Pathology Flashcards
What is normal intra cranial pressure?
0-10mmHg
Value of raised intracranial pressure
20mmHg
What is subfalcine herniation?
Herniation of cingulate gyrus under falx cerebri
What is a transtentorial herniation?
Herniation of medial temporal lobe (uncus) through tentorial notch (uncal herniation)
What is a tonsilliar herniation?
Herniation of cerebellar tonsils through foramen magnum (coning)
What is at risk in a uncal/transtenorial herniation?
Oculomotor nerve
Posterior cerebral artery
Superior cerebellar arteries
What is a duret haemorrhage?
Secondary haemorrhage into brainstem due to downwards displacement of brain
What is an extra dural haemorrhage between?
Inner table to periosteum + dura mater
What vessel is damaged in an extra dural haemorrhage?
Middle meningeal artery
What is a sub dural haemorrhage between?
Dura mater + arachnoid mater
What vessel is damaged in subdural haemorrhage?
Bridging veins
Categories of subdural haemorrhage + causes
- acute: trauma > rapid accumulation of blood
- chronic: elderly + chronic alcoholics (atrophy of brain)
Categories of subarachnoid haemorrhages + causes
- traumatic: basal skull fractures + contusions
- spontaneous: ruptured berry aneurysm, amyloid angioplasty, vertebral artery dissection, arteriovenous malformation
What are contusions?
Brain bruising
What is the most common cause of subarachnoid haemorrhage?
Ruptured berry aneurysm
What is the most common location of berry aneurysm?
Anterior cerebral artery
Who are subarachnoid haemorrhages more common in?
- Connective tissue disorders e.g. ehlers danlos syndrome
- polycystic kidney disease
Risk factor for a stroke
Hyperlipidaemia
Hypertension
Diabetes mellitus
Two categories of strokes
Ischaemic (cerebral infarct) (most common)
Haemorrhagic
What can ischaemic strokes be caused by?
Thrombotic occulsion
Embolic occulsion (most common)
What type of necrosis do you get in the brain?
Coagulative necrosis (wedge shaped)
What vessel is most affected in stroke caused by embolic occulsion?
Middle cerebral artery
Direct extension of ICA
What is the most common type of stroke?
Embolic occlusion ischaemic stroke
Common sites of strokes due to isachemic stroke
Carotid bifurcation
Basilar artery
Origin of middle cerebral artery
Common causes of spontaneous intra cerebral haemorrhage (stroke)
- Hypertension (most common)
- cerebral amyloid angiopathy
- arteriovenous + cavernous malformations
- tumours
Most common cause of spontaneous intracerebral haemorrhage
Hypertension > rupture of small intraparenchymal blood vessels
Common sites affected in spontaneous intracerebral haemorrhage
Basal ganglia
Thalamus
Pons
Cerebellum
What is cerebral amyloid angiopathy?
Amyloid deposition in walls of small + medium sized meningeal + cortical vessels
Difference between hypertensive + cerebral amyloid angiopathy stroke
- hypertension: deeper within the brain
- CAA: lobar
What are cavernous malformations?
Where are they commonly?
- Loose vascular channels with are distended + thin walled
- Cerebellum + pons
What are arteriovenous malformations
Wormlike (tangled) vascular channels
Types of primary CNS tumours
- gliomas
- parenchymal
- meningeal
- neuronal
- poorly differentiated - medulloblastoma
What are secondary CNS tumours?
Tumours which have metastasised from elsewhere
Types of gliomas tumours
- astrocytic tumours (most common - astrocytoma)
- glioblastoma multiforme
- olgiodendrogliomas
- ependyomas
- colloid cysts of 3rd ventricle
What are ependymomas?
Tumours of brain ventricles
Are gliomas benign or malignant?
Malignant
Where do germ cell tumours arise in the CNS
Midline tumours
Pineal
Suprasellar
Are meingiomas benign or malignant?
Benign
How can microbes enter the CNS?
- direct local spread: air sinuses, skull fractures, infected teeth, middle ear infections
- haematogenous: arterial blood, retrograde venous between face + skull
- iatrogenic: lumbar puncture, VP shunts
- peripheral nerves: herpes zoster virus
What can infections of the CNS affect?
Meninges
Aggregates of acute inflammation
Brain parenchyma
What is meningitis?
Inflammation of leptomeninges
Types of meningitis
- acute pyogenic (bacteria)
- aseptic (viral)
- chronic (mycobacterium TB, fungi)
- carinomastosis
Symptoms of meningitis
- headache
- photophobia
- stiff neck
- non blanching rash
- altered consciousness
What is encephalitis?
Infection of brain parenchyma
Examples of viral causes of encephalitis + where they effect
- herpes zoster virus: temporal lobe
- polio: spinal cord motor neurones
- rabies: brain stem
What is prion disease?
Abnormal cellular protein accumulation > cell injury > neurone cell death | synapse loss | microvasculations
Types of causes of prion disease
Sporadic
Familial
Iatrogenic
Types of prion disease
- Creutzfeldt-Jakob disease
- Scrapies
- Bovine spongiform encephalopathy (mad cow disease)
Mechanism of prion disease
- Mutation of protein > conformational change
- change from a helix to B pleated sheet
- abnormal protein is more resistance to proteolysis
+ harder to get rid of - causes normal proteins to undergo conformational change > both become abnormal
Why is prion disease classified as infective?
Abnormal protein can cause normal proteins to undergo conformational change > more abnormal proteins
Outline creutzfeld Jakob disease
- familial
- > 70 years old
- rapidly progressive dementive illness
- subtle changes in memory
- cerebellar ataxis + global dementia
Definitive diagnosis of creutzfeld Jakob disease
Post mortem examination
Presentation of creutzfeld Jakob disease
Dementia
Early neurological signs
Outline variant creutzfeld Jakob disease
- young adults
- slower progression to CKD
- starts with behavioural issues
- due to exposure to prion disease in cattle BSE
Presentation of variant creutzfeld Jakob disease
- behavioural issues
- painful dyesthesiasis
- delayed neurological signs
What is dysesthesia?
Abnormal physical touch sensation without outside cause
