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
In which type of dementia is memory initially preserved, but insight and speech are lost early?
Fronto-temporal dementia
In which type of dementia may you find signs of CVS disease elsewhere?
Vascular dementia
In which type of dementia do people have memory lapses, become disorientated, have trouble planning and organising things?
Alzheimer’s disease
- Impaired cognitive and executive functions
Name the types of cortical dementias:
- Alzheimer’s
- Vascular (mixed)
- Fronto-temporal
Name the type of subcortical dementias:
- Vascular (mixed)
- Dementia with Lewy-bodies
How is dementia classified in the ICD-10?
- Decline in memory
- Decline in other cognitive abilities
- Decline in emotional control/motivation ie labile/irritable/apathetic/coarsening of social behaviour
- Present for >6months
What are some differential diagnoses of dementia?
- Normal ageing
- Delirium
- Trauma
- Stroke
- Depression
- Late-onset schizophrenia
- Amnesia
- Learning disability
- Substance misuse
- Drugs: Opiates, benzo’s
What are the 1st line drug treatments for Alzheimer’s disease?
AchE inhibitors:
- Donepezil
- Galantamine
- Rivastigmine
What is the mechanism of action of Memantine?
NMDA antagonist
What is the initial management of a patient with dementia (before drugs):
- Information + education
- Advance planning
- Contact DVLA
- Social support ie Alzheimer’s society
- Community services ie day care, meals-on-wheels, befriending services
- Aromatherapy, massage, music/art therapy
- Home nursing and personal care
If a patient with dementia is suffering insomnia, what should be prescribed 1st line?
Trazodone