Station 3: Neuro Flashcards
1
Q
Scars in neurology?
A
- Muscle biopsy scar - triceps, deltoid, lateral quadriceps
- Nerve biopsy scar - lateral ankle (sural nerve)
- Sternotomy scar - thymectomy in MG
- Anterior or posterior neck scar - cervical decompression
- Lumbar scar - laminectomy
- Scalp or behind ear - previous burrhole surgery or craniotomy
2
Q
Approach to gait?
A
- Observe surrounding for walking aids, ankle foot orthoses
- Always ask if patients can stand or walk first
- Observe base: narrow or wide?
- If abnormal: symmetrical or asymmetrical?
- If normal: ask to tandem-walk (could you walk heel-to-toe, as if on a tight-rope?) -> brings out subtle gait ataxia
- If normal: walk on tip toes, then on heels -> assess distal power
- Romberg’s test (test of proprioception - peripheral nerves/dorsal column): stable with eyes open, unstable with eyes closed whilst standing in narrow base -> positive Romberg’s -> sensory ataxia
*If in BCC - ask about ADL: How far can they walk? Can they climb stairs? Can they get out of a chair? Can they dress or feed themselves?
3
Q
Describe different types of abnormal gait?
A
- Spastic: narrow-based, stiff, scissoring, toe-scuffing
- Diplegic: extensor and adductor spasm, walking on tip toe, scissoring if no adductor release
- Hemiplegic: circumducting with scuffing of one foot (UL flexor hypertonia, LL extensor hypertonia, distal weakness > proximal)
- Extrapyramidal: shuffling, festinant, poor arm swing, freezing, slow turning
- Ataxic: broad-based, wide staggering quality, titubation, falling towards side of lesion
- Sensory ataxic: stomping, more evident in the dark (loss of proprioception)
- Apraxic: gait ignition failure, difficulty walking, walk of little steps but with upright stance (marche a petit pas) -> frontal lobe pathology (stroke, NPH, MS)
- Neuropathic: high-stepping, stomping
- Myopathic: waddling, hip on the side of weakness drops when stepping forward, and trunk sways to other side to compensate (trendelenburg - pelvis sags down when hip on the affected side is lifted)
4
Q
Approach to cerebellar examination?
A
Ataxia: presence of truncal ataxia if lesion is at cerebellar vermis
Nystagmus
Dysmetric saccades
Impaired smooth pursuit
Scanning or slurred speech
Dysmetria (past-pointing)
Dysdiadochokinesia
Rebound phenomenon - arms outstretched with palms upwards, apply pressure on forearm with sudden release (arms will oscillate or past original position in cerebellar dysfunction)
Hypotonia
Gait - wide based, staggering, falling towards side of lesion
Tandem-gait - subtle ataxia
Romberg’s test - not really cerebellar, actually tests for proprioception
5
Q
Approach to upper limb examination?
A
Inspection, tone, power, reflexes, coordination, sensation (STT pin prick, DCML soft touch, vibration and position sense)
Upper limb
Inspection - muscle biopsy scar on deltoid or triceps, muscle wasting, fasciculations, tremors at rest
Stretch out hands, palms upwards and close eyes - postural tremors, pronator drift (weakness), upward drift (cerebellar), rebound phenomenon (cerebellar)
Turn hands over - pseudoathetosis (sensory ataxia)
Tone - pronator catch for spasticity, cogwheel rigidity at wrist, lead pipe rigidity at elbow
Power - according to nerve root, stabilize proximal joint, test for fatiguability if indicated
Reflexes - supinator, biceps, triceps
Inverted supinator: elbow flexion absent but instead there is finger flexion (C5/C6 cervical myelopathy)
Hoffman reflex: flicking distal middle finger will cause thumb and index finger flexion
Coordination
Dysmetria, intention tremor, rebound phenomenon
Sensation
Depending on earlier findings - if UMN, find sensory level
If LMN - assess for whether there is nerve root or specific nerve problem
If peripheral neuropathy - assess glove distribution
Pin prick
Soft touch
Vibration and joint position sense
6
Q
Approach to lower limb examination?
A
Inspection, tone, power, reflexes, coordination, sensation (STT pin prick, DCML soft touch, vibration and joint position sense)
Lower limb
Inspection - muscle biopsy scars on quadriceps, nerve biopsy scar at lateral ankle (sural), wasting, fasciculations
Tone - move hips and look at foot, lift knee rapidly and look at foot - foot off bed indicates hypertonic, check clonus
Power - according to nerve root, stabilize proximal joint, test fatiguability if indicated
Reflexes - knee, ankle, plantar
Coordination - heel-shin test
Sensation
Depending on earlier findings - if UMN, find sensory level
If LMN - assess for whether there is nerve root or specific nerve problem
If peripheral neuropathy - assess stocking distribution
Gait
7
Q
Causes of absent ankle jerks + extensor plantar responses?
A
Caused by a combination of pyramidal and peripheral nerve lesions
- Stroke + peripheral neuropathy
- Cervical myelopathy + peripheral neuropathy
- Cervical and lumbar myelopathy
- Friedreich’s ataxia
- Subacute combined degeneration
- Neurosyphilis
- MND
- Conus medullaris lesion
8
Q
Spasticity vs rigidity?
A
Spasticity
- Increased muscle tone, velocity-dependent
- More pronounced at the onset of movement
- Decreased with continuous passive movement
- Clasp-knife phenomenon
- Caused by enhanced stretch reflex activity, this is activated whenever there is rapid stretching of muscles, so the muscle will contract to resist the force that is stretching it
- In UMN lesion, inhibitory inputs are lost and so during normal movement there is also enhanced stretch reflex activity
Rigidity
- Increased muscle tone throughout ROM
- Velocity-independent
- Lead-pipe/cogwheel rigidity
9
Q
Spastic paraparesis - approach and clinical signs?
A
Approach:
Spastic gait -> UMN! (brain, cerebellum, spinal cord)
Localise the lesion:
- UMN findings in upper limbs -> C4 or above (spastic quadriparesis)
- LMN signs -> one level indicates lesion at the level (cervical spondylosis), diffuse signs indicate MND
- Cerebellar signs
- Sensory level
- Eyes -> RAPD, INO, optic atrophy suggest MS
- Pseudobulbar signs (brisk jaw jerk, dysarthria) -> brainstem or bilateral cerebral
- Look for surgical scars -> craniotomy or spinal procedure
Clinical signs:
- Stiff, narrow based gait
- Legs longer due to postural change -> toe-scuffing, circumducting
- Hips drawn together due to increased adductor tone (scissoring)
- Pyramidal weakness
- Hyper-reflexia
- Clonus
- Extensor plantar responses
- Wasting and contractures -> in long-standing cases, due to disuse atrophy
10
Q
Spastic paraparesis - causes?
A
Brain
- MS/demyelination (young, INO, RAPD, optic atrophy, cerebellar)
- Bilateral cerebral infarcts
- Parasagittal meningioma (features of parietal lobe - contralateral impaired proprioception, 2 point discrimination)
- Cerebral palsy
Spinal cord
- MND (fasciculations, wasting)
- Friedreich’s ataxia (young, cerebellar, dorsal column, pes cavus)
- Spinal cord compression (cervical spondylosis, trauma, tumour)
- Anterior spinal cord infarction (impaired pain and temperature)
- Transverse myelitis (sensory level)
- Syringomyelia (impaired pain and temperature, UL wasting and hypo-reflexia)
- Hereditary spastic paraparesis (upper limbs normal, no sensory signs)
- Tropical spastic paraparesis (HTLV-1 myelopathy, Afro-Caribbean, proximal > distal weakness, dorsal column, peripheral neuropathy)
11
Q
Spastic paraparesis - how to differentiate the cause?
A
Rapidity of onset:
Seconds to minutes - vascular, trauma (although would not expect to present with spasticity at acute phase)
Hours - compressive (trauma), inflammatory (transverse myelitis - MS, NMO), infective (epidural abscess TB, staph)
Days - compressive (degenerative, slow growing tumours), inflammatory, nutritional (B12, copper)
Weeks to months - degenerative/hereditary (HSP), compressive, infective (HIV/HTLV-1), nutritional
*HSP slowly progressive walking difficulties, with positive FHx
12
Q
Causes of spastic paraparesis + cerebellar signs?
A
- Friedreich’s ataxia
- SCA
- MS
- Syringomyelia
- Lesion at craniospinal junction
- Arnold-Chiari malformation (herniation of cerebellar tonsils into foramen magnum)
- Neurosyphilis
13
Q
Causes of spastic paraparesis + dorsal column signs?
A
- Cervical myelopathy
- Friedreich’s ataxia
- MS
- Subacute combined degeneration
- Neurosyphilis
14
Q
Cerebellar syndromes - approach and clinical findings?
A
- Is it cerebellar or ataxic syndrome?
- Ataxic: combination of cerebellar and sensory
- Cerebellar: scanning speech, eyes (nystagmus, impaired smooth pursuit, dysmetric saccade)
- Sensory: joint position and vibration impairment, Romberg’s, pseudoathetosis (worse when eyes are closed), distal weakness
- Associated features that can help differentiate cause: eye signs (INO, RAPD), pyramidal weakness, peripheral neuropathy - Cerebellar features:
- Head titubation
- Gaze-evoked nystagmus fast phase towards side of lesion (or bidirectional if bilateral lesions)
- Scanning speech
- Truncal ataxia (cerebellar vermis lesion)
- Rebound phenomenon (failure of calibration of muscle forces)
- Hypotonia
- Dysdiadochokinesis (clapping hands, tapping on thigh, rapid pronation/supination of hands)
- Dysmetria
- Intention tremor esp closer to target
- Impaired heel-shin test
- Pendular jerks
- Wide-based staggering gait - Sensory ataxia: is it central or peripheral?
- Central: spinal cord (dorsal column pathology)
- Peripheral: peripheral neuropathy
- Joint position impairment and pseudoathethosis (can be both)
- Distal weakness (peripheral)
- Stomping gait
15
Q
Cerebellar syndromes - causes?
A
Cause is evident in history + cadence of onset
Unilateral
- Vascular: infarct or haemorrhage (acute)
- SOL: tumour, abscess (chronic)
- Demyelination (acute or relapsing-remitting)
Bilateral
- Nutritional: B12, vit E deficiency, coeliac disease (chronic)
- Toxic: alcohol (chronic)
- Hypothyroidism (chronic)
- Demyelination
- Degenerative/hereditary: SCA, Friedreich (chronic)
- Paraneoplastic (acute/subacute and progressive)
- Drugs: phenytoin, carbamazepine, barbiturates (acute or chronic)
16
Q
Cerebellar syndromes - investigations?
A
Cause is evident in history + cadence of onset
Ix guided by history but all with cerebellar ataxia will require brain imaging
- MRI is superior to CT to look at the posterior fossa
- CT has important role in hyperacute presentations when haemorrhage needs to be rapidly excluded
Other targeted Ix
- Alcohol and drug history
- B12, FBC, TFT, VDRL, anti-tissue transglutaminase, anti-endomysial (coeliac)
- Paraneoplastic antibodies
- Lumbar puncture for protein and oligoclonal bands (MS)
- VEP
17
Q
Cerebellar syndromes - management?
A
- Address underlying aetiology
- Manage reversible factors
- MDT: physio, OT to maintain function, preserve strength, provide adaptation
- Review medications: any that are exacerbating or influencing things such as dizziness and unsteadiness?
- Social history: occupation risk, alcohol history (whilst may not be caused by alcohol intake, it may exacerbate the symptoms and so advising to limit intake or stop altogether)
18
Q
Cerebellar syndromes - paraneoplastic cerebellar syndrome, which cancer is most frequently associated?
A
Paraneoplastic cerebellar syndrome:
- Subacute and progressive
- Lose mobility within 1 year
- Antibodies against tumour but cross-react with CNS cells
- Small cell lung Ca, breast, gynaecological, Hodgkin lymphoma
- Anti-Yo (breast, gynae), anti-Hu (SCLCa)
19
Q
Cerebellar syndromes - genetic causes and the features?
A
- SCA (AD): UMN, extrapyramidal, peripheral neuropathy, ophthalmoplegia
- Friedreich’s ataxia (AR): DM, cardiomyopathy, arrhythmia
- Ataxia telangiectasia (AR): skin and eye telangiectasia, dystonia, chorea
- VHL: cerebellar haemangioblastoma, RCC
20
Q
SCA - the genetics?
A
- Autosomal dominant inheritance
- The known mutation is trinucleotide repeat and demonstrate anticipation (earlier onset and more severe disease in subsequent generations)
- More than 25 types described, commonest is SCA1, SCA2, SCA3, SCA6
21
Q
Friedreich’s ataxia - clinical features, investigations and management?
A
Clinical features:
- Onset 10-15yrs, degenerative, wheelchair bound < 25yrs
- Spinocerebellar tract: cerebellar ataxia
- Posterior column: loss of proprioception + vibration sense
- Corticospinal tract: spastic paraparesis, pyramidal weakness, extensor plantars
- Dorsal root: absent reflexes
- Peripheral nerves: pes cavus
- Associations: DM, cardiomyopathy/arrhythmia, kyphoscoliosis, hearing impairment
Investigation:
- Genetic testing ultimately
- Exclude reversible causes: B12, vit E deficiency
- Exclude compressive causes: MRI brain and spinal cord
- Nerve conduction study to investigate for peripheral neuropathy
Management:
- Genetic counselling and patient education
- MDT: OT, physio, neurology, cardiology
- OT: adaptation at home or work, walking aids, devices or orthotics
- Physio: preserve function and strength
- Correction of pes cavus or scoliosis
- Regular ECG and ECHO (important cause of early mortality!)
- Meds for diabetes
22
Q
Friedreich’s ataxia - the genetics?
A
- Autosomal recessive
- Mutation trinucleotide GAA repeat
- Problems with frataxin gene that leads to iron accumulation in mitochondria, oxidative damage, cell death
- Affects spinal cord (corticospinal, posterior column, spinocerebellar tracts), roots and peripheral nerves
23
Q
HINTS exam - when do you perform it and what does it indicate?
A
- Persistent vertigo over hours or days
- Nystagmus
- Normal neurological exam
- Differentiates between central or peripheral cause of vertigo
Central cause: posterior circulation stroke, MS, tumour, trauma, medication
Peripheral cause: BPPV, vestibular neuronitis, Meniere’s disease
24
Q
HINTS exam - describe the components
A
Head impulse
Focus on nose and turn head left to right, and then rapidly back to midpoint
Central: no corrective saccade (also normal)
Peripheral: corrective saccade (eyes move past the midpoint then saccade back)
Nystagmus
Central: bidirectional
Peripheral: none or unidirectional
Test of skew
Focus on nose and cover one eye, then quickly move hand to cover other eye
Central: vertical skew
Peripheral: no vertical skew
25
Multiple sclerosis - approach and clinical signs?
Use term 'demyelinating disease' when presenting
Characterised by lesions separated in space and time
1. Eyes - RAPD, optic atrophy
2. Brainstem - INO (impaired adduction + nystagmus in abducting eye but not necessarily), cranial nerves
3. Cerebellum - nystagmus, dysmetric saccades, impaired smooth pursuit, dysarthria, incoordination, rebound phenomenon
4. Spinal cord (corticospinal tract) - pyramidal weakness, hypertonia, hyperreflexia, spastic paraparesis
5. Spinal cord (dorsal column tract) - pseudoathetosis, sensory ataxia, Romberg's positive, loss of vibration and proprioception
Other signs:
Lhermitte's sign - electrical shock sensation down neck to upper and lower limbs with neck flexion
Uhtoff's phenomenon - worsening of symptoms with heat e.g. exercise, hot bath
26
Multiple sclerosis - investigations?
Diagnosis by 2017 McDonald's criteria
- Allows diagnosis of MS after CIS, without need for 2nd clinical episode
MRI brain demyelination protocol, most useful:
- Periventricular and juxtacortical white matter/brainstem/cerebellum/spinal cord T2 hyperintense lesions
- Gadolinium-enhancing lesions reflect active disease
Visual/auditory evoked potential
- Look at lesions in eyes and brainstem
CSF
- Usually normal
- Unmatched oligoclonal bands (reflect inflammation limited to CNS; if matched with serum suggests spillover into CSF due to systemic disease e.g SLE)
Labs
- Exclude mimics if presence of atypical features: ESR, CRP, autoimmune screen, vasculitis screen, B12, VDRL
- Atypical features: raised inflammatory markers, matched serum/CSF oligoclonal bands, unusual radiological findings
27
Multiple sclerosis - treatment?
Acute relapse:
- Steroids, hastens recovery and reduces duration of relapse, but does not change overall clinical course
- Screen for infection that might trigger relapse
Disease-modifying:
- Mainly reserved for RRMS with evidence of active disease
- B-IFN and glatiramer acetate (subcutaneous or IM), reduce relapse rate by 1/3, associated with injection-site reactions, flu-like symptoms
- B-IFN associated with nAb which reduces efficacy over time
- Natalizumab (monoclonal ab), reduce relapse rate by 2/3, reserved for severe active disease, associated with hypersensitivity and PML
- Mitoxantrone (cytotoxic agent), reduce relapse rate by 2/3, reserved for very aggressive active disease, associated with cardiac failure, bone marrow suppression, leukaemia
- Oral fingolimod
- ALL DMTs should be withdrawn if patient plans to become pregnant, or during pregnancy
Others:
- Physiotherapy, OT, speech and language therapy
- Anti-spastic agents: baclofen, botox
- Laxatives for constipation
- Analgesia
28
Multiple sclerosis - causes?
- Complex aetiology
- Genetic susceptibility - increased risk of MS if there is MS in 1st degree relatives
- Environmental factors - increases with increasing latitude, possible EBV/HHV-6/chlamydia infections
29
Multiple sclerosis - clinical course?
1. Relapsing-remitting (80-85%): short acute attacks with remission and steady baseline state
2. Secondary progressive (30-40%): RR pattern initially then becomes progressive after years (usually 20yrs), with gradual neurological decline but no clear relapse
3. Primary progressive (10-15%): gradually progressive deterioration from onset of symptoms
4. Progressive-relapsing (5-10%): gradually progressive deterioration from onset, with superimposed relapses
30
Multiple sclerosis - 2017 McDonald criteria?
Allows diagnosis of MS after a single CIS, without the need to wait for a 2nd clinical episode
Evidence of lesions disseminated in time and space
Dissemination in time:
- New T2 hyperintense or gadolinium-enhancing lesions on follow-up MRI, compared to baseline scan
- Simultaneous asymptomatic gadolinium-enhancing and non-enhancing lesions at any time
```
Dissemination in space:
> 1 T2 lesion in at least 2 of:
- Juxtacortical
- Periventricular
- Infratentorial
- Spinal cord
```
31
Multiple sclerosis - MS mimics?
Many mimics, suspect if atypical features:
Systemic symptoms, raised inflammatory markers, matched CSF/serum oligoclonal bands, unusual radiological findings
- Vasculitis/autoimmune: NMO, SLE, Sjogren, sarcoidosis
- Vascular: TIA, stroke, CADASIL, APLS
- Metabolic: B12 deficiency
- Infection: HIV, syphilis, PML
32
Neuromyelitis Optica (NMO) - clinical features and treatment?
- Autoimmune mediated: aquaporin-4 antibody
- More severe optic neuritis and more extensive spinal cord involvement > 3 vertebral segments
- Recovers less well
- Treatment with IVIg or plasma exchange in acute setting, steroids and immunosuppressants long-term
33
Upper limb - root, nerve, muscle, sensory, reflex distribution?
Shoulder abduction: C5-C6 (lateral arm, forearm, thumb, index finger), axillary nerve (regimental badge over shoulder), deltoid
Shoulder adduction: C6-C8 (lateral arm, forearm, entire hand), thoracodorsal nerve (purely motor), lat dorsi and pec major
Elbow flexion: C5-C6, musculocutaneous nerve (lateral forearm), biceps, biceps reflex
Elbow extension: C6-C8, radial nerve (extensor forearm, back of hand), triceps, triceps and brachioradialis reflex
Wrist flexion: C6-C7, median and ulnar nerves, flexor carpi radialis and ulnaris
Wrist extension: C5-C8, radial and posterior interosseous nerves, extensor carpi radialis longus and ulnaris
Finger flexion: C8 (little finger, ulnar 1/2 of ring finger and hand), median (FDS) and ulnar (FDP) nerves
Finger extension: C7-C8, posterior interosseous nerve (purely motor), extensor digitorum
Finger abduction: C8-T1, ulnar nerve, 1st dorsal interosseous and abductor digiti minimi
Finger adduction: C8-T1, ulnar nerve, palmar interosseous
Thumb abduction: C8-T1, median nerve, abductor pollicis brevis
Thumb opposition: C8-T1, median nerve, opponens pollicis
Thumb flexion: C8-T1, median nerve, flexor pollicis brevis
34
Median nerve - motor and sensory distribution?
C5-T1
```
Motor:
Pronator teres
Flexor carpi radialis
Flexor digitorum superficialis
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
```
Sensory:
1st 3 and 1/2 digits + thenar eminence
35
Median nerve palsy - features, causes, Ix and treatment?
Proximal median nerve palsy (damage at elbow, pronator teres muscle, anterior interosseous nerve)
Benediction sign (try to make a fist) - weakness of flexion of 1st and 2nd digits
Weakness:
- Thumb opposition (also powered by flexor pollicis longus supplied by ant interosseous nerve, proximal)
- Distal thumb flexion (flexor pollicis longus)
- Wrist flexion (flexor carpi radialis)
- Arm pronation (pronator teres)
Sensory deficit 1st 3 1/2 digits + thenar eminence (palmar cutaneous branch, proximal)
Distal median nerve palsy (damage at wrist or carpal tunnel)
Ape hand sign - wasting thenar eminence, sparing hypothenar eminence
Weakness:
- Thumb abduction (abd pollicis brevis)
- Thumb opposition (opponens pollicis)
- Flexion at MCP joint (flexor pollicis brevis)
Sensory deficit 1st 3 1/2 digits, thenar eminence spared
Special tests
- Tinel's sign: percussion over flexor retinaculum
- Phalen's sign: wrist flexion for 1 min
Causes
- Idiopathic
- Work-related
- Pregnancy
- Endo: hypothyroidism, DM, acromegaly
- MSK: RA, degenerative, gout
- Neuro: HNPP, inflammatory e.g. CIDP/MMN
- ESRF, uraemia, regular dialysis
- Amyloidosis
Ix
- NCS: localise lesion -> median motor and sensory latencies and conduction velocities
- EMG: provide prognosis in terms of recovery -> abductor pollicis brevis denervation
Treatment
- Physiotherapy
- Wrist splint
- Local steroid injections
- Carpal tunnel decompression surgery
36
Ulnar nerve - motor and sensory distribution?
C8-T1
```
Motor:
Flexor carpi ulnaris
Flexor digitorum profundus
Dorsal interosseous
Palmar interosseous
```
Sensory:
1/2 ring finger, little finger, hypothenar eminence
37
Ulnar nerve palsy - features, causes, Ix and treatment?
Proximal ulnar nerve palsy (elbow) -> most common
Hypothenar wasting
Ulnar border of forearm wasting
Weakness:
- Wrist flexion in ulnar direction (flexor carpi ulnaris)
- Finger abd/adduction (palmar and dorsal interossei)
- 4&th & 5th MCP flexion (lumbricals)
- 4th & 5th DIPJ flexion (flexor digitorum profundus)
Sensory deficit 5th and adjacent medial 4th fingers, palmar and dorsal surfaces of medial portion of hand
Distal ulnar nerve palsy (wrist)
Claw hand (4th & 5th extension MCP joint, flexion IP joint)
Hypothenar and 1st dorsal interosseous wasting
Weakness:
- Finger abd/adduction (palmar and dorsal interossei)
- 4&th & 5th MCP flexion (lumbricals)
Sensory deficit 5th and adjacent medial 4th fingers
Special tests
- Froment's sign: testing adductor pollicis -> pinching paper between thumb and index fingers, with thumb in adduction, will lead to thumb flexion (flexor pollicis longus compensating, innervated by median nerve)
Causes
- Compression at elbow: arthritis, fracture, perioperative, mass
- Lesion at wrist: ganglion, tumour, fracture
- DM
- Vasculitis
- HNPP, CIDP, MMN
Ix
- NCS: localise lesion
- EMG: provide prognosis in terms of recovery
Treatment
- Physiotherapy
- Arm or wrist splint
- Manage neuropathic pain: TCA, gabapentin/pregabalin, topical capsaicin
- Decompression surgery
38
Median, ulnar, T1 radiculopathy - how to differentiate?
Abductor pollicis brevis (APB)
First dorsal interosseous (FDIO)
Median nerve lesion: APB weak, FDIO normal
Ulnar nerve lesion: APB normal, FDIO weak
T1 lesion: APB and FDIO weak
39
Radial nerve - motor and sensory distribution?
C5-T1
```
Motor:
Triceps
Brachioradialis
Extensor carpi radialis longus
Extensor carpi ulnaris
Extensor digitorum
```
Sensory:
Extensor forearm, back of hand, dorsum of 1st 4 fingers
40
Radial nerve palsy - features, causes, Ix and treatment?
```
Axilla lesion (tricep)
Wrist drop
Weakness:
- Finger extension at MCP joint
- Wrist extension
- Forearm supination
- Elbow extension
Sensory deficit tricep, posterior forearm, 1st dorsal interosseous
Absent tricep reflex
```
```
Spiral groove lesion (brachioradialis)
Wrist drop
Weakness:
- Finger extension at MCP joint
- Wrist extension
- Forearm supination
- Elbow flexion with forearm held between supination and pronation
Sensory deficit 1st dorsal interosseous
```
```
Proximal forearm lesion
Wrist drop
Weakness:
- Finger extension at MCP joint
- Wrist extension
No sensory deficit (post interosseous nerve purely motor)
```
Wrist lesion
No wrist drop, no weakness
Sensory deficit 1st dorsal interosseous
Causes
- Trauma or fractures
- Compression: crutches, Saturday night palsy
- Tumour, ganglion
Ix
- NCS: localise lesion
- EMG: provide prognosis in terms of recovery
Treatment
- Physiotherapy
- Wrist or elbow splint
- Decompression surgery
41
Radial and C7 radiculopathy - how to differentiate?
C7 radiculopathy affect both median and radial nerves, so weakness at:
- Shoulder adduction
- Elbow extension
- Wrist flexion and extension
Radial nerve lesion, weakness:
- Spares shoulder abduction (C5, axillary nerve) and wrist flexion (C7, median and ulnar nerves)
42
Foot drop - common peroneal nerve palsy:
Clinical signs?
Common causes of injury?
Clinical signs:
- Walking aid, ankle orthosis, shoe scuffing
- Maybe scar at neck of fibula
- Wasting anterolateral calf
- Foot drop, high stepping gait
- Weakness foot and big toe dorsiflexion, ankle eversion
- Ankle inversion spared
- Ankle jerk preserved (S1)
- Sensory deficit lateral calf and dorsum foot
Causes:
- External compression: braces, plaster cast, positioning during surgery
- Trauma: direct trauma esp at neck of fibula region, fibula fracture
- DM
- Mononeuritis multiplex: Wegener's granulomatosis, amyloidosis, RA, SLE, sarcoidosis, PAN, leprosy, carcinoma
*Leprosy: look for palpable thickening of common peroneal nerve, and other nerves
43
Foot drop - L5 root lesion:
| Clinical signs?
Clinical signs:
- Scuffing of shoes, ankle orthosis
- Maybe scar at the back from prev spinal surgery
- Foot drop, high stepping gait
- Straight leg raise test positive
- Weakness foot and big toe dorsiflexion, ankle eversion and inversion
- Ankle jerk preserved (S1)
- Sensory deficit lateral calf, dorsum foot, extending up to lateral thigh
44
Foot drop - differentiating between common peroneal and L5 lesion?
Investigations?
- Ankle inversion and hip abduction weakness in L5
- Sensory deficit limited to lateral calf and dorsum foot in common peroneal, extends to lateral thigh in L5
- Usually pain in posterior lateral leg and positive SLR in L5
Investigations:
- NCS
- EMG at tibialis posterior (supplied by L5, not supplied by common peroneal)
- MRI lumbar spine exclude L5 lesion
45
Foot drop - causes of flaccid foot drop?
- LMN: motor neurone disease, other motor neuropathies
- L5 root: disc prolapse, tumours, neurofibroma
- Sciatic nerve: trauma, hip surgery, damage during IM injection, neurofibroma
- Common peroneal nerve: external compression, trauma, mononeuritis multiplex, DM
- NMJ: MG
- Muscle: myotonic dystrophy, SMA, trauma
46
Foot drop - causes of spastic foot drop?
- Internal capsule: stroke
- Parasagittal cortex: tumour
- High cauda equina: tumour
- Spinal cord: causes of spastic paraparesis
47
Absent ankle jerk - causes?
S1 supply via tibial branch of sciatic nerve
Causes:
- S1 radiculopathy (most common)
- Complete sciatic nerve lesion
- Tibial nerve lesion (uncommon)
*Must ask about history of trauma, back pain, sciatica, red flags
48
Peripheral neuropathy - approach and clinical signs?
Approach:
- Is it sensorimotor, sensory or motor neuropathy?
- If sensory, is it small fibre (pain, temperature, autonomic) or large fibre (light touch, vibration, proprioception)?
- Is there autonomic involvement: resting tachycardia, ask for postural BP?
- Mention you would like to take a complete drug history
Clinical signs:
- Walking aid, ankle orthosis, shoe scuffing
- Wasting and weakness, commonly distal to proximal (length-dependent), toes to knees then hands weakness
- Hyporeflexia, downgoing plantars
- Sensory deficit, commonly symmetrical distal to proximal (length-dependent), toes to knees then hands
- Sensory ataxia + Romberg's positive
- Wide-based gait, maybe foot drop
49
Peripheral neuropathy - clinical signs of atypical, non length-dependent polyneuropathy?
Likely causes?
Clinical signs:
- Proximal weakness/sensory deficit
- Marked asymmetry
- Sensory ataxia: pseudoathetosis, Romberg's positive
Likely causes:
- Inflammatory
- Autoimmune
- Mononeuritis multiplex: WARDS-PLC
50
Peripheral neuropathy - mixed sensorimotor causes?
- DM commonest
- B12 deficiency
- Alcohol
- Hypothyroidism
- Uraemia
- Drugs: phenytoin, isoniazid, ethambutol, metronidazole, amiodarone, chemotherapy
- Inflammatory/autoimmune: GBS, CIDP, paraprotein-associated (MGUS)
- Infections: leprosy, HIV, syphilis
- Vasculitis
- Paraneoplastic
- Hereditary: CMT
51
Peripheral neuropathy - predominantly motor causes?
- Inflammatory: GBS, CIDP, MMN with conduction block, paraprotein-associated (MGUS), inclusion body myositis
- Toxins: heavy metals e.g. lead
- Hereditary: SMA (proximal weakness with bulbar involvement, AR pattern), myotonic dystrophy (distal weakness with myotonia, AD pattern)
- NMJ: MG, LEMS
52
Peripheral neuropathy - predominantly sensory causes?
- DM
- B12 deficiency
- Alcohol
- Drugs
- Paraneoplastic
- Hereditary: Friedreich's ataxia
53
Peripheral neuropathy - causes of thickened nerves?
- Leprosy
- CMT
- Neurofibromatosis
- Acromegaly
- Amyloidosis
54
Peripheral neuropathy - investigations?
Stage 1:
- Exclude common causes: B12, folate, TFT, FBS, HbA1c, RP, LFT
Stage 2:
- If findings are atypical, cause is unclear from stage 1 Ix
- NCS/EMG
- CXR
Stage 3:
- Depending if axonal or demyelinating from NCS
- CSF: probably normal, look for oligoclonal bands
- Serum protein electrophoresis, urine Bence Jones
- Autoimmune screen
- Viral screening
- Paraneoplastic antibodies
- Antiganglioside antibodies
- Look for Ca: skeletal survey, CT TAP, PET scan
- Genetic test: myelin protein 22 gene (commonest cause for CMT type 1)
55
Peripheral neuropathy - what is Miller-Fisher syndrome?
- Autoimmune, usually post-infectious
- Acute or subacute onset
- Ataxia, ophthalmoplegia, arreflexia
- Associated with anti-GQ1b ganglioside antibody
- May overlap with GBS
56
Peripheral neuropathy - causes of pes cavus?
Unilateral
- Spinal cord trauma
- Spinal cord tumours
- Poliomyelitis
Bilateral
- CMT
- Friedreich's ataxia
- Spinal muscular atrophy
- Muscular dystrophies
- Syringomyelia
- Hereditary spastic paraparesis
57
Charcot-Marie-Tooth (CMT) - clinical signs?
Symmetrical distal sensorimotor neuropathy + pes cavus + palpable nerves
Lower limbs affected more significantly than upper limbs
Motor symptoms predominate
Clinical signs:
- Walking aid, ankle orthosis, shoe scuffing
- Wide-based, high-stepping gait, Romberg's positive
- Pes cavus (does not flatten with weight-bearing) -> indicates long-standing neuropathy, hence likely hereditary
- Clawing of toes and hands
- Postural tremor (present in 30-50% cases)
- Distal wasting (inverted champagne bottle appearance, dorsal guttering)
- Hyporeflexia, downgoing plantars
- Glove and stocking sensory deficit
*Mention no scars at fibula neck or elbow: common peroneal nerve and ulnar nerve lesion, important differentials for foot drop and wasting of small muscles of the hand (although usually unilateral)
58
CMT - different types?
Classification is constantly changing, as of now:
- Type 1: demyelination, most commonly AD, myelin protein 22 gene mutation (chromosome 17)
- Type 2: axonal, AD
- Type 3: demyelination, AR, infantile onset, more severe than type 1
59
CMT - management?
Symptomatic, no disease-modifying therapies available
MDT: neurology, ortho, physio, OT
- Patient education and advice
- Physiotherapy to preserve strength and function
- OT for home/work adaptations, walking aids
- Orthotics team for ankle orthosis
- Analgesia for MSK and neuropathic pain
- Surgery to correct deformities
60
Myopathy - types?
1. Muscular dystrophies - myotonic dystrophy, Duchenne's, Becker's, FSHD, limb-girdle, Emery-Dreifuss
2. Metabolic myopathies - mitochondrial disease, glycogen storage disorder (McArdle's)
3. Inflammatory myopathies - dermatomyositis, polymyositis, inclusion body myositis, CTD, infections
4. Endocrine myopathies - hyper/hypothyroid, hyper/hypoPTH, Cushing's, acromegaly
5. Toxic myopathies - statins, fibrates, steroids, amiodarone, HCQ, alcohol, heroine, coccaine
Remember the approach:
Proximal vs distal
No sensory involvement
Complications - resp failure, cardiomyopathy, kyphoscoliosis
61
Myopathy - causes of distal weakness?
- Myotonic dystrophy
- FSHD
- Distal variant of SMA
- Inclusion body myositis
62
Myopathy - causes of proximal weakness?
- Duchenne's muscular dystrophy
- Becker's muscular dystrophy
- Polymyositis, dermatomyositis, antisynthetase syndrome
- Endocrine myopathies
- Metabolic myopathies
63
Myopathy - causes of facial involvement?
WITH extraocular involvement:
- Grave's disease
- Oculopharyngeal muscular dystrophy
- Mitochondrial disease
- MG
WITHOUT extraocular involvement:
- Myotonic dystrophy
- FSHD
64
Myopathy - approach to investigations?
Labs:
- CK
- TFT, HbA1c
- ESR, CRP, ANA, ENA, RF
Others:
- EMG to confirm myopathic changes: motor potentials are polyphasic, of short duration and small amplitude
- Muscle biopsy esp if inflammatory myopathies are suspected
- CXR, CT, PET scans to screen for malignancy esp in inflammatory myopathies
65
Myotonic dystrophy - clinical signs?
- Myopathic facies: lean, expresionless, mouth hanging open
- Frontotemporal balding
- Ptosis (smooth forehead - MG will have furrowing) + cataract
- Facial muscle wasting: temporalis, masseter, SCM
- Facial muscle weakness: close eyes, blow candle, puff out cheeks
- Distal muscle weakness: small muscles of the hands wasting, foot drop
- Diminished reflexes
- Impaired relaxation or percussion myotonia over thenar eminence
Complications:
- Dysphagia: PEG tube in situ
- Cardiac: small pulse, pacemaker
- DM: finger tip skin pricks, dermopathy
- Hypogonadism: gynaecomastia, testicular atrophy
- Nodular thyroid enlargement
66
Myotonic dystophy - the genetics and types?
- Autosomal dominant
- Trinucleotide repeat expansion on chromosome 19
- Demonstrates expansion and anticipation: more severe disease and earlier onset in successive generations
Types:
- Type 1: classical type
- Type 2: similar balding, ptosis, cataract, myotonia, hypogonadism BUT proximal instead of distal weakness, trinucleotide repeat on chromosome 3
67
Myotonic dystrophy - complications?
- Cardiac arrhythmia, conduction defects, cardiomyopathy
- DM
- Hypogonadism
- Goitre (euthyroid)
- Dysphagia, reflux, malabsorption
- Hypoventilation, type 2 resp failure
68
Myotonic dystrophy - management?
- Patient education
- Family counselling and genetic screening
- Manage complications + involve MDT: DM, cardiac, GI, resp, geneticist, dietician
- Ankle orthosis for foot drop
- Meds to help with myotonia e.g. phenytoin
69
Duchenne's & Becker's muscular dystrophies - clinical features?
Duchenne's
- X linked recessive: dystrophin absent
- Wheelchair-bound
- Proximal > distal: neck flexors, wrist extensors, foot drop
- Calf pseudohypertrophy
- Face spared
Becker's
- X linked recessive: dystrophin present but abnormal
- Similar features to Duchenne's but less severe
- Ambulant with waddling gait up to 30-50 years
Complications:
- Kyphoscoliosis and contractures
- Cardiomyopathy
- Resp failure
70
Muscular dystrophies - other types and features?
FSHD
- Autosomal dominant
- Myopathic facies: lean, expresionless
- Facial weakness
- No ptosis, eye movements normal, no frontotemporal balding (important negatives)
- Winging scapula
- Shoulder abduction weakness
- Weaker lower abdomen: Beevor's sign
- Foot drop
- Pelvic girdle muscle weakness occur late
- Complications: SNHL, retinal telangiectasia
Limb-girdle
- Autosomal recessive (more common), some autosomal dominant
- Variable onset: mostly 3rd decade
- Shoulder and pelvic girdle muscle weakness
- Face spared
Emery-Dreifuss
- X linked recessive
- Early contractures before weakness
- Often upper limb weakness
Oculopharyngeal
- Autosomal dominant
- Late onset: 5-6th decade
- Ptosis, dysphagia, dysarthria
71
Metabolic myopathy - features?
- Exercise intolerance or cramping with exercise
- Myoglobinuria + renal impairment
- Proximal weakness
Associations:
- Kearns-Sayre: progressive external ophthalmoplegia, retinitis pigmentosa, cardiac conduction defects
- MELAS: encephalopathy, stroke
- McArdle's: progressive limb weakness
72
Inflammatory myopathy - features?
- Polymyositis (anti-Ro/SSA): middle age
- Dermatomyositis: middle age, heliotrope rash, Gottron's papules, associated with adenoCa/gynae tumours
- Antisynthetase syndrome (anti-Jo1): cracked 'mechanic' hands, ILD
- Inclusion body myositis: older males, weakness quadriceps and finger flexors, occasional dysphagia and foot drop
- Mixed CTD: myositis, SLE, systemic sclerosis (anti-Scl70, anti-centromere)
- Sjogren's (anti-Ro, anti-La), RA
- Sarcoidosis
- Infective/post-infective: HIV, CMV, EBV (acute), HTLV-1, parasites (chronic)
73
Myasthenia Gravis (MG) - clinical signs and associations?
Antibodies against post-synaptic acetylcholine receptors
85% generalised (ocular, facial, bulbar, resp, limb)
15% ocular
Clinical signs:
- Unilateral ptosis (can be bilateral), worsened with sustained upward gaze
- Furrowing of forehead
- Cogan lid twitch sign: lid overshoots when moving back to central position after a period of looking down (rest)
- Curtain sign: lifting the ptotic lid leads to ptosis on the other lid
- Complex ophthalmoplegia or diplopia worsened with prolonged gaze
- Facial weakness, lack of expression
- Nasal speech, worsened with prolonged vocalisation
- Neck flexion weakness
- Proximal weakness with fatiguability, upper > lower limb
- Reflexes normal
Complications:
- Thymectomy scar
- Effects of prolonged steroid therapy
- Respiratory failure: measure FVC
Associations with other autoimmune diseases:
- Hypo/hyperthyroidism
- DM
- SLE
- RA
- Pernicious anaemia
74
MG - investigations?
Causes of false positive Tensilon test?
Causes of false positive AChR antibodies?
Investigations:
- AChR antibody (80-90%)
- MuSK antibody
- Tensilon test: injection of short-acting acetylcholinesterase inhibitor, rarely done now due to potential to cause heart block, and high false positive/negative
- Repetitive nerve stimulation: decrement in response
- Single-fibre EMG: measures difference in firing times of 2 fibres under same motor unit, presence of 'jitter' (increased variability in the interval) suggests abnormal transmission
- CT/MR mediastinum: look for thymoma
False positive Tensilon test:
- LEMS
- Botulism
- MND
- GBS
False positive AChR antibody:
- 1st degree relatives with MG
- LEMS
- MND
- SLE, RA
- Thyroid ophthalmopathy
75
MG - treatment?
| What is the role of thymectomy?
- Assess respiratory function: FVC (< 1.5L HDU, < 1.2L ICU), and blood gas
- Assess safe swallowing
- Cholinesterase inhibitors e.g. pyridostigmine: useful in early symptomatic phase or adjunct to immunosuppressive therapy, side effects of increased muscarinic activity e.g. hypersalivation, secretions, diarrhoea
- Steroids to induce remission: but can cause paradoxical worsening of weakness in the 1st 2 weeks
- Bone-protecting agents whilst on steroids
- Immunosuppressive therapy e.g azathioprine, MMF
- IVIg or plasma exchange during acute severe exacerbations
Role of thymectomy:
- Indicated in all patients with thymoma (15%)
- In patients without thymoma: recommended in < 60yrs, generalised MG, high ab titres, thymic hyperplasia
- Can induce medication free remission
- Role in ocular MG is uncertain
- Not useful in MuSK ab positive patients
76
MG - differentials?
Ophthalmoplegia
- Thyroid eye disease
- Mitochondrial disease (CPEO)
- Miller-Fisher variant of GBS
- Oculopharyngeal muscular dystrophy
Bulbar/resp weakness
- MND
- Botulism
Proximal weakness
- LEMS
- Myopathies
- Inflammatory myositis
77
MG - drugs that can exacerbate weakness?
- Antibiotics: macrolides, fluoroquinolones, aminoglycosides
- Anti-arrhythmics: procainamide, lignocaine
- B-blockers
- Calcium channel blockers
- D-penicillamine
78
LEMS - difference with MG?
Symptoms/signs:
- Ocular, bulbar, resp symptoms rare
- Autonomic symptoms common (dry mouth, constipation, impotence)
- Proximal weakness lower > upper limbs
- Reflexes brisk with repeated activity (so check reflexes first before power if suspecting LEMS)
Investigations:
- Antibody: pre-synaptic VGCC
- RNS: increment in response
- CXR, CT, PET scans important to look for underlying malignancy
Associations:
- Small cell lung Ca, lymphoma, thymoma, other Ca
- Autoimmune disease
Treatment:
- Treat underlying malignancy
- 3,4-diaminopyridine: increases pre-synaptic ACh release
- Immunosuppressive therapy may be useful
- IVIg and plasma exchange less helpful
79
Ptosis - approach?
- Unilateral vs bilateral
- Complete vs partial
- Pupils: dilated (3rd nerve palsy), constricted (Horner's), normal (MG, thyroid, myopathy)
- Ophthalmoplegia: limitation of up/down gaze and adduction (3rd nerve palsy), complex (MG, thyroid, myopathy)
- Facial weakness: MG, myotonic dystrophy, FSHD
- Bulbar involvement: MG, oculopharyngeal muscular dystrophy
- Respiratory weakness: MG, muscular dystrophy
- Limbs: weakness/fatiguability (MG), wasting small muscles of the hand (Horner's - Pancoast)
- No other signs apart from ptosis: senile, congenital, structural eyelid lesion
80
Ptosis - causes?
Unilateral:
- 3rd nerve palsy
- Horner's syndrome
- MG
- Congenital
Bilateral:
- MG
- Myotonic dystrophy
- Mitochondrial myopathy (CPEO)
- Oculopharyngeal muscular dystrophy
- Miller-Fisher syndrome
- Bilateral Horner's syndrome e.g. syringomyelia
- Congenital
81
Visual field defects - approach?
- Look for signs of systemic disease: acromegaly, cerebellar (MS), hemiparesis (stroke)
- Visual confrontation first
- Then cover each eye and test: central vision, then each quadrant without crossing vertical and horizontal midlines
82
Visual field defects - causes of bitemporal hemianopia?
Lesion at optic chiasm:
- Pituitary tumour (compression from underneath)
- Craniopharyngioma (compression from above)
- Suprasellar tumour
- Granuloma
83
Visual field defects - causes of homonymous hemianopia?
Congruous - lesion behind lateral geniculate nucleus, at optic radiation
Incongruous - lesion at optic tract or lateral geniculate nucleus
Causes:
- Infarction or haemorrhage
- Tumour
- Trauma
- Demyelination
84
Pupillary abnormalities - approach?
- Ensure dim lighting
- Presence of anisocoria: usually a disorder of efferent (motor) rather than afferent (sensory)
- Assess direct reflex first, then consensual reflex
- If normal, assess swinging light reflex with 3 seconds in each eye
- Lastly assess accommodation reflex
Light is shone in right eye:
RE afferent problem - both eyes will not constrict
RE efferent problem - only left eye constricts
LE efferent problem - only right eye constricts
85
Pupillary abnormalities - RAPD causes?
Optic nerve
- Optic atrophy or optic neuritis
Retina
- Severe diabetic retinopathy
- Central or severe branch retinal vein occlusion
- Central or severe branch retinal artery occlusion
- Retinal detachment
- Retinal infection e.g. CMV, HSV
- Macular degeneration
86
Pupillary abnormalities - Argyll-Robertson pupils features and causes?
Features:
- Small, irregular pupils
- Reacts to accommodation, but not to light
- Usually bilateral
- Sensory ataxia, dorsal column signs
- Absent ankle jerks
- High stepping gait
Causes:
- Neurosyphilis (most common)
- DM
- Midbrain lesion: tumour, infarct, haemorrhage, demyelination
87
Pupillary abnormalities - Adie's myotonic pupils features and causes?
Features:
- Myotonic pupil: slow and delayed response to light and accommodation, slow to dilate in dim lighting
- Usually unilateral
- Absent deep tendon reflexes
- Anhidrosis
- Autonomic dysfunction
Causes:
- Usually idiopathic
- May be associated with Sjogren's syndrome
88
Pupillary abnormalities - Horner's syndrome approach and features?
Focused history:
- Lung Ca: cough, weight loss, smoking
- Previous neck surgery or procedures
- Unilateral weakness
- Headache or eye pain
Features:
- Mild, partial ptosis
- Mioisis, reacts to light and accommodation
- Ipsilateral anhidrosis over face, arm, upper trunk
Localising features:
- Hemiparesis
- Cerebellar signs
- Neck scars, lymph nodes or masses
- Hands: wasting, fasciculations, C8-T1 sensory deficit, dissociated sensory loss, clubbing, tar staining
- Carotid bruit
- Other CN involvement: III, IV, VI, V ophthalmic and maxillary branches
89
Pupillary abnormalities - Horner's syndrome:
| Describe the sympathetic pathway?
Interruption of the sympathetic chain anywhere from hypothalamus to Muller muscle, pupil and sweat glands.
Central (1st order neurone) and peripheral (2nd and 3rd order neurones) lesions:
1st order neurone:
Hypothalamus -> brainstem -> cervical cord -> T1 root ganglion
2nd order neurone (pre-ganglionic):
T1 root ganglion -> cervical sympathetic chain -> superior cervical ganglion (at level of common carotid artery bifurcation)
*Branch innervating sweat glands travel at or right before superior cervical ganglion, along external carotid artery
3rd order neurone (post-ganglionic):
Superior cervical ganglion -> sympathetic carotid plexus, travel along internal carotid artery, within cavernous sinus -> orbit -> Muller muscle (eyelid), long ciliary nerve (pupil dilator)
90
Pupillary abnormalities - Horner's syndrome, how to localise lesion?
Investigations and management?
Localise lesion:
1. Clinically - pattern of anhidrosis:
- Central: anhidrosis face, arm, upper trunk
- Peripheral (pre-ganglionic, 2nd order neurone): anhidrosis face
- Peripheral (post-ganglionic, 3rd order neurone): no anhidrosis
2. Hydroxyamphetamine 1% eye drops
- Stimulates release of noradrenaline from post-ganglionic terminals
- If post-ganglionic fibres are intact, they will react to the noradrenaline and cause pupil dilatation
- Central and pre-ganglionic lesions: normal pupil dilatation response
- Post-ganglionic lesion: poor or no pupil dilatation response
Investigations depend on the likely location of lesion:
- 1st order neurone: MRI brain/spinal cord
- 2nd order neurone: CXR, CT chest, MRI/MRA head/neck, carotid Doppler, lymph node biopsy
- 3rd order neurone: carotid doppler, MRI/MRA head/neck, MRI cavernous sinus or orbit
Management:
- Treatment of underlying cause
- Unequal pupil does not require treatment
- If ptosis persist, surgical correction can be done for cosmetic purpose
91
Pupillary abnormalities - Horner's syndrome causes?
1st order neurone:
Brainstem - stroke, demyelination, tumour
Cervical cord - infarct, demyelination, tumour, syringomyelia
2nd order neurone:
Lung apex - Pancoast tumour
Neck - mass, lymph node, surgery or central line insertion
Common carotid artery dissection
3rd order neurone:
Internal carotid artery dissection
Cavernous sinus - thrombosis, aneurysm, infection/abscess, tumour
Orbit - cellulitis, infection/abscess, tumour
Congenital - presence of iris heterochromia
92
Ophthalmoplegia - approach?
Disconjugate gaze at primary position:
- Convergent (CN VI eye in adduction) vs divergent strabismus (CN III eye down and out)
- Disconjugate gaze persistent in all directions + vertical component: brainstem lesion
- Disconjugate gaze inconsistent: external ocular muscle problem
Examine eye movements in H-shaped manner
Examine saccadic eye movements:
- Look at palm on the right and fist on the left, then up and down -> can also elicit mild INO
3rd nerve palsy:
- Eye down and out
- Unable to look up, down and adduct
- Ptosis
- Pupils dilated (surgical) or normal (medical)
4th nerve palsy:
- Eye higher than other side (diplopia image is on top of one another)
- Adducted eye unable to look down
- Head tilt away from affected side
6th nerve palsy:
- Eye adducted (convergent squint)
- Unable to abduct (diplopia image side by side)
- No pupil problems
93
Ophthalmoplegia - 3rd nerve palsy approach and causes?
Approach:
- Rapidity of onset: mins (vascular/trauma), days (demyelination), weeks (compression)
- Headache and pain: compression, vasculitis (GCA)
- Screen for vascular risk factors: HTN, DM, lipids, smoking
- Pupils affected: dilated (compression), normal (microvascular)
- Check CN2 and CN4: RAPD, optic atrophy, look down and in - eyes can rotate inwards if CN4 intact
- Contralateral hemiparesis or ataxia: infarction
- Cerebellar signs: MS
Causes:
- Solitary, pupil sparing 3rd: microvascular infarction
- Dilated pupil: compression e.g. PCOM aneurysm, ICA aneurysm, cavernous sinus/superior orbital fissure tumour
- Brainstem infarct: Weber (contralateral hemiparesis - basal midbrain lesion), Benedikt (contralateral ataxia - paramedian midbrain lesion)
- Brainstem demyelination: MS
- Inflammation: GCA
- Mononeuritis multiplex
94
Ophthalmoplegia - 6th nerve palsy causes?
- Raised intracranial pressure
- Brainstem lesion: infarction or haemorrhage, demyelination, tumour
- Cavernous sinus lesion: thrombosis, aneurysm, tumour, inflammation, infection/abscess
- Superior orbital fissure lesion: tumour, inflammation, infection/abscess
- Inflammation: GCA, sarcoidosis
- Mononeuritis multiplex
95
Ophthalmoplegia - complex ophthalmoplegia causes?
- MG
- Mitochondrial myopathy (CPEO)
- Thyroid ophthalmopathy
- Miller-Fisher variant of GBS
96
Cranial nerves - approach?
As a general rule - in CN palsies, always check nerve above and below:
e.g. 3rd nerve palsy - check CNs 2 and 4
CN1 - ability to distinguish smell, check each nostril
CN2 - acuity, field, light and accommodation reflexes, ophthalmoscopy
CN3,4,6 - conjugate gaze and eye movements
CN5 - sensory (ophthalmic, maxillary, mandibular distribution), motor (temporalis and masseter clench teeth, pterygoid open jaw), jaw jerk, corneal reflex (mention to do - loss of corneal reflex is usually the 1st sensory deficit in V1 lesion)
CN7 - sensory anterior 2/3 tongue, motor facial muscles
CN8 - hearing, Rinne's (air conduction), Weber's (bone conduction)
CN9, 10 - symmetrical soft palate elevation, uvula remains central (deviate away from lesion), cough (bovine character in laryngeal palsy), sensory posterior 1/3 tongue
CN11 - sternocleidomastoid and trapezius (shrug shoulder and turn head towards resistance), look for scapula winging
CN12 - fasciculations whilst resting at floor of mouth, wasting and deviation whilst protruding, power wiggling side to side and pressing from inside cheeks
97
Cranial nerves - superior orbital fissure/orbital apex lesion features and causes?
Structures involved:
- CN II, III, IV, VI, V ophthalmic maybe maxillary
Features:
- Ipsilateral II - visual loss (orbital apex syndrome)
- Ipsilateral III, IV, VI palsies
- Ipsilateral V1 and V2 sensory deficit
- Painful ophthalmoplegia
- Proptosis, periorbital oedema
- Horner's syndrome
Causes:
- Inflammation: TB, sarcoidosis, Wegener's granulomatosis, GCA
- Infections: bacterial, fungal mucormycosis, viral VZV
- Tumours: NPC
- Superior orbital fissure fracture
98
Cranial nerves - cavernous sinus lesion features and causes?
Structures in cavernous sinus:
- CN III, IV, VI, V ophthalmic and V maxillary branches
- Intracavernous carotid artery
- Sympathetic carotid plexus
Features:
- Ipsilateral III, IV, VI palsies
- Ipsilateral V1 and V2 sensory deficit
- Painful ophthalmoplegia
- Proptosis, periorbital oedema
- Usually fixed, dilated pupil - sometimes Horner's (due to involvement of sympathetic fibres)
Causes:
- Thrombosis
- Aneurysms: intracavernous carotid artery, PCOM
- Tumours: pituitary, meningioma, NPC
- Infections: bacterial, fungal mucormycosis
- Inflammation: TB, sarcoidosis, Wegener's granulomatosis, PAN, Tolosa-Hunt syndrome (idiopathic)
99
Cranial nerves - unilateral LMN facial weakness causes?
- Bell's palsy: idiopathic, post-viral
- Ramsay-Hunt syndrome: look for vesicles over external auditory meatus and within ear canal
- Brainstem stroke
- Brainstem demyelination
- CPA tumour: acoustic neuroma, neurofibroma
- Infection: TB
- Inflammation: sarcoidosis, vasculitis
100
Cranial nerves - bilateral LMN facial weakness causes?
- Bilateral Bell's palsy
- MG
- Myopathy: myotonic dystrophy, FSHD, oculopharyngeal muscular dystrophy
- Inflammation: sarcoidosis, vasculitis, GBS
101
Cranial nerves - cerebellopontine angle lesion features and causes?
Structures involved:
- CN V, VI (rare), VII, VIII
- If lesions large enough - can extend to cerebellum and lower CNs
Features:
- Absent corneal reflex
- Ipsilateral facial sensory deficit + mastication muscles (temporalis, masseter, pterygoid) weakness
- Ipsilateral eye abduction weakness
- Ipsilateral facial weakness
- Ipsilateral SNHL
- Ipsilateral nystagmus, ataxia, incoordination
Causes:
- Tumours: acoustic neuroma (if bilateral NF2), meningioma, astrocytoma, NPC
- Meningeal infections: TB, syphilis
- Basilar artery aneurysm
102
Cranial nerves - jugular foramen lesion features and causes?
Structures involved:
- CN IX, X, XI
Features:
- Dysphagia
- Dysphonia
- Asymmetrical soft palate elevation + uvula deviated away from lesion
- Ipsilateral posterior 1/3 tongue sensory deficit
- Ipsilateral SCM and trapezius weakness
Causes:
- Neurofibroma, schwannoma, meningioma
- Metastasis
- TB, sarcoidosis
103
Bulbar palsy - features and causes?
Features:
- Speech soft, indistinct, nasal
- Tongue wasting, flaccid, fasciculations
- Jaw jerk absent
- May have LMN facial weakness
- Poor palatal movements
- Weak cough
- Fatiguability
Causes:
- MND
- GBS
- Syringobulbia
- Poliomyelitis
- NMJ: MG, botulism
- Myopathy: FSHD, oculopharyngeal muscular dystrophy
104
Pseudobulbar palsy - features and causes?
Features:
- Speech slow, indistinct, effortful, harsh
- Tongue small, spastic, movements slow and protrusion difficult
- Jaw jerk brisk
- May have UMN facial weakness
- Emotional lability
Causes:
- MND
- MS
- Brainstem stroke or tumour
- Trauma
