Neurology Flashcards
What gene mutation is the most common cause of late onset Alzheimer’s?
ApoE4
What gene mutation is the most common cause of early onset Alzheimer’s?
Presenilin 1
[PSEN1]
What proportion of Alzheimers is genetic?
15%
What is the most common form of dementia?
Alzheimer’s
[Around 50% of cases]
What is the 2nd most common form of dementia?
Vascular dementia
[Around 20% of cases]
What is the mean survivial time from the diagnosis of Alzheimer’s?
7 years
What are the two pathological hall-marks of Alzheimer’s disease?
Beta-Amyloid plaques
Tau tangles
Give two reversible causes of dementia
Vit B deficiency Cerebral tumour Diabetes Syphilis Depression
Which lobes of the brain are most affected by Alzheimer’s atrophy?
Fronto-temporal lobes
[You also see dilated ventricles]
At what threshold of MMSE score would you begin treating ALzheimer’s?
<12 points
What treatment would you use for mild alzheimer’s vs severe?
Mild = Acetylcholinesterase inhibitors:
- Rivastigmine
- Donepezil
- Galantamine
Moderate-Severe = NMDA antagonists:
- Memantamine
How would you manage vascular dementia?
Aspirin/Warfarin therapy
Antihypertensives
What kind of dementia tends to have fluctuating symptoms?
Lewy-Body Dementia
[Pick’s disease]
What is the classic triad of Wernicke’s encephalopathy?
[CAN]
Confusion
Ataxia
Nystagmus (ophthalmoplegia)
True of false, Wernicke’s encephalopathy is reversible?
True
What is the maximum score on the MMSE? What is the threshold for normal?
Max = 30
Normal = 24 or above
What is a seizure?
Spontaneous, uncontrolled brain activity.
What is epilepsy? What is the diagnostic threshold?
A tendency to have seizures
2+ seizures = Dx.
What is the difference between Focal/Partial seizures and Generalised?
Focal affect one hemisphere only. Remain conscious.
Generalised affect both hemispheres. Unconscious.
What is Todd’s paralysis?
Weakness in limbs following a seizure. Can last up to 2 days.
What is the difference between tonic and clonic?
Tonic = Rigid
- Tongue biting
- Incontinence
Clonic = Convulsions
- Eye rolling
- Tachycardia
How do you differentiate between epileptic seizures and non-epileptic seizures?
Epileptic:
- Short duration
- Abnormal EEG
- Eyes open
- Stereotyped movements
- Incontinence
- Self injury
Non-Epileptic:
- Longer
- No EEG changes
- Eyes closed
- Irregular movements
What is a Jacksonian march?
When a focal seizure spreads causing more parts of the body to be affected
How do myoclonic seizures present?
Small muscle twitches
What is status epilepticus?
A seizure that lasts more than 5 minutes
[Treated with IV lorazepam]
What is the first line treatment for focal epilepsy?
Carbamazepine or Lamotrigine
2nd line:
Sodium valproate
What is the first like treatment for generalised epilepsy?
Sodium Valproate or Lamotrigine
2nd line:
Carbamazepine
Give a non-pharmacological treatment for epilepsy
Surgery:
- Temporal lobectomy
- Hemispherectomy
Ketogenic diet
What is the difference between Neuropraxia, Axonotmesis, and Neurotmesis?
Neuropraxia: Impaired nerve conduction due to myelin damage. Can fully recover.
Axonotmesis: Axon is damaged. May possibly recover. (Typically from crushing or stretching)
Neurotmesis: Full lesion of the axon. No recovery.
What is Wallerian degeneration?
When a nerve is cut/crushed the axon distal to the injury dies. Typically occurs 24-36 hours post injury.
What is a TIA?
Transient Ischaemic Attack
- Symptoms must resolve in <24hrs
[80% due to thromboemboli]
What is Amaurosis Fugax?
(TIA of the eye)
Sudden loss of vision for a few minutes in one eye “a curtain coming down”.
Caused by an embolus in the retinal arteries.
How would you investigate an Amaurosis Fugax?
Carotid doppler Echocardiogram CT Lipid profile Clotting screen LFT
What is FAST?
Face, Arms, Speech, Test
Test for signs of a stroke
What are the three kinds of cerebral haemorrhage?
EXTRADURAL
- Skull fracture e.g. RTA
- Tearing of Middle Meningeal Artery can result in rapid increase in ICP and coning.
- Biconvex on CT
SUBDURAL
- Gradual onset headache
- Lesion of bridging veins
- Shaken baby
- Banana shape on CT
SUBARACHNOID
- Thunderclap headache
- Berry aneurysm
- Requires surgical clipping
[There is also intracerebral and intraventricular bleeds caused by hypertension or bleeding disorders]
What is a major risk factor for berry aneurysms?
Polycystic Kidney Disease
What is xanthochromia?
Yellow CSF
Happens when blood gets into the CSF following a subarachnoid bleed.
Why do you do a CT scan following a head injury prior to doing a lumbar puncture?
To avoid coning!
What is lost with Brown Sequard Syndrome?
[Call The Police Later]
Contralateral Temperature Pain and Light Touch
Which cells produce the CSF?
Ependymal cells of the choroid plexus
What two main arteries supply the Circle of Willis?
Internal Carotid (80%) Vertebral arteries (20%)
Which cranial nerves pass through the cavernous sinus?
CN 3, 4, 5 (V1 & V2) and 6.
[Internal carotid + Pituitary]
What is the triad of Horner’s Syndrome?
Miosis (constricted pupil)
Ptosis (eyelid droop)
Anhydrosis (no sweat)
What are the three ascending and three descending spinal tracts?
Ascending:
1) DORSAL COLUMN
- Touch/Vibration/Proprioception
- Gracilis (lower limb below T6) + Cuneate (upper limb above T6)
2) SPINOTHALAMIC
- Lateral (pain/temp)
- Anterior (crude touch/pressure)
3) SPINOCEREBELLAR
- Proprioception
Descending:
1) CORTICOSPINAL (Pyrimidal)
- Lateral (85% decussate in medulla)
- Anterior (15% decussate in spine)
2) CORTICOBULBAR
- Face and eye movements
3) EXTRAPYRIMIDAL
- Autonomic (tectospinal, vestibulospinal, reticulospinal, rubrospinal)
What structures are in the forebrain?
Cortex
BG
Thalamus
Hypothalamus
What structures are in the midbrain?
Tegmentum
Sup/Inf Colliculi
Crus cerebri
What is the role of the Superior and Inferior Colliculus?
Sup - orientates to vision
Inf - orientates to sound
What structures are in the hind brain?
Medulla
Pons
Cerebellum
How many spinal vertebrae are there?
33
7C, 12T, 5L, 5S, 4C
How many spinal nerves are there?
31 pairs
8C, 12T, 5L, 5S, 1C
What is the most common cause of sciatica?
Herniation of the vertebral disc into the intervertebral foramina
At what level does the spinal cord end?
L1-L2
[After this it becomes the Cauda equina]
At what level do you do a lumbar puncture?
L3-L4
Into the subdural space
What nerve passes through the Parotid gland?
The facial nerve (CNVII)
What are the 5 branches of the facial nerve?
Temporal Zygomatic Buccal Mandibular Cervical
What is the Parkinson’s triad?
Resting tremor [pill-rolling = 4-7hz]
Rigidity
Bradykinesia
What is the hallmark histological pathology of Parkinson’s disease?
Lewy body protein in Dopaminergic neurons of the substantia nigra (esp pars compacta)
A patient presents with pain around one eye lasting 30 minutes with reduced vision. Their symptoms are also worse in the dark. What is the most likely diagnosis?
Cluster headache
What is the first line treatment for cluster headaches?
Sumitriptan or Oxygen therapy (100%)
[NB: OTC medications e.g. paracetamol are not effective as they take too long to work. Cluster headaches often only last 30 minutes]
Give three triggers of migraines
Cheese OCP Caffeine Stress Travel Alcohol Lack of sleep Strong smells Weather
A patient presents with a tight band sensation around their head. What is the most likely diagnosis?
Tension headache
What hereditary pattern does Huntington’s disease follow?
Autosomal Dominant
[CAG repeat; 40x = 100% penetrance]
What is the typical age of onset for Huntington’s
Around 40 years old
Give two differences between rigidity and spasticity
Spastic:
- Different flexor/extensor response
- Velocity dependent
- Weak extremities
Rigidity:
- Same flexor/extensor response
- Not velocity depenent
- Extremities aren’t weak
What is the pathophysiology of MS?
Chronic autoimmune demyelination of neurons
True or false, MS symptoms are often exacerbated by heat?
True.
[Uhthoff’s Phenomenon]
What are the four main types of multiple sclerosis?
Primary Progressive
- Gets worse gradually
Secondary Progressive
- Following relapse it just gets worse.
Relapsing Remitting
- Remits back to normal
Progressive Relapsing Remitting
- Relapses a bit but still gets worse
Give two tests you would perform to investigate a diagnosis of multiple sclerosis?
MRI (white matter lesions)
Lumbar puncture (oligoclonal IgG bands)
NB: A consultant will make a diagnosis based on the whole clinical picture.
[Visual evoked potentials no longer done due to MRI]
What are the two hallmark visual pathologies of MS?
Optic neuritis [25% of MS patients] - temporary vision loss (days) and eye pain.
Internuclear Ophthalmoplegia [INO] - lesion of medial longitudinal fasciculus results in impairment of conjugal eye movement. When patient looks right or left, one eye will not pass the midline (unilateral eye movement with one eye covered is fine however!)
What is Lhermitte’s sign?
Shooting pain down the spine on neck flexion
[Often a sign of spinal cord inflammation eg. MS or meningitis]
In MS what is inflammation of the spinal cord called?
Transverse myelitis
[This can cause impairment e.g. bladder or bowel dysfunction].
What is the treatment for MS relapses and for long term?
Relapses:
- Methylprednisolone
Long term:
- Beta interferon
- Baclofen (reduces spasticity)
- Alemtuzumab
What are the two main types of Motor Neuron Disease?
Amyotrophic Lateral Sclerosis
[Lou Gherig’s disease] = 75% of cases. [UMN + LMN signs]
Progressive Bulbar Palsy = 25% of cases. Speech and swallowing affected.
True or false, bladder symptoms are common with motor neuron disease?
False.
You don’t get bladder dysfunction or sensory symptoms with MND
What treatment is available for motor neuron disease?
No cure.
Na channel blocker e.g. Riluzole (delay progression)
GABA agonist (reduce spasticity)
What is the pathophysiology of Myasthenia Gravis?
Autoimmune degeneration at the neuromuscular junction (Acetylcholine receptors)
What test is diagnostic for myasthenia gravis?
TENSILON Test:
- Edrophonium (Ach-esterase inhibitor) + atropine (protect heart). If symptoms improve = +ve Dx.
Give two investigations you would perform in a patient with myasthenia gravis?
EMG MRI Spirometry Serum IgG (+ve 85% patients) Thyroid function test Tensilon test (Diagnostic)
What is the treatment for myasthenia gravis?
Acetylcholinesterase inhibitors
Immune suppression (steroids or azathioprine)
Thymectomy (Thymus enlarged in 75%!)
Plasmapheresis
IVIG
True or false, lifespan with Myasthenia Gravis is normal if treatment is given?
True
What is the difference in presentation between encephalitis and meningitis?
Encephalitis produces cognitive impairment
Meningitis does not
Give a treatment for viral encephalitis
Antiviral IV e.g. aciclovir
Mannitol or hypertonic saline if cerebral oedema.
Steroids (reduce swelling)
Phenytoin (reduce seizure risk)
What is the pathophysiology of encephalitis?
Inflammation of the parenchyma of the CNS. Typically viral.
[Parenchyma = functional tissue (not structural/supportive)]
Give two investigations you would perform in a patient with suspected encephalitis
MRI (gold standard) Lumbar puncture Urine/Stool sample FBC LFT Viral PCR (blood)
What are the two most common virus types that cause encephalitis?
Enterovirus
Herpes
{+ Measles, Mumps, Rubella, Adenovirus etc.]
Give two common causes of GBS
Campylobacterjejuni EBV Influenza HIV CMV
Who do you need to involve if you suspect a patient has GBS
Anaesthetics (may need intubation)
True or false, the CSF of a patient with GBS should be normal?
True.
If it is abnormal then consider an alternative diagnosis e.g. Lyme’s disease or HIV.
What does a positive Babinski sign indicate?
In >2yo
+ve sign = CNS damage
What is a stroke?
Sudden onset neurological dysfunction
Give two investigations you would perform in a patient with a stroke
Carotid Artery Doppler CT scan (excld. haemorrhage) ECG Echocardiogram FBC LFT U&E ESR/CRP
What is the treatment for an ischaemic stroke?
Thrombolysis (alteplase) within 4.5hrs
Antiplatelet + PPI
ACE/Diuretic/CCB
Statin
[+Carotid endarterectomy]
If you have a stroke with mixed MCA + ACA loss and monocular vision loss (A. fugax) where is the block?
Internal Carotid Artery
[Large vessel block]
If you have a stroke with CNS palsy, coma, vertigo and dysphagia, where is the block?
Vestibular artery
[Large vessel block]
If you have a stroke with foot/leg and can’t read, where is the stroke?
ACA block
If you have a stroke with hand and face motor loss, neglect and aphasia where is the stroke?
MCA block
If you get visual loss, hallucination or loss of depth perception, where is the stroke?
PCA block
If you get a 3rd nerve palsy, where is the stroke?
Midbrain
If a patientis clumsy, with sensory loss only on one side of their body or dysarthria, where is the stroke?
Lacunar
[pure sensory or pure motor, not mixed]
Lacunar are v common and tend to be milder.