Pathology of the CNS 1 Flashcards
Why do the differential diagnoses for dementia include metabolic diseases such as vitamin B12 and folate deficiencies?
These deficiencies can also present as dementia
What areas are tested in a neuropsychology test?
Episodic memory Generative fluency; eg: how many animals can you name in 60 sec? Recognition memory (false +ves) Speeded executive function Recognition memory (true +ves) Visuospatial episodic memory Visuospatial learning
What changes can be seen in an MRI in dementia?
Decreased frontotemporal size
Expanded ventricle size
General cerebral atrophy
Do cognitive deficits and MRI changes always correlate in dementia?
No, you can have significant cognitive problems without MRI changes
What does a Pittsburgh B scan show?
Lighting up of amyloid
Not routine scan > confirms diagnosis of Alzheimer’s
What is dementia?
Clinical syndrome of global impairment of higher cortical functions
- Memory
- Reason
- Personality, including social skills
In absence of gross clouding of consciousness
What proportion of dementia is due to Alzheimer’s disease?
75%
What are the main causes of dementia?
Alzheimer's disease Vascular dementia Lewy body dementia Fronto-temporal (Pick's) dementia Genetic - Huntington's disease Infective - Creutzfeldt-Jakob disease - HIV Other - Alcohol/drug abuse - Repeated head trauma - Parkinson's disease
What are the risk factors for Alzheimer’s disease?
Age Genetic predisposition - 1st degree relative with Alzheimer's Down's syndrome Vascular risk factors Decreased physical/cognitive activity Depression Loneliness Smoking
What are the histological abnormalities seen in Alzheimer’s disease?
Amyloid deposition
Loss of neurons and tissue
From what normal protein is amyloid in Alzheimer’s disease derived?
Amyloid precursor protein (APP)
What parts of the brain are predominantly involved in Alzheimer’s disease?
Frontal and temporal lobes
What proportion of strokes are due to an infarct, and what proportion are due to a haemorrhage?
Infarct = 80% Haemorrhage = 20%
What are the causes of an arterial occlusion?
Thrombotic
Embolic
Dissection
What are the causes of a venous occlusion?
Thrombotic
Torsion
Strangulation
What does an occlusion in a vessel lead to in the tissue it supplies?
Reduction in tissue perfusion
What are the investigations for an acute meningitis syndrome?
CT scan - exclude intracranial lesion/hydrocephalus Lumbar puncture - CSF microscopy, including Gram and India ink stains - Culture - Sensitivity - Cell count - Differential of WBCs - Protein - Glucose - Cryptococcal Ag - Herpes virus multiplex PCR
What is an India ink stain usually used for when testing the CSF?
ID of cryptococcal meningitis
What are the potential complications of acute bacterial meningitis and what is their pathogenesis?
Death due to raised ICP and herniation
Permanent neurological deficits
Septicaemia
What does the revised McDonald criteria for the diagnosis of multiple sclerosis require?
1+ episode of demyelination/objective evidence of >1 lesion on MRI
