Nutritional Diseases of the Nervous System

Question 1

Acute effects of ethanol

Answer 1

Severe cerebral edema

Large quantities of alcohol can lead to death from central cardiorespiratory paralysis

Question 2

Chronic effects of ethanol

Answer 2

1. Meningeal fibrosis
2. Cerebral cortex white matter volume loss, neuronal loss and dendritic reduction;
3. Cerebellar vermis: crests of folia most affected, granule cell neurons> Purkinje cell neurons lost

Question 3

Fetal alcohol syndrome

Answer 3

1. Hyperactivity, poor motor skills, learning difficulties; severely affected kids have mental retardation
2. No single laboratory test to make diagnosis
3. Brain damage due to liver disease/cirrhosis

Question 4

Hepatic encephalopathy

Answer 4

1. Asterixis, stupor, coma
2. Putative toxins: ammonia, mercaptans, short-chain fatty acids, benzodiazepine-like substances, GABA-like substances, impaired glutamatergic neurotransmission
3. Grey matter astrocytes transform to “Alzheimer II” (metabolically active) astrocytes, especially in deep cerebral cortex and subcortical structures

Question 5

Wilson’s disease

Answer 5

Autosomal recessive disorder of copper metabolism, gene localized to chromosome 13

Hepatic failure most common presentation in young children (heptatic encephalopathy)

Choreoathetosis and dementia may be present in young adults

The putamen is the major site of damage followed by the globus pallidus

Question 6

Thiamine deficiency

Answer 6

(vitamin B1): associated with chronic alcoholism

Wernicke’s encephalopathy - full triad of ataxia, nystagmus (or ophthalmoplegia) and confusion may be absent

Selective vulnerability: mammillary bodies, walls of third ventricle, medial thalamus, inferior colliculi, brainstem tegmentum

Peripheral neuropathy

Question 7

Cobalamin deficiency (vitamin B12)

Answer 7

Vegans

Can cause megaloblastic anemia

Subacute combined degeneration - paresthesias, ataxia, diminished vibration sense or proprioception

Dementia - psychoses, mood disturbances

Selective vulnerability: posterior and lateral spinal cord white matter, especially in lower cervical and thoracic cord; cerebral white matter

Question 8

Central pontine myelinolysis (CPM)

Answer 8

1. Disease first appeared in 1950’s following “plastic revolution” with advent of intravenous tubing and fluid administration
2. Mostly occurs in patients with chronic medical conditions including cancer, liver disease, liver transplantation, sepsis, burns
3. Patients have fluid and electrolyte imbalances
4. Many cases clinically silent; quadraparesis and “locked in syndrome” with severe lesions
5. Ventral pons and extrapontine sites
6. Excessive, rapid correction and/or overcorrection of hyponatremia is causative
7. Slower correction of hyponatremia and possibly administration of organic osmoles such as myoinositol are preventative/therapeutic

Question 9

Korsakoff Syndrome

Answer 9

Memory loss found in thiamine deficiency

Involvement of the dorsomedial nucleus of the thalamus