CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 7, August 2012
e14
AFRICA
intimal tear causing separation of the aortic wall components,
and collection of blood between the wall layers. Some patients
with acute aortic dissection do not present with typical chest or
back pain. The incidence of absence of pain in aortic dissection
varied in different series in the literature but approximately 6.4 to
14% of aortic dissection patients presented with painless aortic
dissection.
2-4
As chest or back pain is by far the most characteristic
presentation, its absence usually diverts our attention from a
diagnosis of aortic dissection.
Aortic dissection presenting with isolated ischaemia of the leg
is rare, occurring in about 10% of patients, but is has been well
described.
2,3
Because isolated lower extremity ischaemia without
chest pain and other classic symptoms of aortic dissection is rare,
it is frequently misdiagnosed.
In our patient, the isolated lower limb symptoms masked
the oppressive feelings of the dissection. The absence of other
finding, such as mediastinal widening and predisposing risk
factors further hampered a correct diagnosis. If painless aortic
dissection occurs in an older patient, as with our patient, there is
often no indication, and early diagnosis is difficult. A delayed or
missed diagnosis usually portends a poor outcome.
Obstruction of any arterial branch may lead to ischaemia
of several organs or extremities and produce a variety of
symptoms in addition to the characteristic pain originating from
the intimal tear of the aorta. Although chest radiography is
helpful in providing important clues in suspected cases of aortic
dissection, it is rarely diagnostic.
2
Findings such as aortic knob
abnormalities, mediastinal widening, irregular aortic contour,
displacement of intimal calcification and pleural effusion are
indicative. Normal chest radiographs are found in 10 to 20% of
proven aortic dissections.
1,2
We therefore recommend including aortic dissection in the
differential diagnosis of limb ischaemia. In our patient, the
development of acute isolated lower limb ischaemia was so
severe that the differential diagnosis should have been limited to
vascular insult. If a patient has no history of bleeding diathesis
or any cancer, aortic dissection should be strongly considered.
Aortic dissection should be presumed to be the cause of acute
isolated lower limb ischaemia despite angiography not having
been done.
Our case presentation is intended to illustrate a category of
patients with aortic dissection that may easily be overlooked
and therefore untreated. Given the potential lethal nature of
acute aortic dissection, appropriate diagnostic evaluation, such
as echocardiography, CT scan or MRI are warranted for patients
presenting with acute isolated limb ischaemia, particularly if
predisposing risk factors or suggestive signs of aortic dissection
are present.
1
Conclusion
When patients present with or develop signs and symptoms of
isolated limb ischaemic injury without obvious cause, aortic
dissection should be considered, even without the presence of
characteristic pain. The diagnosis can be challenging in patients
with painless aortic dissection.
References
1.
Crawford ES. The diagnosis and management of aortic dissection.
J Am
Med Assoc
1990;
246
: 2537–2541.
2.
Ying CH, Pao YL, Joseph HL. Aortic dissection presenting as isolated
lower extremity ischemia – a case report.
Acta Cardiol Sin
2002;
18
:
79–82.
3.
Chih CW, Tsui LH. Acute paraplegia in a patient with painless aortic
dissection – a case report.
Acta Cardio Sin
2001;
17
: 245–249.
4.
Demircan A, Aksay E, Ergin M, Bildik F, Keles A, Aygencel G. Painless
aortic dissection presenting with acute ischemic stroke and multiple
organ failure.
Emerg Med Australas
2011;
23
: 215–216.
