Lecture 12 - Neuropathology Flashcards
What can maintained increased intracranial pressure cause?
Destruction of brain tissue
Displacement of midline structures
Brain shifts
Cerebral oedema
What are some compensatory mechanisms for regulating normal intracranially pressure?
Reduce venous blood volume
Reduce CSF volume
Brain atrophy
What is the normal intracranial pressure?
What pressure can coughing and straining lead to?
Normal = 0-10mmHg
Inc = max of 20mmHg
What can cause raised intracranial pressure?
Haematoma / Haeamorrhages
Tumours
Space occupying lesions
Cerebral oedema
Infections
How does a brain appear with cerebral oedema?
Loss of sulci
Widening of gyro
What is a subfalcine herniation?
The herniation of cingulate gyrus under the falx cerebri
What consequences can a subfalcine herniation cause on the brain?
Infarction of medial parts of frontal or parietal lobes or the corpus callosum
Why can a subfalcine herniation cause ischaemia of the corpus callosum?
Compression of the anterior cerebral artery
What is a Transtentorial herniation? (uncal herniation)
Herniation of medial part of the temporal lobe (uncus) into the tentorium cerebelli
What is a tonsillar herniation?
Cerebellar tonsils herniates through the Foramen magnum
Label slide 6 on herniations
In slide 7, what is the structure that is being compressed in this subfalcine herniation?
Lateral ventricle
What Cranial Nerve is most commonly damaged in an uncal herniation (trans-tentorial herniation)?
Occulomotor nerve (CN III)
What blood vessels can be occluded in a trans-tentorial herniation (uncal herniation)?
Posterior cerebral and superior cerebellar arteries causing ischaemia
What is a duret haemorrhage?
Secondary haemorrhage down into the brainstem from a transtentorial (uncal) haemorrhage
What is the consequence of tonsillar herniation (cerebellar tonsils)?
Pushed into Foramen magnum compressing brainstem
What are the 3 dural layers?
Dura mater
Arachnoid mater
Pia mater
Go to slide 11 and label the image
What blood vessel is normally ruptured leading to an extra dural haemorrhage?
Middle meningeal artery
What bone does the middle meningeal artery run behind?
Pterion
Where does blood accumulate in an Extradural haemorrhage?
Between the skull and the dura mater
How does the middle meningeal artery enter into the skull??
Foramen spinosum
What does the middle meningeal artery branch from?
Branches from maxillary artery
Which branches from external carotid artery
How does an extra dural haemorrhage present?
Lucid interval (hrs when fine) which then leads to drowsiness then neurological deficits
What causes a subdural haemorrhage?
What layers does the blood accumulate between?
The shearing of bridging veins (venous blood) on the way to the dural venous sinuses (likely the superior Sagittal sinus)
Between the dura mater and arachnoid mater
What causes acute subdural Haematoma?
Trauma leading to rapid blood accumulation
Who often have chronic subdural Haematoma and why?
Elderly and chronic alcoholics
Brain atrophy leading to increased tension on the bridging veins
How do subdural Haematomas present?
Assaults
Falls
RTCs
Minor head injuries (elderly)
Have to be careful of anticoagulant therapy or liver cirrhosis.
How do subdural haemorrhages appear on CT head?
Banana shape
(Branching Banana)
What is the cause of a subarachnoid haemorrhage?
Shearing of meningeal blood vessels
Usually caused by basal skull fractures and contusions
What is a contusion?
Brain bruises
What are some spontaneous causes of a subarachnoid haemorrhage?
Ruptured berry aneurysm
Amyloid angiography
Vertebral artery. Dissection
Arteriovenous malformation
Where does blood accumulate in a subarachnoid haemorrhage?
In the subarachnoid space where CSF is
Blood forced into subarachnoid space
What are the symptoms of a subarachnoid haemorrhage?
Sudden onset headache (worst ever/thunderclap headache)
Rapid neurological deterioration
Sudden collapse
What part of circulation do subarachnoid haemorrhages occur in due to a berry aneurysm?
Anterior circulation of circle of Willis
What conditions increase the risk of forming berry aneurysms in the circle of Willis?
Erhrlos Danlos syndrome (connective tissue)
Polycystic kidney disease
What is a stroke?
Sudden event producing a disturbance of CNS function due to vascular disease
What are the 2 categories of stroke?
Ischaemic stroke
Haemorrhagic stroke
What are the 2 types of ischaemic stroke?
Thrombotic occlusion
Embolic occlusion
What are the 2 types of haemorrhagic stroke?
Intracerebral haemorrhage
Subarachnoid haemorrhage