Pathology Flashcards
How does hypoxia affect the CNS?
Affects neurones first - most vulnerable
Activates glutmate receptors causing uncontrolled calcium entry into the cell
What is the most important histopathological indicator of CNS injury?
Gliosis
What is gliosis?
A nonspecific reactive change of glial cells in response to damage to the central nervous system (CNS)
In most cases, gliosisinvolves the proliferation or hypertrophy of several different types of glial cells, including astrocytes, microglia, and oligodendrocytes
What are oligodendrocytes?
Cells that wrap around axons of neurons forming myelin sheath
Which cells line the ventricular system?
Epyndemal cells
Which cells of the nervous system act as macrophages?
Microglia
What lobe is affected and what clinical signs are produced in cerebrovascular disease affecting the anterior cerebral artery?
Frontal lobe
Contralateral sensory loss in foot & leg
Paresis of arm and foot
What clinical signs are produced in cerebrovascular disease affecting the middle cerebral artery?
Contralateral hemiparesis
Contralateral hemisensory loss
Aphasia/dysphasia
Apraxia
What is an example of a primary demyelination disorder?
Multiple sclerosis
What can be seen histologically with small, active MS plaques?
Evidence of ongoing myelin breakdown with abundant macrophages
Inflammatory cells, including both lymphocytes and monocytes, mostly as perivascular cuffs
Small active lesions often centred round veins
What is the histological appearance of an inactive MS plaque?
Centre contains little or no myelin
Astrocytic proliferation and gliosis are prominent
Reduction in inflammatory cells and macrophages over time
Does MS affect grey or white matter?
White
What is the appearance of chronic MS plaques?
Well-demarcated grey/brown lesions in white matter, classically situated around lateral ventricles
What are some of the genes involved in Alzheimer’s disease?
Amyloid precursor protein (APP) Chromosome 21
Presenilin 1 – Chromosome 14
Presenilin 2 – Chromosome 1
Apolipoprotein E – allele e4
What is the gross appearance of a brain affected by Alzheimers?
- decreased size and weight of brain (cortical atrophy)
- widening of sulci
- narrowing of gyri
- compensatory dilatation ventricles, 2° hydrocephalus
- frontal, temporal and parietal lobes affected
- brainstem and cerebellum normal
What are the histological features of Alzheimer’s?
- intracytoplasmic neurofibrillary tangles
– Aß amyloid plaques (extracellular senile or neuritic plaques)
– amyloid angiopathy
– extensive neuronal loss with astrocytosis
What stain is used to show up amyloid in histology?
Congo red
What are the pathological features seen in dementia with Lewy bodies?
- degeneration of the substantia nigra (as seen in Parkinson’s disease)
- remaining nerve cells contain abnormal structures called Lewy bodies (pathological hallmark)
- degeneration of the cortical areas of the brain with many or all of the features seen in Alzheimer’s disease
What is the histological appearance of Huntington’s disease?
Loss of neurons in caudate nucleus and cerebral cortex accompanied by reactive fibrillary gliosis
What is Pick’s disease?
A progressive dementia commencing in middle life (usually between 50 and 60 years) characterised by slowly progressing changes in character and social deterioration leading to impairment of intellect, memory and language
What pathology can be seen in Pick’s disease?
- extreme atrophy of cerebral cortex in frontal and temporal lobes
- brain weight
- neuronal loss and astrocytosis
- histological hallmarks are Pick’s cells (swollen neurons) and intracytoplasmic filamentous inclusions known as Pick’s bodies
What signs might be seen with a cerebellar lesion?
Ataxia
Wide based gait
Past pointing
Intention tremor
Dysmetria
Dysdiadokineses
Coarse, staccato speech
Horizontal Nystagmus
How might tone and reflexes be affected in a cerebellar examination?
Hypotonia
Reduced reflexes
