Book of Medical Disorders in Pregnancy - Tintash

Pulmonary changes: Eclamptic fits
produce lactic acidemia, Hypercarbia,
and consequently hyperventilation.
Pulmonary edema is common in fatal
cases; heart failure may occur due to
circulatory overload. Aspiration of
gastric contents may result in pulmonary
edema or bronchopneumonia.
Endocrine changes: The elevation of
renin angiotensin aldosterone system has
been reported to occur in case of PET.
The aldosterone levels have been postulated
to be elevated to combat natriuretic
effects of progesterone, but other
investigators have found no change in
aldosterone levels when compared with
progesterone suggesting that this is
probably not true.
HCG levels are inconstantly elevated
while HPL is inconstantly reduced. Pituitary
necrosis has been documented in
fatal cases of eclampsia, but this is very
rare.
Blood chemistry: In pre-eclampsia,
serum potassium, sodium, calcium and
chloride are usually within the normal
range. Although serum sodium may fall
below 130 mEq. Per liter, osmolality is
normal and the relative sodium level per
liter of diminished serum water is
essentially normal patients do not have
physiologic hyponatremia. Blood sugar,
plasma bicarbonate and pH are within
the limits of normal pregnancy. The pH
is often reduced immediately after a
convulsion, but tends to return to normal
when adequate ventilatory exchange
is re-established. Uncompensated
acidosis may ensure when there are
repeated convulsions. Increase in the
tubular reabsorption of urate is the result
of decreased clearance and causes
hyperuricemia in patients with pre-ecl-
46
ampsia. The concentrations of creatine
and creatinine are normal. Total serum
protein, the albumin-globulin ratio and
the osmotic pressure of the plasma are
reduced in normal pregnancy and tend to
be further reduced in preeclampsia
except in the most severe cases when
hemoconcentration occurs. In normal
term pregnancy there is a substantial
increase in the concentration of plasma
fibrinogen. In patients with pre-eclampsia,
levels of fibrinogen are further
increased. Coagulation time, which is
usually shortened in normal pregnancy,
is decreased further in preeclampsia.
Clotting times of less than one minute
have been observed in some patients
with eclampsia. Electrolyte levels are
normal except in cases where vigorous
diuretic therapy has been given, sodium
has been restricted or high water load
with oxytocin has been given which
promotes an antidiuretic effect. Bicarbonate
is reduced in cases of eclampsia
where the body attempts to compensate
metabolic acidosis produced during the
eclamptic fit.
Aorta
Arterioles Capillaries
Arteries
Venules Veins
Fig4.3: Shows arterio venous
anastomosis at peripheral level
(Capillary)
Hematological changes: In normal
pregnancy both circulating plasma and
red cell volumes are increased. But with
Vena Cava