Week 12 Neuro Flashcards
What are cranial nerves?
12 pairs of nerves that exit brainstem which supply face and neck
Sensory, motor and parasympathetic activity
Cranial nerves and their components
CN I Olfactory S
CN II Optic S
CN III Oculomotor M (parasym)
CN IV Trochlear M
CN V Trigeminal B
CN VI Abducens M
CN VII Facial B (parasym)
CN VIII Vestibulocochlear S
CN IX Glossopharyngeal B (parasym)
CN X Vagus B (parasym)
CN XI Spinal Accessory M
CN XII Hypoglossal M
Oh Oh Oh To Touch And Feel Very Good Velvet. Such Heaven
Some Say Marry Money But My Brother Say Big Boobs Matters More
CN I Olfactory
Sensory
Smell
Olfactory cells of nasal mucosa - olfactory bulbs - pyriform cortex
Test: Ask pt if their sense of smell/taste has changed
CN II Optic
Sensory
Function: Vision
Retinal ganglion cells - optic chiasm - thalamus - primary visual cortex in occipital lobe
Test:
Visual Acuity - Snellen Chart
Visual Field and blind spot - move fingers in periphery
Pupillary reflex - Swinging light test, Accomodation
Colour Vision
Fundoscopy - optic disc
Homonymous hemianopia: loss of visual field on same side of both eyes (optic tract, optic radiation, visual cortex - due to aneurym in middle/post cerebral a)
Bitermpral hemianopia: missing outer halves of visual field of both eyes (optic radiation - due to pituitary adenoma, anuerysm in ant/ant communicating a)
CN III Oculomotor
Motor
Nucleus location: midbrain
Movement of eyeball (inferior, superior, medial rectus and inferior oblique) (LR6SO4)
Parasympathetic
Nucleus location: midbrain (Edinger Westphal)
Pupil constriction (cilary muscle, pupillary contrictor muscle)
Oculomotor palsy (decreased/loss of function):
Eye moves down and outwards, ptosis, dilation of pupil
CN IV Trochlear
Motor
Eyeball movement (Superior oblique)
Nucleus location: midbrain (level of inferior colliculus)
Function: depresses adducted eye, intorts (eyes turns in) abdcuted eye
CN II and IV dessucates to contra-lateral side
Trochlear nerve palsy: Diplopia, affected eye will move up causing pt to tilt head (to bring visual fields together)
CN VI Abducens
Motor
Eye movements (Lateral Rectus)
Nucleus: pons
Abducens nerve palsy: Eye turned medially, can’t abduct eye
Internuclear Opthamoplegia:
- Conjugate gaze (movement of both eyes in same direction) palsy
- Lesion in medial longitudinal fasiculus (connects CN III and CN VI)
- Unable to adduct affected eye, and nystagmus of abducted contralateral eye
- Common in MS
Horner’s syndrome
Due to ipsilateral disruption of cervial/thoracic sympathetic chain
Causes: Congenital, Pancoast tumour, MS, Cluster headache
Consists of meiosis, ptosis, anhidrosis, enopthalmos (posterior displacement of eyeball)
CN V Trigeminal
Both
Sensory:
Nucleus location: pons and medulla
Innervates: Face - opthalmic/mandibular/maxillary branches. anterior 2/3 tongue
Motor:
Mastication
Nucleus: pons
Innervates: Masseter, temporalis, medial and lateral and pterygoids
Tests: Sensory: ask pt close eyes, touch forehead, cheek, chin, ask one side feels different)
Motor: ask pt clench teeth and palpate temporalis and masseter
Corneal reflex (afferent: V, efferent: VII)
Herpes Zoster opthalmicus
Reactivation of VZV (singles)
Mostly V1 affected
Elderly, immunocompromised at risk
Treated with oral aciclovir
CN VII Facial
Sensory:
Nucleus: medulla
Function: anterior 2/3 tongue taste
Motor
Nucleus: pons
Function: muscles of facial expression
Parasympathetic
Nucleus: medulla
Salivary/lacrimal glands
Tests:
Ask pt:
Raise eyebrows, Close eyes tightly, blow out cheeks, bare teeth
Corneal reflex: (afferent: V, efferent VII)
Upper and lower motor neuron lesions:
- Bell’s palsy (weakness of facial muscles on one side of face)
Upper: weakens of inf muscles, forehead sparing (due to bilateral innveravation of forehead muscle)
Lower: weakness of sup and inf facial muscles
CN VIII Vestibulocochlear
Sensory
Hearing
Nucleus: pons and medulla
Innervates: Cochlear to autditory cortex in temporal lobes
Balance:
Nucleus: pons and medulla
Innervates: nerve endings in semiciruclar canals - cerebellum and SC
Tests:
Whispering number, ask pt to repeat
Rinne’s (conductive hearing loss), Weber’s (conductive or sensorineural loss)
Describe pathogenesis and clinical presentation of subarachnoid haemorrhage
Definition: Acute cerebrovasuclar event where there is bleeding into the subarachnoid space
Causes:
intracranial aneurysm (bulge in blood vessel due to weakened wall) - most common cause of non-traumatic SA
Other causes: AV malformation, anticoagulants
Risk factors: Marfan syndrome, Ehlers-Danlos Syndrome, polycystic kidney disease
Pathogenesis of SAH
Increased haemodynamic stress leads to inflammatory and immunological reactions - aneurysm formation
Cerebral artery aneurysm ruptures, blood flows in subarachnoid space and ventricles
Clinical presentation:
- Worst headache of their life, nausea/vomiting, photophobia
CN IX Glossopharyngeal
Sensory
Nucleus: medulla
Function: Taste, proprioception for swallowing, BP receptors
Innervates: post. 1/3 tongue, pharyngeal wall, carotid sinuses
Motor: Swallow, gag reflex
Innervates: pharyngeal muscles, lacrimal glands
Parasympathetic: Saliva production
Innervates parotid glands
Tests: Ask pt to cough, use tongue depressor to see palate (soft palate should move up)
Glossopharyngeal palsy:
Uvula moves away from affected side
CN X Vagus
Sensory:
Function: Chemoreceptors, pain receptors (dura) , sensation
Innervates: carotid bodies (BP), respiratory and digestive tracts, pharynx/larynx
Motor:
Function: HR, peristalsis, air flow, speech
Innervates: Heart, smooth muscle of digestive tract, smooth muscles of bronchus, muscles of pharynxlarynx
Parasym:
Innervates smooth msucle and glands as same areas as motor
Tests: Same as glossopharyngeal
CN XI Spinal Accessory
Spinal Acessory
Motor: Trapezius and Sternocleidomastoid
Function: Head rotation, shoulder shrugging
Tests:
- Ask pt to shrug shoulders against your resistance (Trapezius)
- Ask pt to turn head, against your resistance (SCM)
CN VII Hypoglossal
Motor
Function: Speech and swallowing
Tongue
Hypoglossal palsy:
Tongue moves towards lesion
Tests:
Inspect tongue for wasting, fasciculations
Ask pt to move tongue from side to side
CN syndromes
Lesion affected: Jugular foramen
- CN 9, 10, 11
- Paralysis of laryngeal muscles causing voice hoarseness, absent gag reflex, weakness in SCM and trapezius
- Due to tumour
Uvula
Lesion affected: bulbar palsy
CN 9, 10. 11, 12
- Causes dysphagia, difficult in speech, absent gag reflex
- Due to Gullain Barre,
Mononeuropathies: Radial
Entrapment at radial (spiral) groove
Saturday night palsy
Presentation: Wrist and finger drop, painless
Weakness:
Extensor carpi radialis (wrist extension)
Extensor digitorum (finger extension)
Brachioradialis (elbow flexion)
Mononeuropathies: Ulnar
Entrapment at ulnar groove
Presentation: History of elbow trauma, sensory disturbance (4th and 5th digit), painless, weak grip
Weakness:
1st dorsal interosseous (index finger abduction)
Abductor digiti minimi (pinkie abduction)
Flexor carpi ulnaris (wrist flexion)
Adductor policis (thumb adduction)
Mononeuropathies: Median
Entrapment at carpal tunnel
Presentatation: Intermittenet pain during night
- numbness/tingling (first 3 1/2 fingers on palmar surface)
- positive Tinel’s sign (tap on nerve causes pins and needles)
Weakness:
Lumbricals I and II (flexion at MCP joints)
Opponens pollicis (thumb opposition)
Abductor pollicis brevis (abduct thumb)
Flexor pollicis brevis (flex thumb)
Anterior intersosseous branch (of median nerve):
History forearm pain, weak grip, postive Tinel’s sign, cant make OK sign
- pronotor quadtraus (MCP joint flexion)
- flexor digitorum (finger flexion)
- flexor pollicis (thumb flexion)
Mononeuropathies: Common peroneal nerve
L4-S2
Branch of sciatic nerve
Entrapment at fibular head
Presentation:
- History of trauma/surgery/external compression
- Acute onset foot drop, painless,
- Foot inversion not affected (which differentiates it from L5 nerve root neuroapthy)
Weakness:
Tibilas anterior (ankle dorsiflexion)
Extensor hallucis longus (Big toe extension)
Mononeuropathies: femoral nerve
Commonly due to trauma/haemorrhage
Weakness in quads, hip flexion, numbness in medial shin
Weakness:
Quads (extension knee)
Iliopsoas (flexion hip)
Adductor magnus (adduction hip)
Mononeuritis multiplex
Peripheral neuropathy affecting simultaneous or sequential development of 2 or more nerves
Causes:
Diabetes
RA, lupus, sjogren’s syndrome
Sarcoidosis
Hep C/HIV
Lymphoma
What is the peripheral nervous system?
Consists of nerves and ganglia (collection of nerve cell bodies) outside CNS
Allows sensory input to CNS (via dorsal (post) root)
Motor output to muscles (via ventral (ant) root)
Innvervates viscera
Structure:
Bundles of axons in PNS = nerves
Individual axon surrounded by endoneurium
Axon bundled into fascicles and covered by perineurium
Bundle of fascicles covered by epineurium (connective tissue layer)
Nerve Fibre types:
Large myelinated fibres (Motor nerves):
- Proprioception, vibration
Thinly myelinated fibres:
- Light touch, pain, temperation
Unmyelinated fibres:
- Light Touch, pain, temp
Peripheral neuropathy
Damage to peripheral nerves
Presntation depends on which fibres affected:
Motor fibres - weakness
Large fibres - sensory ataxia (due to loss of proprioception), numbness/tingling (loss of light touch), vibration sense,
Small (myelinated/unmyelinated) sensory fibres) - impaired pin prick sensation, temp sensation
Autonomic: postural hypotension, abnormal sweating
Causes: diabetes, hypothyroidism, B12 deficiency
Length dependent axonal neuropathy
Diffuse involvment of peripheral nerves
>50 yrs
Symmetrical
Starts in toes/feet and moves proximally
No significant sensory ataxia
Weakness is distal and mild
Causes:
Diabetes, Alcohol, Nutritional (B12 deficiency), Drugs e.g. Isoniazid, Immune mediated e.g. RA, lupus
Guillain Barre Syndrome
Post-infectious autoimmune neuropathy
Targets myelin sheath
Gradual onset
Medical Emergency
Causes: campylobacter, EBV
- Flaccid, quadraparesis (weakness of all 4 limbs), areflexia (absent reflexes)
+/- Respiratory (e.g. SOB) bulbar duysfunction (e.g. dysphagia), autonomic involvement (tacycardia, HTN)
Treated with IV IG or aphresis
Muscle and Neuromuscular disorders
Clinical features of muscle disorders:
Proximal limb weakness (difficult rasining arms above head, lifting up from seat)
Facial weakness
Eyes: ptosis
Bulbar: dysarthria (difficulty speaking), dysphagia (difficulty swallowing)
Respiratory - breathless esp. when lying flat (as nerves innervating diaphragm isn’t working properly)
Causes of muscle disease:
DMD/BMD
Inflammatory muscle disoders: Polymyositis
NMJ disorders: Myasthenia gravis, Lambert Eaton syndrome
Myasthenia Gravis
Autoimmune disoder where autoantibodies agianst AchR at post-synaptic NMJ.
Decreased generation of muscle APs causing skeletal muscle weakness
Assoc with other autoimmune disorders, and thyoma
Young women, old men
Symptoms:
Fatiguable weakness of ocular, bulbar, respiratory and/or limb muscles
Ptosis, diploplia, dysphagia, dysarthria, proximal muscle weakness
No sensory loss
Investigations:
serum anti-achetylcholine receptor antibodies (AchR) (85% present)
Abnormal single fibre EMG, nerve stimulation
Treatment:
Pyridostigmine (inhibits Ach esterase) and immunosuppressive (steroids, IVIG)
Stroke and TIA
Stroke is defined as an acute neurological deficit lasting more than 24 hours and caused by cerebrovascular aetiology.
Further subdivided into ischaemic stroke (caused by vascular occlusion or stenosis) and haemorrhagic stroke (caused by vascular rupture, resulting in intraparenchymal and/or subarachnoid haemorrhage)
3rd leading cause of death and major cause of disability
Causes: AF, Athersclerosis, AV malformation
Differentials: Migraine, Seizure, Hypoglycaemia, tumour, syncope
Pathophysiology:
- Vessel occlusion due to thrombus from athersclerosis or embolism from carotid a./aorta)
- Reduced cerebral blood flow
- Cell death due to exitoxicity, peri-infart, oxidative stress, depolarisation, inflammation, apoptosis
- Leads to ischaemia (reduced blood flow) and eventually infarction (irreversible damage due to reduced flow)
Transient ischaemic attack (TIA): transient episode of neurological dysfucntion caused by focal ischaemia, without infarction. High risk of ischaemic stroke.
Describe the clinical presentation, investigations and management of stroke / TIA
Clinical presesntation:
Weakness in on side of face/arms/legs (hemiparesis)
Dysphasia (impaired language)
Visual disturbance
Acute light headedness (past-pointing (when pointing at object, will point too far), nystagmus)
Investigations:
FBC, UE, CRP, LFT, lipid profile, glucose, coagulation profile
Glucose, platelet count, coagulation profile may influence acute management
ECG (ischaemic changes, AF)
CT (differentiate between ischaemic/haemorrhagic, exclude tumor)
CT angiogram/MR angiogram (identify site of thrombus, identify ischaemia penumbra - ischaemic tissue that is at risk of infarction but potentially savalgable if reperfusion occurs quickly)
Management:
Ischaemic stroke:
IV thrombolysis (within 4.5 hours) - Alteplase
- NNT: 3.1
Trombectomy (within 6-8 hours) (surgery to remove blood clot)
Aspirin
Admitted to Stroke Unit
Hemicranectomy
Haemorrahagic stroke:
BP control
Admitted to Stroke Unit
Neurosurgical evaluation
Secondary prevention:
Statins, Antiplatelets (clopidorgel or aspirin), antihypertensive e.g. ACEi
Physio, OT, Speech therapy
Risk factors of stroke
Genetics
Poverty
Smoking
Alcohol
Obesity
Hypertension
Common secondary prevention:
Stop smoking, less drinking, lose weight, statins, aspirin
Intracerebral haemorrhage
Defintion: Focal collection of blood in brain parenchyma or ventricular system not due to trauma
Causes:
- Small vessel disease
- Blood clotting disorders
- Tumours
- Drugs e.g. cocaine
Oxfordshire Community Stroke Classification Project
TACS (total anterior circulation syndrome)
- higher cortical dysfunction (dysphasia, visuospatial disturbances), hemiparesis+hemianopia
- MCA (middle cerebral a. or internal carotid a.)
PACS (partial anterior circulation syndrome)
isolated higher cortical dysfunction or 2 of cortical dysfucntion, hemianoipia, hemiparesis
- branch MCA
POCS (posterior circulation syndrome)
- isolated homonymous hemianopia, brainstem syndrome (e.g. nystagmus, cerebellar signs), cranial nerve pasly (ipsilteral) with contralateral motor/sensory defect, bilateral motor/sensory,
- PCA, cerebellar arteries
LACS (lacunar syndrome)
- pure motor (hemiparesis) or sensory stroke or ataxic (lack of voluntary movements) hemiparesis, dysarthria, clumsy hand, mixed sensorimotor
- perforating artery, small vessel disease
The pathophysiological processes that can result in symptoms of stroke
Numbness and weakness in face/arms/legs
Numbness:primary somatosensory cortex becomes damaged
Weakness - primary motor cortex becomes damaged
Ant cerebral a. - motor/sensory symptoms in legs
Middle cerebral a. - symptoms affecting face/upper limbs
Damage to one side will affect body on other side
Dysphasia (difficulty speaking)
Left hemisphere (dominant hemisphere)
Middle cerebral a. supplies Broca’s area (fluid speech production), Wernicke’s area (understanding speech)
Visual disturbances
Posterior cerbral a.
Homonymous hemianopia
Acute lightheadedness
Stroke in cerebellium
(past-pointing (when pointing at object, will point too far), nystagmus)
Describe pathogenesis and clinical presentation of subarachnoid haemorrhage
Definition: Acute cerebrovascular event where there is bleeding into the subarachnoid space and is an emergency
Clinical presentation: Sudden onset headache (worst in their life), nausea/vomiting, loss of consiousness, visual/speech disturbances, seizures
Clinical examination: Photophobia, meningism, vitreous haemorrhage of eye (Terson’s syndrome), speech and limb disturbance
Causes:
Trauma (most common)
Saccular/Berry aneurysms (bulge of intimal layer through muscular wall of a. due to weakened muscular layer of blood vessel wall) - most common cause of non-traumatic SAH
- Most aneursyms at bifurcation of ant. communicating and ant. cerebral a. or ICA and post. communicating a.
- AV malformation, neoplasm, polycystic kidney disease, Ehlers Danlos syndrome
Pathogenesis:
Aneurysm forms due to increased haemodynamic stress which leads to inflammatory and immunlogical reactions and vascular remodelling
Predisposing factors:
Smoking, Female, Hypertension, Ehlers Danlos Syndrome
Graded by WFNS Grades I-V: GCS (lower GCS, higher grade)
Those with non-traumatic SAH, and no aneurysm - perimesencephalic SAH
Discuss the investigation and management of subarachnoid haemorrhage
Investigations:
CT: confirms diagnosis, identifies complications e.g. infarction, hydrocephalus, Fisher Grade used to CT scans for prognosis
Lumbar puncture: xanthochromia (bilirubin in CSF (cerebrospinal fluid)
Once confirmed with CT or LP, causative aneursym can be found using:
CTA (CT angiography - contrast injected to highlight arterial vasculature)
DSA (digital subtraction angiography) - contra-indicated in diabetics, strokes
Hyponatraemia
ECG
Troponin levels
Management:
Bed rest
Fluids - normal saline
Analgeisa
IV Nimodipine: Ca2+ antagonist (prevent vasospams which causes cerebral ischaemia)
Surigcal clipping (close base of aneurysm with a clip)
Endovascular coils (platinum coil inserted into aneurysm, and blodo clot forms around platinum coils which seal aneurysm off.
Complications of subarachnoid haemorrhage
Reharmorrhage (clipping or coiling need to be peformed)
Vasospasm (nimodipine used to prevent it)
Hydrocephalus (accumulation of CSF in brain)
Delayed Ischaemia
Hyponatraemia
Cardiopulmonary complications e.g. arrythmias
Seizures (can be treated with phenytoin)
Predictors of poorer outcome: focal neurological deficit, reduced GCS at presentation, development of complications
Difference between primary headache and secondary headaches syndromes
Primary headache: Headache and assoc. features is primary disorder e.g. migraine, tension, cluster
Secondary headache: Headache is due to underlying disorder e.g. SAH, space-occupying lesion, temporal arteritis, meningitis
Red flags features suggesting secondary headache:
Systemic symptoms e.g. fever, weight loss
Neuroligcal deficit
Onset is acute (thunderclap headache)
Older age onset (>50yrs)
Triggered by posture, valsalva (coughing/straining) - indicates high/low CSF pressure headaches
Important features of taking a history of headache
Onset - time to maximal symptoms, what happened around onset
Severity pain - scale, description
Location
Aura
Timing - duration, frequency
Other symptoms: photophobia, nausea, vomiting (common in migraine)
Age of onset: Childhood (migraine), >50 yrs (secondary)
Triggers e.g. valsalva
Family history (migraine strong FH)
Social history
Medication
Significance of clinical signs when examining a patient with headache
Mostly no abnormal signs, abnormal signs suggest secondary cause
General exam:
Concious level, BP, pyrexia, meningism
Cranial nerve exam:
Pupillary responses, visual fields, eye movements, fundoscopy
Upper motor neuron signs:
Pronator drift, increased tone, extensor plantar repsonse
Cerebellar signs:
Nystagmus (involuntary eye movements)
Migraine
Site: Unilateral
Onset: Gradual (may have aura before)
Aura may be postive (flickering lights) or negative (visual loss)
Character: Throbbing
Radiation: Generalised
Assoc. Symptoms: Photophobia, nausea, vomiting. changes in speech, apetite
Timing: hours-days
Exacerbating symptoms: stress, alcohol, menstruation
Relieving factors: lying in dark room
Severity: Can be severe
Relevant factors: female, young, OCP, family history, medication overuse headache - assoc. with NSAIDs
Pathophysiology: Dysfunction in trigeminovasuclar system involving pain sensitive cranial blood vessels, trigeminal nerves which innervate them and cranial parasympathetic outflow.
- Prodome:up to 48 hrs before headache, symptoms: mood disturbance
- Aura: reversible focal neurological symptoms e.g. visual (scotoma - dark spot in visual field). Due to reduced bloof flow to hemispheric regions opposite to symptoms.
Management:
Analgesia
Triptans e.g. Sumatriptan (5-HT1 agonist)
Metoclopramide (anti-emetics)
Prophylaxis: tricyclic antidepressants (amitriptyline)
Advise pts on triggers
Reduce caffiene, alcohol
Encourage regular meals, good sleep pattern
Thunderclap headache
Definition: sudden onset severe headache, reaches max intensity < 5mins
Considered as SAH until proven otherwise
Site: Occipital
Character:“hit on back of head”
Assoc symptoms:
- Meningismus (photophobia/neck stiffness/headache), vomiting, speech disturbance
Signs:
Positive Kernig’s sign (hip and knee are flexed at 90 degrees, and pain elicited when knee is extended - suggets irritation of meninges)
- Terson’s syndrome, Pulmonary oedema
- IIIrd nerve palsy ( eye down and out, with dilation of pupul - surgical palsy, as parasym fibres which supply pupillary constrictor muscles are compressed from “surgical causes” (from aneurysm - posterior communicating a.). IIrd nerve palsy with no dilation in diabetic pt - ischaemis of small vessels)
Most common non-traumatic cauase: due to berry aneurysms (out pouching of intima through musclar wall)
- Most commonly at anterior cerebral cirulation,. bifurcation of anterior and anterior communicating
- Internal carotid and posteior communicating
at middle cerebral burification
Relevant factors: Usually due to aneurysm, more common in polycystic kidney disease, Ehlers Danlos Syndrome
Risk factors: smoking, alcohol, hypertension
Causes: SAH, intracerebral haemorrhage, bacterial meningitis, primary headache
Investigations
Bloods: FBC, U+Es, LFTs, glucose
ECG - ischaemic changes can be seen
CT - 90% pts will have blood in ventricles (appears white on scan)
LP: xanthochromia (yellow discolouration of CSF due to bilirubin) - only peformed 12 hours after
ICP and signs
Brain, blood, CSF
7-15 mmHg
Monroe-Kellie Hypothesis: increase in one component, causes reduction in other two
Cerebral perfusion pressure (CPP): pressure gradient causing blood flow to brain
CPP = MAP - ICP
When ICP increasesd, brain perfusion decreased
Above 25mmHg intracranial volume can cause marked increase ICP
Signs of raised ICP:
Papilloedema
Restricted visual field
Enlarging blind spot
Abducens nerve palsy may be false localising sign of raised ICP
Raised pressure headaches
History:
Worse when lying flat, better when sitting/standing up
Worse in morning, valsalva, physical exertion
Persistent nausea/vomiting
Examination findings:
Optic disc swelling (papilloedma)
Enlargment of blind spot
Restricted visual field
IIIrd, VIth (oculomotor or abducens) nerve palsy
Causes:
Tumour, hydrocephalus, meningitis
Low CSF pressure
Worse when sitting/standing, better when lying down
Causes:
CSF leakage
Post lumbar puncture
Spontaneous intracranial hypotension - dural tear
Differentials of migraine
Cluster headache (trigeminal autonomic cephalgias)
- Site: Unilateral, around eye
Onset: peaks within mins
Assoc symptoms: red eye, lacrimation, nasal congestion, ptosis+miosis (constricted pupil)
Timing: around 30 mins, usually same time each day
Relevant factors: more in men, heavy smoking/alcohol
Tension headache:
Site: Bilateral
Onset: gradual
Character: tight band aorund head
Assoc symptoms: none
Idiopathic intracranial hypertension:
Site: generalised
Assoc symptoms: visual changes, papilloedema on fundoscopy
Exacerbated by lying down
Better than standing up
Differentials of thunderclap headache
SAH
Intracerebral haemorrhage
Bacterial meningitis
Epilepsy vs seizure
Seizure: episode of neuronal hyperactivity
Epilepsy: at least 2 unprovoked episodes of seizure
Focal vs Generalised seizure
Seizures are either generalised (starts on one point but rapidly spreads bilaterally) or focal (partial) - limited to on area but lead to a generalised seizure
Focal:
History trauma
Focal aura
Post-attack confusion
Automatisms (unconcious movements e.g. picking at clothes)
Nocturnal events
Generalised:
Young
No aura
Photosensitivty
Myoclonus (jerky movements) - esp. in morning
Seizures within 2hrs of awakening
Positive family history
EEG abnormal
Investigations epilepsy
MRI, EEG, systemic provocation
Differentials epilepsy
Syncope
NEAD (non-epileptic attack disorder)
Migraine
Narcolepsy
Panic attacks
Status epilepticus
More than 2 seizures without full recovery, or neurologic function between seizures
or
Contiuous seizures more than 30 mins
- Medical emergency, can cause profound neurlogical damage
Management:
Phenytoin, Gabapentin, Pregabalin
Treatment epilepsy and status epilepticus
Focal epilepsy:
Lamotrigine, Carbamazepine, Levetiracetam
Generalised epilepsy:
Sodium Valproate, Levetiracetam, Lamotrigine
Status epilepticus:
Phenytoin, Gabapentin, Pregabalin
Carbamezepine (inhibits voltage gated Na+ channel on pre-synaptic membrane, decreased neuronal excitability, decreasing AP transmission)
SE: headache, hyponatraemia, SJS
Lamotrigine (inhibits voltage gates Ca+ and Na+ channels on pre-synaptic membrane)
SE: Insomnia, SJS
Levetiracetam (inhibits SV2A (synaptic vesicle) decreasing NT release)
SE: headache, faitgue, anxiety
Sodium valproate (weak Na channel blocker. Increases GABA by decreasing GABA degrading enzymes, leading to neuronal inhibition
SE: hyponatraemia, SJS
Phenytoin (Inhibits voltage gated Na+ channel on pre-synaptic membrane, decreasing AP transmission)
SE: headache, insomnia, SJS
Gabapentin, pregabalin (inhibits voltage gated Ca+ channel)
Anatomical classification of CNS infections
Meningitis - infection of meninges (Bacteria, viral)
Encephalitis - infection of brain itself (Viral, bacterial)
Mass lesion - abscess
Myelitis - infection of SC (staph. aureus or viral (CMV))
Aetilogical classification of CNS infections
Bacterial: Meningitis
Meningococcus, pneumococcus, haemophilus influenzae
Viral: Encephalitis
Enterovirus, HSV, VZV
Fungal: Meningo-encephalitis
Cryptococcosis
Protazoal: Mass lesion
Toxoplasmosis
Meningitis
Inflammation of meninges +/- cerebrum
Acute: bacterial or viral (viral more common, but bacterial more severe)
Sub-acute: Bacterial (listeria (more common in elderly) or TB)
Most common: neisseria meningitidis, strep. pneumoniae,
Meningitis: symptoms and signs
95% will have 2 of: Headache, neck stiffness, reduced GCS or fever
Confusion suggests encephalitis
Rash - pupuric (non-blanching) or petechial, but macular early on (meningococcal)
Complications: Hydrocephalus, hearing loss, seizures
Risk factors pneumococcal meningitis
Pneumococcal:
- Middle ear disease
- Head injury
- Alcohol
- Immunosuppression
Listeria (through unpasterised foods e.g. pate)
- Immunosuppression
- Pregnancy
Pneumococcal meningitis
Neurological complications e.g. CN palsies (CN VIII palsy - hearing loss), focal neurological signs, seizures
Pneumococcal infection usually multi-focal. Can have pneumonia, endocarditis as well
Splenectomised pts more at risk, require pneumococcal vaccination or antibiotic prophylaxis
Prognostic indicators of bacterial meningitis
Adverse outcome:
Pneumococcus
Reduced GCS
Age
CN palsy (pneumococcal)
Bleeding (meningococcal)
Investigations for meningitis
History and exam - examine throat and cervical lymph nodes
Blood cultures (blood PCR)
Bloods - FBC, U&Es, LFTs, CRP
Throat culture
LP:
- gram stain, culture, PCR
- protein and glucose
bacterial meningitis - low glucose, high protein, high lactate
CT - to exclude mass lesion, cerebral oedema (doesn’t exclude raised ICP)
Antibiotics given before scan
CT before LP if:
- GCS <12
- CNS signs
- Seizures
- Papilloedema
- Immunocompromised
Contra-indications of LP
Brain shift
Rapidly reduced GCS
Severe sepsis
Infection at LP site
Coagulopathy
Investigation of CF for CNS infection
Bacterial:
Cells: Neutrophils
Lymphocytes (listeria)
Glucose: < 50% of blood glucose
Protein: High
Other: culture, PCR
Viral:
Cells: lymphocytes
Glucose: Normal
Protein: Raised
Other: PCR
TB
Cells: lymphocytes
Glucose: <50%
Protein: Raised
Other: PCR
Fungal:
Cells: lymphocytes
Glucose: <50%
Protein: High
Other: India ink (shows cryptococcal)
Treatment meningitis
IV Ceftriaxone
If immunocompromised or listeria suspected:
ADD IV amoxicillin
If BM strongly suspected:
ADD IV dexamethasone
Treatment for BM
Meningococcus: IV Ceftriaxone
5 days
Pneumococcus: IV Ceftriaxone
14 days
Listeria: IV Amoxicillin
21 days
- Can give corticosteroids with suspected BM
- Give close secondary contacts prophylaxis e.g. Ciprofloxacin, Rifampicin
Viral meningitis
Diagnosed after excluding bacterial
No confusion
Aetiology: Enterovirus > HSV 2> VZV > HSV 1
Supportive treatment
Aciclovir if immunocompromised
Viral encephalitis
Confusion, fever, seizures
Usually HSV
Investigations:
CSF - lymphocytic, normal glucose
EEG - abnormal acitivity in temporal lobe
MRI
Treatment: Aciclovir
Intra-cerebral TB
Sub-acute (weeks)
Can be found druing TB treatment
CN leisions - CN III, IV, VI, IX (oculomotor, trochlear, abducens, glossopharyngeal)
Usually paradoxical worsening
Treatment: RIPE and steroids
MS
Autoimmune destruction of CNS myelin and oligodendrocytes, characterised by 2 episodes of neurlogical dysfunction separated by time and space
HLA-DR2
Demylination causes loss of neurological function:
- Weak leg
- Visual loss - nystagmus, optic neuritis
- Urinary incontinence
Deficits develop gradually, lasts more than 24 hrs and gradually improves
Types:
Relapsing remitting (unpredictable attacks followed by remission) - 70%
Primary progressive (steady decline) - 10%
Secondary progressive (starts as relapsing remitting, but then declines with no remission)
Benign MS (mild attacks, long periods no symptoms)
Differentials: Sjogren’s syndrome, CNS vasculitis, Behcet’s disease
Syndromes that develop into MS
Optic neuritis
- inflammation of optic nerve
- Painful loss of vision
Transverse myelitis
- inflammtion of SC
Weakness, sensory loss, incontinence
Clinically isolated syndromes
- single episodes of neurological disability due to focal inflammation of CNS
- Can include optic neuritis and transverse myelitis
- May be first attack of MS
Radiologically isolated syndromes
MRI findings that look like MS but no signs/symptoms
Investigations and Diagnosis MS
Diagnosis:
Clinical diagnosis based on history, supported by examinational and investigations
2 or more evidence of demylination disseminated in time and space
Investigations:
MRI brain and cervical spine with gadolinium contrast
- Demyelination in 2 areas - indicates dissemination in space
McDonald criteria:
- periventricular, juxtacortical, infratentorial (e.g. cerebellum), SC
- Enhanced and non-enhanced areas (suggests lesions of different ages) - indicates dissemination in time
LP:
- CSF oligoclonal bands (immunoglobulin bands after protein electrophoresis. Bands in CSF but not blood suggests immunoglobulin production in CSF)
- cell counts
- glucose
- protein
Bloods - exclude other conditions
FBC, B12/Folate, ESR/CRP. LFTs, aquaporin-4 antibody (marker of optic neuritis, transverse myelitis)
Visual evoked potentials (measures speed of impulses travelling along optic nerve. Conduction slower in optic neuritis)
CXR exlcude sarcoidosis
Aetiology MS
Unknown, multi-factorial:
Genetic factors
Low sunlight/vitamin D exposure
Viral - EBV
Smoking
Signs and symptoms of MS
Visual: optic neuritis (manifests as opic disc pallor - optic atrophy, relative afferent pupillary defect), dipoplia. internuclear opthalmoplegia
Speech: dysarthria
Muscle: weakness, spasms
Central: fatigue
Incontinence, diarrhoea/constipation
Uthoff’s syndrome - symptoms worse with heat
Signs:
Hoffman’s sign (UMN sisgn) - flick nail of middle figer and ipsilteral thumb flexes - positive
Clinical features that doesn’t correlate with MS
Sudden onset
Major cognitive involvement
Pyrexial/Evidence of infection
Normal MRI
MS: Relapse vs psuedo relapse
Relapse: involves new neurological deficit that lasts more than 24 hrs, absence of infection
Pseudo-relapse: previous neurological symptoms re-emerge
Treatment:
Not all relapses need treatment
Steroids (not to be given if evidence of infection)
- IV Methylprednisolone (3 days) or oral methylprednisolone (5 days)
and PPI (gastroprotection)
UMN signs
Increased tone
Spastic
Muscle weakness
Hyper-reflexia
Clonus
Entensor plantar (abnormal)
Postive Hoffman’s sign
Differentials MS
Progressive multifocal leukoencelopathy
Sarcoidosis
Lyme disease
Sjorgen’s syndrome
Treatments MS
Relapsing-remitting MS
1st line: Dimethy fumerate (supresses immune system)
Risks: GI side effects
2nd line:
Fingolimod:
Risks: brain infections
Disease modifying dugs:
Natalizumab:
- Risk of PML if infected with JC virus
3rd line: Alemtuzumab
- Risk of secondary autoimmune disorders e.g. thyroid
Escalating therapy: start with weaker treatments, work up
Induction therapy: starts with stronger treatments (Alemtuzumab)
Physio, OT
Primary progressive MS
Currently no disease modifying therapies
Symptom control e.g. Modafinil for fatigue, tamsulosin for urinary symptoms, gabapentin for spasticity
Dementia
Progressive cognitive decline
- Inteferes with ability to function at work/daily activities
- Not explained by delirium or major psychiatric disorder
Needs to involve more than one brain region:
Memory (temporal)
Executive function (frontal)
Language (temporal)
Apraxia/visuospatial (parietal)
Bed side assessment of dementia
MMSE
Addenbrookes cognitive assessment (examines memory, attention, language, visuospatial, executive function)
Memory - tests by recall, anterograde memory (give them a name and get them to repeat, and ask again later), retrograde memory (ask about historical famous people)
Attenttion - filtering information to focus on one stimuli. Testing by orientation, serial 7s
However, bedside testing limited to episiodic and semantic memory
Addenbrooks (ACEr): cut-off score 88 or 83
Alzheimer’s pathology
Starts in temporal lobe and spreads to frontal and parietal
Mild stage: episodic memory
Moderate stage: visuo-spatial
Severe stage: language
Excess amyloid precursor protein being broken down into beta amyloid deposits leading to formation of plaques. Leads to inflammatory process causing neuronal death
Executive function
Frontal lobe
Behaviour/social awareness (orbitofrontal)
Working memory (dorsolateral pre-frontal cortex)
Motivation (anterior cingulate)
Tests: verbal fluency, proverbs
Visuo-spatial function
Parietal lobe
Accurately localise objects
Tests: Drawing pentagons, cubes
Language
Disorders: Progressive non-fluent aphasia
Tests: Repitition, reading
Deficits in ACEr (Addenbrookes cognitive examination)
Loss of:
Episodic memory - AD
semantic memory - semantic dementia (loss of knowledge about world inc. words. Teted by reading irregular words.
Attention: Delirium
Naming: Progressive non-fluent aphasia
Visuospatial: PD plus syndrome
PD
6% cases are monogenic causes e.g. PARK8 (encodes LRRK2 protein)
Pathology: Loss of dopaminergic neurons in SN. Remaining neurons have Lewy bodies. PD manifests when there is loss of 50% dopmainergic neurons
Lewy bodies: a-synucelin, ubiquitin. Formed due to oxidative stress, exitoxicity, inflammation
Pathological progression
Stage 1 - 2: ant. olfactory nucleus, medulla/pons - presymptomatic/pre-motor PD e.g. loss of smell
Stage 3-4: SN in midbrain - PD
Stage 5-6: neocortex - PD dementia
Clinical features PD
Bradykinesia (slowness in initiating voluntary movements, progressive reduction in speed of repetitive actions)
And at least one of:
- Muscular rigidity
- Rest tremor
- Postural instability
Non-motor symptoms:
Cognitive: Dementia
Autonomic: constipation, postural hypotension
Fatigue
Differentials of PD
Essential tremor
Demential with Lewy bodies
Parkinson plus disoders
Drug induced Parkinsonism
Investigations
Bloods
(if tremor present - thyroid function tests, copper (Wilson’s disease)
CT/MRI
- normal in PD
- abnormal in vascular parkinsonism
Functional imaging -
DAT-SPECT (image presynaptic dopaminergic function) abnormal
Treatment PD
Clinical aim: imrpove motor symptoms, QOL
L-DOPA
Taken up by dopaminergic neurons and decaroxylated to dopamine in presynaptic terminals. Striatal dopaminergic neurotransmission increased.
+
dopamine decarboxylase inhibitor (carbidopa, benserazide) - to reduce being converted in periphery
Adverse effects: nausea, vomiting, postural hypotension, hallucinations, dyskinsia
Dopamine agonists:
Apomorphine
Sitmulates post-synaptic striatal dopamine receptors (D2)
Longer half life than L-dopa, fewer motor complications
Adverse effects: nightmares, impulse control disorders e.g. pathological gambling
MAO-inhibitors: Selegelline
Prevents dopamine breakdown by inhibiting enzyme, monoamine oxidase
COMT-inhibitors: Entacapone
Co-pescribed with L-dopa
Inhibits COMT, prevents peripheral breakdown of levodopa so more reaches the brain
SE: dyskinesia, nausea, vomiting
Multi-disciplinary care of PD
GP
Neurologist
Physio
OT
SALT
Other causes of Parkinsonism
Degenerative: Dementia with Lewy bodies
Secondary: Drug induced parkinsonism (e.g. chronic use of dopaminergic antagonists)
Cerebrovasuclar disease
Toxins (e.g. MPTP)
Role of basal ganglia
Posture and voluntary movement
Input:cortex
Output: cortex and brainstem
Basal ganglia loops
Motor: movement
Eye movement: oculomotor
Lateral - orbito frontal: social behaviour
Dorsolateral prefrontal cortex: working memory, executive function
Causes of raised ICP
Tumour
Hydrocephalus
Meningitis
Idiopathic intracranial hypertension
What is a non-traumatic SAH called, when no aneurysm found?
Perimesencephalic SAH
Upper motor neuron signs and cerebellar signs
Upper motor neuron:
Increased tone
Pronator drift
Extensor plantar reflex
Cerebellar signs:
Nystagmus
Past pointing
Dysdiadochokinesis (inability to peform repeating, alternating movements)
Broad-based ataxic gait
Treatments to reduce furthur risk of stroke
Antiplatelets e.g. aspirin (if had thrombolytic therapy, should not have it until 24 hrs after, and not until CT has excluded haemorrhage)
Statins
ACEi and thiazide (aim below 140/80)
Physio, OT, speech therapy
Ramsay Hunt Syndrome
VZV infection of facial nerve
Complication of shingles
Facial palsy and hearing loss
Vesicles on auditory canal, soft palate
