Previous Exam Questions Flashcards
Discuss the three main histological features of Alzheimer’s
The senile plaque (neuritic plaque)
o occur mainly in the hippocampus (also in other areas of cortex and deep grey matter)
o up to 200 m in diameter
o initially is a collection of dilated pre-synaptic neuronal processes which contain many organelles
o with maturation observe:
➢ enlargement
➢ degeneration of the neuronal processes
➢ core of aluminosilicates and amyloid protein develops
➢ reactive astrocytes and microglia collect at the periphery of the plaque
o burnt out phase of plaque development
➢ the neuronal processes have degenerated completely
➢ the plaque is an extracellular collection of amyloid protein
Neurofibrillary tangles (developing in cytoplasm of affected cells)
o appear in the cytoplasm of neurons
o occur mostly in hippocampal neurons (occur in other parts of CNS also)
o observe the following changes:
➢ thickening of fibrils in the neuronal cytoplasm
➢ the fibrils form tortuous, elongated, cork-screw like structures
➢ the fibrils resemble neurofilament and microtubule associated proteins
Diffuse Neuronal Loss
As name suggests
List the causes of Guillan Barre Syndrome
Factors predisposing to GBS:
- follows infection (bacterial and viral agents)
- Campylobacter jejuni (onset variable; affected patients commonly experience more rapid deterioration)
- EBV
- Herpes
- Lyme disease
- HIV
- Zika virus
- Gangliosides (grey matter lipids in the brain) are targeted by immunoglobulins and share antigenic epitopes with some bacterial and viral antigens
- Linked to vaccines
- swine flu
Discuss the clinical features of GBS
Painless onset of mild weakness in the lower extremities
- the pt often does not notice the weakness unless walking up hill/climbing stairs etc.
- may have tingling/paraesthesia in toes and fingers
- deep tendon reflexes are diminished
Weakness becomes more profound
- after a few days since onset
- often extends to involve upper limbs and eventually the face (landry’s ascending paralysis)
- deep tendon reflexes disappear
- loss of proprioception in arms and legs
- breathing and swallowing becomes difficult
- clinical findings include: symmetrical motor weakness (both proximal and distal mm of all limbs
Weakness progresses for several days to a couple of weeks, and finally stabilises, remaining constant for a variable period of time.
Recovery then begins (85% of pt. healing is complete in several weeks to months)
Write notes on complex partial seizures
It is synonyms with the temporal lobe = psychomotor seizures
- usually originating in one of the temporal lobes
- the seizure results in an impairment or loss of consciousness
Observe 2 variants:
1st
- an initial partial seizure with symptoms and signs reflecting its origin in the temporal lobe
- a change in the initial symptoms and signs in which we observe motor complaints (automatisms) e.g. lip smacking, chewing, fumbling of hands, complex behaviour
- the pt gradually experiences varying degrees of impaired consciousness and memory (may have postictial amnesia)
Define mononeuritis multiplex
When several peripheral nerves are affected in a specific point in time
What is the main cause of mono neuritis multiplex?
Vasculitis
Discuss the diagnosis of Fibromyalgia
week 11
Define and describe the three types of neuronal degeneration and their key features
Axonal degeneration
- primary degeneration of the axon followed by secondary degeneration of the myelin sheath
- results in degeneration of the distal axon (then degeneration follows a distal to proximal pattern)
- usually symmetric
- most common pathologic reaction occurring in polyneuropathies
- often secondary to metabolic aetiology
Following manifestations can be evident:
- symmetrical glove and stocking sensorimotor disturbances
- diminished/loss of deep tendon reflexes
disordered ANS function
Segmental demyelination
is the focal degeneration of the myeline sheath with sparing of the axon. occurring mainly in focal mononeuropathies; also seen in generalised sensorimotor or predominantly motor neuropathies
*Can be acquired (caused by immune ir inflammatory conditions) or hereditary (Charcot-Marie-Tooth disease)
*classification:
Primary: schwann cell is damaged
Secondary: follows axon degeneration
Wallerian degeneration
When the axon degenerates distal to a focal lesion that interrupts its continuity
Define and describe the three types of neuronal degeneration and their key features
Axonal degeneration
- primary degeneration of the axon followed by secondary degeneration of the myelin sheath
- results in degeneration of the distal axon (then degeneration follows a distal to proximal pattern)
- usually symmetric
- most common pathologic reaction occurring in polyneuropathies
- often secondary to metabolic aetiology
Following manifestations can be evident:
- symmetrical glove and stocking sensorimotor disturbances
- diminished/loss of deep tendon reflexes
disordered ANS function
Segmental demyelination
is the focal degeneration of the myeline sheath with sparing of the axon. occurring mainly in focal mononeuropathies; also seen in generalised sensorimotor or predominantly motor neuropathies
*Can be acquired (caused by immune ir inflammatory conditions) or hereditary (Charcot-Marie-Tooth disease)
*classification:
Primary: schwann cell is damaged
Secondary: follows axon degeneration
Wallerian degeneration
When the axon degenerates distal to a focal lesion that interrupts its continuity
* caused by:
- trauma
- infarction of peripheral nerve (diabetic mononeuropathy, vasculitis)
- neoplastic infiltration
Write notes on MS plaques
The characteristic feature of MS is the “plaque” i.e. an area of demyelination. (abnormal area in CNS)
a) acute plaque (i.e. early lesion)
- occurs during acute inflammatory episode in CNS
- 0.1 - several centimetres in diameter
- often occurs in periventricular areas of CNS
- plaque is soft and pink
- ill-defined borders
- oedema **
- histologically: breakdown of myelin & phagocytosis by macrophages
- perivascular infiltration and accumulation (cuffing) of inflammatory cells (T-cells, plasma cells)
- perivascular (around blood vessel) infiltration of monocytes & lymphocytes (found in infection – immune system activated)
b) chronic plaque: (i.e. myelin breakdown & inflammation subsides)
- lesion that occurs as acute inflammatory episode in CNS dies down
- reactive fibrillary gliosis occurs
o gliosis = specialized CNS scar tissue produced by the enlargement of astrocyte cellular processes.
o When CNS is damaged astrocyte processes enlarge & expand to fill gaps left behind by dead cells
o Process referred to as gliosis, but resulting permanent scar tissue is called a chronic plaque
- sharply defined, grey/translucent areas of demyelination (as previous inflammatory process has destroyed the myelin sheath)
- few/absent oligodendrocytes
- subsidence of perivascular infiltrates
- induration (hardening / stiffening) of affected tissues (hence sclerosis = scaring)
• Commonest sites of development of the patches of demyelination is the white matter of the brain & spinal cord. The following areas are characteristically involved:
- optic nerves (= the commonest initial site)
- brain stem
- cerebellar peduncles
- dorsal and lateral (pyramidal) spinal tract
Clinical features of MS
• Observe sudden development of a focal neurological deficit which spontaneously recovers (very first manifestation)
• Frequency of initial symptoms and signs:
- limb weakness 40-50%
- optic neuritis 20% → pale optic nerve → visual field . lost in L eye on R side
- bladder dysfunction 5%
- paraesthesia 20% (fingers & toes arise 1st)
- diplopia 10%
- vertigo 5%
