Week 5 Neurology Flashcards
How does the gait of someone with a functional leg weakness present differently to a structural?
It is often a dragging gait rather than a swinging one
What is the telltail sign of a functional tremor?
Can be eased by distracting the patient
How does a functional seizure present differently to an epileptic seizure?
Do you get changes in the brain in NFD?
Yes
How to treat FND?
An explaination fo the illness plus PT/OT
What is Anhedonia
Finding little pleasure in doing things or little motivation to do things
Which chemicals are commenly diminished in patients with depression?
Common antidepressant and how it works?
Sertraline
It is an SSRI which stands for selective seritonin reuptake inhibitor.
It prevents your synapse from taking seritonin back up thus there is more available in the synapse
What is the timeframe for when pain moves from acute to chronic?
Acute: 0-3 months
Chronic: 3-6 months
What is the difference between primary and secondary chronic pain?
Primary: No known cause
Secondary: Due to an underlying condition
Where is the perception of pain modulated?
In the thalamus.
Pain signal travel up the spinothalamic tract. Once they reach the thalamus they are combined with other sensory inputs, cognitive and emotional signals into the perception of pain.
Under normal conditions how is pain downregulated?
What stimulates this pathway?
In an area called the periaqueductal grey mater serotonin is released and travels down where it triggers the release of endogenous opioids in the dorsal horn spinal cord interneurons.
This pathway can be stimulated by the anticipation of pain relief e.g. placebo pain medication or by emotionally supportive efforts by the clinition
What is the periaqueductal grey mater?
This is grey meter surround the cerebral aquaduct in the midbrain.
It releases serotonin triggering the downregulation of pain signals.
Where is periaqueductal grey mater?
Surrounding the cerebral aquaduct in the midbrain.
What is the part of the brain that releases serotonin beginning the process of downregulation of pain?
Periaquaductal grey meter.
Hint: to be around rivers and streams in soothing
What is the area of the spinal chord that recieves seroronin from the periaquaductal grey mater and in responses releases endogenous opiods?
dorsal horn spinal cord interneurons
When it comes to the peripheral nervous system what does the term sensitization mean?
It refers to how strong a signal is produced by the same noxous stimuli.
For example in infected tissue a reduced acidic pH results in the stimulation threshold being decreased, thus pressure on an infected area causes more pain than pressure on an unaffected area.
What are the three steps to pain management.
What does this tell you about reviewing?
There is a fine balance between suffering and addiction risks.
Regular reviews are necessary in order to establish which level a person is it.
What are these features of?
Constricted pupils
Reduced respiratory effort
Hypotension
Low GCS
opioid overdose
Which opioid receptors are responsible for respiritory depression?
μ-opioid receptors
When excited these are responsible for respiratory rate, inspiratory volume, CO2 chemoreception and pharyngeal function
WHat is the mechanism of naloxone?
It has a higher affinity for opioid recptors but doesn’t depress them in the same way.
WHat is the definition of neuropathic pain?
Pain caused by damage to a nerve through degregation, inflamation, compression etc.
What is the mechanism of amitriptyline and what drug class is it?
Tricyclic antidepressant.
It is a serotonin reuptake inhibito like SSRIs however it also affects the reuptake of norepinephrine.
What is the mechanism of gabapentin and pregabalin?
Gabapentin and pregabalin act on calcium channels pre-synaptically to reduce release of pro-nociceptive neurotransmitters. They decrease excitability, especially in the spinal cord.
What is the mechanism by which opioids decrease pain?
The bind to opioid receptors blocking dopamine inhitory neurons. This encourages the reslease of dopamine between the secondary and tertiary neuron where the tertiary neurons releive pain.
HInt: opioids are dope
Where do pain patchs work?
At the skin nociceptors.
What does a benzo overdose look like?
Similar to an opioid overdose but without the contricted pupils.
Use flumazenil if you are sure of drug and dose and airway is threatened
Presentation and treatment of an SSRI overdose
Presents as serotonin syndrome.
“Serotonin syndrome”
N&V, agitation, tremor, nystagmus, dilated pupils, tachycardia, neuromuscular hyperactivity, hyperthermia.
Monitoring & Supportive treatment
Treatment of an amitryptaline overdose?
Amitriptyline (Antidepressant / Neuropathic analgesia)
Inihibits serotonin & noradrenaline reuptake, blocks Na+ channels but non-specific & broad symptoms.
Arrhthymia, seizure, coma.
Sodium bicarb to correct acidosis.
What is the everyday purpose of stretch reflexs?
Contraction of a muscle in response to sudden stretch in order to maintain balance
Which parts of the labarynth are responsible for hearing and which parts balance?
- Vestible & Semicircular canals (balance)
- Cochlea (hearing)
Which forms of awareness are the vestible and semicircular canal responsible for?
Vestibule
Oval structure at the centre of the labyrinth
Utricle and saccule
detect linear acceleration - head position with respect to gravity
Semicircular Canals
3 ‘loops’: anterior, posterior and lateral
Detect angular (rotational) acceleration
Which spacial planes do the different semicircular canals occupy?
Anterior and posterior in vertical plane
Lateral in horizontal plane
How do the cells of the vestibular system recieve movement information?
Cells of the vestibular system detect movement of fluid in the labyrinth using mechanosensitive hair cells
Apical surface covered by cilia, membrane-bound hair like projections.
The cells are covered by the otolithic membrane, a jelly like structure containing many small crystals called otoliths.
Movement results in the otolithic membrane lagging behind the layer of hair cells due to inertia
Hair cells act as transducers, converting kinetic energy into nervous impulses.
Three different types of dizzyness and what they mean for the causes
What is benign paroxysmal positional vertigo (BPPV)
Pathophysiology, prognosis, diagnoses and treatment?
Presence of otolithic debris affecting free flow of endolymph in semicircular canals
Typically spontaneous, may follow after minor head injury
Transient (seconds) precipitated by movement
Self-limiting after weeks or months
Dix-Hallpike manoeuvre is diagnostic, Epley manoeuvre helps move debris to utricle and saccule
What is the Dix-Hallpike manoeuvre?
You rotate the patients head by 90 degrees. Then ask them to lie down radidly while supporting the head.
If this makes the dizzyness worse and you observe nystigmus then it is a dianogses of BPPV
What is Nystagmus?
Nystagmus is a rhythmical, repetitive and involuntary movement of the eyes. It is usually from side to side, but sometimes up and down or in a circular motion.
What does BPPV stand for?
Benign paroxysmal positional vertigo (BPPV)
What is the Epley manoeuvre?
Patient turns their head to the affected side and performs dix-hallpike.
They then wait and turn their head to the other side.
Then also rotate the body and sit up.
This should help move the debris to the vestible
What manouvre would you use to treat BPPV?
Epley manouvre
What manouvre would you use to diagnose BPPV?
Dix-hallpike manouvre
What could it be if a patient presents with vertigo combined with tinitis, increasing deafness and feeling of fullness in the ear?
Ménière disease
Examples of vestibular sedatives?
Drugs that decrease vertigo.
- Antihistamines: Cinnarizine, dimenhydrinate, and meclizine
- Dopamine receptor antagonists: Prochlorperazine
- Anticholinergics: Scopolamine
- Benzodiazepines: Diazepam (Valium), clonazepam, lorazepam, and alprazolam
Short answer: ines
Prevelence of delirium?
Very common, affecting ~25% of all hospital in-patients
The top clinical presentation for a junior doctor to be familiar with
What is the screening tool for dilerium called?
4AT
Hint: The 4 legged ATATs fell over due to dilerium
What do each of these labels say?
And decribe the pathways of visual information
Light enters form the visual field, is focussed, crosses over then lands on the temporal or nasal regions of the retina.
It then travels up the optic nerve.
Information from the nasal portion of the optic nerve (temporal visual field) then crosses over at the optic chiasm.
Information from each visual field then travels up the optic tract and to the lateral geniculate body.
Fibres from the lower and upper visual fields separate with lower travelling through the temporal lobe and upper travelling through the anterior parietal.
They then reach the occipital cortical areas in the optic radiation.
What are the names for the following visual field defects?
Decribe the experience of the following visual field defects
What visual field defects would you get from lesions at the following sites?
When there is a lesion in the visual cortex why do you get macular sparing?
Macular sparing occurs because the visual cortex has a dual blood supply from the middle cerebral artery (MCA) and the posterior cerebral artery (PCA). If one vascular pathway is damaged, the macular regions of the visual cortex can still rely on the other blood supply
What is pappilodema a sign of?
Increased ICP
Which part of the retina is responsible sensing red/green light?
Cones
2 major layers:
* Neurosensory retina
* Retinal pigment epithelium
Neurosensory retina
* Photoreceptors – specialised neurons for phototransduction
* Rods - ↑sensitive, ↓acuity, no colour
* Cones - ↓sensitive , ↑acuity, red/green
* Ganglion – new (2007), blue, circadian rhythm
Retinal pigment epithelium:
* Maintain overlying neurosensory layer
* Absorbing scattered light
* Blood/eye barrier
Hint: Traffic cones are red
Which part of the retina is responsible sensing blue light and circadian rythm?
Ganglion
2 major layers:
* Neurosensory retina
* Retinal pigment epithelium
Neurosensory retina
* Photoreceptors – specialised neurons for phototransduction
* Rods - ↑sensitive, ↓acuity, no colour
* Cones - ↓sensitive , ↑acuity, red/green
* Ganglion – new (2007), blue, circadian rhythm
Retinal pigment epithelium:
* Maintain overlying neurosensory layer
* Absorbing scattered light
* Blood/eye barrier
What does the primary visual cortex do?
Primary Visual Cortex
Occipital lobe
Receives direct visual signal input originating from the contralateral side (e.g. left visual field to right PVC)
Higher Visual Centres (ventral-dorsal model)
Dorsal Stream
Posterior parietal cortex
‘where/how’ pathway
Integrates vision with motor/sensation
Ventral Stream
Inferior temporal cortex
‘what’ pathway
Form recognition, object representation, visual memory
What does the dorsal stream do and where is it?
Primary Visual Cortex
Occipital lobe
Receives direct visual signal input originating from the contralateral side (e.g. left visual field to right PVC)
Higher Visual Centres (ventral-dorsal model)
Dorsal Stream
Posterior parietal cortex
‘where/how’ pathway
Integrates vision with motor/sensation
Ventral Stream
Inferior temporal cortex
‘what’ pathway
Form recognition, object representation, visual memory
What does the ventral stream do and where is it?
Primary Visual Cortex
Occipital lobe
Receives direct visual signal input originating from the contralateral side (e.g. left visual field to right PVC)
Higher Visual Centres (ventral-dorsal model)
Dorsal Stream
Posterior parietal cortex
‘where/how’ pathway
Integrates vision with motor/sensation
Ventral Stream
Inferior temporal cortex
‘what’ pathway
Form recognition, object representation, visual memory
What is visual agnosia?
Which part of the brain is likely affected?
Visual Agnosia
- Inability to visually recognise objects
- Lesions of ventral stream - occipital and/or temporal lobes
What is the part of the brain that communicates information about coordination of eye’s movements from the midbrain and pons to the cranial nerves responsible for eye movement?
Medial longitudinal fasciculus (MLF)
What does a lesion in the MLF result in?
Disconjugate eye movements
Also known as Internuclear Ophthalmoplegia
What is an ocularvestibular response?
A reaction where you look towards an irritation in the ear
When might you test for an ocularvestibular response?
To look for MLF lesions in comatose patients (you can’t ask them to move eyes)
How does Internuclear Ophthalmoplegia present and what does it signify?
Inability to adduct. Dysconjugste eye movements.
Signifies a lesions in the medial longitudinal facsiculus
This is different to an occulomotor nerve palsy as the resting gaze will be normal. And diplopia will only be present when looking horizontally.
Where are visual movements cordinated?
In the midbrain and pons
What is the difference between wernicke’s area and broca’s area?
Wernicke’s Area (Sensory)
* Location: posterior temporal lobe
* Inputs:
1. Sounds of words sent from auditory pathways
2. Visual representation of words from visual pathways
* Function: temporal speech/language comprehension
Broca’s Area (Motor Programming)
* Location: dominant inferior frontal gyrus
* Inputs: Temporal and parietal lobes via the arcuate fasciculus
* Outputs: cranial nerve nuclei in pons, medulla controlling bulbar muscles
Describe the differences between expressive dysphasia, receptive disphasia and conduction dysphasia.
Which parts of the brain are affected?
Expressive Dysphasia (Broca’s area)
Effortful and broken speech (telegraphic)
Comprehension may be intact
Receptive Dysphasia (Wernicke’s area)
Difficulty understanding language
Fluent and effortless speech, but may lack meaning
Conduction Dysphasia (arcuate fasciculus)
Intact comprehension and fluent speech, but poor speech repetition
What is the arcuate fasciculus?
Connects Wernicke’s to Broca’s.
Disruption of this area causes conduction dysphasia where articulation and understanding are fluent however you can’t repeat words when instructed as communication between reception and expression is broken therefore the two aren’t linked.
Difference between dysarthria, dysphonia and anathria?
Dysarthria – Impairment of speech production due to neurological damage to the motor component of speech. Sounds slurring
Anarthria – Total loss of speech production
Dysphonia – Impairment of speech production due to changes in the vocal apparatus. Sounds hoarse, raspy
WHat is it called when speech is impaired due to Impairment of speech production due to neurological damage to the motor component of speech and it sounds slurring?
Dysarthria
What is it called when speech is impaired due to changes in the vocal apparatus and it sounds hoarse, raspy
Dysphonia
What is 5-hydroxytryptamine known as?
Serotonin
