Degenerative Conditions Flashcards
What is meant by demyelination?
Preferential destruction of myelin sheath around axon
Relative preservation of axons themselves
What is the myelin sheath derived from in the CHS?
Oligodendrocytes
Is MS more common in males or females?
Females:Males is 2:1
What is the diagnostic criteria for MS?
Brain and spinal cord lesions disseminated in both time and space
What are the most common manifestations of MS?
Visual disturbance, paraesthesia, spasticity of one or more of the extremities, speech disturbance, gait abnormalities
How does MS present on MRI?
Abnormal plaques in the white matter areas of the nervous system
What are active plaques in the context of MS?
Evidence of ongoing myelin breakdown with abundant macrophages. Inflammatory cells present, including lymphocytes and monocytes. Small active lesions are often centred around veins
What are inactive plaques in the context of MS?
The centre will contain little or no myelin. Astrocytic proliferation and gliosis are prominent
What are the main histological features of MS?
Demyelination - plaques
Inflammation - perivascular inflammation and oedema
Gliosis: astrocytic gliosis
What are the primary dementias?
Alzheimer’s disease
Dementia with Lewy bodies
Huntington’s Disease
Pick’s disease
What are the secondary dementias?
Vascular Hydrocephalus Metabolic Infection - viral encephalitis, meningitis Trauma - sport Intracranial space occupying lesions etc.
Name the genes thought to be linked to familial Alzheimer’s disease
Amyloid precursor protein (APP) gene on chromosome 21
Presenilin 1 gene on chromosome 14
Presenilin 2 gene on chromosome 8
Apolipoprotein
What type of memory loss is demonstrated in Alzheimer’s disease?
Retrograde memory loss - can remember years ago but not more recent memories
Which lobe of the brain tends to be spared in Alzheimer’s disease?
The occipital lobe
cerebellum and brainstem also spared
What are the macroscopic changes to the brain in Alzheimer’s disease?
Widening of sulci Narrowing of gyri Atrophy of frontal, temporal, parietal lobes Decrease in size and weight of brain Compensatory dilatation of ventricles
What are the microscopic changes in the brain in Alzheimer’s disease?
Intracytoplasmic neurofibrillary tangles
Amyloid Beta plaques
Amyloid angiopathy
Extensive neuronal loss with astrocytosis
What are the hallmarks of lewy body dementia?
Hallucinations
Fluctuating levels of attention
Which type of dementia is commonly associated with Parkinson’s disease?
Lewy body dementia
What immunochemical staining is used to detect Lewy bodies?
Staining for protein ubiquitin
How can multi-infarct dementia be distinguished from other types?
Abrupt onset
Step by step progression
History of HT/Stroke (evidence of past stroke on MRI)
Name the four different clinical courses MS can take
Relapsing remitting
Secondary progressive
Relapsing progressive
Primary progressive
