ISCHEMIC STROKE Vas3 (1) Ischemic Stroke Last updated: August 8, 2020 DEFINITIONS → see p. Vas1 >> PATHOPHYSIOLOGY-PATHOLOGY .......................................................................................................... 1 Ischemic cascade .............................................................................................................................. 1 Ischemic zones ................................................................................................................................. 2 Time course ...................................................................................................................................... 2 Types of ischemic injury .................................................................................................................. 5 ETIOPATHOPHYSIOLOGY ......................................................................................................................... 5 1. EMBOLIC STROKES ............................................................................................................................. 5 Thrombembolism ............................................................................................................................. 6 Fat embolism .................................................................................................................................... 6 Air embolism .................................................................................................................................... 8 2. THROMBOTIC STROKES ...................................................................................................................... 8 Large-vessel strokes ......................................................................................................................... 8 Lacunar strokes ................................................................................................................................ 9 3. WATERSHED (S. BORDER ZONE) INFARCTS ....................................................................................... 10 4. ANOXIC INJURY................................................................................................................................ 10 TIA ...................................................................................................................................................... 10 EPIDEMIOLOGY ...................................................................................................................................... 11 Risk factors for ischemic stroke ..................................................................................................... 11 Mortality ......................................................................................................................................... 12 Morbidity ........................................................................................................................................ 12 CLINICAL FEATURES ............................................................................................................................. 12 TIME COURSE ...................................................................................................................................... 12 Embolic strokes .............................................................................................................................. 13 Thrombotic strokes ......................................................................................................................... 13 Lacunar strokes .............................................................................................................................. 13 VITAL SIGNS ........................................................................................................................................ 13 NEUROLOGIC EXAMINATION ................................................................................................................ 13 National Institutes of Health Stroke Scale (NIHSS) ...................................................................... 14 VASCULAR TERRITORIES ...................................................................................................................... 15 Anterior Cerebral Artery (ACA) distribution ................................................................................. 15 Middle Cerebral Artery (MCA) distribution .................................................................................. 15 Posterior Cerebral Artery (PCA) distribution ................................................................................ 16 Internal Carotid Artery (ICA) distribution ..................................................................................... 16 Vertebral Artery (VA), Basilar Artery (BA) distributions ............................................................. 16 Central penetrating branches (lacunar strokes) .............................................................................. 17 Watershed infarcts .......................................................................................................................... 18 Anoxic injury .................................................................................................................................. 18 DIFFERENTIAL DIAGNOSIS .................................................................................................................... 18 DIAGNOSIS – SEARCH FOR CAUSE ......................................................................................................... 19 Blood tests ...................................................................................................................................... 19 Cardiac examination ....................................................................................................................... 19 Doppler ultrasonography ................................................................................................................ 19 Lumbar puncture ............................................................................................................................ 19 Ophthalmoscopy ............................................................................................................................. 19 Vascular Imaging ........................................................................................................................... 19 DIAGNOSIS – SEARCH FOR STROKE ....................................................................................................... 19 EEG ..................................................................................................................................................... 19 STRUCTURAL IMAGING ........................................................................................................................ 20 CT ................................................................................................................................................... 20 MRI ................................................................................................................................................ 21 CIRCULATION / VASCULAR / METABOLIC IMAGING ............................................................................. 23 MRA ............................................................................................................................................... 23 Diffusion-weighted MRI (DW-MRI) ............................................................................................. 23 Perfusion-weighted MRI (PW-MRI) ............................................................................................. 23 Diffusion-Perfusion mismatch ....................................................................................................... 24 Perfusion CT (pCT) ........................................................................................................................ 24 MR Spectroscopy (MRS) ............................................................................................................... 25 PET ................................................................................................................................................. 26 SPECT ............................................................................................................................................ 26 Angiography ................................................................................................................................... 26 IMAGING FEATURES IN TIME LINE ........................................................................................................ 27 DIAGNOSTIC FEATURES OF DIFFERENT ETIOLOGIES .......................................................................... 27 EMBOLIC STROKES ............................................................................................................................... 27 LACUNAR STROKES .............................................................................................................................. 27 WATERSHED STROKES ......................................................................................................................... 28 ANOXIC INJURY .................................................................................................................................... 28 COMPLICATIONS ...................................................................................................................................