mechanism behind attacks is uncontrolled release of bradykinin resulting in oedema of tissues.
Investigation:
Symptoms:
Management:
Each one of the following is associated with Noonan's syndrome, except:
Correct Answer E:
In contrast to Turner's syndrome, the karyotype is normal.
Noonan's syndrome:
Often thought of as the 'male Turner's', Noonan's syndrome is an autosomal dominant condition associated with a normal karyotype. It is thought to be caused by a defect in a gene on chromosome 12.
As well as features similar to Turner's syndrome (webbed neck, widely-spaced nipples, short stature, pectus carinatum and excavatum), a number of characteristic clinical signs may also be seen:
What is the most common target of pANCA?
Myeloperoxidase is a neutrophil protein whose primary role is the generation of oxygen free radicals.
ANCA:
There are two main types of anti-neutrophil cytoplasmic antibodies (ANCA) - cytoplasmic (cANCA) and perinuclear (pANCA).
For the exam, remember:
pANCA:
Other causes of positive ANCA (usually pANCA):
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