Exam 1: IS: Introduction to Clinical Neurology and Neuropathology (Neuropathology section) Flashcards
red neuron change
Ischemia:
- Neurons are the most sensitive cell to ischemic injury
- Acutely, acidosis develops and the basophilic Nissl in the cytoplasm disperses. This causes the cytoplasm to be red (“red neuron change”).
*In image: Red Neuron Change- Acidosis causes disruption of Nissl substance. Eosinophilia (i.e. red change) develops.
Chromatolysis/axonal reaction
Axonal Injury/Transection:
• In injury to the very proximal axon, the neuronal cell body can show changes including swelling and rounding of the cell body, peripheral displacement of the nucleus, and peripheral dispersion of the Nissl substance.
*In image: Chromatolysis/Axonal Injury – Note the described changes in Figure 22-1 C from Kumar V, Abbas AK, Aster JC. Basic Pathology, 9th ed., 2013. These include swelling of cell body and peripheral dispersal of Nissl substance. Compare with histology slides of normal neurons.
abnormal accumulations of proteins or pigments
Inclusions in nucleus and/or cytoplasm of affected cells:
- Degenerative – Lewy body in Parkinson disease, Neurofibillary tangle in Alzheimer disease
- Viral – Large intranuclear inclusions in cytomegalovirus (CM)
- Pigment – Accumulation of lipofuscin in aging
*In image: Cytoplasmic inclusion - Neurofibrillary tangle in Alzheimer Disease is an example of an inclusion. The tangle is composed of hyperphosphorylated tau, a microtubule associated protein. The presence of this tangle disrupts the normal cellular processes in the neuron. The neuron is dysfunctional and will eventually degenerate/die. Neuronal loss results.
Glial - Astrocytes
Name 3 times Astrocytes inclusions are seen in the brain
***GFAP is an antigen that appears on glial cells (not on neurons) and stains brown if (+)***
1) Gliosis – Reaction to injury (akin to fibrosis elsewhere)
- Gemistocytic astrocytes – hyperplastic astrocytes with prominent cytoplasm.
- Alzheimer Type 2 Astrocytes – Hepatic encephalopathy
2) Cellular Swelling – Acute Ischemia/Toxic Exposures
3) Degenerative Diseases
•Glial Inclusions in astrocytes and/or oligodendroglial cells in progressive supranuclear palsy (PSP) and multiple system atrophy (MSA).
*In image: Note that this is a GFAP (glial fibrillary acid protein) stain, an immunochemical stain that stains astrocytes. The positive cells stain brown. Note the stellate processes.
Glia - Oligodendroglial Cells
Name 2 times Oligodendroglial inclusions are seen in the brain
***Luxol fast blue PAS stains for myelin. Normal myelin is dark blue***
Problems with the Oligodendroglial Cells result in loss of myelin. The loss of salutatory conduction results in neurologic dysfunction.
1) Loss of myelin/Decreased production
- Demyelinating Diseases (MS, demyelinating neuropathies)
- Leukodystrophies (Genetic Diseases)
- Infections (HIV, PML)
- Toxic (Carbon Monoxide)
2) Viral inclusions
• Progressive Multifocal Leukoencephalopathy (PML)
*In image: Note that this is a GFAP (glial fibrillary acid protein) stain, an immunochemical stain that stains astrocytes. The positive cells stain brown. Note the stellate processes.
Glia - Ependymal Cells
Name 1 times Ependymal inclusions are seen in the brain
Ependymal cells line the ventricles. With injury (hydrocephalus), the ependymal cells can form elevations as a reaction. CMV has a propensity for infecting ependymal cells lining the ventricle.
1) Viral Inclusions (CMV)
*In image: Note that this is a GFAP (glial fibrillary acid protein) stain, an immunochemical stain that stains astrocytes. The positive cells stain brown. Note the stellate processes.
Glia - Microglial Cells
Name 1 times Microglial Cells proliferations are seen in the brain
***In normal brain sections stained with H&E, microglia cells blend into the background.***
1) Proliferations seen often with viral infections
- Microglial nodules
- Rod Cells (Syphilis)
- Neuronophagia (Polio)
*In image: Microglial nodule in viral encephalitis (infection of brain). In normal brain sections stained with H&E, microglia cells blend into the background.
Blood Cells - Neutrophils
Are seen or associated with what infections or disorders?
Acute infections
Limited in CVA’s
Blood Cells - Lymphocytes
Are seen or associated with what infections or disorders?
Viral infections
Blood Cells - Macrophages/Microglia
Are seen or associated with what infections or disorders?
Liquefactive Necrosis in CVA’s
HIV
Stains - H & E
is normally used for?
Most important and general-purpose
Stains - Luxol Fast Blue
is normally used for?
Myelin stains blue
Stains - Silver Stains (.g. Bielchowsky)
is normally used for?
Alzheimer plaques and tangles
Stains - Glial Fibrillary Acid Protein (GFAP)
is normally used for?
Glial differentiation
