Stroke 

(what is it?) 

What are the two major categories of stroke? 

1. hypoxia, ischemia, infarction

2. hemorrhage d/t rupture of vessels 

Global Cerebral Ischemia 

hypoxia --> hypoxemia --> diffuse hypoxic/ischemia encephalopathy in assoc. w/ severe hypotension --> decr. perfusion ('low flow states) --> global ischemia 

Focal Cerebral Ischemia 

Only a portion of the brain is damaged, around vessel area d/t occlusion of a large or small blood vessel

Diffuse Encephalomalacia 

Softening and shrinkage and fragmentation of the gray matter combined w/ chalky, white discoloration of the white matter 

Acute Neuronal Injury 

Dead-Red Neuron 

irreversible cell injury indicating coagulation necrosis; shrinkage of entire cell (pyknosis); nucleolus shrinks to an amorphous dot; cytoplasm loses its Nissl material and assumes bright pink/red color 

How much time needs to pass before the acute neuronal injury manifests itself? 

@ least 12 hours 

What are the 3 main causes of vascular occlusions

1. thrombosis

2. embolism

3. cerebral edema w/ compression of an artery due to herniation 

Ischemic infarct 

(infarct- 48 hrs)

Acute Neuronal injury (Dead-Red Neurons), edema, endothelial swellig and PMN cells 

Subacute Phase

(24 hrs-2 weeks)

Lymphocytic infiltrate, microglia --> macrophages, reactive gliosis w/ gemistocytes

Phase of repair or resorption 

> 2 weeks 

Pseudolaminar Necrosis 

Random loss of neurons in the various layers of laminae; damage is not limited to one specific layer 

Venous Thrombosis 

Thrombosis to sinus structure, 2nd to infection, dehydration & hypercoaguability. Results in hemorrhagic (red) infarct, in distribution of vein or sinus.

Focal Embolism 

Occlusion of a large artery or tributaries by a large fragment (from heart valve, heart tumor) & may contain foreign body. 

Paradoxial Embolism 

Global or Shower Embolism 

Release of multiple, small embolic particles arising from bone fractures, which lodge in small vessels [of white matter] --> multiple small hemorrhages, giving it a "flea-bitten" appearance. 

Primary and Secondary vasculitis are other causes of infarction & hemorrhage. List a cause(s) of each: 

Systemic Collagen Vascular dz (LE) --> Primary Vasculitis 

Infection (meningitis) --> Secondary Vasculitis  

Cerebral Autosomal-Dominant Arteriopathy w/ Subcortical Infarcts & Leukoencephalopathy 

(CADASIL)

• rare hereditary 
• mutation: NOTCH 3 gene of chromosome 19
• abnl thickening of CNS vessels --> repeated infarcts of white matter 
• diffuse, incomplete necrosis of centrum semiovale 

Cerebral Amyloid Angiopathy

(a.k.a Congophilic Angiopathy) 

What kind of hemorrhage does HTN cause? 

Intracerebral Intraparenchymal hemorrhages 

What are some examples of extraparenchymal hemorrhages? 

epidural, subdural and subarachnoid hemorrhages 

(due to trauma) 

What kind of vessels does HTN affect? 

small arteries and arterioles w/ loss of muscular layers and fragility & rupture

What parts of the brain does HTN hemorrhages most frequently occur? 

cerebral hemispheres, cerebellum and brain stem 

What is the name of the hemorrhages that affect the basal ganglia, esp. the putamen?

Ganglionic Hemorrhages 

Where do Lobal Hemorrhages occur? 

Cerebral locations, like centrum semiovale, excluding basal ganglia 

Why do old hemorrhages often have a golden-brown discoloration? 

Hemosiderin-laden macrophages (siderophages)

Lacunar infarcts 

small, cavitary lesions reflecting areas of small, remote hemorrhage 

Binswanger's Dz

HTN Encephalopathy 

assoc. w/ severe bouts of malignant hypertension

What is the most frequent cause of clinical subarachnoid hemorrhage (SAH)? 

Berry Aneurysms (a.k.a Rupture saccular aneurysms)

What is the most frequent cause of non-clinical subarachnoid hemorrhage (SAH)? 

TRAUMA 

Where do saccular (berry) aneurysms most usually develop? 

In points of bifurcation in the wall of a congenitally defective major cerebral artery or branches 

What is the vessel defect in a saccular (berry) aneurysm? 

absence of the elastica and media, muscular layer --> outpouching into round, thin-wall structure (like a balloon :)

What is the most common site of a berry aneurysm? 

Anterior communicating artery 

Fusiform Aneurysm 

assoc. w/ atherosclerosis w/ frequen involv. of the basilar artery 

Mycotic Aneurysm 

 Results from secondary infection of arterial wall --> wall wkended & ruptures

(NOT specific to fungal infections)

Dissecting Aneurysm 

What kind of vascular malformation do telangiectasias and hemangiomas fall under? 

small vessel or capillary malformation 

What kind of vascular malformation do arteriovenous (AV) and venous malformation fall under?

Large vessel malformations

What kind of vessels do arteriovenous (AV) malformations have?  

arteries and veins (duh!); vessels can be identified as arteries based on the presence of elastic layer. 

Foix-Alajouaine Dz

Spinal Cord Venous malformation, frequently in lower lumbar area --> lesion compress spinal cord tissue --> compression atrophy, ischemia and myelomalacia