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Review ofLiterature
Changes involved in the pathophysiology of
(1) Vasospasm:
preeclampsia and eclampsia
Vasospasm is considered as the basic event in pathophysiology of
preeclampsia. This concept. first advanced by (Gilhard, 1981) and was
based on direct observation of small blood vessels in the nail beds.
occular fundi. and bulbar conjunctiva and it has been reported and
supported from histological changes seen in various' affected organs
(Walker and Gant, 1997). Vasospasm is alternating process with
segmental dilatation. which commonly accompanies the segmental.
arteriolar spasm. probably contribute further to the development of
vascular damage. since endothelial integrity may be compromised by
stretched dilated segments (Cunningham et al., 1993). Vascular
constriction causes resistance to blood flow and accounts for the
development of arterial hypertension. It is likely that vaso-spasm itself
also exerts a damaging effect on vessels. as the circulation in the vasa
vasorum is impaired leading to vascular damage. Moreover angiotensin II
causes endothelial cells to contract these changes lead to cellular damage
and inter-endothelial cell leaks through which blood constituents.
including platelets and fibrinogen are deposited subendothelialy (Walker
and Gant, 1997).
(2) Increased pressor response:
Normally pregnant women develop refractoriness to infused
vasopressors (catecholamines and angiotensin II). Increased vascular
reactivity to pressor hormones in women in early preeclampsia has been
identified by using either norepinephrin or angiotensin II and by using
vasopressin.• (Gant et aI., 1973) demonstrated that increased vascular
sensitivity to angiotensin II clearly preceded the onset ofpreeclampsia.
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