11 - Herniation + Dementias Flashcards
What is the normal ICP range?
0 - 10 mmHg
What are the compensatory mechanisms to reduce RICP?
- Reduce blood volume
- Reduce CSF volume
- Brain atrophy
What are the 3 types of brain herniation?
- Subfalcine
- Tentorial
- Tonsillar
What is the most common type of brain herniation? Describe it:
Subfalcine
Cingulate gyrus is pouched under the free edge of the fall cerebri
Which blood vessel is most at risk during a subfalcine herniation? This results in infarction of which areas?
ACA
Medial frontal + parietal lobes + corpus callosum
What are the main MRI findings in a subfalcine herniation?
- Ipsilateral loss of lateral ventricle
- Contralateral dilatation of lateral ventricle
Describe a tectorial herniation:
Uncus/medial part of parahippocampal gyrus herniates through tectorial notch
Which nerve(s) and vessel(s) are most at risk in a tectorial herniation?
CN III
PCA + superior cerebellar artery
Which type of herniation involves the uncus?
Tentorial herniation
Describe a tonsillar herniation:
Cerebellar tonsils pushed into foramen magnum = compresses brainstem
Which type of brain herniation is associated with a Duret haemorrhage? What is a duet haemorrhage?
Tentorial herniation
Haemorrhage in midbrain and upper pons
Which type of brain herniation involves the foramen magnum?
Tonsillar herniation
From which layer of the meninges does a meningioma arise?
Arachnoid mater
Brain metastases usually arise from which primary cancers?
- Breast
- Lung
- Colon
- Kidney
- Skin
List some causes of reversible dementia:
- Intracranial tumour
- Chronic subdural haematoma
- Alcohol
- Trauma
- Cushing’s syndrome
- Hypothyroidism
- Vitamin deficiencies: B12, folic acid, thiamine, nicotinic acid
- Normal pressure hydrocephalus
Apart from neurodegenerative diseases, what are some other causes of irreversible dementia?
- Infection - HIV, encephalitis, syphilis, CJD
- Drugs - Benz’s, barbiturates
- Alcohol
- CVD = vascular dementia
- Trauma
Tau protein tangles and β-amyloid plaques are associated with what type of dementia?
Alzheimer’s disease
What is the normal time span from onset of Alzheimer’s disease to death?
7-10yrs
Which type of dementia exhibits a continuous progressive cognitive decline?
Alzheimer’s disease
Which type of dementia exhibits a step-wise cognitive decline?
Vascular dementia
Which type of dementia exhibits a random, fluctuating cognitive decline?
Dementia with Lewy-bodies
Which which type of dementia is it common to experience recurrent visual hallucinations?
Dementia with Lewy-bodies
Antipsychotics are contraindicated in which type of dementia?
Dementia with Lewy-bodies
What type of dementia is Pick’s disease?
Fronto-temporal dementia
