Most strokes in pregnancy manifest either during labor and delivery or in the puerperium. In a study of 2850 pregnancyrelated strokes, approximately 10 percent developed antepartum, 40 percent intrapartum, and almost 50 percent postpartum (James, 2005). In contrast, Lefert (2016) reports a timing of 45 percent antepartum, 3 percent intrapartum, and 53 percent postpartum in 145 women. Several risk factorsunrelated and related to pregnancy-have been reported from studies that included more than 10 million pregnancies. These include age; migraines, hypertension, obesity, and diabetes; cardiac disorders such as endocarditis, valvular prostheses, and patent foramen ovale; and smoking. hose related to pregnancy include hypertensive disorders, gestational diabetes, obstetrical hemorrhage, and cesarean delivery. By ar, the most common risk actors are pregnancy-associated hypertensive disorders. A third of strokes are associated with gestational hypertension, and hypertensive women compared with normotensive counterparts have a three-to eightfold greater risk of stroke (Scott, 2012; Wang, 2011). Women with preeclampsia undergoing general anesthesia may be at higher risk of stroke compared with those given neuraxial anesthesia (Huang, 2010). Another risk factor for peripartum stroke is cesarean delivery, which raises the risk 1.5-fold compared with vaginal delivery (Lin, 2008).
Pregnancy-induced efects on cerebrovascular hemodynamics include enhanced autoregulation that maintains blood low despite changes in systemic blood pressure (van Teen, 2016). Although cerebral blood low decreases by 20 percent from midpregnancy until term, it increases signiicantly with gestational hypertension (Zeeman, 2003, 2004b). Such hyperperfusion at least intuitively would be dangerous for women with certain vascular anomalies.
FIGURE 60-2 Illustrations of a brain showing various types of strokes seen in pregnancy: (1) subcortical infarction (preeclampsia), (2) hypertensive hemorrhage/ (3) aneurysm, (4) embolism or thrombosis in middle cerebral artery, (5) arteriovenous malformation, and (6) cortical vein thrombosis.
Cocaine, amphetamines
From Smith, 2015; Yager, 2012. Neurological Disorders 1161
Acute occlusion or embolization of an intracranial blood vessel causes cerebral ischemia, which may result in death of brain tissue (Fig. 60-2). he more common associated conditions and etiologies of ischemic stroke are shown in Table 60-3. A transient ischemic attack (TIA) is caused by reversible ischemia, and symptoms usually last less than 24 hours. Approximately 10 percent of these patients have a stroke by 1 year (Amarenco, 2016). Patients with a stroke usually have a sudden onset of severe headache, hemiplegia or other neurological deicits, or occasionally seizures. In contrast, focal neurological symptoms accompanied by an aura usually signiy a irst-episode migraine (Liberman, 2008).
Evaluation of an ischemic stroke includes echocardiography and cranial imaging with CT, MR, or angiography. Serum lipids are measured with the caveat that their values are distorted by normal pregnancy (Appendix, p. 1259). Tests to detect antiphospholipid antibodies and lupus anticoagulant are performed. These underlie up to a third of ischemic strokes in otherwise healthy young women (Chap. 59, p. 1143). Also, sickle-cell syndromes are evaluated when indicated (Buonanno, 2016).