| 1. |
A 43 year old gentleman with good past health presents to you with a left
sided weakness. Physical examination is unremarkable. A CAT scan of brain
confirms two small right parietal infarcts. Routine blood tests are normal,
including a 75gm OGTT and a fasting lipid profile. The EKG is in sinus
rhythm. The autoimmune markers and clotting factors screening are normal.
What will be the next most appropriate investigation?
(A) Holter study
(B) Echocardiography
(C) MRA
(D) Transcranial Doppler
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(B) This is
a young patient with cryptogenic stroke. The presence of two small right
parietal infarcts points to an embolic phenomenon. An echocardiogram (transthroacic
and transesophageal) will help to rule out any cardiac source of emboli.
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| 2. |
Patent
foramen ovale is associated with cryptogenic stroke. True or false?
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Several case
control studies using contrast echocardiography have established a strong
association between the diagnosis of cryptogenic stroke and the presence
of patent foramen ovale (PFO) in young adults less than 55 years of age
(1,2,3,4,5) . Therefore, contrast echocardiography with agitated saline
and Valsalva maneuver is required to rule out the presence of PFO. At
the same time, one needs to look for any high risk characteristics of
PFO which predispose patients for paradoxical embolism and stroke. Such
features include a large PFO size, a greater degree of right to left shunt
as assessed by the amount of crossing microbubbles and atrial septal aneurysm.
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| 3. |
What
are the treatment options of cryptogenic stroke and the recurrent risk
of ischemic events?
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In this case,
contrast echocardiography confirms the presence of a PFO with instantaneous
right to left shunt. There are no other high risk characteristics. One
may conclude that this gentleman has cryptogenic stroke with presumed
paradoxical embolism. Three treatment modalities are currently available:
Antiplatelet (aspirin, clopidogrel), antithrombotic agent (warfarin) and
PFO closure (surgical or percutaneous). The risk of recurrent neurological
events during medical treatment with either aspirin or oral anticoagulant
has been retrospectively examined in patients with PFO and cryptogenic
stroke less than 60 years of age. The average annual rate of recurrence
was 3.4% for the combined endpoint of TIA and CVA (6) . In another study,
the average annual recurrence rate was 3.8% with no significant difference
between aspirin and anticoagulant (7) . With the availability of percutaneous
PFO closure technique, surgical PFO closure is not the procedure of choice
in most patients. Concerning the risk of recurrent neurological events
after percutaneous PFO closure, Windecker S et al showed that the annual
risk of recurrent ischemic events was 3.4% (8) . After all, the best therapeutic
modality remains unknown at this time because no head to head comparison
between these therapeutic options is available.
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| 4. |
This
gentleman has recurrent transient ischemic events seven months after the
initial event despite sequential treatment with aspirin and warfarin.
Once again, all the investigations are normal. What is your management
strategy?
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PFO-occluder
is indicated in this gentleman. In April 2002, U.S. Food and Drug Administration
(FDA) approved the Amplatzer-PFO-occluder for the non-surgical closure
of a patent foramen ovale (PFO) in patients with recurrent cryptogenic
stroke due to presumed paradoxical embolism through a PFO and who have
failed conventional drug therapy. It is also the authors' practice to
reserve percutaneous PFO closure for those patients with failed conventional
drug treatment only.
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-
Webster MW, Chancellor
AM, Smith HJ, Swift DL, Sharpe DN, Bass NM, Glasgow GL. Patent foramen ovale
in young stroke patients Lancet. 1988 Jul 2;2(8601):11-2
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Lechat P, Mas JL,
Lascault G, Loron P, Theard M, Klimczac M, Drobinski G, Thomas D, Grosgogeat
Y. Prevalence of patent foramen ovale in patients with stroke. N Engl J
Med. 1988 May 5;318(18):1148-52.
-
Hausmann D, Mugge
A, Becht I, Daniel WG. Diagnosis of patent foramen ovale by transesophageal
echocardiography and association with cerebral and peripheral embolic events.
Am J Cardiol. 1992 Sep 1;70(6):668-72.
-
Cabanes L, Mas JL,
Cohen A, Amarenco P, Cabanes PA, Oubary P, Chedru F, Guerin F, Bousser MG,
de Recondo J. Atrial septal aneurysm and patent foramen ovale as risk factors
for cryptogenic stroke in patients less than 55 years of age. A study using
transesophageal echocardiography. Stroke. 1993 Dec;24(12):1865-73.
-
de Belder MA, Tourikis
L, Leech G, Camm AJ. Risk of patent foramen ovale for thromboembolic events
in all age groups. Am J Cardiol. 1992 May 15;69(16):1316-20.
-
Mas JL, Zuber M. Recurrent
cerebrovascular events in patients with patent foramen ovale, atrial septal
aneurysm, or both and cryptogenic stroke or transient ischemic attack. French
Study Group on Patent Foramen Ovale and Atrial Septal Aneurysm. Am Heart
J. 1995 Nov;130(5):1083-8.
-
Bogousslavsky J, Garazi
S, Jeanrenaud X, Aebischer N, Van Melle G. Stroke recurrence in patients
with patent foramen ovale: the Lausanne Study. Lausanne Stroke with Paradoxical
Embolism Study Group. Neurology. 1996 May;46(5):1301-5.
-
Windecker S, Wahl
A, Chatterjee T, Garachemani A, Eberli FR, Seiler C, Meier B. Percutaneous
closure of patent foramen ovale in patients with paradoxical embolism: long-term
risk of recurrent thromboembolic events. Circulation. 2000 Feb 29;101(8):893-8.
| 1. |
What
is the clinical diagnosis? |
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The diagnosis
is impetigo contagiosa. This is the most common bacterial skin infection
in children. Staphylococcus aureus is the most common pathogen. Group
A beta-haemolytic streptococcus may also be isolated. In some cases, both
organisms can be cultured. The bacteria enter through damaged skin. Impetigo
is very contagious and can be spread by direct contact or scratching.
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| 2. |
What
are the clinical differential diagnoses?
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The differential
diagnoses include infected eczema, herpes simplex, pustular drug eruption,
erythema multiforme, and subcorneal pustular dermatosis.
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| 3. |
What
are the investigations? |
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A Gram stain
of the blister fluid will reveal gram-positive cocci. A skin swab from
pustules should be taken for culture and sensitivity test. In patients
with recurrent staphylococcal impetigo, nasal swab should be taken as
they may be nasal carrier of Staphylococcus aureus.
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| 4. |
What
are the possible complications? |
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Infection
due to nephritogenic Group A beta-haemolytic s t reptococci could be complicated
by acute glomerulonephritis occurring in 10-15%. Sepsis may also develop
in neonates.
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| 5. |
What
is the treatment?
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The wound
should be dressed with antiseptic followed by application of topical antibiotics
such as fucidin, mupirocin or bacitracin. Systemic antibiotic is indicated
except in mildest cases and may include semisynthetic penicillin (e.g.,
cloxacillin or erythromycin), first-generation cephalosporins (e.g., cephalexin)
or fusidic acid. As the condition is contagious, the patient should not
return to school until all lesions clear. Topical mupirocin or systemic
rifampicin should be given to eradicate nasal carriage of Staphylococcus
aureus if present.
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