6Cerebral Herniation Complication of Intracranial Hypertension Tonsillar herniationCerebellar tonsils herniate into the foramen magnum.Causes "coning" of the cerebellar tonsilsProduces cardiorespiratory arrestComa and Death
7It can occur as an complication of Lumber Puncture
8Complications of Tonsillar Herniation & Increased ICP Hemorrhagic lesion of the mid Brain and Pons : Secondary Brain stem or Duret hemorrhageLinear hemorrhage
9Duret hemorrhage: pathogenesis Kinking of the penetrating median and paramedian pontine arteries that branch off the basilar artery.
22SyringomyeliaNote the collapsed cystic cavity (syrinx) in the center of the cervical spinal cord22
23Brain contusionThe contrecoup injury involves the frontal and temporal lobes (left arrows)The coup lesion (site of impact) involves the cerebellum (right arrow).23
24Epidural and Subdural Hematoma A, Schematic of epidural hematoma and subdural hematoma. B, Epidural hematoma. Note the blood is located on top of the dura (arrow). C, Subdural hematoma. The reflected dura shows the outer membrane of an organized venous clot covering the convexity of the brain.2424
25Red NeuronRed neurons. Note the brightly eosinophilic staining cells with the pyknotic nuclei within spaces representing apoptotic neurons.2525
26Border zone infarct: Watershed infarct : Follows a Hypotensive episode. Lesion lies at the boundary between the anterior and middle cerebral artery territories.
28Amaurosis fugaxCholesterol embolus to retinal artery. Note the yellow embolus trapped at the bifurcation of the retinal artery (arrow). This produces a sudden, painless loss of vision ("curtain coming down") followed in a variable period of time by restoration of vision ("curtain coming up") as the embolus dislodges. This is called amaurosis fugax.2828
29Embolic StrokeEmbolic stroke showing a wedge-shaped hemorrhagic infarction (arrow) along the periphery of the cerebral cortex in the distribution of the middle cerebral artery. It is hemorrhagic because blood flow was reestablished when the embolus dislodged and converted a pale infarct to a hemorrhagic infarct.2929
30Intracerebral Hemorrhage Intracerebral hemorrhage, showing a large blood clot within the basal ganglia area of the brain.3030
32Subarachnoid Hemorrhage Subarachnoid hemorrhage. Note the presence of blood covering the surface of the brain.3232
33Lacunar InfarctsThe arrows show multiple small cystic spaces (liquefactive necrosis) that are most prominent in the basal ganglia. Sections under these lesions showed hyaline arteriolosclerosis.The arrows show multiple small cystic spaces (liquefactive necrosis) that are most prominent in the basal ganglia.3333
34Lacunar infarctsCause : Chronic hypertensionSite: The pons.
36Microscopically, a neutrophilic exudate is seen involving the meninges
37Bacterial infections. A, Pyogenic meningitis Bacterial infections. A, Pyogenic meningitis. A thick layer of suppurative exudate covers the brain stem and cerebellum, and thickens the leptomeninges. B, Cerebral abscesses in the frontal white matter (arrows). (A, From Golden JA, Louis DN: Images in clinical medicine: acute bacterial meningitis.
38Mechanism for the conversion of PrPc through protein-protein interactions. The initiating molecules of PrPsc may arise through inoculation (as in directly transmitted cases) or through an extremely low-rate spontaneous conformational change. The effect of the mutations in PrPc is to increase the rate of the conformational change once PrPsc is able to recruit and convert other molecules of PrPc into the abnormal form of the protein. Although the model is drawn with no other proteins involved, it is possible that other proteins play critical roles in the conversion of Prpc to PrPsc.
39Spongiform encephalopathy of gray matter : brain lesion in CJD
40Complications: sequel Edema can lead to herniation and death.Communicating hydrocephalous.
41Meningeal Syphilis 1 of 2Neurosyphilis is a tertiary stage of syphilis – only in 10% with untreated syphilisMay involve spinal Meninges: produce thickening.Produce meningeal fibrosis and secondary Hydrocephalous.