202 Neuropathology 2023-24 MKoenig - Tagged.pdf

Neuropathology Micha Koenig MD Brighton and Sussex Medical School 202 2023/24 [email protected] learning objectives Histology of the neural tissues Cerebrospinal fluid circulation and increased intracranial pressure Traumatic intracranial injury (esp. vascular injury) Stroke Neoplasms Infect...

Neuropathology Micha Koenig MD Brighton and Sussex Medical School 202 2023/24 [email protected] learning objectives Histology of the neural tissues Cerebrospinal fluid circulation and increased intracranial pressure Traumatic intracranial injury (esp. vascular injury) Stroke Neoplasms Infections [email protected] 2 histology Neurons Glia Nuclei or ganglia (e.g. basal ganglia) Columns or layers (e.g. cortex) Structural and metabolic functions Astrocytes (metabolism) Oligodendrocytes (structure) Ependyma (lining of fluid compartments) Microglia (monocyte-lineage population) Meninges Blood vessels [email protected] 3 Ependymal cells histology Astrocyte Neuron (cell body) Neuron (axon) Oligodendrocyte Myelin sheath Microglial cell Capillary vessel [email protected] 4 meninges [email protected] 5 cerebrospinal fluid Normal volume 150ml Production by choroid plexus in the lateral ventricles (450ml per 24h) Resorption by arachnoid granulations in the subarachnoid space venous system Metabolic importance Cushioning of the CNS Role in immune regulation and defense Cerebral autoregulation of blood flow [email protected] 6 CSF circulation and ventricular system [email protected] 7 CSF circulation and ventricular system [email protected] 8 expanded ventricular system / hydrocephalus Obstruction to CSF flow Impaired resorption at arachnoid granulations Shrinking of brain tissue (e.g. dementias) = ex vacuo Very rarely overproduction Communicating = obstruction at arachnoid granulations Non-communicating = obstruction before the lateral and median apertures Robbins and Cotran Pathologic Basis of Disease, 2015, Fig 28-2. [email protected] 9 Hydrocephalus occurring Before fusion of the cranial sutures causes enlargement of the head circumference. https://upload.wikimedia.org/wikipedia/commons/3/3c/ Vimont_Traite_de_Phrenologie_022.jpg [email protected] raised intracranial pressure Mean CSF pressure above 200mm H2O - increased CSF volume Obstruction of CSF flow (infection, inflammation, neoplasm, trauma, congenital) Intracranial space occupying lesion (neoplasm, haemorrhage, abscess) Cerebral oedema [email protected] 11 raised intracranial pressure consequences - herniation Subfalcial (cingulate) Central/transtentorial Tonsillar/cerebellar Tonsillar/cerebellar herniation may cause compression of the medulla with impairment of cardiorespiratory centres. Robbins and Cotran Pathologic Basis of Disease, 2015, Fig 28-3. [email protected] 12 tonsillar herniation at autopsy Coning herniation and compression of the medulla oblongata Duret haemorrhages Ref: XTwitter @BrainsSlicer 8 Oct 20 8:50 [email protected] 13 tonsillar herniation at autopsy Coning herniation and compression of the medulla oblongata Duret haemorrhages Robbins and Cotran Pathologic Basis of Disease, 2015, Fig 28-4. [email protected] 14 subfalcine and transtentorial herniation Glioblastoma tumour in the left hemisphere [email protected] 15 [email protected] 16 cerebral oedema Vasogenic Cytotoxic Increased vascular permeability e.g. trauma Neuronal, glial or endothelial cell damage e.g. infection [email protected] 17 space occupying lesions Extradural/epidural haemorrhage Subdural haemorrhage Subarachnoid haemorrhage Intracerebral haemorrhage Ischaemic infarct with subsequent oedema or haemorrhage Neoplasm Abscess [email protected] 18 mechanics of head trauma Skull fracture Parenchymal injury Contusion (bruising) Concussion is a clinical term/syndrome Laceration (penetration or tearing) Diffuse axonal injury Coup and contrecoup Vascular injury https://commons.wikimedia.org/w/index.php? curid=71496323 [email protected] 19 coup and contrecoup Coup / blow Stationary head Impact results in a contusion/bruise in the contact area Impact onto a stationary head does not necessarily produce a contrecoup injury because the brain has no inertia at the time of impact. BUT: Impact onto a stationary head may produce a contrecoup injury if the impact force is strong enough. [email protected] Contrecoup / counterblow Moving head Brain inertia rebounds (‘sloshes’) the brain into the opposite direction where it hits the other side of the cranium resulting in a second contusion/bruise 20 vascular injury Extradural Severe trauma with arterial laceration Subdural Subarachnoid Intracerebral Trauma may be minor in atrophy (bridging veins) Rupture of saccular (berry) aneurysm (circle of Willis) artery) (medial meningeal (hypertension) Robbins and Cotran Pathologic Basis of Disease, 2015, Fig 28-10. [email protected] 21 extradural haematoma arrow: middle meningeal artery groove [email protected] 22 extradural - subdural haemorrhage/haematoma Robbins and Cotran Pathologic Basis of Disease, 2015, Fig 28-11. [email protected] 23 subarachnoid haemorrhage Robbins and Cotran Pathologic Basis of Disease, 2015, Fig 28-19. [email protected] 24 subarachnoid haemorrhage ruptured berry aneurysm [email protected] 25 intraventricular/intracerebral haemorrhage http://neuropathology-web.org/chapter2/chapter2cCerebralhemorrhage.html [email protected] 26 [email protected] 27 cerebral infarction / stroke 15% of cardiac output 20% of O2 demand Stroke = sudden onset of neurological symptoms Hypoxia vs ischaemia (global vs focal) Neurons are the most O2 sensitive cells Haemorrhagic infarction in emboli (petechial lesions e.g. bacterial meningitis, sepsis) Ischaemic infarction (liquefactive necrosis) in thrombosis or vasospasm [email protected] Robbins and Cotran Pathologic Basis of Disease, 2015, Fig 28-14. 28 [email protected] 29 Ischaemic infarct- liquefactive necrosis [email protected] 30 [email protected] 31 cerebral infarct / stroke histology Acute neuronal injury ‘Red neurons’ Pyknosis of nucleus Shrinkage of the cell body Loss of nucleoli Intense eosinophilia of cytoplasm Liquefactive necrosis Owing to irreversible hypoxic/ischaemic insult [email protected] 32 old stroke area with cyst formation [email protected] 33 CNS/PNS neoplasms Approx. 75% primary (hence 25% metastatic) 20% of malignant childhood tumours are located in the CNS Gliomas (astrocytoma, oligodendroglioma, glioblastoma) Neural tumours (ganglion cell tumours) Meningiomas Poorly differentiated neoplasms (medulloblastoma) Primary CNS lymphoma Metastasis (lung, breast, skin/melanoma, kidney, GI tract) Peripheral nerve sheath tumours (schwannoma, neurofibroma, MPNST) [email protected] 34 [email protected] Robbins and Cotran Pathologic Basis of Disease, 2015, Fig 28-28. 35 a meningioma can be very dangerous meningioma obstructing the foramen magnum with medulla and cord compression [email protected] 36 glioblastoma [email protected] 37 infections Meningitis Abscess Encephalitis Localised bacterial (acute or chronic) viral fungal mycobacterial neurosyphilis, lyme disease, malaria Usually bacterial Viral (HSV, CMV, HIV, JC polyoma virus) Toxoplasmosis, cysticercosis [email protected] 38 Bacterial meningitis at pm (streptococcus pneumoniae) [email protected] 39 [email protected] 40 [email protected] 41 toxoplasmosis [email protected] 42 questions? 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