Angioedema
caused by angiotensin converting enzyme (ACE) inhibitors not only
can lead to recurrent skin swellings but also to life-threatening
laryngeal edema with risk of asphyxiation. It is therefore of
great practical importance, especially as ACE inhibitors are
being widely used.
The clinical
picture includes a circumscribed swelling of the skin or mucous
membrane lasting 1 to 5 days. Angioedema of the skin does not
itch, but is associated with a sensation of tension or tension
pain. Angioedema in the face, the region of the mouth, the tongue,
and the region of the throat and larynx may develop surprisingly
quickly into a massive laryngeal edema with the risk of
asphyxiation. Therefore it may potentially become life-threatening.
It must not be underestimated because its course is unpredictable.
A swelling that is initially regarded as mild and reversible may
progress into a life-threatening obstruction of the airways. A
number of patients in different parts of the world have died of a
glottal edema caused by ACE inhibitors. Angioedema caused by ACE
inhibitors very often is localized on the lips, the tongue,
pharynx and larynx, and in many cases is necessitating emergency
measures. Other sites are the hands and feet, arms, legs and
scrotum, in rare cases also the gastrointestinal tract.
About a
quarter to a third of all these forms of angioedema are
classified as life-threatening. In retrospect, the remainder
followed a mild course.
The risk of
angioedema due to ACE inhibitors is greatest in the first three
weeks of treatment, however, angioedema may occur months or,
rarely, even years after the beginning of treatment and after
complication-free long-term use. It is important to recognize the
causal role of ACE inhibitor also in patients in whom angioedemas
occur after a long latency.
The
pathogenesis of angioedema caused by ACE inhibitors is still
unclear. All the findings to date argue against an immunological
mechanism. Various criteria suggest a similar mechanism to that
observed in angioedema due to C1-inhibitor deficiency with major
involvement of the kinin system. There are no indications of
predisposing factors.
Other types
of angioedema have to be excluded. Recurrent angioedema may also
be induced by angiotensin-II-receptor antagonists.
In
patients with angioedema due to an ACE inhibitor, the drug must
be discontinued. Patients with ACE-inhibitor-induced angioedema
in the region of the head with edema of the skin, pharynx or
larynx require an emergency treatment because of the risk of
asphyxiation and should be treated in hospital immediately. As
the course of angioedema cannot be foreseen and because, as
mentioned above, a swelling that is initially regarded as mild
and reversible may develop into life-threatening obstruction of
the airways, in-patient treatment or observation even with minor
swellings in this region is necessary. An ENT specialist or
anesthetist should be called in without delay, depending on the
severity of the symptoms. Facilities for immediate intubation and
a tracheotomy should be available.
It is
important to instruct the patient thoroughly about the possible
clinical symptoms and the action to take in the event of
angioedema. In addition, it is necessary to monitor the patient
during the entire period of treatment with ACE inhibitors, which
usually have to be administered for a long time. Check-ups should
include routine specific questioning of the patient about
angioedema. If angioedema has occurred during treatment with ACE
inhibitors, all drugs of this group should be avoided in future.
