Toxic Metabolic Flashcards
(31 cards)
Acute effects of alcohol?
massive cerebral edema and death seen with acute intoxication / binge drinking
Chronic effects of alcohol?
brain atrophy
meningeal fibrosis
earliest effects appear to be on white matter
cerebellar degeneration / drop out of perkinje fibers
ESPECIALLY SUPERIOR VERMIS
We see cerebellar degeneration in chronic alcoholism … what is important to note about the cause?
may be due to vitamin deficiency as well as direct toxicity
Where do we see atrophy of superior vermis? (perkinje and granule cell neurones)
chronic alcoholism
what is Hepatic encephalopathy related to?
elevation of blood ammonia - ammonia readily crosses BBB - taken up by astrocytes which are rich in glutamine synthetase - neurotoxicity
Symptoms of hepatic encephalopathy?
confusion
asterixis - (hand flap tremor)
HE - pathologic substrate?
edema
alzheimer’s type II cells (cortex and basal ganglia)
neuronal destruction in deeper cortical layers and putamen (in addition to alzheimer II astrocytes)
known as chronic acquired non-wilsonian hepatocerebral degeneration
Wilsons
an inherited disorder of copper metabolism - causes liver cirrhosis - produces identical changes as HE cns damage -
thus, brain damage in Wilsons disease is due to repeated bouts of HE and not copper toxicity -
Can manifest with jaundice or movement disorder (12 years old avg)
do most toxic disorders have morphologic correlates?
no, most do not
we looked at those that do :)
Kwashiorkor with edema –> effects glial formation - synaptic branching - myelin formation - can we restore normal neurologic development?
most children can have restoration of normal neurologic development if proper nutrition is restored
What causes Wernicke Korsakoff syndrome?
Vitamin B1/Thiamine deficiency
Presentation of Wernicke-Korsakoff
syndrome of oculomotor abnormalities and mental symptoms
most common in alcoholics or hyperemetics
ocular motility problems, nystagmus (involuntary eye movement), ataxia, confusion —- presenting problems are variable
Wernicke’s encephalopathy
example of a toxic metabolic problem that shows selective vulnerability ? Involves mammillary bodies - Hypothalamus - medial thalamus - periaqueductal grey - floor of 4th ventricle
histology varies with stage and severity
edema, necrosis, demyelination, neuron loss, gliosis
often see confabulation with Wernicke’s encephalopathy
example of a toxic metabolic problem that shows selective vulnerabilty
Wernicke’s encephalopathy
If we see a person with ataxia, nystagmus, and demonstrated lesions in the mammilary bodies, medial thalami, and PAG, what should we be thinking?
Wernicke’s encephalopathy which is due to vitamin B1 / thiamine deficiency
Which vitamin deficiency disease often fucks with mammillary bodies?
Wernicke’s encephalopathy - vitamin B1 deficiency
What does vitamin B1 do?
pentose phosphate shunt in the nervous system
Wernicke’s encephalopathy is associated with decreased blood transketolase activity
So we see thiamine deficiency leading to wernicke’s encephalopathy in alcholics - but who else?
we can see in patients who have undergone bariatric surgery - because vitamin stores can be depleted in a few weeks - thiamine is stored in the heart, kidneys, liver, brain, muscles
Apparently IV glucose in patient with borderline deficiency can trigger disease?
Korsakoff’s syndrome
sequelae of Wernicke’s encephalopahty usually due to alcoholism / vitmain B1 deficiency - major symptoms include
- anterograde amnesia
- retrograde amnesia
- confabulation
- minimal content in convos
- lack of insight
- apathy
Vitamin B12 deficiency (cobalamin)
what is our source?
meat and dairy
vitamin b12 (cobalamin) what does it do?
in stomach vitamin b12 (cobalamin) is bound to IF - a glycoprotein produced by the parietal cells of the stomach - the complex binds to receptors and is absorbed - therefore strict vegan diets or problems with malabsorpton are the main cause of vitamin b12 deficiency
stored for many years 3-4
why does vit b12 deficiency (cobalamin) dmage nervouse system?
incorporation of fatty acids into biological membranes results in myelin instability
subacute combined degeneration
may also affect DNA synthesis
vitamin b12 deficiency and spinal cord?
spinal cord disease is characterized by involvement of ascending sensory and descending motor tracts -
symptoms develop over weeks, usually with inital slight ataxia, numbness, and tingling in lower extremities - can progress into spastic weakness or paraplegia
vitamin b12 deficiency - nuerological complications -
cognitive deficits
subacute combined degeneration
