Page 1793 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

1262 PART 11: Special Problems in Critical Care

maternal and fetal morbidity and mortality. 89,90 Risk factors include a pri- with periportal or focal parenchymal necrosis. The associated micro-
migravid state, multiple gestations, the presence of hydatidiform mole, angiopathic hemolytic anemia and consumptive coagulopathy may lead
preeclampsia in a prior pregnancy, a family history of preeclampsia, to DIC.
chronic hypertension, chronic renal disease, diabetes mellitus, obesity, The diagnosis of preeclampsia may be difficult as hypertension may
age ≥40 years, autoimmune disease, and the presence of antiphospho- be mild and proteinuria minimal or absent. 89,90 As edema is common in
lipid antibodies. 91,92 Preeclampsia may progress to a convulsive and normal pregnancy, this nonspecific finding is no longer necessary for
potentially lethal phase, termed eclampsia, without warning or overt diagnosis. Diagnostic criteria vary but include new onset hypertension
preeclampsia. Eclampsia may occur up to one month postpartum. with a systolic blood pressure ≥140 mm Hg or diastolic blood pres-
93
94
An especially fulminant complication of preeclampsia is the HELLP syn- sure ≥90 mm Hg on two or more occasions, and ≥300 mg protein in
drome, which occurs in 10% to 20% of cases of severe preeclampsia. 90,95 a 24-hour urine collection. Although the classic triad of hypertension,
Maternal and fetal morbidity and mortality are higher if eclampsia or generalized edema, and proteinuria occurring after 20 weeks of gesta-
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the HELLP syndrome develops, or if preeclampsia develops prior to 34 tion should suggest the diagnosis, the presentation of preeclampsia is
weeks of gestation. often subtle and the onset may be postpartum. Nonspecific signs and
The etiology of preeclampsia remains unclear, but a genetic predis- symptoms include malaise, headache, visual changes, nausea, vomiting,
position and host factors seem to favor its development. It is thought and epigastric or right upper quadrant pain. There has been consider-
that abnormal development of blood vessels supplying the placenta able interest in the development of a reliable biomarker. Elevated
100
cause placental ischemia and oxidative stress, followed by the altered levels of antiangiogenic factors such as fms-like tyrosine kinase 1 and
production of angiogenic factors which enter the maternal circulation endoglin, and decreased levels of the proangiogenic protein placental
and disrupt endothelial function. 90,96 This results in increased vascular growth factor have been useful in suggesting the diagnosis in research
permeability, increased sensitivity to endogenous and exogenous vaso- settings but are not yet recommended for general use. 101,102 Hemolysis
pressors, and activation of the coagulation cascade. A study of hemody- on a peripheral blood smear, increased serum bilirubin, increased
namics in preeclampsia found that the majority of patients had a normal serum transaminases, and thrombocytopenia suggest the diagnosis of
Ppw, a normal to high cardiac index, and a higher SVR compared to the HELLP syndrome. The differential diagnosis for HELLP syndrome
historical pregnant controls. 97 includes acute fatty liver of pregnancy.
Preeclampsia variably involves the central nervous system, kidneys, Manifestations of severe preeclampsia include seizures, cerebral hem-
liver, heart, systemic vasculature, and clotting cascade, with a myriad orrhage or edema, cerebral vascular accidents, renal dysfunction, pulmo-
of associated symptoms and clinical findings (Table 127-7). Cerebral nary edema, placental abruption with DIC, the HELLP syndrome, and
vasospasm, ischemia, or edema, and hypertensive encephalopathy may hepatic infarction, failure, subcapsular hemorrhage, or rupture. Acute
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contribute to eclamptic seizures. Glomeruloendotheliosis is the charac- renal failure is uncommon, but can occur when the course is complicated
teristic finding on renal histopathology, although renal dysfunction may by the HELLP syndrome, placental abruption, massive hemorrhage, or
also occur from ischemia or intravascular volume depletion. Pulmonary coagulopathy. The differential for renal dysfunction also includes hemo-
edema may result from increased left ventricular afterload, myocardial lytic uremic syndrome (HUS) or thrombotic thrombocytopenic purpura
dysfunction, decreased colloid osmotic pressure from proteinuria, vig- (TTP). Finally, posterior reversible encephalopathy syndrome, an acute
orous fluid therapy, or increased capillary permeability. While it most condition characterized by transient headache, altered mental status, sei-
98
commonly occurs after parturition, antepartum pulmonary edema zures, and loss of vision with findings of posterior leukoencephalopathy
develops in a subgroup of patients. These patients are typically obese on imaging studies, can be seen in preeclampsia. 104
99
and chronically hypertensive with secondary left ventricular hypertro-
phy and diastolic dysfunction. The HELLP syndrome is characterized Management: The principles of management include early diagno-
by a more extreme multiorgan dysfunction from secondary fibrin depo- sis, close medical observation and a well-timed delivery in order
sition and hypoperfusion. Elevated liver function tests are associated to maximize both maternal and fetal well-being (Table 127-8). 89,90

TABLE 127-7 Differential Diagnosis of the Characteristic Features of Preeclampsia and Its Complications
Feature Pregnancy-Specific Etiologies Nonspecific Etiologies Differentiation
Hypertension Preeclampsia Essential hypertension Comparative pre-pregnancy blood pressures,
Preeclampsia superimposed on chronic hypertension Secondary hypertension (renal, creatinine, urine analysis
Transient hypertension pheochromocytoma)
Thrombocytopenia Preeclampsia TTP Blood smear, LFTs, creatinine, ADAMTS13, urine
HELLP syndrome ITP analysis, infection evaluations
Acute fatty liver of pregnancy Sepsis
Elevated liver enzymes Preeclampsia Viral hepatitis Abdominal ultrasound, hepatitis testing (A, B, and C),
HELLP syndrome Drug-induced hepatitis urine analysis, ANA
Acute fatty liver of pregnancy Auto-immune hepatitis
Cholestasis of pregnancy
Renal dysfunction Preeclampsia Sepsis Creatinine, LFTs, blood smear, ADAMTS13, urine
Acute fatty liver of pregnancy Hypovolemia/hemorrhage analysis
Idiopathic postpartum renal failure TTP/HUS
Pulmonary edema Preeclampsia Valvular heart disease CXR, echocardiogram, ABG, troponin, urine analysis
Peripartum cardiomyopathy Ischemic heart disease
Tocolytic pulmonary edema ARDS
ADAMTS13, a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13; ANA, anti-nuclear antibody; ARDS, acute respiratory distress syndrome; CXR, chest x-ray; ABG, arterial blood gas;
HELLP, hemolysis, elevated liver enzymes, and low platelets; HUS, hemolytic uremic syndrome; ITP, idiopathic thrombocytopenic purpura; LFTs, liver function tests; TTP, thrombotic thrombocytopenic purpura.

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