Module 3C Neurology and Vision - Conditions DONE Flashcards
Basic pain pathway
- Nociceptors (pain receptors) at the end of nerves detect damage to tissues
- Nerve signals are transmitted along the afferent nerves to the spinal cord
- The signal then travels in the CNS, up the spinal cord (mainly in the spinothalamic tract and spinoreticular tract) to the brain (thalamus) where it is interpreted as pain (somatosensory cortex)
Two types of nerve fibres
- C fibres (unmyelinated) - transmit signals slowly and produce dull and diffuse pain sensations
- A-delta fibres (myelinated) - transmit signals fast and produce shapr and localised pain sensations
Headaches - red flags
-Fever, photophobia or neck stiffness (meningitis, encephalitis or brain abscess)
- New neurological symptoms (haemorrhage or tumours)
- Visual disturbance (giant cell arteritis, glaucoma or tumours)
- Sudden-onset occipital headache (subarachnoid haemorrhage)
- Worse on coughing or straining (raised intracranial pressure)
- Postural, worse on standing, lying or bending over (raised intracranial pressure)
- Vomiting (raised intracranial pressure or carbon monoxide poisoning)
- History of trauma (intracranial haemorrhage)
- History of cancer (brain metastasis)
- Pregnancy (pre-eclampsia)
What does papilloedema on fundoscopy indicate?
Suggests raised intracranial pressure
- brain tumour
- benign intracranial hypertension
- intracranial bleed
Tension headache - typical presentation + what is it associated with?
- mild ache or pressure in a band-like pattern around the head
- develop gradually and do not produce visual changes
.
Associated with: - Stress
- Depression
- Alcohol
- Skipping meals
- Dehydration
What is defined as a chronic tension-type headache?
TTH occurring on more than 15 days per month for at least 3 months
Tension (or tension-type) headache - Management
- Reassurance +/- simple analgesia
- Amitriptyline - 1st-line for chronic TTH
Sinusitis - presentation
- usually following a recent viral URTI
- tenderness and swelling on palpation of the affected areas
- usually resolves in 2-3 weeks
Sinusitis - management of prolonged cases
- steroid nasal spray
- antibiotics (phenoxymethylpenicillin 1st line)
Medication-overuse headache - treatment
- withdrawal of the analgesia
(challenging in pts with chronic pain)
Hormonal headache (menstrual migraines) - presentation
Related to low oestrogen
- unilateral, pulsatile headache associated with nausea
Hormonal headache (menstrual migraine) - treatment
- Triptans and NSAIDs (eg. mefenamic acid)
Trigeminal neuralgia - treatment
- Carbamazepine 1st-line
- Surgical options can be considered if symptoms persist
Types of migraine
- Migraine without aura
- Migraine with aura
- Silent migraine (migraine with aura but without a headache)
- Hemiplegic migraine
- Chronic migraine - pt experiences for more than 15 days per month for at least 3 months
Migraine - clinical features
Symptoms can last up to 72hrs, typical features are:
- Severe, unilateral, throbbing headache - pounding/throbbing in nature
- Aura (can last up to 60 mins)
- Photophobia/phonophobia/osmophobia - pts usually go toa darkened, quiet room during an attack
- nausea and vomiting
Migraines - what is aura
Aura can affect vision, sensation, or language - visual symptoms are the most common:
- sparks in vision
- blurred vision
- lines across vision
- loss of visual fields (eg. scotoma)
.
- Sensation changes - tingling/numbness
- Language changes - dysphasia
What is a hemiplegic migraine and what should be ruled out?
Migraine with hemiplegia (unilateral limb weakness)
- other symptoms may include ataxia and impaired consciousness
- note: can mimic a stroke/TIA - so it is important to rule this out
Migraine - triggers
- stress
- sensory stimuli - eg. bright lights, loud noises, strong smells
- sleep disturbances - eg. insomnia, irregular sleep patterns
- Dietary factors - eg. caffeine, alcohol
- Hormonal changes - eg. menstruation, menopause
Migraines - Acute management
(pts may develop strategies for managing symptoms - eg. going into a dark, quiet room)
1. Oral triptan (eg. sumatriptan) +/- NSAID +/- paracetamol
2. Anti-emetic (eg. metoclopramide)
What medication should NOT be given to pts with migraines (eg. acute attack)
Opiates - can make condition worse
Migraines - Prophylactic management
(a headache diary can help identify triggers and access response to treatment)
1. Propranolol OR Topiramate OR Amitriptyline
(menstrual migraine treatment - frovatriptan or zolmitriptan as “mini-prophylaxis”)
Who should not take topiramate (an option of medication used in migraine prophylaxis)?
Women of childbearing age - teratogenic + can reduce the effectiveness of hormonal contraception
Cluster headaches - Clinical features
- Severe pain - stabbing pain around one eye
- typically occurs once or twice a day - each episode lasting 15 mins to 2hrs
- “clusters” typically last 4-12 weeks
- red, swollen, and watering eye
- +/- miosis and ptosis
(note: alcohol can be a trigger)
Cluster headache - Acute treatment
- High-flow 100% oxygen
- Subcutaneous triptan
Cluster headache - Prophylaxis
- Verapamil
What is the most common viral cause of encephalitis?
Herpes simplex virus (HSV)
- Children - HSV-1 from cold sores
- Neonates - HSV-2 from genital herpes, contracted during birth
Encephalitis - clinical features
Rapid onset of symptoms:
- fever
- headache
- altered consciousness
- +/- neurological deficits
Encephalitis - investigations
- Lumbar puncture - send CSF for viral PCR testing
- (CT scan if LP contraindicated - -eg. GCS < 9, hemodynamically unstable, active seizures or post-ictal)
- MRI brain - after LP
- EEG - not routinely required
- HIV testing is recommended
Encephalitis - Management
- IV antiviral
- Aciclovir for HSV and VZV
- Ganciclovir for CMV - Supportive care - fluids, monitor ICP, +/- manage seizures
- Repeat lumbar puncture - to ensure successful treatment prior to stopping antivirals
(4. Follow-up and rehab - manage any complications)
Meningitis - Aetiology
Usually bacterial or viral:
- Bacterial
- Neisseria meningitidis - gram -ve diplococcus (meningococcal meningitis)
- Strep. pneumoniae
- Haemophilus influenzae
- Listeria monocytogenes, E. coli, and group B Strep (neonates) - Viral
- Enteroviruses (eg. coxsackievirus) - most common
- Herpes simplex virus (HSV)
Meningitis - Pathophysiology (invasion –> survival –> replication and tissue damage)
- Invasion
- Pathogen colonises nasopharynx
- pathogen then invades bloodstream
- bacteria then cross the blood-brain barrier (BBB) - Survival
- bacteria evades immune responses to survive and proliferate
- various mechanisms - antigenic variation, inhibition of complement activation, intracellular survival inside phagocytes, production of immunomodulatory molecules, and formation of biofilms - Replication and Tissue damage
- bacteria multiply in the subarachnoid space - leading to increased ICP
- Inflammatory response leads to damage of neuronal tissue and the BBB - results in symptoms
Meningitis - Clinical features
(a prodromal phase often precedes the classic symptoms - malaise, headache, myalgia, and low-grade fever)
.
Classic symptoms:
- Fever - moderate to high grade
- Neck stiffness - worse with passive flexion of neck
- Altered mental state
Meningococcal septicaemia - what is it and what symptom is often associated with it?
- When the meningococcus bacterial infection is in the bloodstream
- non-blanching rash
Meningitis - additional signs that there is meningeal irritation are Kernig’s sign and Brudzinski’s sign, what are these? (aka. Kernig’s and Brudzinski’s test)
- Kernig’s sign - pt in supine position with hips and knees flexed at 90 degrees, pain on straightening the knee suggests meningeal irritation (causes a stretch in the meninges)
- Brudzinski’s sign - pt supine, use your hands to lift their head and neck off the bed and flexing their chin to their chest - +ve sign is when this causes the pt to flex their hips and knees involuntarily
Meningitis - Investigations
- Blood cultures - to help identify causative organism
- FBC - elevated WCC
- CRP and ESR - often raised in bacterial infections
- Blood glucose - important for comparison with CSF glucose lvls
- Lumbar puncture - essential for confirming a diagnosis (culture, viral PCR, CSF glucose and protein)
Meningitis - using a lumbar puncture (CSF analysis) to differentiate between bacterial and viral cause
Think about what is going on:
- bacteria swimming in the CSF will release proteins and use up glucose
- Viruses may release a small amount of protein and do not use up glucose
- The immune system releases more neutrophils with bacteria and lymphocytes with viruses
Meningitis - Bacterial meningitis management
Ideally blood cultures and a LP should be performed before starting antibx, however don’t delay antibx if pt is acutely unwell (once causative organism identified - start specific antibx)
- Ceftriaxone + amoxicillin (to cover Listeria)
(cefotaxime - if under 3 months) - +/- Acyclovir (only if HSV encephalitis is suspected)
- +/- Vancomycin (if there is a risk of penicillin-resistant pneumococcal infection - eg. recent foreign travel or prolonged antibx exposure)
- Steroids (eg. dexamethasone) - to reduce hearing loss complications
- Close monitoring for complications - raised ICP, seizures, neuro deficits
- Supportive care - analgesics/antipyretics/antiemetics +/- fluids +/- oxygen
Is bacterial meningitis a notifiable disease?
YES
- notify the UK Health Security Agency
What is the most common complication of bacterial meningitis?
Hearing loss
- Sensorineural hearing loss can occur due to cochlear damage
Meningitis - Post-exposure prophylaxis
If close contact - give a single dose of ciprofloxacin as prophylaxis
Brain tumours - Clinical features
May be asymptomatic (particularly when small in size)
- headaches - persistent, morning, worse on lying down, +/- nausea and vomiting
Seizures - focal or generalised - Progressive focal neuro symptoms (depending on location) - cognitive, motor, sensory, vision, speech, personality changes
- Raised ICP signs
Raised intracranial pressure - Signs and symptoms
- constant headache
- nocturnal
- worse on waking
- worse on coughing, straining, or bending forward
- nausea and vomiting
- papilloedema on fundoscopy
more signs:
- altered mental state
- visual field defects
- seizures
- unilateral ptosis
- 3rd and 6th nerve palsies
Raised ICP - why does it cause papilloedema?
Papilloedema = swelling of the optic disc secondary to raised ICP
- the sheath around the optic nerve is connected with the subarachnoid space
- the raised CSF pressure flows into the optic nerve sheath, increasing the pressure around the optic nerve behind the optic disc causing the optic disc to bulge forward
Name some types of brain tumour
- Gliomas (can be benign or malignant) - tumours of the glial cells in brain or spinal cord
- Glioblastoma - most common primary brain tumour in adults
- Pilocystic astrocytoma - most common primary brain tumour in children - Meningiomas (typically benign) - tumours growing from the cells of the meninges, cause symptoms by compression not invasion
- Secondary metastases (bad) - most common form of brain tumours, often multiple lesions
- Pituitary adenoma (benign tumours) - can be hormone secreting or non-secreting
- Vestibular schwannoma (or acoustic neuroma) - benign tumour of the Schwann cells that surround the 8th cranial nerve (vestibulocochlear)
Which tumours most commonly spread to the brain to cause secondary metastases?
- Lung (most common)
- Breast
- Bowel
- Skin (melanoma)
- Kidney (renal cell carcinoma)
Glioma - which type is the most malignant and also the most common primary tumour in adults?
Glioblastoma multiforme
What type of visual field defect do pituitary adenomas cause if they grow large enough?
Bitemporal hemianopia
- pituitary sits close to the optic chiasm
Pituitary adenomas - presentation
They can cause hromone deficiencies (hypopituitarism) or excessive release of hormones, leading to:
- Acromegaly (excessive GH)
- Hyperprolactinaemia (excessive prolactin)
- Cushing’s disease (excessive ACTH and cortisol)
- Thyrotoxicosis (excessive TSH and thyroid hormones)
Pituitary adenomas - management
- Trans-sphenoidal surgery (thorugh the nose and sphenoid bone)
- Radiotherapy
- Bromocriptine (blocks excess prolactin)
- Somatostatin analogues (eg. octreotide) - to block excess GH
What do Schwann cells do?
provide the myelin sheath around neurones of the peripheral NS
Where do vestibular schwannomas (or acoustic neuromas) occur?
the cerebellopontine angle
(arises from the 8th cranial nerve - vestibulocochlear)
Vestibular schwannoma (or acoustic neuroma) - presentation
- Unilateral sensorineural hearing loss (often first symptom)
- unilateral tinnitus
- dizziness or imbalance
- sensation of fullness in the ear
- facial nerve palsy (if tumour grows large enough to compress the facial nerve)
Brain tumours - General management (include investigations)
- MRI brain
- Biopsy - gives defintive histological daignosis
.
Management depends on type and, grade - guided by MDT:
1. Surgery
2. Chemotherapy
3. Radiotherapy
4. Palliative care
How are brain tumours classified / graded?
Grades 1 to 4 - where 1 is least aggressive and 4 is most aggressive, based off:
- cellular appearance
- mitotic activity (how quickly cells are dividing)
- necrosis (dead tissue within the tumour)
- vascular proliferation
Which lobe would the tumour be in if the pt has an unusual change in personality and behavior?
Frontal lobe
- the frontal lobe is responsible for personality and higher-level decision-making
Brain abscesses - aetiology (where do they usually originate from)
- Contiguous spread of infection - sinusitis, otitis media, or dental infections
- Haematogenous spread from distant sources - eg, endocarditis, pulmonary infections
- Direct inoculation - trauma or neurosurgical procedures
(risk factors - immunocompromised, IV drug use)
Symptoms and signs of brain abscesses are usually quite non-specific and hard to localise, what investigations would you do for a suspected brain abscess or to rule it out?
- Neuroimaging - MRI (with gadolinium) and CT both have roles
- Stereotactic needle aspiration - can aid diagnosis and serve as treatment
(note: lumbar puncture is contraindicated due to risk of brain herniation)
Brain abscesses - Management
- Surgery - craniotomy –> abscess cavity debrided
- IV antibiotics
- Intracranial pressure management (eg. dexamethasone)
2 causes of ischaemic strokes
- Thrombotic - eg. atherosclerosis (ruptured plaque)
- Embolic - eg. AF
Oxford classification of stroke (Bamford classification)
Risk factors for a stroke
- Main –> smoking, AF, hx of previous stroke or TIA
- Other –> hypertension, hypercholesterolemia, obesity, family hx, vasculitis, combined oral-contraceptive pill
(stroke is associated with co-morbidities such as cardiovascular disease and vascular disease –> share the same risk factors)
Definition of stroke, TIA, crescendo TIAs
- Stroke = a clinical syndrome characterised by rapidly developing clinical symptoms and/or signs of focal neurological deficit lasting more than 24hrs and thought to be of vascular origin
- TIA = neurological signs/symptoms that are consistent with a stroke that resolve within 24hrs
- Crescendo TIAs = two or more TIAs within a week and indicate a high risk of stroke
Common symptoms of a stroke
- One-sided muscle weakness (hemiparesis)
- Dysphasia (speech disturbance)
- Aphasia (expressive/receptive/global)
- One-half visual field defects (hemianopia) - often lose one-half of visual field in each eye which results in neglect on one side of the body
- Sensory loss
- Ataxia and vertigo
Does stroke always affect the contralateral side of the body?
Not always –> if cerebellum affected then ipsilateral presentation
Label the cerebral arteries.
- Which arteries supply anterior brain
- Which arteries supply posterior brain
- Blood is delivered to brain through 4 main arteries, two internal carotid arteries (anterior supply), and two vertebral arteries (posterior supply to the brain)
- Anterior supplied by internal carotid arteries which form the ACA and MCA
- Anterior connects with Posterior via posterior communicating artery
- Posterior supplied by vertebral arteries which combine to form the Basilar artery
(The brain also has a venous drainage system which drain into the venous sinuses)
Which arteries form the Circle of Willis?
- What is function of Circle of Willis?
- Formed by basilar artery, internal carotid artery, and middle cerebral artery
- Safeguards the oxygen supply from interruption by arterial blockage
- For example, if there is stenosis in one artery then other source arteries to the Circle of Willis can provide an alternative blood flow (collateral circulation)
The limbic system is made up of the hippocampus and amygdala, what are their functions?
Limbic system is involved in behavioural and emotional responses (survival, fight or flight)
- Hippocampus –> memory centre, spatial orientation, neurogenesis occurs here (key brain structure for learning new things)
- Amygdala –> central role in emotional responses (pleasure, pain, fear, anxiety, anger), attaches emotional content to memories
Functions of frontal lobe, parietal lobe, temporal lobe, and occipital lobe
- Frontal lobe –> higher executive function (emotions, planning, reasoning, problem-solving), primary motor cortex (responsible for voluntary movement)
- Parietal lobe –> sensory info (touch, temp., pressure, pain), two-point discrimination can be used to assess
- Temporal lobe –> sensory info (hearing, recognising language, forming memories), primary auditory cortex (can understand what we hear), making sense of complex visual info (faces and scenes), hippocampus (memory, learning, emotions)
- Occipital lobe –> Primary visual cortex (major visual processing centre in the brain)
MCA infarct:
- locations affected?
- symptoms associated
- Locations affected –> frontal, parietal, and temporal lobes
Symptoms:
- hemiparesis –> arm worse than leg
- Sensory loss
- Facial weakness –> facial droop/dysarthria
- Dysphasia –> expressive, receptive, global
- Hemianopia –> without macula sparing
Broca’s aphasia vs Wernicke’s aphasia
- Broca’s –> expressive dysphasia (pt can understand what is said but cannot express with words, difficult to speak)
- Wernicke’s –> receptive dysphasia (pt doesn’t understand what is being said, but can still talk normally, but it doesn’t make any sense)
If a right-hand dominant patient has Broca’s or Wernicke’s aphasia then which side is the stroke?
- Left MCA
- Broca’s and Wernicke’s area are found in the dominant cerebral hemisphere
- left side for right-handed
- right side for left-handed
ACA infarct:
- locations affected?
- symptoms associated
- Locations affected –> frontal and parietal lobes
Symptoms:
- hemiparesis –> leg worse than arm
- Apathy –> lack of interest, enthusiasm, or concern
- incontinence
- Disinhibition –> lack of restraint in social scenarios (affects motor, emotional, cognitive, instinctual, and perceptual behaviours)
- Mutism
Lacunar stroke:
- locations affected?
- symptoms associated
Locations affected –> Lenticulostriate arteries (small penetrating arteries that supply deep structures
(susceptible to injury secondary to uncontrolled hypertension)
Symptoms:
- Pure motor –> hemiparesis or hemiplegia, dysrthria, dysphagia
- Pure sensory –> numbness/tingling/pain on one side of body
- Sensorimotor –> hemiparesis or hemiplegia with contralateral sensory impairment
What are the watershed zones?
- Symptoms for each
Watershed zones are prone to infarction as they receive blood supply from two arteries
PCA infarct:
- locations affected?
- symptoms associated
Locations affected –> mainly occipital, parts of temporal
Symptoms:
- Hemianopia –> with macular sparing
- Amnesia
- Sensory loss (thalamus)
- Thalamic pain
Where does basilar artery supply and if basilar artery is affected in a stroke, what is the serious condition that can result? + what structure is damaged to cause this
- Supplies lower midbrain, pons, and medulla (and occipital lobe)
- Infarction causes locked-in syndrome –> individual has full consciousness but is paralysed
- due to damage to corticospinal tracts (quadriplegia)
- Respiratory muscles also paralysed so individual has to be ventilated –> resp. failure and coma/death can be result
Acute stroke management
- Non-contrast CT is mainstay investigation
- Thrombectomy –> Can be done together with IV thrombolysis if within 4.5hrs onset –> CT perfusion or CT angiography used to assess salvageable brain tissue
Contraindications for thrombolysis
- pt on DOAC or Warfarin (check INR)
- Hx of surgery, Hx of bleeding (external/internal)
- Uncontrolled hypertension –> BP > 180/120mmHg
What investigation should be done 24hrs after onset of a stroke
Repeat CT head to check for haemorrhagic transformation
Longer-term management of ischaemic stroke
- Aspirin 300mg daily –> for 2 weeks (start aspirin 24hrs after thrombolysis and once repeat CT confirms no haemorrhage)
- After the 2 weeks –> Clopidogrel 75mg –> lifelong
- Atorvastatin 20-80mg (after 48hrs) –> lifelong
- Address modifiable risk factors –> smoking, diabetes control, AF control (if ECG showed AF to be the cause), exercise
Indications for carotid endarterectomy
- If carotid artery doppler ultrasound confirms > 50% carotid stenosis
- (risk of clot embolising and causing stroke)
ROSIER score
(recognition of stroke in the emergency room)
Exclude hypoglycaemia first then assess the following:
- a stroke is likely if > 0
FAST tool for stroke
simple way to identify stroke in the community
F – Face
A – Arm
S – Speech
T – Time to call 999
NIH stroke scale (NIHSS) + criteria for no stroke/mod stroke/mod-sev/severe
NIH Stroke Scale (NIHSS) used as an initial assessment of the patient for suspected stroke and gives a rough idea of how severe the stroke is
(used in secondary care)
- < 5 –> no stroke/minor
- 5-15 –> moderate
- 16-20 –> moderate-severe
- 21-42 –> severe
Vascular territories
Dense MCA sign –> visible immediately, shows the responsible arterial clot
Warfarin reversal agents
Vitamin K and prothrombin complex concentrate
Heparin/LMWH reversal
Protamine sulfate
Dabigatran reversal agent
Idarucizunab
Apixaban, edoxaban, and rivaroxaban reversal agent
Andexanet alfa
For patient’s on anticoagulant therapy, what is the INR target range? + what value indicates a risk of bleeding?
- 2.0-3.0
- > 4.9 is high risk of bleeding
Complications of stroke (hospital problems)
- dysphagia/aspiration pneumonia –> most common cause of death pst-stroke in hospital setting –> SLT assessment + fluids
- DVT/PE –> normal pt (antiplatelets), stroke pt (mechanical stockings –> we don’t want to turn an ischaemic stroke into a haemorrhagic stroke)
- UTI –> stroke can cause bowel/bladder issues
- spasticity
- shoulder subluxation
- depression
- nutrition
- pressure sores –> look for bruising on pressure areas of body
How would you manage a patient who has had an ischaemic stroke and they have atrial fibrillation?
Anticoagulants should not be started until brain imaging has excluded haemorrhage, and not until 14 days after the onset of an ischaemic stroke
Cerebellar stroke symptoms
- Problems with moving/walking –> balance (cerebellum is part of brain responsible for balance)
- Vertigo –> ‘room spinning’
- muscle weakness or tremors
- headache
- nausea and vomiting
- hearing and vision problems
Management of crescendo TIAs
Aspirin 300mg and review in TIA clinic within 24hrs
Stroke/TIA –> DVLA guidelines for car drivers
- Must stop driving immediately
- Must stop for 1 month
- Must inform DVLA if after 1 month you still have –> weakness in arms or legs, eyesight problems (visual filed loss or double vision), or problems with balance, memory, or understanding –> or if doctor says not safe to drive