Online
Clinical Case Study (October 2003)
Clinical
Cardiology Series
臨床心臟科個案研究
The
content of the Clinical Cardiology Series is provided by:
Dr. Wong Shou Pang, Alexander
F.R.C.P., F.H.K.A.M.(Med.), F.H.K.C.P., Specialist in Cardiology
Dr. Li Siu Lung, Steven
M.B.,B.S.(H.K.),
M.R.C.P.(U.K.), F.H.K.A.M., F.H.K.C.P., F.R.C.P.(Glasg.), Specialist in Cardiology
臨床心臟科個案研究之內容誠蒙王壽鵬醫生及李少隆醫生提供。
A 45 year old gentleman
comes to your office for advice on the management of his coronary heart disease.
He is scheduled for a coronary angioplasty later for his stenosed coronary arteries.
He would like to know more about the use of drug-eluting coronary stents during
coronary angioplasty.
Answers
| 1. |
What
are drug-eluting stents (DES)?
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DES are metal
stents with drugs coated on their surface. The drug molecules can then
be delivered locally to the treated segment of the coronary arteries to
exert their effect.
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| 2. |
What
are the commonly available drug-eluting stents?
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The two commonly
available stents are Sirolimus-eluting stents (Cypher) and Paclitaxel-eluting
stents (Taxus).
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| 3. |
What
are the mechanisms of DES in reducing restenosis?
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Restenosis
after balloon angioplasty and stent implantation is due to local neointimal
hyperplasia. The drugs on DES inhibit smooth muscle cell proliferation
and thereby prevent neointimal hyperplasia.
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| 4. |
What
is the restenosis rate of drug-eluting stents?
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Depending
on the size of the vessels and the characteristics of the lesions and
the patients, the restenosis rate of traditional bare stents may be up
to 20-40%. The restenosis rate of DES is reduced down to 5-8%.
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| 5. |
How
safe are drug-eluting stents?
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There is no
excessive major adverse cardiac event when compared with bare stents.
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Dermatology Series
皮膚科病例研究
A 35 year old lady
presented with recurrent itchy wheals and red lines for one year. There was
no obvious precipitating factor for the skin rash. She enjoyed good general
health and there was no family history for skin diseases. A test was done on
the back (figure).
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The
content of the Dermatology Series is provided by:
Dr. Tang Yuk Ming, William and Dr. Chan Loi Yuen
Specialist in Dermatology & Venereology
皮膚科病例研究之內容誠蒙鄧旭明醫生及陳來源醫生提供。 |
Answers
| 1. |
What
is the clinical diagnosis? |
|
Chronic idiopathic
urticaria (CIU) and symptomatic dermographism. CIU refers to frequent
occurrence of urticaria lasting longer than six weeks without any obvious
causes as excluded by careful history and clinical examination and sometimes
a battery of laboratory tests. Symptomatic dermographism is a form of
physical urticaria induced by stroke or scratching.
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| 2. |
What
feature is shown in the photo?
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The patient
shows a positive dermographic test. Direct pressure, as induced by drawing
a line on the skin results in itchy wheal.
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| 3. |
How
persistent is an individual lesion? |
|
Individual
urticarial lesion resolves from within minutes to hours and seldom exceed
24 hours. However, while lesions resolve, new lesions may appear on other
sites.
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| 4. |
What
investigations are usually carried out for the condition? |
|
The laboratory
tests commonly employed include complete blood count with differential,
thyroid function test, antithyroid antibodies, antinuclear antibody, and
stool for ova and cyst. However, none of these tests are diagnostically
important for the condition. A positive test may not imply a direct causal
relationship with the urticaria. In some patients, intradermal injection
of their sera reproduces urticarial lesions (positive autologous serum
test) and recent evidence has shown that a subset of CIU is an autoimmune
disorder.
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| 5. |
What
is the treatment?
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Factors that
would exacerbate urticaria in that individual patient should be avoided.
Alcohol, nonsteroidal anti-inflammatory drugs and aspirin which cause
mast cell degranulation should only be taken with caution and medical
advice. Heat, pressure and scratching could also increase itching in CIU
and symptomatic dermographism, and hence these factors should also be
avoided. Oral antihistamines are the first line treatment, and selective
H1 blockers have the advantage of being non-sedative. A short course of
systemic steroid is effective for acute exacerbation but should not be
used on a long-term basis. Rarely, CIU may be associated with angioedema
which requires urgent medical management.
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