Neuroscience Flashcards
What is migraine?
Severe, episodic headache that may have a prodrome of focal neurological symptoms (aura) and is associated with systemic disturbance
Recall the medical management of migraine both in the acute setting and for prophylaxis
Acute:
- Anti-emetic - IV metoclopramide
- Analgesia - aspirin, paracetamol, NSAID (NO OPIOIDS)
- Triptan (5HT1-R agonist) - sumitriptan
Prophylaxis:
1st line = propranolol (BB) or topiramirate (anticonvulsant)
2nd line = TCA - amitriptyline
When does migraine usually present?
Teenager - young adult OR middle age
What are the risk factors for migraine?
FHx
Lifestyle - caffeine, stress, lack of sleep
Change in barometric pressure - high altitude/weather changes
Female
Obesity - increases risk of chronic migraine
Habitual snoring
Overuse of headache meds
What are the symptoms of migraine?
Prolonged headache - 4-72h Episodic/recurrent Throbbing/pulsating N+V Decreased ability to function Headache worse with activity Sensitivity to light/smell/noise Aura
What causes migraine?
Brain is hyperexcitable to a variety of stimuli
Neuronal depolarisation is more easily triggered
Genetic
How is migraine diagnosed?
Clinically
Any investigations are normal
What are the complications of migraine?
Status migrainosus - migraine attack > 72h - ?medication overuse as cause, tx w corticosteroids
Depression
Chronic migraine
Seizures
Migrainous infarction
What is Bell’s palsy?
Acute unilateral peripheral facial nerve (CNVII) palsy
How is Bell’s palsy diagnosed?
Clinical diagnosis of exclusion
What are the risk factors for Bell’s palsy?
Intranasal flu vaccine
Pregnancy
What are the symptoms of Bell’s palsy?
- Single episode
- Unilateral
- No constitutional symptoms
- Dry eyes
- Post-auricular pain
- Otalgia
- Sometimes sensory disturbances
What are the signs of Bell’s palsy?
Acute, unilateral facial palsy, with an o/w normal physical examination
Equal distribution of facial weakness across facial zones
Why does Bell’s palsy affect the whole face?
Involves all nerve branches (bc blockade originates proximal to geniculate ganglion, prior to any branching)
What causes Bell’s palsy?
Reactivation of HSV-1 within the geniculate ganglion after cellular immune suppression
What is the most common cause of unilateral facial palsy in those over 2?
Bell’s palsy
In what age group is Bell’s palsy most common?
15-45yo
How is Bell’s palsy managed acutely?
- Corticosteroid - prednisolone - 60mg OD for 5 days, then daily down 10mg until 0 - start within 72h of onset
- Eye protection
- glasses + artificial tears during day
- ophthalmic lubricant + eyelid taped shut at night
What is the prognosis for Bell’s palsy?
Incomplete paralysis on presentation - 94% fully recover
vs 61% of those with complete paralysis
What is cluster headache?
Unilateral headache attacks lasting from 15-180 minutes associated w/autonomic symptoms (parasympathetic hyperactivity and sympathetic hypo-activity)
What are the risk factors for cluster headache?
Male FHx Head injury Smoking Heavy drinking
What is the most common trigger for cluster headache?
Alcohol
What are the signs and symptoms of cluster headache?
Unilateral headache attack 15m-3h Around 4/day Excruciating pain Autonomic: lacrimation, rhinorrhoea, partial Horner's Agitated - can't sit still Photophobia + phonophobia Migrainous aura
Recall the aetiology of cluster headache
Idiopathic
How is cluster headache investigated?
Brain CT/MRI - normal in primary, abnormal in secondary (tumour, cavernous sinus pathology)
ESR - normal in primary, to exclude GCA in patients > 50
Pituitary function tests - normal, abnormalities –> secondary causes resulting from pituitary adenoma
What is encephalitis?
Inflammation of the brain parenchyma associated with neurological dysfunction
Recall the aetiology of encephalitis
Mainly viral
Usually HSV-1
What are the risk factors for encephalitis?
Age <1 or >65 Immunodeficiency Viral infections Blood/body fluid exposure Organ transplant Animal or insect bites Swimming or diving in warm freshwater or nasal/sinus irrigation
What are the presenting symptoms of encephalitis?
Fever Rash Altered mental state - drowsy-coma Headache Photophobia Neck stiffness Seizure
What are the signs of encephalitis?
Pyrexia Altered mental state Focal neurological deficit Meningismus - headache, photophobia, neck stiffness Seizures
How is encephalitis investigated?
1. BLOODS FBC - high lymphocytes UE - SIADH possible (low Na) Glucose - compare w CSF glucose Viral serology ABG
- MRI/CT –> HSV - temporal oedema
Also exclude mass lesion before LP - LP: high lymphocytes and monocytes + high protein
Culture/PCR
Why must you do a CT brain before a lumbar puncture in suspected encephalitis?
To exclude a mass lesion
What is extradural haemorrhage?
Bleeding between the dura mater and the inner surface of the skull
What is subdural haemorrhage?
Bleeding into the subdural space (between dura and arachnoid mater)
What is subarachnoid haemorrhage?
Bleeding into the subarachnoid space (between arachnoid and pia mater)
What causes subdural haemorrhage?
Usually TRAUMA:
Blow to temporal side of head
Ruptures bridging cranial veins
Also: Rupture of cerebral aneurysm Rupture of arteriovenous malformation Cerebral hypotension Malignancy (rare)
What causes subarachnoid haemorrhage?
Traumatic injury OR spontaneous
Spontaneous causes: Ruptured intracranial aneurysms 70% Arteriovenous malformation 10% Unknown aetiology 15% Rare disorders <5%
What is the classic history for extradural haemorrhage?
Head trauma + severe headache
Immediate fluctuating level of consciousness following trauma before appearing lucid (lucid interval) - tiredness, confusion
Rapid deterioration some time following regaining consciousness
What are the earl signs of extradural haemorrhage?
Severe headache after trauma, can persist
Initial loss/fluctuance in consciousness - tiredness, confusion
Period of lucidity after initial LOC - lasts 6-8h, but can last days
What investigations must be done for extradural haemorrhage?
Urgent non-contrast CT head
What does an extradural haemorrhage look like on CT?
Lemon
Biconvex lens
Midline shift
Brain stem herniation
What are the late signs of extradural haemorrhage
- GCS drops as ICP rises and BS begins to herniate
- LOC
- Focal neurological deficitis in eyes (CN compression) - blown pupil = fixed dilated ipsilateral pupil
- Contralateral hemiparesis, can become bilateral (compression of ipsilateral motor cortex)
- UMN signs - positive Babinski’s sign (upgoing toes), hyperreflexia + hypertonia
- Cushing’s triad due to raised ICP
- Persisting unconsciousness -deep coma and v low GCS
- Death - resp arrest
What upper motor neuron signs may you see in EDH?
Positive Babinski’s - upgoing toes
Hyperreflexia
Hypertonia - spasticity
What is Cushing’s triad and what causes it?
Bradycardia
HTN
Deep/irregular breathing
Raised ICP
What investigation are absolutely contraindicated in EDH and why?
Lumbar puncture
Result in drop in CSF pressure
May speed up brain herniation
What investigation are absolutely contraindicated in EDH and why?
Lumbar puncture
Result in drop in CSF pressure
May speed up brain herniation
What are the risk factors for subdural haemorrhage?
Recent trauma
Coagulopathy
Anticoagulant use
>65yo
What are the presenting symptoms of SDH?
Headache N+V Confusion Irritability Seizure
What are the signs of SDH?
Head trauma - abrasions, lacerations
Low GCS:
Diminished eye response: anisocoria (unequal pupil size) - BS herniation
Diminished verbal response
Diminished motor response
Confusion
Focal neurological signs (much more common in acute)
How is SDH investigated?
Urgent non-contrast CT: banana/moon
How is SDH managed initially?
Resuscitation and stabilisation of vitals: ABCDE
Senior doctor + neurosurgeon + anaesthetist
What are the complications of SDH
Complications result from damage from bleed itself + standard post-op complications from surgical Mx
Neuro deficits Coma Seizure Infection Recurrent haemorrhage
What are poorer functional outcomes in SDH associated with?
Older age More serious injury Lower GCS Midline shift, multiple parenchymal lesions Raised ICP Early need for surgery
How can SDH be classified?
Acute <3d
Chronic >21d
How does SDH clinically present?
History of trauma Older Alcohol misuse Child - non-accidental injury Gradual deterioration (worsening headache and confusion)
How is acute SDH managed once confirmed by non-contrast CT?
Bleed <10mm size (midline shift <5mm non-expansile without significant neurological dysfunction):
- Admit, observe, monitor + follow-up CT in 2-3wks
- Prophylactic antiepileptics - IV phenytoin, phenobarbital or oral/IV levetiracetam
- ICP monitoring if GCS is <9
- Correct coagulopathies (i.e. vitamin K)
- Lower ICP
Bleed w 1+ of following: ≥10mm size; w midline shift >5mm; expansile or significant neurological dysfunction - SURGERY FIRST - decompressive craniectomy
What does the management of acute SDH once confirmed depend on?
Size of haemorrhage
How is chronic SDH managed once confirmed?
- Antiepileptic medication - IV phenytoin, IV phenobarbital, oral/IV levetiracetam
- Surgery for symptomatic patients- i.e. burr hole irrigation and drainage, craniotomy
- Correct coagulopathy- i.e. with vitamin K
- Lower ICP
What are the 3 main ways in which SAH damages the brain?
- Hypoxia
- Raised ICP
- Direct cranial injury
What are the risk factors for spontaneous SAH?
HTN Smoking FHx Autosomal dominant polycystic kidney disease <50yo Female (1.5x baseline risk) Black
Compare the pathophysiology of EDH, SDH and SAH
EDH: rupture of middle meningeal artery on temporal surface of skull
SDH: rupture of bridging cranial veins
SAH: rupture of a berry aneurysm
How does SAH clinically present?
Sudden onset severe headache, reaching max intensity within seconds = thunderclap headache
N+V
Photophobia
Reduced consciousness level
Neck stiffness
Kernig’s sign
What is Kernig’s sign?
Patient is supine w hip and knee flexed to 90 degrees
Inability/pain on straightening leg
What causes a positive Kernig’s sign?
Irritation of motor nerve roots passing through inflamed meninges as they are under tension
How is SAH investigated?
Bloods: FBC, U+Es, coagulation studies (useful prior to LP or surgery)
Urgent plain CT head - blood in SA space or hydrocephalus
CT angiogram - can identify aneurysm
LP - only if SAH suspected but CT clear and no evidence of raised ICP
When is a lumbar puncture necessary in suspected SAH?
When CT scan clear and shows no evidence of raised ICP (risk of BS coning)
When must a lumbar puncture be performed in suspected SAH for the results to be reliable?
At least 12h after onset of symptoms
What does an LP show in SAH?
Xanthochromia
Due to infiltration of blood from haemorrhage
Bilirubin
Oxyhaemoglobin
What is Guillain-Barré syndrome?
Acute inflammatory demyelinating polyneuropathy
Recall the aetiology of GBS
- Immune-mediated demyelination of PNS
- Often triggered by Campylobacter infection (or Salmonella) about 2 weeks after infection
What are the risk factors for GBS?
Preceding viral illness - gastroenteritis or flu-like weeks before onset
Preceding bacterial infection
Hep E infection
Increasing age
What are the presenting symptoms of GBS?
- Ascending symmetrical muscle weakness/paralysis a few weeks after infection
- Proximal muscles more affected - trunk, resp, CN VII esp
- Pain - back, limb
- Autonomic: sweating, high HR, BP changes, arrhythmia, urinary retention
- Areflexia
- Diplopia
- Slurred speech
What are the signs of GBS?
- Symmetrical muscle weakness/paralysis
- Proximal muscles
- Tachycardia
- Areflexia
How is GBS investigated?
- ABs: 25% +ve for anti-GM1
- NCS: slow conduction
- LP - CSF: high protein <5.5g/L; normal WCC
- Spirometry to monitor lung function (diaphragm involvement)
What are anti-GM1 antibodies indicative of?
Guillain-Barre syndrome
What symptoms make up Horner’s syndrome?
Ptosis
Miosis
Anhydrosis
What causes Horner’s syndrome?
Disruption of SNS to face
Lesion
Where is the lesion located in Horner’s syndrome?
Ipsilateral side of symptoms
What tests are used in Horner’s syndrome?
Cocaine eye drops - should block reuptake of post-ganglionic NA –> lack of NA in cleft –> mydriatic failure (no effect)
Paredrine - helps localise cause - if 3rd order neuron intact, amphetamine causes NT vesicle release –> NA into cleft –> mydriasis - if lesion in of 3rd order neuron - no effect - pupil stays constricted
Dilation lag test
How is Horner’s syndrome managed?
Depends on location and cause of lesion of tumour
Surgical removal
Radiation and chemotherapy
Genetic counselling if have genetic form
What is Huntington’s disease?
An autosomal dominant, slowly progressive, neurodegenerative disorder
When does Huntington’s disease usually appear?
Mid-adult life
Recall the aetiology of Huntington’s disease
Caused by an expanded CAG repeat at the N-terminus of the gene that codes for the huntingtin protein
What are the symptoms of Huntington’s disease?
Chorea Personality change Irritability and impulsivity Twitching or restlessness Loss of coordination Deficit in fine motor coordination Slowed saccades Motor impersistence Impaired tandem walking
What are the signs of Huntington’s disease?
Slowed saccades - ask pt to look between your 2 fingers held shoulder width apart - head turning or eye blinking
Motor impersistence - ask pt to protrude tongue or close eyes tightly for 10s - pt struggles to maintain
Deficit in fine motor coordination - tapping finger to thumb quickly - pt slow and irregular tempo
How is Huntington’s disease investigated?
Nothing initially - clinical diagnosis
CAG repeat testing can be done later - 40+ CAG repeats on 1 of the 2 alleles = +ve
intermediate result = 36-39 repeats
MRI/CT - evident caudate or striatal atrophy