Neuropathology 2 Flashcards
Name some common neurodegenerative diseases
- Motor neuron disease (amyotrophic lateral sclerosis),
- Dementia,
- Parkinson’s disease,
- Spongiform encephalopathies,
- Multiple Sclerosis
What is ALS?
- Most common form of motor neuron disease.
- Usually begins with unilateral cramps and progression to same area on other side.
- Sparing of neuron damage is around the extra-ocular area however both UMN and LMN are effected.
- Patients normally die from respiratory complications
What are common characteristics of ALS?
- Focal weakness and clumsiness which spreads.
- Painful fasciculation and cramping,
- Some have dysarthria, dysphagia or resp issues,
- UMN and LMN signs,
- Sensory and mental exam are normal.
List the types of dementia in order of how common
1) Alzheimers,
2) Dementia with lewy bodies,
3) Vascular dementia,
4) Frontotemporal dementia
What are the anatomical effects of Alzheimer’s on the brain?
Reduced brain weight, cortical atrophy, enlarged ventricles, and cell loss evident in medial temporal lobes and hippocampi
What are the microscopic pathological features of alzheimers?
- Neurofibrillary tangles (composed of tau). Tangle progression is the spread of these tangles throughout the brain.
- Amyloid plaques, Diffuse plaques can be found in older people without dementia and neurotic plaques are strongly associated with cognitive decline
Parkinson’s disease is characterised by what?
- Neuronal loss in the substantia nigra,
- Degeneration of nigrostriatal tract,
- Profound loss of dopamine in basal nuclei,
- Surviving neurons contain lewy bodies made of alpha-synuclein
Describe features of prion disease in spongiform encephalopathies
Cause misfolded cell surface protein and causes cells and proteins to clump together resulting in cell death. Most common form is CJD - creutzfeldt-jakob disease.
What are symptoms of CJD?
- Rapidly developing dementia,
- Difficulty walking,
- Muscle stiffness and fatigue,
- speech problems,
- In later stages it can present with hallucinations and confusion
What is Multiple Sclerosis?
Autoimmune disease of CNS where immune cells are stimulated to phagocytose the myelin normally found insulating the axons of nerve cells. Therefore signal transmission along the fibre slows and can become delayed.
Proprioceptive feedback systems don’t synchronise well with motor output. Presents with muscle fatigue.
What are Dawson’s fingers?
Radiographic feature of periventricular demyelinating plaques (sign of MS)
Describe what mats are and their effects in MS?
Overgrown astrocytes form dense mats due to recurrent inflammation and this interferes eventually with oligodendrocytes re-myelinating axons
What are the common causes of peripheral neuropathy?
- Diabetes mellitus,
- Idiopathic,
- Toxic (alcohol or drugs)
- Vitamin Deficiency (B12),
- Post-infectious,
- paraneoplastic,
- leprosy,
- Amyloid or other inflammation such as vasculitis.
What are different types of
peripheral neuropathy neuron changes?
- Distal axonal degeneration,
- Segmental demyelination
Name an example of peripheral neuropathy and its effects
- Charcot marie-tooth which is a loss of distal motor and sensation with associated muscle wasting and weakness.
- Demyelination condition in peripheral NS due to genetic problem with peripheral myelin 22 gene
- (Inverted champagne legs)
What are the issues of sural nerve biopsy?
It can cause loss of sensation and 30% will get neuropathic pain.
Describe the innervation of the different muscle fibres?
Slow twitch fibres which have low ATPase activity are innervated by alpha 2 motor neurons (smallest motor neuron fibres)
Fast twitch fibres which have high ATPase activity are innervated by alpha 1 motor neurons (largest motor neurons)
Describe features of muscle biopsy
It is usually done under local anaesthetics and usually taken from deltoid, quadriceps or tibialis anterior.
Name some of the inherited muscle diseases
- Dystrophies (DMD - X linked recessive inheritance),
- Congenital myopathies,
- Mitochondrial (from maternal line),
- Metabolic,
- Myotophic
What are some acquired muscle diseases
- Inflammatory (polymyositis),
- Toxic (alcohol/simvastatin),
- Metabolic (excess steroid and Cushing’s),
- Disuse atrophy,
- Rhabdomyolysis
What is the molecular pathophysiology behind muscular dystrophies?
- Issue with dystrophin proteins (connect cytoskeleton of muscles cells to the outer membrane)
