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Flashcards in Metabolic Diseases Affecting the CNS Deck (21)
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1
Q

What are Neuronal Storage Diseases?

How do they occur?

A

Neuronal Storage Diseases are disfunctional enzymes that cannot perform their normal task of breaking down specific proteins, leading to a build up of those proteins in the brain.

  • The enzymes themselves are dysfunctional due to inheritance of a set of faulty genes (autosomal recessive)
  • Specifically, this results in an accumulation of sphingolipids, mucopolysacharrides in neuronal lysosome
2
Q

What is neuronal ceroid lipofuscinoses?

What is its symptoms and onset?

A

Neuronal Ceroid Lipofuscinoses: This is a lack of enzymes that typically modify/degrade proteins in neurons

-The result is a build up of lipofuscin inside of the neurons –> dysfunctional neurons

Onset = Childhood –> adult

Symptoms: Blindness, mental and motor deterioration, seizures

3
Q

What is Tay-Sachs Disease?

What are its symptoms?

A

Tay-Sachs Disease results from a deficiency of Hexosaminidase A

This results in an accumulation of ganglioside in all tissues (but nervous system shows the most symptoms)

  • Ganglioside = a fatty acid that is normally broken down

Onset: Early infancy

Signs: Developmental delay, paralysis, loss of neurologic function (Eventually the child will die in several years)

4
Q

What is a quick diagnostic feature of Tay-Sachs?

A

There is a cherry red spot that appears in the eye

-Everything around the spot is defective:The white stuff that is accumulating around the spot are the gangliosides that are building up.

5
Q

What are Leukodystrophies?

What are some common symptoms of Leukodystrophies?

A

Leuko = white (white matter in the brain i.e. Myelin)

These are a bunch of autosomal disorders in the myelin that involve lysosomal and peroxisomal enzymes

Symptoms = motor defects more than anything else, ataxia, hypotonia, spacity

6
Q

What is Krabbe Disease?

What is the onset like?

What are the symptoms?

A

Krabbe Disease is a deficiency of galactosylceramidase which results in a build up of galactocerebroside

-Galactocerebroside –> Galactosphingosine in the neuron; this is toxic to oligodendrocytes leading to their death.

The net effect of this is a loss of myelin and oligodendrocytes in the CNS and PNS

Onset: 3-6 months

Symptoms: Rapidly progressive muscle stiffness/weakness (The child is just beginning to stand and then crumbles)

-Begin to see fatty macrophages that build up in the brain called Globoid Cells

7
Q

What are the first signs of Krabbe disease?

A

A spastic hand or muscle stiffness is one of the first signs.

8
Q

What are the two syndromes stemming from B1 (Thiamine) Deficiency?

What does B1 Deficiency usually stem from in the U.S.?

A

There are two diseases that relate to B1 deficiency -Comes from severe malnutrition (usually from alcoholism in the U.S.)

Two Syndromes:

  • Wernicke Encephalopathy: Reversible
  • Korsakoff Syndrome: Non-reversible
9
Q

What is Korsakoff Syndrome?

What are the symptoms?

Is this reversible?

A

A B1 deficiency –> hemmorhage in the mamillary bodies and the walls of the ventricles however macrophages have come and eaten out big holes/cysts.

-Can also result in thalamic lesions

Symptoms: Memory disturbances (make up memories = Confabulation)

This is irreversible if it becomes prolonged

10
Q

How do you get a B12 deficiency and what can it lead to?

A

Hard to get deficiency of B12 because they are stored really well (can’t get it from malnutrition). Usually it happens because of malabsorption.

  • Anemia: Can be reversed with B12 administration
  • Subacute combined degeneration of spinal cord
  • This leads to lower extremity numbness, ataxia, and weakness
  • This is reversible until you are parapalegic
  • Also has swelling of the myelin layers and vacuolization
11
Q

What is Subacute Combined Degeneration of Spinal Cord?

A

Combined because both motor and sensory pathways are involved - the Myelin layers of the spinal cord get swollen and drop out.

12
Q

What are the two types of abnormal blood sugar?

A

Hypoglycemia (low blood sugar)

Hyperglycemia (high blood sugar)

13
Q

What is Carbon Monoxide Poisoning?

What tissues are particularly vulnerable to CO poisoning?

A

CO can bind to hemoglobin way stronger than oxygen does –> carboxy hemoglobin instead of oxygenated hemoglobin - this does not allow for oxygen distribution

  • The CO bound to blood also gives the person a pinkish rosy color
  • Particularly vulnerable areas are due to hypoxia: Cortex (layers III and V), hippocampus, purkinje cells -Can sometimes see demyelination of white matter tracts
14
Q

Methanol toxicity results in degeneration of what?

What are the symptoms?

A

Also a toxin (like CO poisoning) - People sometimes drink this as a recreational drug

Symptoms: The eye is really at risk: develop blurred vision and possibly blindness

This can also result in degeneration of ganglion cells –> death

15
Q

Ethanol toxicity affects what part of the brain?

What are the symptoms?

A

Ethanol mainly affects the cerebellum by causing atrophy there

It can also result in loss of granule cells, perkinje cells, and Bergmann gliosis (Proliferation of astrocytes)

  • Symptoms in chronic exposure: Truncal ataxia, Unsteady gait, Nystagmus (eyes jolting back and forth)
16
Q

What are the two broad categories of metabolic disorders in neurons?

What are the subdisorders within those categories?

A

Genetic Metabolic Diseases

  • Neuronal Storage Disease
  • Leukodystrophies (white matter diseases)

Toxic and Acquired Metabolic Diseases

  • Vitamin Deficiencies
  • Metabolic and Toxic Distrubances
17
Q

Are Neuronal Storage Diseases and Leukodystrophies autosomal recessive or autosomal dominant diseases?

A

Autosomal recessive

18
Q

What are the symptoms of Neuronal Storage Diseases?

A

Symptoms: Loss of cognitive function and possibly seizures

19
Q

What causes Wernicke Encephalopathy?

What are the symptoms of this disease?

Is it reversible?

A

Cause: Vitamin B1 (Thiamine) deficiency from malnutrition (usually alcoholism in the U.S.) or malabsorption of B1

Lack of B1 –>Hemorrhage and necrosis of the Mamillary Bodies, and walls of the 3rd and 4th ventricles

Symptoms: Opthalmoplegia (can’t move your eyes), ataxia, confusion

The hemmoraging is reversible but this can lead to necrosis which is not reversible!

20
Q

What tissues are most vulnerable to hypoglycemia?

What other tissues are vulnerable?

A

Most vulnerable tissues: Large pyramidal neurons of the cortex (pseudolaminar necrosis)

Other vulnerable: Hippocampus and Cerebellum

21
Q

What chronic condition is Hyperglycemia most associated with?

What other disorders are associated with hyperglycemia?

A

Hyperglycemia is most commonly seen in diabetes mellitus

It is also associated with Ketoacidosis or hyperosmolar coma (the increase of sugar pulls water out of cells)

Symptoms: Dehydration, confusion, stupor, coma