CNS Pathology I Flashcards
What are the major clinical presentations of raised intracranial pressure (ICP)?
Nausea, headache, and altered consciousness.
What are the two main processes involved in cerebrovascular disease?
Ischaemia (hypoxia) and haemorrhage.
What is the definition of a stroke?
Neurologic signs and symptoms explained by a vascular mechanism, with acute onset and lasting beyond 24 hours.
What are the causes of non-communicating hydrocephalus?
Obstruction between the ventricular and subarachnoid space due to space-occupying lesions, congenital malformations (e.g., Arnold-Chiari malformation), or mass lesions like tumors.
What are the common clinical symptoms of raised ICP?
Vomiting, nausea, headache, papilledema, and possibly cerebral herniation leading to life-threatening conditions.
How does hypertension affect cerebrovascular health?
Hypertension can lead to lacunar infarcts, hypertensive encephalopathy, and hypertensive intracerebral hemorrhage.
What is the typical cause of intracerebral haemorrhage in younger patients?
Ruptured arteriovenous malformation (AVM).
What is the key clinical sign of a subarachnoid hemorrhage?
Sudden, severe “thunderclap” headache.
What is the pathogenesis of raised intracranial pressure (ICP)?
Increased intracranial volume due to fluid (cerebral edema, hydrocephalus) or tissue (space-occupying lesions like tumors or hemorrhages).
What are the two types of hydrocephalus?
Non-communicating (obstruction between ventricles and subarachnoid space) and communicating (defective absorption, overproduction, or venous drainage insufficiency).
What is cerebral herniation and its most dangerous form?
Displacement of part of the brain into another compartment due to increased ICP. The most dangerous form is tonsillar herniation (“coning”), which can lead to cardiorespiratory arrest.
What is a lacunar infarct and its common location?
A small infarct (<15mm) due to occlusion of deep penetrating arteries or arterioles, commonly found in the basal ganglia, internal capsule, thalamus, or pons.
What are the two types of cerebral infarctions?
Pale/Non-haemorrhagic infarcts and Red/Haemorrhagic infarcts, which require different treatments (thrombolytics are avoided in haemorrhagic infarcts).
What is a “watershed infarct” and what causes it?
A type of infarction that occurs in the regions between major arteries (e.g., between MCA and ACA), caused by global hypoperfusion, such as in cardiac arrest or shock.
What are the characteristic microscopic changes in a brain infarction over time?
12 hours: Ischaemic neuronal change (red neurons)
24-48 hours: Neutrophil infiltration
2 days: Macrophages
1-3 weeks: Reactive gliosis and liquefactive necrosis.
What is Charcot-Bouchard aneurysm and its association with intracerebral hemorrhage?
Small aneurysms in the deep brain structures (e.g., basal ganglia) often caused by chronic hypertension, leading to intracerebral hemorrhage.
What are the primary causes of subarachnoid hemorrhage?
Ruptured saccular (berry) aneurysms, often located in the Circle of Willis, or ruptured arteriovenous malformations (AVMs).
What imaging feature distinguishes an epidural hematoma?
A biconvex (lenticular) appearance on a CT scan, often caused by the laceration of the middle meningeal artery following trauma.
What is the clinical presentation of hypertensive encephalopathy?
Acute hypertensive encephalopathy presents with diffuse cerebral dysfunction, headaches, confusion, convulsions, and can progress to coma if ICP increases.
What differentiates subdural from epidural hemorrhage?
Subdural hemorrhage is typically caused by tearing of bridging veins (due to acceleration-deceleration injuries), while epidural hemorrhage is caused by arterial injury (e.g., middle meningeal artery), often with a lucid interval followed by rapid deterioration.
