Stroke Pathophysiology and Infarction Causes

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Questions and Answers

What type of infarction is primarily caused by the obstruction of a blood vessel due to a blood clot?

Global ischaemia

Thrombotic infarction (correct)

Lacunar infarction

Embolic infarction

Which type of infarction results from the obstruction of a blood vessel by a particle that travels through the bloodstream?

Global ischaemia

Thrombotic infarction

Embolic infarction (correct)

Lacunar infarction

What is the primary definition of a stroke?

A condition resulting from high blood pressure

A chronic disease affecting the muscles

A degenerative disease affecting the spinal cord

An abnormality of the brain of acute onset caused by a pathological process affecting blood vessels (correct)

Lacunar infarctions are most commonly associated with which of the following conditions?

Chronic hypertension Signup and view all the answers

Which of the following changes occur macroscopic in the first 12 to 24 hours after cerebral infarction?

None Signup and view all the answers

Global ischaemia primarily affects which aspect of the body?

Generalized blood flow reduction Signup and view all the answers

What microscopic feature is observed within 12 to 24 hours after a cerebral infarction?

Red neurons Signup and view all the answers

Which condition is characterized by a lack of oxygen to tissues due to reduced blood flow?

Hypoxia Signup and view all the answers

What type of haemorrhage is commonly associated with berry aneurysms?

Subarachnoid Signup and view all the answers

Which of the following is NOT a type of haemorrhage listed?

Extraparenchymal Signup and view all the answers

What happens to the edema in the brain 10 to 21 days after an infarction?

Oedema decreases Signup and view all the answers

What is the primary cause of an embolic infarction?

Air or fat particles in circulation Signup and view all the answers

During which phase of cerebral infarction does liquefaction primarily occur?

2 to 3 days Signup and view all the answers

Acute subdural haemorrhage is typically associated with which event?

Head injury Signup and view all the answers

What distinguishes lacunar infarctions from other types of infarctions?

They occur in small, penetrating arteries Signup and view all the answers

Which type of haemorrhage is primarily characterized by a slow onset of symptoms?

Chronic subdural Signup and view all the answers

The process of creating a thrombus leading to thrombotic infarction is often initiated by which factor?

Blood vessel injury Signup and view all the answers

Which molecular event is crucial in the pathophysiology of cerebral ischemia?

Lactic acidosis due to anaerobic metabolism Signup and view all the answers

Intracerebral haemorrhage most commonly occurs where?

Within the brain tissue Signup and view all the answers

What identifies the stage of infarction occurring months to years after the initial event?

Thickened meninges Signup and view all the answers

Which of the following is NOT a clinical feature of cerebral infarction?

Constant fever Signup and view all the answers

What is a common cause of extradural haemorrhage?

Blunt trauma Signup and view all the answers

Which haemorrhage type is primarily linked to acute events such as trauma?

Extradural Signup and view all the answers

Which of the following haemorrhage types is least likely to be recurrent?

Subarachnoid Signup and view all the answers

What is the most common form of dementia?

Alzheimer's disease Signup and view all the answers

What percentage of individuals over the age of 85 are affected by Alzheimer's disease?

50% Signup and view all the answers

How many people worldwide are currently diagnosed with Alzheimer's disease?

30 million Signup and view all the answers

Which of the following is NOT a common clinical sign of Alzheimer's disease?

Increased ICP Signup and view all the answers

What age group has a 10% prevalence of Alzheimer's disease?

Individuals over 65 Signup and view all the answers

Which pathology is most commonly associated with Alzheimer's disease?

Amyloid beta plaques Signup and view all the answers

Which demographic is MOST affected by Alzheimer's disease according to the provided data?

Individuals over 85 Signup and view all the answers

How many Australians are estimated to have Alzheimer's disease?

250,000 Signup and view all the answers

What is the first noticeable change in frontotemporal dementia?

Personality changes Signup and view all the answers

What is true regarding the diagnosis of frontotemporal dementia?

MMSE is important for diagnosis. Signup and view all the answers

What type of treatment is available for frontotemporal dementia?

Symptomatic treatment Signup and view all the answers

Which aspect of Parkinson's Disease is specifically addressed in the provided content?

Epidemiology Signup and view all the answers

What does the term 'Disease-Modifying' refer to in the context of treatments?

Interventions that alter the disease progression. Signup and view all the answers

Which of the following is NOT a characteristic of frontotemporal dementia?

Primarily affects cognitive functions before personality. Signup and view all the answers

What is the main limitation of the MMSE in diagnosing frontotemporal dementia?

It cannot assess personality changes. Signup and view all the answers

What do epidemiological studies of Parkinson's Disease typically explore?

Environmental influences on occurrence. Signup and view all the answers

Study Notes

Stroke

A stroke is an acute brain abnormality caused by a vascular process.
Infarction occurs when blood flow to an area of the brain is interrupted, causing brain tissue to die.
Causes of Infarction:
- Thrombotic infarction: A blood clot forms in a cerebral artery, blocking blood flow.
- Embolic infarction: A blood clot travels from another part of the body to the brain, blocking a cerebral artery.
- Lacunar infarction: A small infarct occurs in a deep brain structure, often caused by a blood clot in a small artery.
- Global injury: A widespread lack of oxygen and blood flow to the brain, often due to cardiac arrest or severe hypotension.
Clinical features of cerebral infarctions:
- Neurological deficits depend on the location and severity of the infarct.
- Common symptoms include weakness, paralysis, numbness, speech problems, and vision loss.
Evolution of Infarction:
- 12-24 hours: Microscopic changes like "Red Neurons" and a few neutrophils are visible.
- 2-3 days: A blurring of the grey/white matter junction, severe oedema, and liquefaction are visible macroscopically.
- 10-21 days: Oedema fades, and gliosis begins.
- Months to years: A thin-walled cyst formed, filled with glial fibres.
Molecular events in Cerebral Ischaemia:
- Depletion of oxygen and glucose, leading to reduced ATP production.
- Activation of ion channels, causing an influx of sodium and calcium, leading to cell swelling and neurotransmitter release.
- Release of free radicals, damaging cell membranes and increasing inflammation.
- Lactic acidosis due to anaerobic metabolism from ischaemia.
Haemorrhage occurs when a blood vessel in the brain ruptures, causing bleeding.
Types of Haemorrhage:
- Extradural: Bleeding between the skull and the dura mater, usually caused by a skull fracture that tears an artery.
- Subdural: Bleeding between the dura mater and the arachnoid mater, commonly caused by a tear in a vein.
- Subarachnoid: Bleeding within the subarachnoid space, often caused by a ruptured berry aneurysm.
- Intracerebral: Bleeding within the brain tissue itself, often due to hypertension, aneurysms, or trauma.

Neurodegenerative Diseases

Alzheimer's Disease (AD):
- Affects 30 million people worldwide, including 250,000 Australians.
- Accounts for 10% of people over 65 and 50% of those over 85.
- The most common cause of dementia.
- Pathophysiology:
  - Amyloid beta plaques: Abnormal protein fragments accumulate outside neurons.
  - Neurofibrillary tangles: Abnormal protein filaments (tau) accumulate inside neurons.
  - These accumulations disrupt brain function and lead to neuronal death.
- Clinical signs and symptoms:
  - Memory loss, confusion, disorientation, and difficulty with language and problem-solving.
  - Personality changes are often the first sign in frontotemporal dementia.
- Diagnosis:
  - Based on clinical assessment, history, and physical examination.
  - Mental status tests like the Mini-Mental State Examination (MMSE) are used.
- Treatment:
  - No cure, but medications help manage symptoms.
  - Disease-modifying therapies are being developed to slow or halt the progression of the disease.
Parkinson's Disease (PD):
- A chronic and progressive neurological disorder that affects movement.
- Epidemiology:
  - The prevalence of Parkinson's Disease is increasing, affecting approximately 1% of the population over the age of 60.
- Pathology:
  - Aetiology: The exact cause is unknown, but it's thought to be a combination of genetic and environmental factors.
  - Pathophysiology: Degeneration of dopamine-producing neurons in the substantia nigra, a region in the brain involved in movement control.
  - Clinical features:
    - Resting tremor: A rhythmic shaking of the limbs.
    - Bradykinesia: Slowness of movement.
    - Rigidity: Stiffness of muscles.
    - Postural instability: Difficulty maintaining balance.
- Treatment:
  - No cure, but medications can improve symptoms and quality of life.
  - Deep brain stimulation (DBS) can be used to treat severe motor symptoms.
  - Lifestyle interventions, such as exercise and a healthy diet, can be beneficial.

Meningitis

Meningitis is an inflammation of the meninges, the membranes surrounding the brain and spinal cord.
Causes:
- Bacterial meningitis: Caused by bacteria, such as Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae.
- Viral meningitis: Caused by viruses, such as enteroviruses, herpes viruses, and arboviruses.
- Fungal meningitis: Caused by fungi, such as Cryptococcus neoformans.
Symptoms:
- Fever, headache, stiff neck, nausea, vomiting, sensitivity to light, confusion, and seizures.
Diagnosis:
- Based on clinical examination, medical history, and laboratory tests, including lumbar puncture to analyze cerebrospinal fluid.
Treatment:
- Treatment depends on the underlying cause and can include antibiotics for bacterial infections, antiviral medications for viral infections, and antifungal medications for fungal infections.
- Vaccines are available for some types of bacterial meningitis.
Complications:
- Brain damage, hearing loss, seizures, and death.
- Hydrocephalus (accumulation of fluid in the brain), can occur.

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Description

This quiz covers the critical aspects of stroke, including the types of infarction, their causes, and clinical features. Test your understanding of how different factors lead to brain damage and the neurological outcomes associated with cerebral infarctions.