Old-time clinicians surmised the presence of eclamptic hypertension
from the hard, bounding pulse, but confirmation
was long delayed for want of methods for measuring the
blood pressure. Sphygmographic tracings were interpreted
as showing arterial hypertension, but no absolute values
could be specified. Mahomed reported that such tracings
indicated the presence of hypertension in nearly all pregnant
women, and he concluded that “Puerperal convulsions and
albuminuria were accounted for by the predisposing condition
of high tension in the arterial system existing during
pregnancy.”52,53 The sphygmographic features pointing to
hypertension were: (1) the increased external pressure required
to obtain optimal tracings, (2) a well-marked percussion
wave separated from the tidal wave, (3) a small dicrotic
wave, and (4) a prolonged tidal wave.We now know that the
hemodynamic changes of normal pregnancy do not include
hypertension, but the increased cardiac output changes
the character of the pulse. The ancient Chinese recognized
the altered pulse perhaps as long as 4500 years ago; in the
Yellow Emperor’s Classic of Internal Medicine we find:
“When the motion of her pulse is great she is with child”
(translation by Veith).54
Ballantyne, from sphygmograms made in two eclamptic
and one severely preeclamptic women, concluded that arterial
blood pressure is considerably increased.55 One of the
patients died 10 hours after delivery, and the tracings suggested
that “after the completion of labor there is a great
tendency to complete collapse (of the arterial pressure) and
that unless checked will go on till death closes the scene.”
His description of terminal hypotension is descriptive of
many cases of fatal eclampsia, although he generalized too
broadly. Galabin wrote: “From sphygmographic tracings
taken during the eclamptic state, I have found that the pulsepregnant woman should “excite the apprehension of
eclampsia.” They observed that proteinuria was usually associated
with hypertension and thought that the blood pressure
was the better guide to prognosis.
The differentiation of preeclampsia–eclampsia from renal
disease and essential hypertension was long delayed, and
although we nowrecognize that they are separate entities, the
correct diagnosis is often difficult. Although Lever looked
for proteinuria in eclamptic women because of their clinical
resemblance to patients with glomerulonephritis, he concluded
that the diseases are different because eclamptic proteinuria
cleared rapidly after delivery.50 Others of that era,
however, cited his discovery of proteinuria as evidence for
the identity of the diseases.