Lecture 28- Disorders of the nervous system I

Question 1

How many people are affected by mental and neurological disorders?

Answer 1

450 million

Question 2

What are four categories of the WHO of the mental and neurological disorders?

Answer 2

1. Mental diseases 2. Neurological disorders 3. Learning and developmental disabilities 4. Substance abuse disorders

Question 3

What is the classification of the disorders based on?

Answer 3

-antiquated notion that some disorders were organic (the subject of neurology= neurological disorder) and others just purely functional (the subject of psychiatry= mental)= a malfunction in the mental operations of the brain without an organic cause

Question 4

What are learning and developmental disabilities?

Answer 4

-include functional limitations that manifest in infancy or childhood as a result of disorders of or injuries to the developing nervous system

Question 5

What are the causes of the mental illnesses and neurological disorders? (8)

Answer 5

1.Genetic 2.Multifactorial 3.Nutritional 4. Infections 5.Toxic exposure 6.Perinatal complications 7.Injury 8.Poverty, economic disadvantage

Question 6

What are the five types of genetically caused neurological disorders?

Answer 6

1. Chromosmal: Down syndrome, chromosomal rearrangements 2. Seg. autosomal syndromes: Prader-Willi, Angelmans syndromes 3. Sex-linked, single gene: Fragile X syndrome, Rett syndrome 4. Autosomal recessive: Phenylketonuria, Tay Sachs disease 5. Autosomal dominant: Neurocutaneous syndromes such as neurofibromatosis

Question 7

What is the multifactorial cause of mental illness or neurological disorder?

Answer 7

Genetic and nutritional: Neural tube defects

Question 8

What is the nutritional cause of neurological disorders?

Answer 8

-prenatal and childhood: maternal iodine deficiency, developmental iodine deficiency disorder

Question 9

What are the two types of causes of infection neurological disorders?

Answer 9

1. Prenatal or perinatal: toxoplasmosis, rubella, cytomegalovirus, STD (eg. AIDS) 2.Postnatal or childhood: Encephalitis, meningitis, cerebral malaria, otitis media

Question 10

What is the toxic cause of neurological disorder?

Answer 10

-prenatal: alcohol, lead, mercury, antimicrobials, other drugs (e.g. thalidomide)

Question 11

What are the perinatal complication neurological disorders?

Answer 11

-brain injuries associated with premature birth, asphyxia: cerebral palsy, cognitive disabilities, seizure disorders

Question 12

What are the injury induced neurological disorders?

Answer 12

-traumatic brain injuries, vehicle crashes, child abuse and neglect, warfare etc.: cognitive, motor, speech, vision, hearing, seizure and behavioural disabilities

Question 13

What is the neurological disorder caused by poverty or economic disadvantage?

Answer 13

-mild mental retardation

Question 14

What are mental disorders?

Answer 14

-diseases that affect cognition, emotion, and behavioural control and substantially interfere with the ability of children to learn and ability of adults to function in their families, at work, and in the broader society -tend to begin early in life and often run in a chronic recurrent course

Question 15

Do mental disorders have complex aetiologies?

Answer 15

-yes, involve interactions among multiple genetic and non-genetic risk factors

Question 16

When is gender related to risk of mental disorders?

Answer 16

-males have higher rates of attention deficit hyperactivity disorder, autism, and substance use disorders -females have higher rates of major depressive disorder, most anxiety disorders and eating disorders

Question 17

What are the four most significant mental disorders?

Answer 17

1. Schizophrenia 2. Bipolar affective disorder 3. Major depressive disorder 4. Panic disorder

Question 18

What does the development of pharmacological therapies for mental disorders suggests?

Answer 18

-the development of pharmacological therapies that treated the symptoms of schizophrenia, depression, anxiety disorders and others suggests possible underlying pathophysiology

Question 19

What are the six classifications of anxiety disorders?

Answer 19

-these are all abnormal experiences of anxiety 1. Generalised anxiety disorder 2. Panic attack 3. Panic disorder 4. Phobias 5. Obsessive compulsive disorder 6. Post-traumatic stress disorder

Question 20

What does benzodiazepine do?

Answer 20

• gets rid of anxiety
• GABA gates a Cl- channel, if you make it more or less sensitive to GABA then you change the excitation/ inhibition in the system
• simple drug changes sth so complicated
• can modulate a very complex tthing like anxiety by just one drug
• ethanol can do a similar thing! why we lose inhibition when drunk!

Question 21

How is schizophrenia treated?

Answer 21

-with D2 antagonists -D2= dopamine

Question 22

What are the 4 most significant neurological diseases?

Answer 22

1. Alzheimer’s disease and other dementias 2. Epilepsy 3. Parkinson’s disease 4. Stroke

Question 23

What is dementia?

Answer 23

-deterioration of intellectual function and other cognitive skills that is of sufficient severity to interfere with social or occupational functioning

Question 24

What is the most common form of dementia and what is it characterised by?

Answer 24

-Alzheimer’s -first described by Alois Alzheimer in 1907 -characterised by deposition of amyloid protein and the disruption of the neuronal cytoskeleton

Question 25

What does Alzheimer’s do to the neuronal cytoskeleton?

Answer 25

• disruption
• the cells start dying
• neurofilaments give the cell the phenotype of neurons

Question 26

What happens with the amyloid protein in Alzheimer’s?

Answer 26

• extracellular plaques caused by a build up of an abnormal configuration of a protein amyloid
• this causes neurons to produce abnormal intracellular aggregations of tau protein
• in brains producing amyloid, an intracellular tau forms aggregates (neurofibulary tangles) = this may be cause of neuronal death

Question 27

What are neurofibulary tangles?

Answer 27

-aggregates of tau protein in brains producing amyloid -possible cause of death of neurons

Question 28

What does tau protein do normally?

Answer 28

-tau protein is normally present in neurons where it stabilises microtubules

Question 29

Where are most of the amyloid plaques and neurofibulary tangles in an Alzheimer brain?

Answer 29

• tends to be localised so some function not as bad
• medial temporal lobe= role in memory formation

Question 30

What is epilepsy characterised by?

Answer 30

-common brain disorder -characterised by two or more unprovoked seizures -more of a symptom than a disease

Question 31

How prevalent is epilepsy?

Answer 31

-around 7 to 10% of the population may experience a seizure during their lifetime, epilepsy is the condition of recurrence of seizures -this affects about 1% of the population -50-70 million worldwide

Question 32

What is epilepsy? (in terms of what is happening in the brain at the time?

Answer 32

• epilepsy is abnormal coherent behaviour of the brain
• increasingly synchronasied state of the brain and not compatible with normal brain activity

Question 33

What are epileptic seizures?

Answer 33

-seizures are discrete events caused by transient, hyper-synchronous, abnormal neuronal activity -seizures can occur in close temporal association with acute stroke, sepsis or alcohol withdrawal -however the vast majority of seizures have no immediate identifiable cause

Question 34

What are the three categories of epilepsy?

Answer 34

1: Idiopathic epilepsy (such as childhood-onset absence epilepsy), which is thought to have a genetic basis (10%) 2: Secondary or symptomatic epilepsy, which is caused by a known central nervous system injury or disorder such as infection, stroke, or traumatic injury 3: Cryptogenic epilepsy, for which there is no clear evidence of an etiological factor (60%)

Question 35

Have the genetic mutations underlying the familial (inherited) epilepsies been uncovered?

Answer 35

-yes -genes associated with synaptic transmission is involved in epilepsy -genes encoding proteins directly associated with neuronal excitability such as ion channels, neurotransmitter receptors -even a little change can have an impact

Question 36

What can initiate spreading synchronous firing?

Answer 36

-an imbalance of excitation and inhibition, beginning at a site of brain damage or as a result of a mutation in an ion channel gene can initiate the coherent firing –the change is very nuanced

Question 37

Who was one of the first people to suffer from Multiple Sclerosis?

Answer 37

-Jacqueline du Pré, british cellist -she started experiencing loss of sensation on her fingers and other parts of her body -irreversible

Question 38

What are the risk factors associated with multiple sclerosis?

Answer 38

-young -female -middle class

Question 39

What is MS (multiple sclerosis)?

Answer 39

-chronic autoimmune disease characterised by destruction of myelin in the CNS -MS can cause a variety of symptoms, including changes in sensation, visual problems, muscle weakness, depression, difficulties with coordination and speech, sever fatigue, cognitive impairment problems with balance, overheating and pain