Neuro Flashcards
What do oligodendrocytes myelinate?
Brain
What do Schwann cells myelinate?
Peripheral Nervous System (PNS)
Define nuclei
Collection of nerve cell bodies within the CNS
Define ganglia
Collection of nerve cell bodies outside the CNS and some in the CNS (in a capsule)
What sort of information is carried on afferent fibres?
Sensory fibres towards the CNS
What sort of information is carried on efferent fibres?
Motor fibres away from the CNS
What is the function of the frontal lobe?
Voluntary movement on opposite side of the body
Dominant frontal lobe control speech (Broca’s area) and writing
Intellectual functioning, thought processes, reasoning and memory
What is the function of the parietal lobe?
Receives and interprets sensations - pain, touch, pressure, proprioception
What is the function of the temporal lobe?
Understanding spoken word (Wernicke’s area)
Memory and emotion
What is the function of the occipital lobe?
Understanding visual images and meaning of written word
What are the components of the basal ganglia?
Striatum (Caudate nucleus + Putamen)
Globus pallidus
Subthalamic nucleus
Substantia nigra
What are the components of the striatum?
Caudate nucleus
Putamen
What are the components of the lentiform nucleus?
Globus Pallidus
Putamen
What is the function of the cerebellum?
Co-ordinates movement and balance
Describe the function of the hippocampus
Episodic memory
Construction of mental images
Short term memory
Spatial memory and navigation
How many axons can oligodendrocytes myelinate?
Multiple
How many axons can Schwann cells myelinate?
One
What is the function of ependymal cells?
Line ventricles of the brain and regulate the production and flow of CSF
Which cells make up the blood-brain-barrier?
Endothelial cells, pericytes and astrocytes
What are the features of the BBB?
Endothelial tight junctions
Astrocyte end feet
Pericytes
Continuous basement membrane
What is the name given to areas of the brain that lack a BBB?
Circumventricular organs
E.g. Posterior pituitary
Where does the CSF circulate?
Subarachnoid space
What is the volume of CSF?
120 mls
What is found in the CSF?
Protein, urea, glucose and salts
Where is CSF produced?
By ependymal cells in the choroid plexus (mainly in lateral ventricles)
How is CSF reabsorbed?
Via arachnoid granulations (villi) into the superior sagittal sinus
Describe the passage of CSF
Produced by ependymal cells in choroid plexuses of lateral ventricles –> 3rd ventricle via interventricular foramen –> 4th ventricle via the cerebral aqueduct –> subarachnoid space vis the median foramen of Magendie and 2 lateral foramen’s of Luschka –> absorbed via arachnoid granulations (vili) into superior sagittal sinus
Describe what happens in hydrocephalus
Abnormal accumulation of CSF in the brain which leads to a build-up of pressure often due to a blocked cerebral aqueduct
What are the 5 processes of synaptic transmission?
- Manufacture (intracellular biochemical processes)
- Storage - vesicles
- Release - AP
- Interaction with post synaptic receptors
- Inactivation
What are the 2 main acethylcholine receptors?
- Muscarinic
2. Nicotinic
Which enzymes is responsible for the breakdown of ACh in the synaptic cleft?
Acetylcholinesterase
ACh –> Choline + acetate
What functional area of the brain surrounds the primary auditory cortex?
Wernicke’s area (processes language)
Inferior colliculus and medial geniculate body are important for what sense?
Hearing
I’M Auditory
The superior colliculus and lateral geniculate body are important for what sense?
Vision
Which part of the eye is involved in the accommodation reflex?
Ciliary muscle
What does the iris do?
Controls the size of the pupil (which lets light into the eye)
What does the dilator papillae muscle do?
Dilates the pupil (sympathetic)
What does the sphincter papillae do?
Constricts the pupil (parasympathetic)
What fibres cross at the optic chiasm?
Nasal portions of the retina carrying the temporal visual field
Where in the thalamus do the optic tracts join to?
Lateral geniculate body
Outline the order of the visual pathway from the eye to visual cortex
Eye –> optic nerve –> optic chiasm –> optic tract –> lateral geniculate body (thalamus) –> optic radiation –> visual cortex
What is the name of the optic radiation that passes through the parietal lobe and what information does it carry?
Baum’s loop - information from the superior retina (so inferior visual fields)
What is the name of the optic radiation that passes through the temporal lobe and what information does it carry?
Meyer’s loop - information from inferior retina (so superior visual fields)
What is the effect of a lesion on the left optic nerve?
Left anopia = no vision in left eye
right lesion = right eye blindness
What is the effect of a lesion at the optic chiasm?
Loss of temporal visual fields = bilateral hemianopia
What is the effect of a lesion on the right optic tract?
Loss of vision of temporal field of the left eye
Loss of nasal field of the right eye
= right homonymous hemianopia
What is the effect of a lesion on the left Meyer’s loop?
Carries information from inferior retina and thus the superior visual field so:
- Loss of vision in the superior nasal field of the left eye
- Loss of vision in the superior temporal field of the right eye
What is the effect of a lesion on the left Baum’s loop?
Carries information from the superior retina and thus the inferior visual field so:
- Loss of vision in the inferior temporal field of the right eye
- Loss of vision in the inferior nasal field of the left eye
What is the name given to internal rotation of the eye (towards midline)?
Intorsion
What is the name given to external rotation of the eye (away form midline)?
Extorsion
What are the 6 ocular eye muscles?
- Superior rectus
- Inferior rectus
- Lateral rectus
- Medial rectus
- Superior oblique
- Inferior oblique
Which muscles of the eye are supplied by the oculomotor nerve (CN III) and what are their functions?
Superior rectus = medial rotation, elevation and adduction
Inferior rectus = lateral rotation, depression and adduction
Medial rectus = Adduction
Inferior oblique = extorsion, elevates and abducts
Which muscles of the eye are supplied by the abducens nerve (CN VI) and what are the functions?
Lateral rectus = abduction
Which muscles of the eye are supplied by the trochlear nerve (CN IV)?
Superior Oblique = intorsion, depresses and abducts
What does the somatic nervous system innervate?
Skeletal muscle
Do neurones of the somatic nervous system synapse before the skeletal muscle?
No
What is the only neurotransmitter involved in the somatic nervous system?
Acetylcholine
What does the autonomic nervous system innervate?
Smooth and cardiac muscle, glands, neurones in the GIT
Where is the first synapse of an autonomic nerve?
Synapses outside the CNS in the autonomic ganglion
What’s the name of the autonomic nerve between the CNS and the ganglia?
Preganglionic fibres
What’s the name of the autonomic nerve between the ganglion and the effect cells??
Postganglionic fibres
What are the 2 division of the autonomic nervous system?
- Sympathetic
2. Parasympathetic
Where do the sympathetic nerves leave the spinal cord?
Between T1 and L2
Where do the ganglia of the sympathetic neurones lie?
Close to the spinal cord = sympathetic chain
What neurotransmitter is used by the preganglionic sympathetic fibres?
Acethylcholine acts at nicotinic receptors
What neurotransmitter is used at the effector cell synapse in sympathetic fibres?
Noradrenaline acts at adrenergic receptors
What are the effects of the sympathetic nervous system?
Increased HR (+ve chronotropic) Increased force of contraction (=ve inotropic) Vasoconstriction Bronchodilation Reduced gastric secretion Reduced gastric motility Sphincter contraction Male ejaculation
Where do parasympathetic nerves leave the spinal cord?
Brainstem and sacral regions of the spinal cord
Which cranial nerves are parasympathetic?
CN 3, 7, 9 and 10 (1973)
Where do the ganglia of parasympathetic nerves lie?
Close to the organs that the postganglionic fibres innervate
What is the neurotransmitter used by preganglionic parasympathetic fibres?
Acetylcholine at nicotinic receptors
What is the neurotransmitter used by postganglionic parasympathetic fibres?
Acetylcholine at muscarinic receptors
What are the effects of the parasympathetic nervous system?
Decreased heart rate (-ve chronotropic) Decreased force of contraction (-ve inotropic) Vasodilation Bronchoconstrition Increased gastric motility Increased gastric secretion Sphincter relaxation Male erection
Define CNS
Consists of the brain and spinal cord
Define PNS
Nerves and ganglia outside the brain and spinal cord
How many vertebrae are there?
Total = 33
- 7 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 4 coccyx
How many spinal nerves are there?
31 pairs of spinal nerves
- Cervical = 8 nerves (1 higher than the corresponding vertebrae and an extra below C8)
- 12 thoracic nerves (1-2 vertebra below corresponding vertebra)
- 5 lumbar nerves (3-4 vertebra below)
- 5 sacral (5 vertebrae below)
- 1 coccyx nerve
Define dermatome
Area of skin supplied by a single spinal nerve
Define myotome
A volume of muscle supplied by a single spinal nerve
What are the 2 division of the descending motor pathways?
Pyramidal and extrapyramidal
Describe the corticospinal pathway
Controls voluntary muscles
Originates in the cortex –> internal capsule –> crura cerebri
- 85% decussate in medulla through anterior white commissure = lateral –> limb muscles
- 15% ipsilateral = anterior –> axial muscles
Describe the extrapyramidal pathways
Originate in the brainstem and carry motor fibres to the spinal cord
Responsible for the involuntary autonomic control of all musculature
What are the extrapyramidal tracts?
Rubrospinal - Facilitates flexors and inhibits extensors (fine hand movements) - Originates in red nucelus - Decussate in midbrain (contralateral) Tectospinal - Head turning in response to visual stimuli - Originates from tectum - superior colliculus - Decussate in midbrain Vestibulospinal - Muscle tone, balance and posture - Originates at vestibular nucleus - Non-decussating (Ipsilateral)
What are the ascending sensory tracts?
- Dorsal/medial lemniscus columns
- Spinothalmic tract
- Spinocerebellar tract
Dorsal/medial lemniscus column consists of what and carries what sensations?
Fasciculus cuneatus and gracilis
Ascend to medulla and decussate to become the medial lemniscus –> thalamus –> somatosensory cortex
Proprioception, vibration and fine touch
What does the fasciculus cuneatus carry?
It is lateral and carries information from the UPPER body to the cuneate tubercle in the medulla
What does the fasciculus gracilis carry?
It is medial and carried information from the LOWER body to the gracile tubercle in the medulla
Describe the spinothalamic tract
Lateral = pain and temperature
Medial/anterior = Crude touch
Ascend on same side then decussate before ascending to thalamus
Describe the spinocerebellar tract
Posterior = carries proprioception to ipsilateral inferior cerebellar peduncle Anterior = carries proprioception to the contralateral superior cerebellar peduncle
Describe Brown Sequard Syndrome
Hemi-section of the spinal cord
- Ipsilateral weakness below the lesions due to damage to the ipsilateral descending motor corticspinal tract (decussated at the medulla)
- Ipsilateral loss of vibrations and proprioceptive sensation due to damage to dorsal column
- Contralateral loss of pain and temperature below the lesion due to spinothalamic damage (decussate within spinal cord)
What is the basal ganglia?
Group of nuclei lying deep within the cerebral hemispheres
What are the main functions of the basal ganglia?
Purposeful behaviour and movement
Inhibits unwanted movements
Controls posture and movement
Facilitation, integration and fine tuning of movements
What are the 3 coverings of the spinal cord form outermost to innermost?
- Dura
- Subarachnoid
- Pia
What are the 2 enlargements of the spinal cord?
Cervical (C3-T1) = uper limbs
Lumbar (L1-S3) = lower limbs
Describe the anatomy of the spinal cord after it ends at L1/2
Tapers into a cone (conus medullaris) and ends in a strand of tissue called filum terminale
What information does the lateral spinothalamic tract carry?
Pain and temperature
What does the medial spinothalamic tract carry?
Crude touch
What is the somatic motor function of the facial nerve?
Muscle of facial expression
What is the visceral motor function of the facial nerve?
Lacrimal glands
Submandibular and sublingual glands
What are the functions of the facial nerve?
Motor to facial movements Salivation (submandibular and sublingual) Lacrimination Sensation from external ear Taste from anterior 2/3 of tongue
What are the 2 motor functions of the glossopharyngeal nerve?
Elevate the pharynx by supplying the stylopharyngeus
Secretion of the parotid gland (parasympathetic)
What are the sensory functions of the glossopharyngeal nerve?
Sensation to external ear Posterior 1/3 of tongue Pharynx Eustachian tube Carotid sinus, baro and chemoreceptors
What are the functions of the vagus nerve?
Taste - posterior pharynx
Swallowing - muscle of pharynx and larynx except stylopharyngeus
CV and GI regulation (parasympathetic)
What does the accessory nerve supply?
Sternocleidomastoid
Trapezius
What does the hypoglossal nerve supply?
Intrinsic and extrinsic muscles of the tongue
What is the sensory and taste innervation of the posterior 1/3 of the tongue?
Glossopharyngeal nerve
What is the sensory sensation of the anterior 2/3 tongue?
Lingual branch of the V3 from trigeminal (mandibular branch)
What is the taste sensation for the anterior 2/3 of tongue?
Chorda tympani branch of the facial nerve carried by lingual branch
What passes through the cavernous sinus?
O TOM CAT: Oculomotor (CN III) Trigeminal (CN V) Ophthalmic trigeminal (CN Va) Maxillary trigeminal (CN Vb) Carotid (internal) Abducens (CN VI) Trochlear (CN IV)
Damage to Broca’s area results in what sort of aphasia?
Expressive aphasia
Understand what is being said and know what they want to say but can’t express it in meaningful words
Damage to Wernicke’s area results in what sort of aphasia?
Comprehension aphasia
Difficulty understanding written or spoken language but hearing and vision not impaired
Have fluent speech but may scramble words
What is the most common artery for a berry aneurysm to occur?
Anterior cerebral artery
What are the functions of the ophthalmic division of the trigeminal nerve?
Sensation to the anterior head and face (superior 1/3) including scalp, forehead, cornea and tip of nose
What are the functions of the maxillary division fo the trigeminal nerve?
Sensation to middle 1/3 of face including cheek, nose, upper lip, upper teeth and palate
What are the functions of the mandibular division of the trigeminal nerve?
Sensation to inferior 1/3 of face including lower lip, lower teeth, chin, jaw and anterior 2/3 of tongue
Motor to muscles of mastication and tensor tympani muscle
What is cerebellar syndrome?
Ataxia = loss of full control of body movements
Nystagmus = rapid eye movements
Deficit on IPSILATERAL side as cerebellar lesion
What is the criteria for brainstem death?
Pupils Corneal reflex Caloric vestibular reflex Cough reflex Gag reflex Respirations Response to pain
Name 3 types of primary headache
No underlying cause
- Migraine
- Tension headache
- Cluster headache
Name 2 types of secondary headache
Underlying cause
- Meningitis
- Subarachnoid haemorrhage
- Giant cell arteritis
- Idiopathic intracranial hypertension
- Medication overuse headache
Give an example of a tertiary headache
Trigeminal neuralgia
Give 6 questions that are important to ask when taking a history of headache
- Time = onset, duration, frequency, pattern
- Pain = severity, quality, site, spread
- Associated symptoms - n/v, photophobia, phonophobia
- Triggers/aggravating/relieving factors
- Response to attack = is medication useful?
- What are the symptoms like between attacks?
Give 5 red flags for suspected brain tumour in a patient presenting with a headache
- New onset headache and history of cancer
- Cluster headache
- Seizure
- Significantly altered consciousness, memory, confusion
- Papilloedema
- Other abnormal neurological exam
How long do migraine attacks tend to last for?
Between 4-72 hours
Briefly describe the pathophysiology of migraines
Cerebrovascular contstriction –> aura, dilation –> headache
Spreading of cortical depression
Activation of CN V nerve terminals in meninges and cerebral vessels
Name 3 triggers of migraines
- Chocolate
- Cheese
- Excessive/not enough sleep
- Hangovers
- Orgasms
Describe the pain of a migraine
A symptoms:
- Unilateral
- Throbbing
- Moderate/severe pain
- Aggravated by physical activity
What other symptoms may a patient with a migraine experience other than pain?
B symptoms:
- Nausea
- Photophobia
- Phonophobia
- Aura
What is a prodrome?
Precedes migraine by hours-days
- yawning
- food cravings
- changes in sleep, appetite or mood
What would a patient experiencing a migraine with aura complain of?
Visual = fortification spectra (zig-zags), hemianopia, scotoma
Paraesthesia
Dysphagia
Ataxia
Name 3 differential diagnoses for a migraine
- Other headache type
- Hypertension
- TIA
- Meningitis
- Subarachnoid haemorrhage
What is the diagnostic criteria for a migraine?
4-72 hour attack +
2 A symptoms (unilateral, throbbing, moderate/severe pain, aggravated by physical activity) +
1 B symptom (nausea, photophobia, phonophobia)
With or without aura
How can migraines be subdivided?
- Episodic with (20%)/without (80%) aura
2. Chronic migraine
Describe the treatment for migraines
- Lifestyle modification and trigger management
- Psychological and behavioural treatment
- Preventative treatment = propranolol (BB)/topiramate, amitriptyline, acupuncture
- Oral triptan + NSAID/paracetamol
- Botox
How does triptan work?
Selectively stimulates 5-hydroxytryptamine (serotonin) receptors in the brain
How long do tension headaches usually last for?
From 30 minutes to 7 days
Describe the pain of a tension headache?
Bilateral
Pressing/tight band like pain
Mild to moderate pain
Not aggravated by physical activity
Would a patient with a tension headache experience any other symptoms other than pain?
NO
Nausea, photophobia and photophobia would NOT be associated
How do you treat a tension headache?
Regular exercise and stress relief
Symptomatic treatment = aspirin, paracetamol, NSAIDs, tricyclic antidepressant (amitriptyline)
Describe the pain of a cluster headache
- UNILATERAL
- Rapid onset severe orbital pain
- Severe/very severe pain
- Accompanied by lid swelling, lacrimation, facial flushing, rhinorrhoea, miosis +/- ptosis
How can cluster headaches be subdivided?
Episodic = >2 cluster periods lasting 7 days - 1 year separated by pain free periods lasting >1 month Chronic = attack occur for >1 year without remission or remission lasting <1 month
How long do cluster headaches tend to last?
Between 15 minutes and 3 hours
Mostly nocturnal
How do you treat cluster headaches?
Attack = 100% oxygen, sumatriptan (selective serotonin (5HT) agonist) Prevention = avoid triggers, short term corticosteroids (prednisolone), verapamil, lithium
What is the most common type of secondary headache?
Medication overuse headache - episodic headache becomes daily chronic headache
What types of medications can cause drug overuse headaches?
Opioids, mixed analgesics, ergotamine, triptans
What is the diagnostic criteria for a medication overuse headache?
- Headache present for >15 days/month
- Regular use for >3 months of >1 symptomatic treatment drugs
- Headache has developed or markedly worsened during drug use
Describe the pain of trigeminal neuralgia
- Unilateral face pain
- Severe intensity
- Electric shock like, shooting, stabbing or sharp
- No radiation beyond the trigeminal distribution
Describe the epidemiology of trigeminal neuralgia
Peak age = 50-60 years
Women > men
Give 3 causes of trigeminal neuralgia
- Compression of tirgeminal nerve by a loop of vein or artery
- Aneurysms
- Meningeal inflammation
- Tumours
How long does the pain associated with trigeminal neuralgia usually last for?
A few seconds
Maximum 2 minutes
What is the treatment for trigeminal neuralgia?
Carbamazepine - suppresses attacks
Less effective options = phenytoin, gabapentin
Surgery = microvascular decompression
What features might be present in the hostly of a headache that make you suspect meningitis?
- Pyrexia
- Photophobia
- Neck stiffness
- Non-blanching purpura rash
Name 3 symptoms of giant cell arteritis
- Unilateral temple/scalp pain and tenderness
- Jaw claudication
- Visual symptoms - amaurosis fugax
- Associated with PMR
- Raised ESR and CRP
What is the treatment for giant cell arteritis?
High dose Prednisolone, guided by ESR and symptoms
PPI and bisphosphonate also given
At what level is a lumbar puncture done and why is an LP done?
L3/4 or L4/5
To obtain a CSF sample
What main regions of the brain does the anterior cerebral artery supply?
Motor cortex and top of brain
What main regions of the brain does the middle cerebral artery supply?
Majority of the outer surface of the brain
What main regions of the brain does the posterior cerebral artery supply?
Supplies peripheral vision
Where does the circle of willis lie?
In the subarachnoid space
Where do the meningeal vessels lie?
In the extradural space
What does a small response on an nerve conduction study suggest?
There is axon loss
What does a slow response on an nerve conduction study suggest?
There is myelin loss
What are the main arteries that come off the aortic arch?
- Brachiocepahlic trunk
a) right common carotid artery
b) right subclavian artery - Left common carotid artery
- Lef subclavian artery
- Left vertebral artery (<1%)
At what level does the common carotid artery bifurcate?
C3/4 into the internal and external carotid artery
What 2 arteries does the internal carotid artery terminate in to?
Middle cerebral artery and anterior cerebral artery
Name the 4 segments of the internal carotid artery
- Cervical
- Petrous
- Cavernous
- Supraclinoid (intramural)
What branches does the supraclinoid segment of the internal carotid artery have?
- Ophthalmic artery
- Superior hypophyseal arteries/trunk
- Posterior communicating artery
- Anterior choroidal artery
Where do the vertebral arteries arise from?
Subclavian arteries
Give an example of a branch of the extracranial vertebral arteries
Neck muscles Spinal meninges (cervical spine) Spinal cord (cervical cord)
Give an example of a branch of the intracranial vertebral arteries
Anterior spinal artery
Small medullary perforators
Posterior inferior cerebellar artery (PICA)
What areas of the brain does the posterior inferior cerebellar artery supply?
Medulla and inferior cerebellum
What forms the basilar artery?
The vertebral arteries unite to form the basilar artery
What are the branches of the basilar artery?
- Multiple perforating arteries to brainstem - pontine arteries
- Bilateral anterior inferior cerebellar arteries (supply cerebellum, CN VII and CN VIII)
- Bilateral superior cerebellar arteries
What are the terminal branches of the basilar artery?
Posterior cerebral arteries arise from terminal bifurcation of the basilar artery
Define encephalopathy
Reduced level of consciousness/diffuse disease of brain substance
Define neuropathy
Damage to one or more peripheral nerve, usually causing weakness and/or numbness
Define myelitis
Inflammation of the spinal cord
Define meningitis
Infection and inflammation of the meninges
Name 3 bacterial organisms that cause meningitis in adults
- N. meningitidis
- S. pneumoniae
- H. influenzae
Name 2 bacterial organisms that cause meningitis in neonates
- E.coli
2. Group B strep
Name 3 viruses that can cause meningitis
- Enterovirus (most common viral)
- HSV
- CMV
- Varicella zoster virus
Name 2 organisms that can cause meningitis in immunocompromised patients
- Listeria monocytogenes
- Cryptococcus
- TB
Give the main triad of symptoms of meningitis
Headache + neck stiffness + fever
Give 5 symptoms of meningitis
- Neck stiffness
- Photophobia
- Papilloedema (due to increased ICP)
- Petechial non-blanching rash
- Headache
- Fever
- Decreased GCS
Give 2 signs of meningitis
Kernig’s sign = unable to straighten left treated than 135 degrees without pain
Brudzinski’s sign = severe neck stiffness cause hip and knees to flex when neck is flexed
How would you describe the rash associated with meningococcal sepsis?
Petechial non-blanching rash
What investigations might you do in someone you suspect has meningitis?
- Blood cultures (pre LP)
- Bloods - FBC, U+E, CRP, ESR, serum glucose, lactate
- Lumbar puncture
- CT head
- Throat swabs - bacterial and viral
What is the treatment of bacterial meningitis?
Cefotaxime
+ amoxicillin
+ dexamethasone
What is the treatment of viral meningitis?
Watch and wait
What is the treatment for meningococcal septicaemia?
Immediate IV cefotaxime or IV benzylpenicillin
What can be given as prophylaxis against meningitis?
Ciprofloxacin
For which bacteria is meningitis prophylaxis effective against?
N. meningitidis
When is a child vaccinated against Meningitis B?
At 8 weeks, 16 weeks and a booster at 1 year
When is a child vaccinated against Meningitis C?
At 1 year
When is a child vaccinated against Meningitis ACWY?
At age 14
Give 4 potential adverse effect of a lumbar puncture
- Headache
- Paraesthesia
- CSF leak
- Damage to spinal cord
What investigations would you do on a CSF sample?
Protein and glucose levels
MCS
Bacterial and viral PCR
When would you do a CT before an LP?
>60 Immunocompromised History of CNS disease New onset/recent seizures Decreased GCS Focal neurological signs Papilloedema
What is the colour of the CSF in someone with a bacterial infection?
Cloudy (normally it is clear)
Give 4 reasons why a LP might be contraindicated
- Thrombocytopenia
- Delay in Abx admin
- Signs of raised ICP
- Unstable cardio or resp systems
- Coagulation disorder
- Infections at LP site
- Focal neurological signs
Define encephalitis
Infection and inflammation of the brain parenchyma
In what group of people is encephalitis common?
Immunocompromised
What area of the brain does encephalitis mainly affect?
Frontal and temporal lobes
Give 4 viral causes of encephalitis
- HSV (most common)
- CMV
- EBV
- VZV
- HIV
- MMR
Name 2 non-viral causes of encephalitis
- Bacterial meningitis
- TB
- Malaria
- Lyme’s disease
Name the main triad of symptoms of encephalitis
Fever + headache + altered mental state
Give 5 signs and symptoms of encephalitis
- Headache
- Fever
- Lethargy
- Change in behaviour
- Seizures
- Focal neurological signs - hemiparesis, dysphagia
- Decreased GCS
- Travel or animal history
What would the LP show from someone with encephalitis?
Lymphocytosis
Raised protein
Normal glucose
What investigations might you do on someone with encephalitis?
Bloods - culture, serum viral PCR, malaria film
Contrast CT head
LP
EEG
What is the treatment for encephalitis?
Acyclovir
Primidone = anti-seizure medication if needed
Briefly describe the pathophysiology of rabies
RNA virus, transmitted by saliva in mammals
Spreads to CNS via peripheral nerves
Prevented by a vaccine
Give 3 symptoms of rabies
- Fever
- Anxiety
- Confusion
- Hydrophobia
- Hyperactivity
- Hallucinations
Name the organism responsible for causing tetanus
Clostridium tetani
It infects via dirty wounds
Give 3 symptoms of tetnaus
- Trismus (lockjaw)
- Sustained muscle contraction
- Facial muscle involvement
How does herpes zoster occur?
Reactivation of varicella zoster virus
Give 4 symptoms of herpes zoster
- Pain and paraesthesia in dermatomal distribution priced rash for days
- Malaise
- Myalgia
- Headache and fever
Describe the rash associated with herpes zoster
Papules and vesicles
- neuritis pain
- crust formation and drying occurs
- infectious until lesions are dried
Describe the treatment for herpes zoster
Antiviral therapy within 72 hours of rash onset - acyclovir, valavivlovir, famciclovir
Analgesia
Briefly describe the pathophysiology of herpes zoster
Latent virus is reactivated in dorsal root ganglia –> travels down affected nerve via sensory root in dermatomal distribution –> perineural and intramural inflammation
What dermatome is herpes zoster most likely to affect?
Thoracic nerves
Then ophthalmic division of trigeminal
Give 2 complications of herpes zoster
- Ophthalmic branch of trigmeinal = damages sight
2. Post herpetic neuralgia - pain lasts >4 months after
What is MS?
A chronic autoimmune inflammatory condition of the CNS characterised by multiple plaques of demyelination disseminated in space and time
Briefly describe the pathophysiology of MS
AI inflammation –> CD4 mediated destruction of oligodendrocytes –> demyelination of CNS neurones –> myelination with short thin nodes or neuronal death
What is MS characterised by?
Disseminated in space and time
Hypercellular plaque formation
BBB disruption
Name 2 types of MS
- Relapsing remitting (80%) = random attacks –> disabilities accumulate, between attacks no disease progression
- Chronic progressive = steady neurological decline
Describe the aetiology of MS
Unknown
Environment and genetic components
Describe the epidemiology of MS
Presenting between 20-40 y/o
Females > Males
More common in white populations
Give 3 eye signs associated with MS
- Optic neuritis - impaired vision and movement pain
- Nystagmus
- Double vision
Give 5 signs of MS other than problems with the eyes
- Spastic weakness
- Paraesthesia
- Lhermitte’s sign (electric spine)
- Bladder, GI and sexual dysfunction
- Fatigue
- Vertigo
- Cognitive problems and depression
What can exacerbate the symptoms of MS?
Heat (e.g. a warm shower)
Name 3 differential diagnosis’s of MS
- SLE
- Sjogren’s
- AIDS
- Syphilis
What investigations might you do in someone to see if they have MS?
MRI = plague detection LP = oligoclonal IgG bands = CNS inflammation Electrophysiology = delayed nerve conduction suggests demyelination
What is the diagnostic criteria for MS?
> 2 CNS lesions disseminated in time and space (>2 attack affected different parts of the CNS)
Describe the non-pharmacological treatment for MS
Regular exercise, smoking and alcohol cessation, low stress lifestyle
Psychological therapies
Speech therapists
Physio and OR
Describe the pharmacological treatment for MS
- Disease modifying drugs - dimethyl fumarate
- Biologics - natalizumab
- Beta interferon s/c
What symptomatic treatments can you give to those with MS?
Spasticity = baclofen Depression = SSRI (citalopram) Fatigue = modafinial Pain = amitryptilline, gabapentin
What medication might you give to someone to reduce the relapse severity of MS?
Short course steroids - methylprednisolone
Define epilepsy
Recurrent, spontaneous, intermittent abnormal electrical activity in part of the brain, manifesting seizures
Define epileptic seizure
Paroxysmal event in which changes of behaviour, sensation or cognitive processes are caused by excess, hypersynchronous neuronal discharge in the brain
Give 5 causes of epilepsy
- Idiopathic
- Old head injury
- Stroke
- Tumour
- Alcohol withdrawal
- CNS infection
- Flashing lights
What 2 categories can epileptic seizures be broadly divided into?
- Focal epilepsy - only one portion of the brain is involved
- Generalised epilepsy - whole brain is affected
Give 2 examples of focal epileptic seizures
- Simple partial seizures
2. Complex partial seizures
Give 3 examples of generalised epileptic seizures
- Absence seizures (petit mal)
- Tonic-clonic seizure (grand mal)
- Myoclonic seizure
- Atonic seizure
Give 3 major characteristics of an epileptic seizure
30-120 seconds long
Positive ictal symptoms
Post ictal symptoms
Describe a generalised tonic clonic seizure
Sudden onset rigid tonic phase followed by a convulsive clonic phase
LOC, tongue biting, urine incontinence and drowsiness/coma also associated
Give 2 features of absence seizures
- Commonly present in childhood
2. Ceases activity and stares for few seconds
Describe a myoclonic seizure
Sudden jerk of limb, face or trunk
Often fall backwards
Describe a atonic seizure
Sudden loss of muscle tone –> fall forwards
What is aura?
A sensation perceived which precedes a condition affecting the brain
If a patient experienced epilepsy with aura, what other symptoms would they get?
Strange feeling in gut
Deja vu
Strange smells
Flashing lights
Name 3 post-ictal symptoms
- Headache
- Confusion
- Myalgia
- Temporary weakness (focal seizure)
What is the diagnostic criteria for epilepsy?
At least 2 or more unprovoked seizures occurring >24 hours apart
What is the treatment for focal epileptic seizures?
Lamotrigine = 1st line Carbamazepine = 2nd line
How do lamotrigine and Carbamazepine work?
Inhibit pre-synaptic Na+ channels so prevent axonal firing
What is the treatment for generalised epileptic seizures?
Sodium valproate = 1st line
Lamotrigine = 2nd line
How does sodium valproate work?
Inhibits voltage gated Na+ channels and increases GABA production
What medication can control seizures?
Diazepam or lorazepam
What possible surgery could you do to treat epilepsy?
Vagal nerve stimulation
Resection of affected area
Give 4 potential side effects of anti-epileptic drugs (AED’s)
- Cognitive disturbances
- Heart disease
- Drug interactions
- Teratogenic
Give 4 differential diagnosis’s of epilepsy
- Syncope
- Non-epileptic seizure
- Migraine
- Hyperventilation
- TIA
Define syncope
Insufficient blood or oxygen supply to the brains causes paroxysmal changes in behaviour, sensation and cognitive processes
Caused by sitting/standing
5-30 seconds duration
Define non-epileptic seizure
Mental processes associated with psychological distress causes paroxysmal changes in behaviour, sensation and cognitive processes
1-20 minute duration
Closed eyes and mouth
A patient complains of having a seizure. An eye-witness account tells you that the patient had their eyes closed, was speaking and there was waxing/waning/pelvic thrusting. They say the seizure lasted for about 5 minutes. Is this likely to be an epileptic or a non-epileptic seizure?
A non-epileptic seizure
A patient complains of having a seizure. An eye-witness account tells you that the patient was moving their head and biting their tongue. They say the seizure lasted for just under a minute. Is this likely to be an epileptic or a non-epileptic seizure?
An epileptic seizure
A patient complains of having a ‘black out’. They tell you that before the ‘black out’ they felt nauseous and were sweating. They tell you that their friends all said they looked very pale. Is this likely to be due to a problem with blood circulation or a disturbance of brain function?
This is likely to be due to a blood circulation problem e.g. syncope
What can be the affect of a non-missile trauma to the scalp?
Contusions and lacerations
What can be the affect of a non-missile trauma to the skull?
Fracture
Give 2 risk associated with a skull fracture
- Haematoma
2. Infection
What can be the affect of a non-missile trauma to the meninges?
Haemorrhage and infection (due to skull fracture)
What can be the affect of a non-missile trauma to the brain?
Contusions
Lacerations
Haemorrhage
Infection
Describe the pathophysiology of a diffuse traumatic axonal injury
Acceleration/deceleration –> shearing rotational forces –> axons tear
Give a sign of diffuse vascular injury due to non-missile trauma
Multiple petechial haemorrhages throughout the brain
What is more severe: diffuse traumatic axonal injury to diffuse vascular injury?
Diffuse vascular injury - usually results in near immediate death
Describe the mechanism behind acceleration/deceleration damage
A force to the head can cause differential brain movements –> shearing, traction and compressive stresses –> risk of axon tear and blood vessel damage
What is a contusion?
Superficial ‘bruises’ of the brain
What is a laceration?
When a contusion is severe enough to tear the Pia mater
What is the cause of chronic traumatic encephalopathy?
Often seen 8-10 years after repetitive mild traumatic brain injury
Give 3 initial symptoms of chronic traumatic encephalopathy
- Irritability
- Impulsivity
- Aggression
- Depression
Give 3 later symptoms of chronic traumatic encephalopathy
- Dementia
- Gait and speech problems
- Parkinsonism
Give 3 signs of chronic traumatic encephalopathy
- Atrophy of deep brain structures
- Enlarges ventricles
- Tau neurofibrillary tangles deposited in sulci
Give 3 types of missile head injuries
- Depressed = don’t penetrate skull
- Penetrating
- Perforating = missile enters and exits the skull, passing through the brain
Name 3 intra-cranial haemorrhages
- Sub-arachnoid haemorrhage
- Sub-dural haemorrhage
- Extra-dural haemorrhage
What can cause a subarachnoid haemorrhage?
- Rupture of berry aneurysm (80%)
- Atriovenous malformation (10%)
- Trauma
Give 3 risk factors for a subarachnoid haemorrhage
- Previous berry aneurysm
- Smoking
- Alcohol
- Hypertension
- Family history
Briefly describe the pathophysiology of a subarachnoid haemorrhage
Ruptured aneurysm –> tissue ischaemia and rapid raised ICP –> pressure on the brain
Name 3 symptoms of a subarachnoid haemorrhage
- Sudden onset ‘thunderclap’ headache
- Neck stiffness
- Vomiting
- Photophobia
- Drowsiness –> coma
Name 3 signs of a subarachnoid haemorrhage
- Kernig’s sign (can’t straighten leg past 135 degrees)
- Reduced GCS
- Papilloedema
What investigations might you do to see if someone has a subarachnoid haemorrhage?
- Head CT = star pattern (diagnositic)
2. LP = bloody or xanthochromic
Describe the treatment for a subarachnoid haemorrhage
- Hydration, bed rest and BP control and frequent neurological obs
- Nimodipine (CCB) = reduced vasospasm
- CT angiography for aneurysm identification – coiling/clipping
Give 3 possible complications of a subarachnoid haemorrhage
- Rebleeding (common = death)
- Cerebral ischaemia
- Hydrocephalus
- Hyponatraemia
What can cause a subdural haemorrhage?
Head injury –> vein rupture
Describe the pathophysiology of a subdural haemorrhage
Rupture of bridging veins between hemispheres and sagittal sinus
Accumulating haematoma –> raised ICP –> tentorial herniation/coning
What causes water to be sucked up into a subdural haematoma 8-10 weeks after a head injury?
Clot starts to break down and there is massive increase in oncotic pressure –> water is sucked up by osmosis into the haematoma
Give 3 risk factors of a subdural haemorrhage
- Elderly - brain atrophy
- Frequent falls - epileptics, alcoholics
- Anticoagulants
Give 4 signs and symptoms of a subdural haemorrhage
- Fluctuating GCS
- Headache
- Confusion
- Drowsiness
- Raised ICP –> seizures
Name 3 differential diagnosis’s of a subdural haemorrhage
- Stroke
- Dementia
- CNS masses (tumour vs abscess)
What would you see on a CT or MRI of a subdural haemorrhage?
Unilateral crescent shaped blood collection
Blood clot
Midline shift
What is the treatment for a subdural haemorrhage?
Surgical evacuation of the clot
Treat cause
Mannitol = decreases ICP
What can cause an extradural haemorrhage?
Traumatic head injury resulting in a skull fracture (often temporal bone) –> middle meningeal artery rupture –> bleed
Describe the disease pattern of a extradural haemorrhage
Head injury –> unconscious –> lucid interval –> worse symptoms
Occurring over hours
Give 4 symptoms of an extradural haemorrhage
- Reduced GCS
- Severe headache
- Confusion
- Seizures
- Hemiparesis
- Ipsilateral pupil dilation
- Coma
What investigations might you do to see if someone has an extradural haemorrhage?
CT = lens shaped haematoma
LP is CONTRAINDICATED
What do the ventricles do to prolong survival in someone with an extradural haemorrhage?
Get rid of CSF to prevent rise in ICP
What is the treatment for an extradural haemorrhage?
Immediate clot evacuation
Mannitol to decrease ICP
Give 3 differences in the presentation of a patient with a subdural haemorrhage in comparison to an extradural haemorrhage
- Time frame: extra-dural symptoms are more acute
- GCS: sub-dural GCS will fluctuate whereas GCS will drop suddenly in someone with an extra-dural haematoma
- CT: extra-dural haematoma will have a lens appearance whereas subdural will have a crescent shaped haematoma
Define weakness
Impaired ability to move a body part in response to will
Define paralysis
Ability to move a body part in response to will is completely lost
Define ataxia
Willed movements are clumsy, ill-direction or uncontrolled
Define involuntary movements
Spontaneous movement independent of will
Define apraxia
Disorder of conscious organised pattern of movement or impaired ability to recall acquired motor skills
Give 3 things that modulate LMN action potential transmission to effectors
- Cerebellum
- Basal ganglia
- Sensory feedback
What is a Lower motor neurone?
A neurone that carries signals to effectors
Cell body is located in the brainstem (CN nuclei) or spinal cord
Give 5 potential sites of damage along the ‘final common pathway’
- Cranial nerve nuclei
- Motor neurones
- Spinal ventral roots
- Peripheral nerves
- NMJ
- Muscles
Give 3 disease that are associated with motor neurone damage
- Motor neurone disease
- Spinal atrophy
- Poliomyelitis
- Spinal cord compression
Give 3 pathologies that are associated with ventral spinal root damage
- Prolapsed intervertebral disc
- Tumours
- Cervical or lumbar spondylosis
Name a disease associated with NMJ damage
Myasthenia Gravis
What are muscle spindles innervated by?
Gamma motor neurones
innervate the stretch receptors in muscle spindles
What is the function of muscle spindles?
Control muscle tone and tell you how much a muscle is stretched
Describe the pyramidal pattern of weakness in the upper limbs
Flexors are stronger than extensors
Describe the pyramidal pattern of weakness in the lower limbs
Extensors are stronger than flexors
What is a UMN?
A neurone that is located entirely in the CNS
Its cell body is located in the primary motor cortex
Give 3 causes of UMN weakness
- MS
- Brain tumour
- Stroke
- MND
Give 4 sites of UMN damage
- Motor cortex lesions
- Internal capsule
- Brainstem
- Spinal cord
Give 4 signs of UMN weakness
- Spasticity
- Increased muscle tone (hypertonia)
- Hyper-reflexia
- Positive babinski’s reflex
Give 4 signs of LMN weakness
- Flaccid
- Hypotonia
- Hypo-reflexia
- Muscle atrophy
- Fasciculation’s
Define motor neurone disease
Cluster of major degenerative diseases characterised by selective loss of neurones in motor cortex, cranial nerve nuclei and anterior horn cells
Does MND affect UMN or LMN?
Both UMN and LMN are affected
Does MND affect eye movements?
Never affects eye movements (cf of myasthenia gravis)
Does MND cause sensory loss or sphincter disturbance?
No (cf of MS)
Name 4 types of MND
- Amyotrophic lateral sclerosis (ALS) = motor cortex and anterior horns affected = LMN + UMN
- Progressive bulbar palsy = destruction of CN 9-12 = LMN
- Progressive muscular atrophy = anterior horn destruction = LMN
- Primary lateral sclerosis = betz cell loss in motor cortex = UMN
What symptoms might present in someone with progressive bulbar palsy form of MND?
Dysarthria (slurred speech)
Dysphagia
Wasting and fasciculations of tongue
What investigations might you do in someone you suspect to have MND?
Head/spine MRI Blood tests = muscle enzymes, autoantibodies Nerve conduction studies EMG LP
What is the diagnostic criteria for MND?
LMN + UMN signs in 3 regions
What is the treatment for MND?
Disease modifying drugs = riluzole - inhibits glutamates release (Na channel blocker) - slow down disease progression
Excess saliva = propantheline/amitriptyline
Anti-spasticity = baclofen
Dysphagia = NG/PEG feeding
Palliation
Give 3 limb onset symptoms of MND
- Weakness
- Clumsiness
- Wasting of muscles
- Foot drop
- Tripping
Give 3 respiratory onset symptoms of MND
- Dyspnoea
- Orthopnoea
- Poor sleep
Would you do a LP in a patient that has a raised ICP?
NO
LP is contraindicated if they have a raised ICP due to the risk of coning
Give 4 signs of raised ICP
- Papilloedema
- Focal neurological signs
- Loss of consciousness
- New onset seizures
What is the treatment for raised ICP?
Osmotic diuresis with mannitol
Explain the ICP/volume curve
Volume increase –> ICP plateau (compensate) –> rapid ICP increase
What are the 3 cardinal presenting symptoms of brain tumours?
- Raised ICP –> headache, decrease GCS, n+v, papilloedema
- Progressive neurological deficit –> deficit of all major functions (motor, sensory, auditory, visual) + personality change
- Epilepsy
You ask a patient with a brain tumour about any facts that aggravate their headache, what might they say?
- Worse first thing in the morning
2. Worse when coughing, straining or bending forward
Name 2 differential diagnosis’s for a brain tumour
- Aneurysm
- Abscess
- Cyst
- Haemorrhage
- Idiopathic intracranial hypertension
What investigations might you do in someone you suspect to have a brain tumour?
CT/MRI head and neck
Biopsy
LP = CONTRAINDICATED (high ICP)
Where might secondary brain tumours arise from?
- LUNG
- Breast
- Melanoma
- Renal
- GI
- Thyroid
- Prostate
Describe the treatment for secondary brain tumours
- Surgery and adjuvant radiotherapy
- Chemotherapy
- Supportive care
From what cells to primary brain tumours originate?
Glial cells (gliomas)
- Astrocytoma (85-90%)
- Oligodendroglioma
Other primary = meningioma, schwannoma, medulloblastoma
Describe the WHO glioma grading
Grade 1 = benign paediatric tumour
Grade 2 = Pre-malignant tumour (benign)
Grade 3 = ‘Anaplastic astrocytoma’ (cancer)
Grade 4 = Glioblastoma multiforme (GBM) - malignant
Describe the epidemiology of grade 2 gliomas
Disease of young adults
Give 3 causes of grade 2 glioma deterioration
- Tumour transformation to a malignant phenotype
- Progressive mass effect due to slow tumour growth
- Progressive neurological deficit form functional brain destruction by tumour
Describe the common pathway to a GBM (grade 4 brain tumour)
Initial genetic error of glucose glycolysis –> Isocitrate Dehydrogenase 1 mutation –> excessive build up of 2-hydroxyglutarate –> genetic instability of glial cells –> grade II-IV glioma transform into glioblastoma
Give 5 good prognostic factors for GBM
- <45 y/o
- Aggressive surgical therapy
- Good performance post-surgery
- Tumour that has transformed from previous lower grade tumour
- MGMT mutant - will respond will to chemo
Describe the treatment for GBM
- Resective surgery
- Adjuvant chemotherapy with Temozolomide
- Dexamethasone - reduces tumour infalmamtion/oedema
- Palliative care
How does Temozolomide work in treatment for GBM?
Methylates guanine in DNA making replication impossible
MGMT gene reverses it = tumour resistance
Define dementia
A set of symptoms that may include memory loss and difficulties with thinking, problem solving or language
There is a progressive decline in cognitive function
Describe the epidemiology of dementia
Rare <55
10% of people >65
20% of people >80
Give 3 causes of dementia
- Alzheimer’s disease (50%)
- Vascular dementia (25%)
- Lewy body dementia (15%)
- Fronto-temporal (Pick’s)
- Huntington’s
- Liver failure
- Vitamin deficiency - B12 or folate
Give 3 risk factors of dementia
- Family history
- Age
- Down’s syndrome
- Alcohol use, obesity, HTN, hyperlipidaemia, DM
- Depression
Describe the pathophysiology of Alzheimer’s disease
Degeneration of temporal lobe and cerebral cortex, with cortical atrophy
Accumulation fo beta-amyloid peptide –> progressive neuronal damage, neurofibrillary tangles, increase in number of amyloid places and loss of ACh
Give 4 symptoms of AD
- Short term memory loss
- Slow disintegration fo personality and intellect
- Language impairments - difficulty aiming and understand
- Apraxia
- Visuopatial impairments
- Agnosia
Give 2 histological signs of AD
- Plagues of amyloid
2. Neuronal reduction
25% of all patients with AD will develop what?
Parkinsons
What does vascular dementia often present with?
Signs of vascular pathology = raised BP, past strokes and focal CNS signs
Stepwise deterioation
Describe the pathophysiology of Lewy body dementia
Deposition of abnormal protein (levy bodies) within neurones of the occipito-parietal cortex
Give 4 signs of Lewy body dementia
- Fluctuating cognition
- Prominent or persistent memory loss
- Impairment of attention, frontal, subcortical and visuospatial ability
- Depression and sleep disorders
- Visual hallucination
- Parkinsons
- Loss of inhibitions
Frontal lobe atrophy is seen on an MRI, what kind of dementia is this patient likely to have?
Fronto-temporal
= frontal and temporal lobe atrophy
Give 3 symptoms of Fronto-temporal dementia
- Behaviour variants - personality and behavioural change
- Language variants - progressive aphasia
- Lowers inhibitions and emotional unconcern
- Early memory preservation
- Association with MND
What is functional memory dysfunction?
Acquired dysfunction of memory that significantly affects a person’s professional/private life in absence of an organic cause
How could you determine whether someone has functional memory dysfunction or a degenerative disease?
When asked the question ‘when was the last time your memory let you down?’, someone with functional memory dysfunction would give a good detailed answer whereas someone with degenerative disease would struggle to answer
What investigations can you do in primary care to determine whether someone might have dementia?
- Good history of symptoms
- 6 item cognitive impairment test (6CIT)
- Blood tests - FBC, liver biochemistry, TFTs, vitamin B12 and folate
- Mini mental state examination = screening
What questions are asked in 6CIT?
- What year is it?
- What month is it?
- Give an address with 5 parts
- Count backwards from 20
- Say the months of the year in reverse
- Repeat the address
What secondary care investigation can you do to investigate a dementia diagnosis?
Brain MRI - where and extent of atrophy
Brain function tests = PET, SPECT and functional MRI
Brain CT
Myeloid and tau histopathology
Name the staging system that classifies the degree of pathology in AD
Braak staging
Stage 5/6 = high likelihood of AD
Stage 3/4 = intermediate likelihood
Stage 1/2 = low likelihood
Give 3 ways in which dementia can be prevented
- Smoking cessation
- Healthy diet
- Regular exercise
- Low alcohol
- Engaging in leisure activités
What support should be offered to patients with dementia?
Social suport
Cognitive support
Specialist memory service
What medications might you use in someone with dementia?
Acetylcholinesterase inhibitors - increase ACh = donepezil, rivastigmine Control BP (ACEi) to reduce further vascular damage
Define myasthenia gravis
Autoimmune disease against nicotinic acetylcholine receptors in the neuromuscular junction
Describe the pathophysiology behind myasthenia gravis
Autoantibodies (IgG) attach to ACh receptor and destroy them –> fewer action potentials fire –> muscle weakness and fatigue
Describe the aetiology and associations of myasthenia gravis
If <50 = associated with other AI conditions (pernicious anaemia, SLE, RA) and more common in women
If >50 = associated with thymic atrophy or thymic tumour and more common in men
Give 4 symptoms of myasthenia gravis
- Muscle weakness
- Increasing muscular fatigue
- Ptosis
- Diplopia
- Myasthenic snarl
- Tendon reflexes normal but fatigable
What muscle groups are affected in myasthenia gravis?
Extra-ocular –> bulbar –> face –> neck –> trunk
What can weakness due to myasthenia gravis be worsened by?
Pregnancy Hypokalaemia Infection Emotion Exercise Drugs (opiates, BB, gentamicin, tetracycline)
What investigations might you do to see if someone has myasthenia gravis?
- Serum anti-ACh receptors or muscle specific tyrosine kinase (muSK) antibodies
- EMG and NCS = EMG detect MG
- CT thymus
- Tensilon test = IV edrophonium (short acting anti-cholinesterase) given –> muscle power increases within seconds
Give 3 possible differential diagnosis’s for myasthenia gravis
- MS
- Hyperthyroidism
- Acute Guillain-Barre syndrome
- Lamert-Eaton myasthenia syndrome
What is treatment for myasthenia gravis?
Anti-cholinesterase (more Ach in NMK) = pyridostigmine
Immunosuppression = prednisolone
Steroids can be combined with azathioprine or methotrexate
Thymectomy
When is a thymectomy considered as a treatment for myasthenia gravis?
Onset <50 y/o and it is poorly controlled
Give a complication of myasthenia gravis
Myasthenic crisis
Weakness of respiratory muscle during relapse
Treatment = plasmapheresis and IV immunoglobulin
What is Lamert-Eaton myasthenia syndrome?
Paraneoplastic condition where there is defective ACh release at NMJ resulting in proximal limb weakness with some absent reflexes
What is the function of the cerebellum?
Responsible for precise control, fine adjustment and coordination of morose activist based on continual sensory feedback
What is the cerebellums output?
Purkinje cells only
What does cerebellar dysfunction mean?
Cerebellar ataxia
How can cerebellar ataxia be classified?
- Inherited
a) autosomal recessive
b) autosomal dominant - Acquired
Give an example of an AR inherited cerebellar ataxia
Friedrichs ataxia = motor and sensory problems, presenting in childhood
Give an example of an AD inherited cerebellar ataxia
Spinocerebellar ataxia 6
Episodic ataxia
Give 3 causes of acquired cerebellar ataxia
- Toxic - alcohol, lithium
- Idiopathic
- Neurodegenerative
- Immune mediated
Give 2 examples of immune mediated cerebellar ataxia
- Post infection cerebellitus
- Gluten ataxia
- Paraneoplastic cerebellar degeneration
- Primary autoimmune cerebellar ataxia
How can the severity of ataxia be classified?
Mild = mobilising independently or with 1 walking aid
Moderate = mobilising with 2 walking aids or walking frame
Severe = predominantly wheelchair dependent
Scale for the Assessment and Rating of Ataxia (SARA) can also be used - looks at gait, stance, sitting and speech
Give 4 symptoms of cerebellar dysfunction
- Slurred speech
- Swallowing difficulties
- Clumsiness (arms and legs)
- Loss of precision of fine movement/motor skills
- Stumbles and falls
- Cognitive problems
Give 4 signs of cerebellar dysfunction
- Nystagmus
- Action tremor
- Dysdiadochokinaesia - inability to perform rapid, alternating movements
- Truncal ataxia
- Limb ataxia
- Gait ataxia
What investigations might you do in someone who is presenting with signs of cerebellar ataxia?
MRI = cerebellar atrophy and will exclude other causes (CV, tumour, hydrocephalus)
Define Parkinson’s disease
Degenerative movement disorder caused by a reduction in dopamine in the pars compacta of the substantia nigra
What is dopamine produced from?
Tyrosine –> L-dopa –> Dopamine
Describe the pathophysiology of Parkinson’s disease
Death of dopaminergic neurones (in substantia nigra) –> reduced dopamine supply –> thalamus inhibits –> decrease in movement + symptoms
Lewy body formation in basal ganglia
What is the 3 cardinal symptoms for Parkinsonism?
Tremor + Rigidity + Bradykinesia
Describe the symptoms of Parkinson’s disease
- Resting tremor
- Rigidity - cogwheel
- Bradykinesia - slow movements and initiation, repetition = decreased amplitude, small steps/shuffling gait
- Constipation and urinary frequency
- Psychiatric issues (depression, anxiety, dementia)
Would you describer the symptoms of Parkinson’s disease as symmetrical or asymmetrical?
Asymmetrical = One side is always worse than the other
You ask a patient who you suspect to have Parkinson’s disease to walk up and down the corridor to assess their gait, what features would be suggestive of PD?
Stopped posture
Asymmetrical arm swing
Small steps
Shuffling
Give 2 histopathological signs of Parkinson’s disease
- Loss of dopaminergic neurones in the substantia nigra
2. Lewy bodies
What investigations might you do in someone you suspect to have PD?
Functional neuroimaging - PET
Can confirm by reaction to levodopa
Describe the pharmacological treatment for Parkinson’s disease
Compensate for loss of dopamine - L-dopa (levodopa) - Dopamine agonists - COMT inhibitors - MAO-B inhibitors Anticholinergics SSRIs (citalopram) for depression
How does L-dopa work in the treatment of PD?
Precursor to dopamine and can cross the BBB (unlike dopamine)
How do dopamine agonists work in the treatment of PD and give an example of one?
Reduced risk of dyskinesia
First line in patient <60
Ropinirole, pramipexole
How do MAO-B inhibitors work in the treatment of PD and give an example of one?
Inhibit MAO-B enzymes which breakdown dopamine
Rasagiline, selegiline
How do COMT inhibitors work in the treatment of PD and give an example of one?
Inhibit COMT enzymes which breakdown dopamine
Entacapone, tolcapone
What surgical treatment methods are there for Parkinson’s disease?
Deep brain stimulation of the sub-thalamic nucleus
Surgical ablation of overactive basal ganglia circuits
Describe an essential tremor
Action tremor, no rest tremor
What is the treatment for an essential tremor?
Beta blockers
Primidone (anticonvulsant)
Gabapentin
Define Huntington’s disease
Neurodegenerative disorder characterised by the lack of inhibitory neurotransmitter GABA
Define chorea
Continuous flow of jerky, semi-purposeful movements, flitting from one part of the body to another
Describe the inheritance pattern seen in Huntington’s disease
Autosomal dominant inheritance
What triplet code is repeated in Huntington’s disease?
Cagoules triplet repeat
Adult onset = 36-55 repeats
Early onset = >60 repeats
Briefly describe the pathophysiology of Huntington’s disease
Progressive cerebral atrophy with marked loss of neurones in caudate nucleus and putamen - specifically loss of corpus striatum GABA-nergic and cholinergic neurones
GABA = main inhibitory neurotransmitter –> decreased inhibition of dopamine release –> excessive thalamus stimulation –> excessive movements
Name the 3 cardinal features of Huntington’s disease
- Chorea
- Dementia
- Psychiatric problems - personality change, depression, psychosis
Name 3 other signs of Huntington’s disease
- Abnormal eye movements
- Dysarthria
- Dysphagia
- Rigidity
- Ataxia
What investigations might you do in someone you suspect to have Huntington’s disease?
Genetic testing - CAG repeats (extensive counselling)
CT/MRI = caudate nucleus atrophy and increase size of frontal horns of lateral ventricles
Describe the treatment of Huntington’s disease
Chorea
- Benzodiazepines
- Sulpiride (neuroleptic - depresses nerve function)
- Tetrabenazine - dopamine depleting agent
Depression = SSRIs (seroxate)
Psychosis = haloperidol
Agression = risperidone
Define mononeuropathy
Lesions of individual peripheral or cranial nerves
Define mononeuritis multiplex
2 or more individual nerves affected
Give 3 causes of mononeuritis multiplex
WARDS PLC
- Wegner’s grnaulomatosis
- ADIS/amyloidosis
- RA
- DM
- Sarcoidosis
- Polyarteritis nodosa
- Leprosy
- Carcinoma
What investigation can help you identify the site of a mononeuropathy lesion?
Electromyography (EMG)
What nerve is affected in carpal tunnel syndrome?
The median nerve (C6-T1)
Give 3 risk factors of carpal tunnel syndrome
- Pregnancy
- Obesity
- RA
- DM
- Hypothyroidism
- Acromegaly
Describe the symptoms of carpal tunnel syndrome
- Intermittent and gradual onset
- Pain and paraesthesia = LLOAF muscles affected and thenar wasting
- Sensory loss - radial 3.5 fingers and play
- Worse at night, relieved by shaking
What investigations might you do in someone who you suspect to have carpal tunnel syndrome?
EMG = slowing conduction velocity in median sensory nerves
Phalen’s test = 1 min maximal wrist flexion –> symptoms
Tinel’s test = tapping over nerve at wrist –> tingling
What is the treatment for carpal tunnel syndrome?
Splinting
Local steroid injection
Decompression surgery
Define polyneuropathy
Generalised disorders of peripheral and cranial nerves
Describer the distribution of polyneuropathies
Symmetrical and widespread
Distal weakness and sensory loss
How can polyneuropathies be classified?
- Time-course = Acute, chronic
- Function = motor, sensory, autonomic, mixed
- Pathology = demyelination, axonal degeneration, mixed
Give 3 causes of sensory neuropathy
- DM
- CKD
- Alcohol
- Vasculitis
- Leprosy
Give 3 signs of sensory neuropathy
Glove and stocking distribution of numbness and paraesthesia
Deep tendon reflexes may be decreased or absent
Signs of trauma - finger burns due to sensory loss
Are large sensory fibres myelinated or unmyelinated and name the types of fibre?
Myelinated
A-alpha
A-beta
Are small sensory fibres myelinated or unmyelinated and name the types of fibre?
A-gamma = myelinated C-fibres = unmyelinated
What do A-alpha sensory fibres sense?
Proprioception
What do A-beta sensory fibres sense?
Light touch, pressure and vibration
What do A-gamma sensory fibres sense?
Pain and cold sensation
What do C fibres sensory fibres sense?
Pain and hot sensation
Give 3 cause of motor neuropathy
- Gullian-Barre syndrome
- Charcot-Marie-Tooth syndrome
- Lead poisoning
- Paraneoplastic
Give 3 signs of motor neuroapthies
- Weakness/clumsiness of hands
- Difficulty walking
- LMN signs - hypotonia, hyporeflexia, fasciculations
- Involvement of respiratory muscles –> decreased FVC
Give 3 causes of autonomic neuropathy
- DM
- HIV
- SLE
- Gullian-Barre syndrome
Give 3 signs of autonomic neuropathy
- Postural hypotension
- ED
- Decreased sweating
- Constipation/nocturnal diarrhoea
- Urinary retention
Name 3 types of axonal neuropathy presentation
- Symmetrical sensorimotor
- Sensory ganglionopathies (asymmetrical sensory)
- Asymmetrical sensorimotor
Describe symmetrical sensorimotor neuropathy
Long fibres affected first (toes and fingers) = length dependent
Initially sensory but eventually sensorimotor
Describe sensory ganglionopathies (asymmetrical sensory)
Patchy distribution of symptoms
Dorsal root ganglia are affected
Describe asymmetrical sensorimotor
Mononeuritis multiplex
Randomly affect any nerve
What investigations might you do in someone with a polyneuropathy?
- Clinical exam - reduced/absent tendon reflexes, sensory deficit, weakness
- NCS
- EMG
Give an example of an acute polyneuropathy
Guillain-Barre syndrome
What is autoimmune Guillain-Barre syndrome?
Acute inflammatory demyelinated ascending polyneuropathy affecting the PNS following an URTI or GI infection
What can cause Guillain-Barre syndrome?
Bacteria - Camplylobacter jejuni - Mycoplasma Viruses - CMV - EBV - HIV - Herpes zoster
Describe the pathophysiology of Guillain-Barre syndrome
Same antigens on infectious organisms as Schwann cells –> autoantibody mediated nerve cell damage
Schwann cell damage –> demyelination –> reduction in peripheral nerve conduction –> acute polyneuropathy
Give 4 signs of Guillain-Barre syndrome
- Ascending symmetrical muscle weakness (proximal muscles most affected - trunk, respiratory, CN)
- Pain
- Paraesthesia
- Reflexes lost
- Autonomic features = sweating, tachycardia, BP changes, arrhythmias
What investigations might you do in someone you suspect has Guillain-Barre syndrome?
NCS = slowing of conduction, prolonged distal motor latency +/- conduction block
LP at L4 = raised protein and normal WCC
Spirometry = respiratory involvement
Describe the treatment for Guillain-Barre syndrome
If FVC <1.5L/80% = ventilate and ITU monitoring
IV immunoglobulin for 5 days = decrease duration and severity of paralysis
Plasma exchange
Low molecular weight heparin
Analgesia
When is IV immunoglobulin contraindicated in the treatment for Guillain-Barre syndrome?
If a patient has IgA deficiency
Define stroke
Rapid onset of neurological deficit due to a vascular lesion lasting >24 hours and associated with infarction of central nervous tissue
How can strokes be classified?
- Ischaemic (80%)
2. Haemorrhagic (20%)
Give 2 causes of an ischaemic stroke
Occlusion of brain vasculature
- Atheroma
- Embolism –> AF, Infective endocarditis, carotid artherothromboembolism
Give 2 causes of an haemorrhagic stroke
Bleeding from the Brian vasculature
- Hypertension
- Trauma
- Aneurysm rupture
- Sub-arachnoid haemorrhage
Give 4 risk factors for stroke
- Hypertension
- DM
- Smoking
- PVD
- Hyperlipidaemia
- Heart disease
Give 3 signs of an ACA stroke
- Leg weakness
- Sensory disturbance in legs
- Gait apraxia
- Incontinence
- Drowsiness
- Akinetic mutism - decrease in spontaneous speech
Give 3 signs of a MCA stroke
- Contralateral arm and leg weakness and sensory loss
- Hemianopia
- Aphasia
- Dysphasia
- Facial droop
Give 3 signs of a PCA stroke
- Contralateral homonymous hemianopia
- Cortical blindness
- Visual agonisa
- Prosopagnoisa
- Dyslexia
- Unilateral headache
What is visual agnosia?
An inability to recognise or interpret visual information
What is prosopagnosia?
Inability to recognise a familiar face
A patient presents with upper limb weakness and loss of sensory sensation to the upper limb. They also have aphasia and facial drop. Which artery is likely to have been occluded?
Middle cerebral artery
A patient presents with lower limb weakness and loss of sensory sensation to the lower limb. They also have incontinence, drowsiness and gait apraxia. Which artery is likely to have been occluded?
Anterior cerebral artery
A patient presents with a contralateral homonymous hemianopia. They are also unable to recognise familiar faces and complain of a headache on one side of their head. Which artery is likely to have been occluded?
Posterior cerebral artery
Give 3 differential diagnosis’s for a stroke
- Hypoglycaemia
- Intracranial tumour
- Head injury +/- haemorrhage
What investigation could you do to determine whether someone has had a haemorrhagic or ischaemic stroke?
Head CT scan (before treatment)
What is the treatment for an ischaemic stroke?
Thrombolysis - 4.5. hour limit = alteplase
Thrombolectomy
How does alteplase work?
Converts plasminogen –> plasmin
So promotes breakdown of fibrin clot
When can you do thrombolysis in someone with an ischaemic stroke?
Up to 4.5. hours post onset of symptoms
What is primary prevention of strokes?
Risk factor modifcaiton
- Antihypertensives for HTN
- Statins for hyperlipiaemia
- Smoking cessation
- Control DM
- AF treatment = warfarin/NOAC’s
What is secondary prevention of strokes?
2 weeks of aspirin –> long term clopidogrel
What non-pharmacological treatment options are there for people after a stroke?
- Specialised stroke units
- Swallowing and feeding help
- Phsyio and OT
- Neurorehab - physio + speech therapy
What is a TIA?
Sudden onset focal neurology lasting <24 hours due to temporal occlusion of part of the cerebral circulation
Give 3 causes of a TIA
- Artherothromboembolism of the carotid
- Cardioembolism
- Hyperviscosity
- Vasculitis
Describe the pathophysiology of a TIA
Cerebral ischaemia due to lack of O2 and nutrients –> cerebral dysfunction
Give 3 signs of a carotid TIA
- Amaurosis fugax = retinal artery occlusion –> vision loss
- Asphasia
- Hemiparesis
- Hemisensory loss
Give 3 signs of a vertebrobasilar TIA
- Double vision
- Choking
- Ataxia
- Hemisensory loss
- Vomiting
Name 3 differential diagnosis’s for a TIA
- Migraine
- Epilepsy
- Hypoglycaemia
- Hyperventilation
What investigations would you do in someone who you suspect to have a TIA?
Bloods
CT imaging
What is it essential to do in someone who has had a TIA?
Assess their risk of having stroke in the next 7 days = ABCD2 score
What is the ABCD2 score?
Assesses risk of stoke in the next 7 days for those who have had a TIA - Age > 60 (1 point) - BP > 140/90mmHg (1 point) - Clinical features a) Unilateral weakness (2 points) b) Speech disturbance (1 point) - Duration a) >60 minutes (2 points) b) <60 minutes (1 point) - Diabetes (1 point) Score >6 predicts stroke Score >4 assessed within 24 hours
What classifies as a high risk stroke patient?
ABCD2 score >4
AF
>1 TIA in a week
Within how long should someone with a suspected TIA been seen by a specialist?
Within 7 days
What is treatment for a TIA?
2 weeks aspirin and dipyridamole
Long term clopidogrel
Control CV risk factors - antihypertensives, statins, anticoagulants
Define myelopathy
Spinal cord disease - UMN problem
Define radiculopathy
Spinal nerve root disease - LMN problem
Give 3 causes of spinal cord compression
- Vertebral tumour (metastases from lung, breast, kidney, prostate, myeloma)
- Disc herniation
- Disc prolapse
- Trauma
- Infection
Give 3 signs and symptoms of spinal cord compression
- Back pain
- Progressive spastic leg weakness
- UMN symptoms below lesion - hypertonia, hyper-reflexia
- LMN weakness and signs at level of lesion
- Sensory loss below lesion
- Bladder sphincter problems –> hesitancy, frequency, painless retention
What investigations might you do in someone with suspected spinal cord compression?
Urgent MRI/CT scan
What is the treatment for spinal cord compression?
Decompressive surgery
Dexamethasone and radiotherapy - if malignancy
Briefly describe the pathophysiology of cauda equina syndrome
Spinal compression at or distal to L1 –> disrupts sensation and movement
Give 3 causes of cauda equina syndrome
- Lumbar disc herniation
- Tumour
- Trauma
- Infection
Give 4 signs of cauda equina syndrome
- Flaccid and areflexic leg weakness
- Back pain –> alternating/bilateral sciatica
- Saddle anaesthesia
- Loss of sphincter tone –> bladder/bowel dysfunction
- Erectile dysfunction
What investigations might you do to see if someone has cauda equina syndrome?
- MRI/CT of spine
- CRE = reduced anal tone
- Reflex tests
How do you treat cauda equina syndrome?
- Immediate surgical decompression
2. Treat cause
What is treatment for sciatica without neurological signs?
Conservative management - physio and NSAIDs
Define spondyloisthesis
Slippage of vertebra over the one below
Define spondylosis
Degenerative disc disease
What are the 4 stages of a seizure?
- Prodromal - often emotional signs
- Aura
- Ictal
- Post-ictal - often drowsy and confused
Give 3 activities that can trigger trigeminal neuralgia
- Washing your face
- Eating
- Shaving
- Talking
How long do you wait for before doing a lumbar puncture in someone with a suspected subarachnoid haemorrhage?
At least 12 hours
You need to wait or the Hb to break down and then CSF will become yellow - sign that there is a bleeding in subarachnoid space (xanthochromia)