Online
Clinical Case Study (August
2006)
Clinical
Cardiology Series
臨床心臟科個案研究
The
content of the Office Cardiology Series is provided by:
Dr. LI Siu Lung, Steven
F.H.K.A.M. (Med), F.R.C.P. (Glasg), F.R.C.P. (Edin), F.R.C.P.
(Lond), Specialist in Cardiology
Dr. WONG Shou Pang, Alexander
F.R.C.P., F.H.K.A.M.(Med.), F.H.K.C.P., Specialist in Cardiology
臨床心臟科個案研究之內容誠蒙李少隆醫生及王壽鵬醫生提供。
A 65 year old lady
presented with sinus bradycardia at 45 bpm. She was asymptomatic and there was
no history of dizzy spells or syncope. A 24 hour Holter study was done. The
following tracing was recorded.
Answers
| 1. |
What
did the tracing show?
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Sinus rhythm
with sinus pause for 3.17 seconds.
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| 2. |
What
is the diagnosis?
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Sinus node
dysfunction (sick sinus syndrome) with sinus arrest.
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| 3. |
What
treatment will you recommend? |
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The decision
for pacemaker implantation for sinus node dysfunction is mainly based
on the correlation of symptoms with the bradycardia. If the patient is
asymptomatic with no history of dizzy spell or syncope, no active treatment
is needed. Medications that suppress sinus node automaticity should be
stopped if possible. According to ACC/AHA/NASPE guideline in 2002, pacemaker
implantation is indicated (Class I indication) only in patients with documented
symptomatic bradycardia or when bradycardia will develop as a consequence
of essential long term drug therapy of a type and dose for which there
are no acceptable alternatives.
In symptomatic
patients for which pacemaker implantation is indicated, dual chamber pacemakers
are the devices of choice over ventricular pacemakers. Studies (including
large scale randomized controlled trials) have consistently shown that
in patients with sinus node dysfunction, the incidence of atrial fibrillation
in patients receiving atrial or dual chamber pacemakers is lower than
in patients receiving ventricular pacemakers. Published data concerning
stroke, heart failure and mortality benefit, however, are less clear-cut.
In addition, pacemaker syndrome in more common in patients treated with
ventricular pacemakers.
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Reference:
1. ACC/AHA/NASPE 2002
guideline update for implantation of cardiac pacemakers and anti-arrhythmia
devices. |
Dermatology
Series 皮膚科病例研究
A 10 year old boy
presented with a hypopigmented rash over his left arm since birth. It was persistent
and asymptomatic. There was no other developmental anomaly. Physical examination
reviewed an irregular non-scaly hypopigmented macule over his left arm. The
lesion became inapparent under Wood's lamp examination.
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The
content of the Dermatology Series is provided by:
Dr. KU Lap Shing, Simon, Dr. CHAN Loi Yuen & Dr. TANG Yuk
Ming, William
Specialist in Dermatology & Venereology
皮膚科病例研究之內容誠蒙顧立誠醫生、陳來源醫生及 鄧旭明醫生提供。 |
Answers
| 1. |
What
are the differential diagnoses?
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The differential
diagnoses are naevus anaemicus, naevus depigmentosa, piebaldism, vitiligo
and tinea versicolor.
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| 2. |
What
is the most likely clinical diagnosis?
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The most likely
diagnosis is naevus anaemicus. Naevus anaemicus is a pharmacologic naevus
and is an uncommon congenital localized vascular malformation.
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| 3. |
What
other clinical tests would you perform?
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Pressure on
the lesion from a glass slide makes the lesion unapparent so that it is
indistinguishable from the surrounding skin. Unlike true hypomelanosis,
the lesion also becomes less apparent under Wood’s lamp examination. Friction,
cold or heat application also fail to induce erythema in the hypopigmented
area.
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| 4. |
What
are the histology findings and what is the underlying pathophysiology?
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The histology
is normal and electron microscopy shows normal vascular structures. It
is likely to be due to a defect at the motor end-plate or smooth muscle
effector cells of the blood vessels and a focal increased blood vessel
sensitivity to catecholamines.
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| 5. |
What
is the treatment?
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No treatment
is required and cosmetic camouflage may be necessary for lesions occurring
in cosmetically important areas.
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