Raised intracranial pressure - Definition - Causes

CSF pressure above 200mm H2O Causes: - Hydrocephalus - Intracranial space occupying lesion [neoplasm, bleed, abscess] - Cerebral oedema [e.g in hypoxia, injury, trauma] Consequence= herniation

Vascular brain injury causes [include vessels involved] - Extradural - Subdural - Subarachnoid - Intraparenchymal

Extradural bleed - Severe trauma with arterial laceration - Middle meningeal artery Subdural - Trauma minor in atrophy - Caused by ruptured vein [bridging vein] - Seen in old age Subarachnoid - Rupture of saccular aneurysm in circle of willis Intraparenchymal - Bleeding into the brain, from BV inside the brain. - Hypertension

Glioma- neoplasm of glial cells Examples - Astrocytoma - Oligodendroglioma - Glioblastoma [very malignant]

Inflammation of the brain Viral causes: - Herpes simplex - CMV - HIV

Spinocerebellar degenerative diseases - Definition - Symptoms

Accumulation of protein aggregates---> loss of cellular then CNS function Symptoms: - Dementia - Personality changes - Language disturbance - Paralysis - Movement distrubance

Neuropathology Flashcards by aderonke adesanoye

Role of CSF

Transport of metabolites

Cushions the brain and spinal cord

Immune regulation and defence

Auto regulation of blood flow to the brain

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Circulation of CSF

[500ml a day circulates]

Lateral ventricle-[Foramen of Monro]—> Third ventricle
[Cerebral aqueduct]

Fourth ventricle–[Foramen of Luschka/ Magendie]–> Cisterna magna

Ascends over cerebellum and cerebral hemispher–[arachnoid granulation]–> Superior sagittal sinus

Ascends ventral subarachnoid space—> Over cerebral hemisphere—> arachnoid granulation…

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Hydrocephalus Ex vacuo

Enlargement of ventricles and subarachnoid space due to shrinking of brain tissue.

Occurs in dementia

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Raised intracranial pressure

Definition
Causes

CSF pressure above 200mm H2O

Causes:

Hydrocephalus
Intracranial space occupying lesion [neoplasm, bleed, abscess]
Cerebral oedema [e.g in hypoxia, injury, trauma]

Consequence= herniation

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Herniations

- Different types

Subfalcine
- Cingulate gyrus dispace under the free edge of the falx cerebri

Central/ transtentorial
- Cerebral hemisphere tissue pushed through tentorium cerebelli

Tonsillar/ cerebellar

Cerebellar tissue pushed through foramen magnum
Can compress the medulla and cause breathing and cardiac impairments.

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Duret haemorrhages

Small linear bleeds in the midbrain and upper pons.

- Caused by tonsillar herniation—> compression in medulla oblongata

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Examples of space occupying lesions

Haemorrhages:

Extradural
Subdural
Subarachnoid
Intracerebral

Oedema + haemorrhage [from ischemic infarct]

Neoplasm
Abscess

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Vascular brain injury causes [include vessels involved]

Extradural
Subdural
Subarachnoid
Intraparenchymal

Extradural bleed

Severe trauma with arterial laceration
Middle meningeal artery

Subdural

Trauma minor in atrophy
Caused by ruptured vein [bridging vein]
Seen in old age

Subarachnoid
- Rupture of saccular aneurysm in circle of willis

Intraparenchymal

Bleeding into the brain, from BV inside the brain.
Hypertension

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Saccular aneurysm

Known as ‘berry aneurysm’
- Most common type of intracranial aneurysm

Can lead to subarachnoid haemorrhage if it ruptures

Vessels affected:

Anterior communicating [40%, most common]
Middle cerebral
Internal carotid
Tip of basilar

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Cerebral oedema

- Causes

Vasogenic
- Increased vascular permeability

Cytotoxic
- Neuronal, glial/ endothelial cell damage

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Global vs focal ischemia

Global- Includes wide range of brain tissue

Hypoxia [low O2 in blood]
Can still preserve brain if kept cold

Focal

Localised to brain tissue
Obstruction of blood flow
More dangerous

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Hemorrhagic vs ischemic cerebral infarction

Haemorrhagic

Red blood cell in infarcted tissue
Caused by emboli
Petechial (small bleeds) lesions [ from bone marrow emboli]

Ischemic

Lack of blood flow= infarction
Caused by thrombosis

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Histology of ischemic infarcts

ACUTE NEURONAL INJURY

Pyknosis [irreversible condensation of chromatin] in nucleus of neurones

Red neurones

Shrunken cell bodies

Loss of nucleoli

Eosinophilia [increased eosinophils] of cytoplasm

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Glioma examples

Glioma- neoplasm of glial cells

Examples

Astrocytoma
Oligodendroglioma
Glioblastoma [very malignant]

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Neoplasm of the brain example

[25% are metastatic]

Gliomas

Ganglion cell tumours- neural tumours

Meningiomas

Medulloblastoma [poorly differentiated]

Primary CNS lymphona

Peripheral nerve tumours

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Peripheral nerve tumours example

Schwanoma - Schwann cells

Neurofibroma [nerve cell tumour]

MPNST [malignant peripheral sheath tumour]

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Encephalitis

Inflammation of the brain

Viral causes:

Herpes simplex
CMV
HIV

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Examples of parasitic infection of the brain

Toxoplasmosis

Cyscticerosis

-Localised infections

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Spinocerebellar degenerative diseases

Definition
Symptoms

Accumulation of protein aggregates—> loss of cellular then CNS function

Symptoms:

Dementia
Personality changes
Language disturbance
Paralysis
Movement distrubance

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Prion disease

Progressive neurodegenerative condition

Example:
CJD [Creutzfeldt-Jakob]

Consequences of head trauma

Skull fracture

Contusion [bruise]
Laceration
Diffuse axonal injury [widespread lesion in white matter]

Vascular injury

Coup and contrecoup head injury

Coup- Injury of the brain occurs under the site of impact
- stationary head striking moving object.

Contrecoup

Injury occurs in the opposite site of where head was hit.
e.g moving head hitting a stationary object

Hydrocephalus

Causes
Clinical differences

Obstruction of CSF flow

Impaired arachnoid granulation absorption

Dementia- shrinking of brain tissue

Over production of CSF [rare]

Clinical classification

Communicating [or obstructive]
Non-communicating

Concussion

Clinical term used to describe symptoms associated head trauma

Spinal cord injury

C4 injury and above - May paralyse the diaphragm [C3-5 innervation] C4 injury below - Quadriplegia Thoracic spine injury - Paraplegia

Berry aneurysm risk factors - Lifestyle - Acquired conditions - Genetic

Lifestyle - Hypetension - Obesity - Smoking - Excessive alcohol Acquired conditions - Head trauma - Infections Genetics: - Marfan's syndrome - Autosomal dominant polycystic kidney disease - Ehlers-Danlos syndrome - Inherited hemorrhagic telangiectasia

Extradural bleed

Haemorrhage between the periosteum and periosteal dura mater. Causes: - ARTERIAL laceration from severe head trauma - Most likely of middle meningeal artery

Treatment of berry aneurysm

If ruptured - Decrease intracranial pressure [i.e craniotomy] - Restoration of respiration Prevention of rupture - Surgical clipping [craniotomy required] - Endovascular coiling [endovascular approach, radiology]

Subdural haemorrhage

Haemorrhage between the meningeal dura layer and arachnoid layer. Causes: - Ruptured bridging vein - Head trauma minor in atrophy - Shaken baby syndrome Risk factors: - Old age [more brittle veins and larger subdural space] - Infants [ larger subdural space] - Blood thinners - Dementia - Long-term alcohol use

Subarachnoid bleed

Hematoma between the subarachnoid matter and pia mater [subarachnoid space] Cause: - Rupture of saccular aneurysm in the Circle of Willis

Intraparenchymal bleed - Mechanism - Causes [9]

Haemorrhage into the neural parenchyma - Caused by rupture of small vessels within the brain - Can be accompanied with oedema Causes: - Hypertension - Sickle cell disease - Arteriovenous malformation - Amyloid deposits - Intracranial neoplasm - Coagulopathy - Infection - Vasculitis - Trauma

Cauda equina syndrome - Definition - Symptoms [7] - Causes [6]

Set of symptoms due to damage/compression of spinal cord below the cauda equina [end of spinal cord] Symptoms: - Severe back pain - Saddle anesthesia - Bladder and bowel dysfunction----> decreased tone of the urinary and anal sphincters. - Urinary retention---> Detrusor weaknesses - Weakness of the muscles of the lower legs (often paraplegia) - Sexual dysfunction - Absent anal reflex Cause: - Disc herniation in the lower region of the back. - Spinal stenosis - Neoplasm - Epidural abscess - Epidural hematoma - Trauma

Spine tumours

Primary - Tumour originated in spinal tissue Secondary - Metastatic - Originated from cancers, common to spread to bone - Breast, thyroid, prostate, lung [bronchi], myeloma Can compress spinal cord or spinal nerves

Spinal abscess

Caused by infection - Can be caused by IV drug use - Can destroy spinal disc Bacterial - S. aureus - TB - Meningitis Fungal

Causative agent of meningitis in the elderly [4]

Streptococcus pneumoniae Meningococcus Listeria monocytogenes

Causative agent of meningitis in newborns

Escherichia coli | Group B streptococci

Causative agent of meningitis in children

Streptococcus pneumoniae Meningococcus Haemophilus

Viral causative agents of meningitis

HIV HSV VZV CMV Enterovirus

Fungal causative agents of meningitis

Candida Crytococcus neoformans Histoplasma

Parasitic causative agents of meningitis

Angiostrongylus Schistosoma, Toxocariasis Schistosoma Cysticerosis

Signs and symptoms of meningitis

Stiff neck Vomiting Confusion Photophobia Butterfly rash- does not blanche under pressure.

Investigations for meningitis

Lumbar puncture [except when intracranial pressure is high, due to tonsillar herniation risk] - Cloudy CSF - Increased protein levels [viral] - Increased WBC count [bacterial] - Decreased glucose levels CT/MRI done before lumbar puncture to check ICP.

Meningitis risk factors

IV drug use Cerebral shunt Cochlear implant Young children- developmental abnormalities Skull trauma, allowing nasal cavity bacteria to enter CSF space

Non-infections causative agents of meningitis [5]

Drug interactions: - Antibiotics - Immunoglobulins - NSAIDs Sarcoidosis Malignant/metastatic Lupus erythematosus Vasculitis

Bacterial causative agents of meningitis for adults

Meningococcus [N.meningitides] | Step. pneumoniae

Causative agents for meningitis in the immunosuppressed

Meningococcus Step. pneumoniae Listeria monocytogenes virus, TB, fungi

Risk factors for spinal S.aureus abscess [5]

Skin abcess Septicaemia/ bacteraemia Back injury/ trauma Lumbar puncture Surgery

Intraparenchymal haemorrhage risk factors [6]

Age, >60 Hypertension System coagulopathies Vuscular malformations Vasculitis Cerebral amyloid angiopathy

Complications of subarachnoid haemorrhage

Acute: - Vasospasm= focal/global ischaemia Late: - Hydrocephalus due to scarring and CSF obstruction.