Toxic & Acquired Metabolic Diseases Flashcards
What 3 disorders does thiamine (B1) deficiency lead to?
What is these largely due to?
- Wernicke encephalopathy
- Korsakoff syndrome
- Beriberi (cardiac failure)
D/t chronic alcocolism
What is Wernicke encephalopathy? Is it reversible?
Hemorrhage & necrosis in mamillary bodies & walls of 3rd and 4th ventricle that leads to acute psychosis & ophthalmoplegia
- May reverse w thiamine
What is Korsakoff syndrome? Is it reversible?
Chronic lesions containing hemosiderin & cystic spaces that causes memory disturbances & confabulation
- Largely irreversible
What is the progression of B12 deficiency?
Is this progression reversible?
- Anemia
- Neurologic defect in myelin formation which leads to numbness, tingling, ataxia in bilateral LE
- Spastic weakness in bilateral LE
- Complete paraplegia
B12 replacement can improve sx unless paraplegia has developed
What is the histo of B12 def?
What is B12 def also called
Swelling in myelin layers leads to vacuoles
- Begins at midthoracic level with axons of both the ascending tracts of posterior columns and descending pyramidal tracts degenerate
“Subacute combined degeneration of the spinal cord”
What area of the brain does hypoglycemia affect?
Pyramidal neurons of Sommer’s sector of hippo and Purkinje cells of cerebellum
What is pseudolaminar necrosis in regards to hypoglycemia?
Hypoglycemia selective for the large pyramidal neurons of cerebral cortex
What can hyperglycemia lead to? What is important to note about correction of hyperglycemia
Dehydration and then confusion, stupor, eventually lead to ketoacidosis or hyperosmolar coma
Fluid repletion must be gradually corrected to avoid severe cerebral edema
What leads to hepatic encephalopathy? What specific cell do we see and where do we see it?
Elevated ammonia levels & proinflammatory cytokines
- Alzheimer type II cells in the cortex, basal ganglia, and other subcortical grey matter regions
What parts of the brain does carbon monoxide affect?
Layers III & V of cerebral cortex, Sommer’s sector, Purkinje cells
Bilateral necrosis of globus pallidi
What parts of the brain does methanol affect?
Retinal ganglion cells (blindness)
Selective bilateral putamenal necrosis
What parts of the brain does ethanol affect?
What do these lead to?
Atrophy & loss of granule cells in the anterior vermis (truncal ataxia, unsteady gait, nystagmus)
Advanced cases have loss of purkinje cells & proliferation of adjacent astrocytes (Bergmann gliosis)
What can radiation lead to?
Induce tumors including sarcomas, gliomas, and meningiomas
What histo do we see with radiation?
Large areas of coagulative necrosis
- Thickened vessel walls w intramural fibrinoid necrosis & sclerosis
- Axons & cell bodies near radiation undergo dystrophic mineralization
