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.
