Nervous system diseases III Flashcards
What is dementia?
associated with progressive decline of brain functioning that effects quality of life
What type of disease is dementia?
a syndrome
What is the most common type of dementia?
alzheimers
What is alzheimers?
progressive cognitive decline
What is an early symptom of Alzheimers?
memory lapse
What are mid-stage symptom of Alzheimers?
worsening memory problems
increasing confusion and disorientation
obsessive and repetitive disorientation
obsessive and repetitive behaviours
changes in mood
What are more mid-stage symptom of Alzheimers?
sleep disturbance
hallucinations
aphasia
What are later symptom of Alzheimers?
weight loss
incontinence
difficulty moving
gradual loss of speech
dysphagia
Neuropathology of Alzheimer’s disease
Senile plaques
->Extracellular deposition of β-amyloid peptide
Neurofibrillary tangles
-> Intracellular
-> Phosphorylated tau protein
-> Tau – microtubule associated protein
Neuroinflammation
Massive loss of neurons and synapses in the hippocampus & cortex
Alzheimer’s disease
Risk factors
- Age (risk doubles every 5 years after 65 years old)
- Downs syndrome
- Cardiovascular disease
- Head injuries
- Apolipoprotein (APOE) on xsome 19 – APOE ε4
Early Onset Dementia
3 gene mutations that affect breakdown of APP
Amyloid precursor protein (APP) on xsome 21
Presenilin 1 (PSEN1) on xsome 14
Presenilin 2 (PSEN2) on xsome 1
Brain atrophy in Alzheimer’s disease
Treatment
- No cure
- Acetylcholinesterase inhibitors – increase Ach levels
Frontotemporal dementia (FTD) (Pick’s disease)
- Rare form of dementia
- Shrinking of the frontal and temporal lobes of the brain
- Tends to occur at a younger age than AD (40 - 65 years) but also later in life
Frontotemporal dementia (FTD) (Pick’s disease) - Causes
Intracellular depositions of abnormal form of tau
protein inside neurons
Degeneration of neurons, microvacuoles formation, and astrocytosis
Frontotemporal dementia (FTD) (Pick’s disease)
Symptoms
Dramatic changes in personality
eg. Inappropriate social behaviour
Language disturbance
- Difficulty using and understanding language
- Hesitant speech
Spatial skills and memory remain intact
Frontotemporal dementia (FTD) (Pick’s disease)- Treatment
- No cure or specific treatment
- Medications used to manage symptoms
- Antidepressants
- Anti-psychotics
- Therapies
Vascular Dementia - Cause
- Reduced blood flow to the brain
- Sub-cortical vascular dementia: narrowing of blood vessels in the brain
- Single-infarct dementia: stroke cuts of blood supply to part of the brain (blood clot)
- Multi-infarct dementia: multiple strokes
Vascular Dementia - Symptoms
- Confusion
- Short-term memory problems
- Wandering & getting lost in familiar places
- Losing bladder or bowel control
- Difficulty following instructions
Vascular Dementia
Treatment
- No treatment to reverse brain damage
- Prevention of future strokes
- Address risk factors
Parkinson’s disease
Motor system disorder
Parkinson’s disease - cause
Loss of dopamine-producing neurons in the substantia nigra
Parkinson’s disease - Symptoms
- Tremor
- Rigidity – muscle stiffness
- Slowed movement (bradykinesia)
- Postural instability
- impaired balance and coordination
- Speech changes
Parkinson’s disease Treatment
No cure
Levodopa
- Enters brain and converted to dopamine
- Combined with carbidopa to prevent premature conversion
Deep brain stimulation
- Control dyskinesia (involuntary movements)
Huntington’s disease
Motor system disorder
Huntington’s disease - Cause
Familial hereditary disease (autosomal dominant )
Huntingtin gene mutation
Abnormally long version of huntingtin protein
- Expansion of CAG repeats (normally 10-35; mutation 36 – 120 repeats)
Smaller, toxic fragments - bind together and accumulate in neurons
Loss of huntingtin protein’s DNA repair function
- Accumulation of DNA damage in neurons?
Striatum and cerebral cortex particularly affected
- Co-ordinate movement and control thinking and emotions
Huntington’s disease Symptoms - Early
Memory lapses
Stumbling and clumsiness
Mood swings
Huntington’s disease Symptoms - Advanced
Uncontrolled jerking (“Huntington’s Chorea”)
Slurred speech
Slow or rigid movements
Personality changes
Breathing and swallowing problems
Huntington’s disease Symptoms - Treatment
No cure
Medications to manage
symptoms
Cerebral Aneurysm
Characteristics
- Ballooning/bulge in the wall of a blood vessel in the brain
- Caused by a weakness in the blood vessel wall, usually where it branches
Cerebral Aneurysm - Symptoms
Unruptured
- Depends on size and rate of growth - loss of feeling in the face or visual problems
After rupture
- Sudden agonising headache
- Stiff neck, vomiting & loss of consciousness
Cerebral Aneurysm Treatment
Unruptured
- Only treated if high risk
Surgery
- Endovascular coiling - fill the aneurysm with tiny platinum coils
- Neurosurgical clipping - tiny metal clip clamped on aneurysm
Ruptured
- Nimodipine - reduce risk of disruption to brain blood supply
(cerebral ischaemia)
- Clipping or coiling
Two types of CNS infections
Leptomeningitis & Encephalitis
Leptomeningitis & Encephalitis
Inflammatory conditions of the brain (encephalitis) and meninges of brain & spinal cord (meningitis)
Leptomeningitis & Encephalitis - Causes
Meningitis: bacterial or viral infections
Encephalitis: viral infections e.g., HSV, enteroviruses
Symptoms of meningitis
High fever
Severe & persistent headache
Stiff neck, nausea and vomiting
Confusion, sleepiness, and difficulty waking up
Increased sensitivity to light
Infants: irritability or fatigue, lack of appetite, fever
Symptoms of encephalitis
Sudden fever, headache, vomiting
Increased sensitivity to light
Stiff neck, confusion and impaired judgment
Drowsiness
Weak muscles, unsteady gait
Irritability
Severe symptoms of encephalitis
loss of consciousness, seizures, muscle weakness, or sudden severe dementia
Leptomeningitis & Encephalitis
Treatment
Bacterial infections: antibiotics
Viral infections: antiviral medications
Anticonvulsants to prevent or treat seizures
Corticosteroids to reduce brain swelling & inflammation
Sedatives may be needed for irritability or restlessness
Medications for fever and headache
Creutzfeldt-Jakob Disease (CJD)
Characteristics
Rare, degenerative, invariably fatal brain disorder
Spongiform encephalopathy
Creutzfeldt-Jakob Disease (CJD) - Cause
Abnormal, infectious protein = prion (no nucleic acid)
Prions accumulate at high levels in the brain & cause irreversible damage to neurons
No diagnostic test - confirmed by brain biopsy or autopsy
Creutzfeldt-Jakob Disease (CJD) - Treatment
None available
Death usually as a result of respiratory infections
Creutzfeldt-Jakob Disease (CJD)
Types
Sporadic
Variant
Familial
Creutzfeldt-Jakob Disease (CJD) - Sporadic
Normal brain protein changes abnormally (“misfolds”) and turns into a prion
Creutzfeldt-Jakob Disease (CJD) - Variant
Likely caused by consuming meat from a cow with bovine spongiform encephalopathy (BSE, or “mad cow” disease)
Creutzfeldt-Jakob Disease (CJD) - Familial
Very rare genetic condition
Mutation causes prions to form in the brain during adulthood
Creutzfeldt-Jakob Disease (CJD) – Initial symptoms
Neurological symptoms
- Problems with walking, balance & co- ordination
- Slurred speech
- Numbness
- Dizziness
- Visual problems
- Hallucinations
Psychological symptoms
- Severe depression
- Anxiety
- Irritability
- Insomnia
- Withdrawing
Creutzfeldt-Jakob Disease (CJD) – Advanced symptoms
Neurological symptoms
- Loss of physical co-ordination
- Muscle twitches and spasms
- Loss of bladder & bowel control
- Blindness
- Dysphagia
- Loss of speech
Psychological symptoms
- Severe memory loss
- Confusion
- Agitation
- Aggression
- Paranoia
- Appetite loss
Kuru
Rare and fatal brain disorder
When was kuru epidemic?
Epidemic levels during the 1950s-60s
Where is Kuru relevant?
Fore people in the highlands of New Guinea
Kuru - Causes
Transmissible spongiform encephalopathy (prion protein)
Ritualistic cannibalism
Kuru Symtoms
Cerebellum affected
Unsteady gait, tremors, and slurred speech
Behavioural & mood changes often present
