MRCP Revision Notes Random Selection

Aortic Regurgitation

Patients with Marfan’s syndrome are at inceased risk of developing aortic regurgitation. Symptoms include dyspnoea on exertion, syncope, chest pain and congestive cardiac failure. On examination patients have displacement of the apex, prominent S3 sound over the apex, a low pitched apical diastolic rumble (Austin-Flint murmur) and an early systolic apical ejection murmur. CXR may reveal LVH and aortic dilatation. Ideally surgery should be considered before the ejection fraction falls to below 55%.

Complete Heart Block

A basal systolic murmur is consistent with the diagnosis. There is a slow, regular pulse that does not vary with exercise. Usually there is an increase in stroke volume with a large-volume pulse and systolic flow murmur. In an asymptomatic patient, a permanent pacemaker is indicated in second and third degree heart block at the distal conduction system. ‘Cannon waves’ in the JVP occur when the right atrium contracts against a closed tricuspid valve, these occur irregularly in complete heart block. CHB presents with bradycardia, relative hypotension and syncope. The patient needs to be referred for a permanent pacemaker. (Cannon waves are also seen in conjunction with VT)

African Tick Typhus

A man goes to Kruger National Park, saw animals being bitten by mosquitoes and tsetse flies. Returns to the UK and develops fever and a black spot on the thigh as well as a faint macular rash. The most likely diagnosis is African tick typhus. Malaria should be excluded. The organism is Rickettsia conorii. Treatment is with doxycycline which often leads to quick resolution.

Haemochromatosis:

Autosomal recessive disorder more commonly seen in middle aged men. Diabetes, hypogonadism, hepatomegaly and increased skin pigmentation are suggestive of the disorder. Serus iron and ferritin levels are raised. HFE gene, chromosome 6. High transferring saturation and a low total iron binding capacity.

Wallenberg Syndrome:

Left lateral medullary syndrome. Usually die to occlusion of the posterior inferior cerebellar artery or its parent, the vertebral artery. The syndrome leads to ipsilateral pain and numbness on the face, contralateral pain and temperature loss, nystagmus and an ipsilateral Horner syndrome. MRI imaging is the investigation of choice.

Henoch-Schonlein Purpura

A young man is seen in clinic with a rash over his buttocks and lower legs, pain and swelling in both knees. Two weeks previously he had an URTI. He has hypertension. Bloods show a raised IgA + raised ESR – urinalysis shows proteinuria. HSP is characterised by raised IgA levels causing IgA nephropathy. It is a small vessel vasculitis usually occurring in young adults and children.

Type II vs Type I Statistical Error

Type II error occurs when the null hypothesis is wrongly accepted ie. a false negative results – the risk of not detecting a significant difference when there is one. The Type I Error is most closely related to the p value. Standard deviation is the measure of the spread of a sample distribution.