Neurology Flashcards
Pyramidal weakness
UL: flexors stronger than extensors
LL: extensors stronger than flexors
Tremor
Slow tremor = 3-5Hz
Fast tremor = >10Hz
Rest tremor = present during muscle relaxation. E.g. parkinsonian tremor
Intention tremor = present during deliberate movement and more pronounced at the end of movement. Due to cerebellar disease.
Physiological tremor = assoc with holding a posture or performing a movement slowly
Benign / essential tremor = inherited disorder, tremor but no other signs
Akithesia: def
motor restlessness
Constant semi-purposeful movements of arms and legs
Athetosis: def
withering, slow movements, esp of hands and wrists
Chorea: def
Jerky small rapid movements, often disguised by a purposeful final movement
Dyskinesia: def
Purposeless and continuous movements, often of the face and mouth.
Often secondary to antipyschotics
Dystonia: def
sustained contractions of muscle groups of agonist and antagonist muscles, usually in flexion or extremes of extensions
Hemiballismus
an exaggerated form of chorea involving one side of the body
Myoclonic jerk
a brief muscle contraction which causes a sudden purposeless contraction of a limb
Apraxia
Inability to perform deliberate actions in the absence of paralysis
Receptive dysphasia
Def: patient cannot understand, speaks nonsense
Aeit: leison (infarction, haemorrhage, tumour) in the dominant hemisphere in the posterior part of first temporal gyrus (WERNICKE’S AREA)
CFx:
- Patient cannot understand or follow commands
- Speech is fluent but disorganised
- Cannot name objects or repeat ‘no ifs, ands or buts’
Expressive dysphasia
Def: patient understands but cannot speak properly
Aeit: posterior part of the dominant third frontal gyrus (BROCA’S AREA)
CFx:
- Non fluent speech
- May be able to name objects and repeat phrases
- Can follow commands
- If hemiparesis present UL>LL affected
Nominal dysphasia
Def: cannot name objects but other aspects of speech normal
Aeit: lesion of the dominant posterior temporoparietal area
CFx:
- May use long sentences to overcome not remembering specific words
Conductive dysphasia
Def: can follow commands but difficulty in repeating statements and naming objects
Aeit: lesion of the arcuate fasciculus and other fibres linking wernicke’s and broca’s areas.
Dysarthria
Difficulty with articulation of speech
Parietal lobe dysfunction (higher centres CFx)
DOMINANT:
- Acalculia (can’t do basic sums)
- Agraphia (can’t write)
- Left-right disorientation (show R then L hand, then touch R ear with L hand and L ear with R hand)
- Finger agnosia (can’t name fingers)
NON-DOMINANT:
- Graphaesthesia (can’t recognise numbers drawn on the skin)
- Tactile extinction (can’t tell which side being touched when both sides touched)
GENERAL:
- Sensory and visual inattention (get inattention on L side with R sided lesion)
- Lower quandrantinopia
- Astereogenesis (tactile agnosisa)
- Two point discrimination
- Dressing and constructional apraxia
- Spatial neglect (incomplete clock drawing)
Temporal lobe dysfunction (higher centres CFx)
- Decreased short term memory (recall 3 objects)
- Confabulation
- Upper quadrantinopia
- Receptive dysphasia if dominant lobe
Frontal lobe dysfunction (higher centres CFx)
- Personality change
- Primitive reflexes (grasp [stroke palms, graps on side contralateral to the lesion], pout [stroke upper lip with tendon hammer induces pouting of lips])
- Anosmia
- Optic nerve compression-> atrophy (rare due to a space occupying lesion)
- Gait apraxia
- Leg weakness
- Loss of micturition control
- Expressive dysphasia
- Concrete thinking (can’t interpret proverb)
Occipital lobe dysfunction (higher centres CFx)
- Homonymous hemianopia
- Alexia (can’t read)
Causes of blindness
BILATERAL
- Sudden: bilateral occipital lobe infarction, bilateral occipital lobe trauma, bilateral optic nerve damage (e.g. methyl alcohol poisoning)
- Slow: cataracts, acute glaucoma, mascular degeneration, diabetic retinopathy (viterous haemorrhages), bilateral optic nerve or chiasmal compression
UNILATERAL:
- Sudden: retinal artery or vein occlusion, temporal arteritis, non-arteritic ischaemic optic neuropathy, optic neuritis or migraine
Causes of papilloedema
- Space occupying lesion (causing raised ICP)
- Hydrocephalus: obstructing (e.g. block in ventricle, aqueduct or outlet to 4th ventricle), communicating, increased CSF formation (e.g. choroid plexus papilloma), decreased CSF absorption (e.g. tumour causing venous compression)
- Benign intracranial hypertension: idiopathic, OCP, addison’s disease, drugs (nitrofurantoin, tetracycline, vitamin A, steroids), head trauma
- Hypertension, grade 4
- Central retinal vein thrombosis
Causes of optic neuritis
- Multiple sclerosis
- Toxic (e.g. ethambutol, chloroquine, nicotine, alcohol)
- Metabolic (e.g. vit B12 deficiency)
- Ischaemic (e.g. DM, temporal arteritis, atheroma)
- Familial (e.g. Leber’s disease)
- Infective (e.g. infectious mononucleosis)
Visual field defects: tunnel vision
Concentric diminution
Aeit: glaucoma, retinal abnormalities such as chorioretiniits, papilloedema, acute ischaemia, migraine.
CFx: normally widens as objects moved further away
Visual field defects: central scotomata
Loss of central (macular) vision
Aeit: demyelination of optic nerve (MS), toxic (methyl alcohol), vascular lesions, gliomas of optic nerve
Visual field defects: unilateral total loss
Aeit: optic nerve lesion or unilateral eye disease
Visual field defects: bitemporal hemianopia
Aeit: lesion affecting optic chiasm (e.g. pitiuitary tumour, craniopharyngioma and suprasellar meningioma)
Visual field defects: binasal hemianopia
Rare!
Aeit: bilateral lesions affecting uncrossed optic fibres
Visual field defects: homonymous hemianopia
Aeit: lesion that damages optic tract or radiation.
Right sided lesion = left temporal and right nasal loss of vision.
Visual field defects: homonymous quadrantinopia
Upper = temporal lobe
Lower = parietal lobe
vascular lesions or tumours
Pupil reflexes
MIOSIS = constriction of pupils
- Afferent limb = optic nerve
- Efferent limb = parasympathetic innervation by CN III
- Motor
MYDRIASIS = dilation of pupils
- Afferent limb = optic nerve
- Efferent limb = parasympathetic innervation from fibres from thalamus to ciliopsinal C8/T1/T2 to cervical ganglion via internal carotid artery + optic nerve
CN III palsy
CFx:
- Complete ptosis
- Eye down and out (divergent strabismus)
- Dilated pupil unreactive to direct light (consensual reaction in the opposite normal eye is intact)
- Unnreactive to accomodation
Motor function
- Superior rectus
- Inferior oblique
- Medial rectus
- Inferior rectus
Aeit:
- CENTRAL: vascular lesions in brainstem, tumours, demyelination
- PERIPHERAL: compressive lesions (usually aneurysm on PICA, tumour, orbital lesion), ischaemia (arteritis, DM, migraine)
CN IV palsy
CFx:
- Can’t turn eye inward and down when eye adducted
Motor function
- superior oblique (intorts eye / depresses eye when adducted)
Aeit:
- Isolated palsy rare, usually idiopathic or trauma
CN VI palsy
CFx:
- Failure of lateral movement, maximum of looking to the affected side
Motor function
- lateral rectus
Aeit:
BILATERAL: trauma, Wernicke’s encephalopathy (opthalmoplegia, confusion and ataxia), mononeuritis multiplex, raised ICP
Supranuclear palsy: def
Loss of vertical and/or horizontal gaze
Features that distinguish from CN palsies:
- Both eyes affected
- Pupils may be fixed and are often unequal
- Usually no diplopia
- Reflex eye movements (e.g. on flexing the neck) are intact
Progressive supranuclear palsy: CFx
- Loss of vertical and then horizontal gaze
- Neck rigidity
- Dementia
Nystagmus
Direction is defined as that of the fast (correcting) movement
Physiological at the extremes of gaze
Jerky horizontal nystagmus: causes
- Vestibular lesions (acute= away from the side of the lesion; chronic = towards the side of the lesion)
- Cerebellar lesion (unilateral disease causes nystagmus towards the side of disease)
- Toxic e.g. phenytoin, alcohol
- Intranuclear opthalmoplegia (nystagmus in the abducting eye and failure of adduction of the other [affected] side; due to a lesion of the medial longitudinal fasiculus {MS young people, vascular disease in elderly)
Jerky vertical nystagmus: causes
- Brain stem lesion
- Upbeat suggests midbrain or floor of fourth ventricle
- Downbeat suggests foramen magnum lesion
- Toxic, e.g. alcohol, phenytoin
Causes of a CN V palsy
CENTRAL (pons, medulla or upper cervical cord)
- Vascular lesion
- Tumour
- Syringobulbia (fluid filled cavities)
PERIPHERAL (middle fossa)
- Aneurysm
- Tumour
- Chronic meningitis
TRIGEMINAL GANGLION (petrous temporal bone):
- Trigeminal neuroma
- Meningioma
- Fracture of the middle fossa
CAVERNOUS SINUS: [Involve only opthalmic (V1) division and typically assoc with CN IV and VI palsy] - Aneurysm - Tumour - Thrombosis
If only one division of CN V affected then it must be a post ganglionic lesion.
Dissociated sensory loss suggests a brainstem or upper cord lesion.
Causes of CN VII palsy
UMN (supranuclear; forehead sparring):
- Vascular
- Tumours
LMN (forehead not spared, when pt tries to shut eye get upward movement of eyeball and incomplete closure):
- Pontine causes (often assoc with CN V and VI lesions): vascular lesions, tumours, syrringobulbia, MS
- Posterior fossa: acoustic neuroma, meningioma, chronic meningitis
- Petrous temporal bone: bell’s palsy, fracture, ramsay hunt syndrome (herpes zoster), ottitis media, parotid gland tumour or sarcoidosis
Causes CN IX and X palsy
CENTRAL:
- Vascular lesions (lateral medullary infarction due to vertebral or posterior inferior cerebellar artery disease)
- Tumours
- Syringobulbia
- MND
PERIPHERAL (posterior fossa):
- Aneurysms at the base of skull
- Tumours
- Chronic meningitis
- Guillian-Barre syndrome
CNXII lesion Cfx
LMN:
- wasting and fasciulations of tongue
- Deviation towards the side of a unilateral LMN lesion
UMN:
- Small immobile tongue
- No deviation if unilateral lesion (as tongue has bilateral UMN innervation)
CNXII palsy causes
BILATERAL UMN:
- Vascular
- MND
- Tumours
UNILATERAL LMN:
- Central: vascular lesions (e.g. thrombosis of vertebral artery), MND, syringobulbia
- Peripheral (at posterior fossa or upper neck): aneurysms, tumours, chronic meningitis, trauma, lymphadenopathy, arnold-chiari malformation (base of skull congenital malformation with herniation of a tongue of cerebellum and medulla into the spinal canal causing lower cranial nerve palsies, cerebellar signs and UMN signs in legs)
BILATERAL LMN:
- MND
- Guillian-barre syndrome
- Poliomyelitis
- Arnold-Chiari malformation
Causes of multiple CN lesions
- Unilateral III, IV, V, VI suggests carvenous sinus lesion.
- Unilateral V, VII and VIII suggests a cerebellopontine angle lesion (usually tumour)
- Unilateral IX, X, and XI suggests jugular foramen lesion
- Bilateral X, XI and XII
- Bulbar palsy if LMN signs
- Psuedobulbar palsy if UMN signs - Weakness of eye and facial muscles that worsens with repeated contraction suggests mysasthenia
Pseudobulbar palsy: def
Pseudobulbar palsy = bilateral UMN lesions of CN IX, X and XII
Pseudobulbar palsy: CFx
Pseudobulbar palsy = bilateral UMN lesions of CN IX, X and XII
CFx
- Increased gag reflex
- Spastic tongue
- Increased jaw jerk
- Spastic dysathria (speech)
- Bilateral limb UMN (long tract) signs
- Labile emotions
Causes:
- Bilateral cerebrovascular disease (e.g. both internal capsules)
- Multiple sclerosis
- Motor neurone disease
Pseudobulbar palsy: causes
Pseudobulbar palsy = bilateral UMN lesions of CN IX, X and XII
CFx
- Increased gag reflex
- Spastic tongue
- Increased jaw jerk
- Spastic dysathria (speech)
- Bilateral limb UMN (long tract) signs
- Labile emotions
Causes:
- Bilateral cerebrovascular disease (e.g. both internal capsules)
- Multiple sclerosis
- Motor neurone disease
Bulbar palsy: def
Bulbar palsy = bilateral LMN lesions of IX, X and XII
Bulbar palsy: CFx
Bulbar palsy = bilateral LMN lesions of IX, X and XII
CFx:
- Absent gag relfex
- Absent or normal jaw reflex
- Nasal speech
- Normal emotions
Causes:
- MND
- Guillain-Barre syndrome
- Poliomyelitis
- Brainstem infarction
Bulbar palsy: causes
Bulbar palsy = bilateral LMN lesions of IX, X and XII
CFx:
- Absent gag relfex
- Absent or normal jaw reflex
- Nasal speech
- Normal emotions
Causes:
- MND
- Guillain-Barre syndrome
- Poliomyelitis
- Brainstem infarction
Causes of multiple CN palsies
- Nasopharyngeal carcinoma
- Chronic meningitis (e.g. carinoma, haem malig, TB, sarcoidosis)
- Guillian-Barre syndrome (spares sensory nerves)
- Brainstem lesions (usually due to vascular disease causing crossed signs)
- Arnold-Chiari malformation
- Trauma
- Paget’s disease
- Mononeuritis multiplex (rare, e.g. DM)
Horner’s syndrome: CFx
Due to interruption of the sympathetic innervation of the eye.
CFx:
- Partial ptosis (sympathetic fibres supply the smooth muscle of both eyelids)
- Constricted pupil (miosis; due to unbalanced parasympathetic action)
- Decreased sweating
Horner’s syndrome: causes
- Carcinoma of the apex of the lung (usually squamous cell carcinoma)
- Neck
- Malignancy e.g. thyroid
- Trauma or surgery - Lower trunnk brachial plexus lesions
- Trauma
- Tumour - Carotid artery lesion
- Carotid aneursym or dissection
- Pericarotid tumours
- Cluster headache - Brainstem lesion
- Vascular disease (e.g. lateral medullary syndrome; see nystagmus to the side of the lesion, ipsilateral pain and temperature loss (CN V), CV IX and X lesions, ipsilateral cerebellar signs and contralateral pain and temperature loss over the trunk and limbs)
Horner’s syndrome: clinical exam
EYES:
- Partial ptosis
- Miosis
- Check for drecrease in sweating
FACE:
- Check for signs of lateral medullary syndrome
– Nystagmus to side of the lesion
– Ipsilateral pain and temperature loss (CN V)
– CN IX and X lesions (uvula deviation [to side of lesion’] and gag reflex, cough)
– ipsilateral cerebellar signs
– contralateral pain and temp loss over trunk and limbs
VOICE
- Hoarseness may be from a recurrent laryngeal nerve palsy
HANDS
- clubbing
- weakness of finger abduction
(if present do resp exam concentrating on the apices for lung carcinoma)
NECK
- lymphadenopathy
- Thyroid carcinoma
- Carotid aneursym or bruit
Myotonia: def
Myotonia = inability to relax muscles after voluntary contraction
Test by getting patient to hand grip and then watch for delayed relaxation.
Can also test for percussion myotonia (percuss thenar eminance and look for a dimple of contraction which only slowly disappears
Pronator drift: causes
- Upper motor neurone: DOWNWARD drift due to muscle weakness, typically starts distal and moves proximally
- Cerebellar disease: UPWARDS drift. Also includes slow pronation of the wrist and elbow
- Loss of proprioception: PSEUDOATHETOSIS, searching movement and usually affects only the fingers
Causes of fasiculations
- Motor neurone disease
- Motor root compression
- Peripheral neuropathy, e.g. diabetic
- Primary myopathy
- Thyrotoxicosis
Muscle power grading
0 Complete paralysis
1 Flicker of contraction
2 Movement possible when gravity excluded
3 Movement possible against gravity but not if any further resistance is added
4- Slight movement against resistance
4 Moderate movement against resistance
4+ Submaximal movement against resistance
5 Normal power
Sensory pathways
Spinothalamic
- Pain
- Temperature
Posterior column
- Vibration
- Proprioception
- Light touch
Dermatome (rough guide)
C5 = shouldertip C6 = lateral forearm and thumb C7 = middle finger C8 = little finger T1 = medial aspect upper arm and elbow
Radial nerve
Radial nerve - C5-8
Motor (extends UL!)
- Triceps
- Brachioradialis
- Extensor muscle of hand
Sensation
- Anatomical snuff box
Cfx palsy
- Wrist drop
- Test for triceps involvement (if affected lesion is above the upper third of the arm)
Median nerve
Median nerve C6-T1
Motor Wrist flexion Finger flexors Lumbricals (leyton Hewitt sign) Thumb abduction - front muscles of the forearm except flexor carpi ulnaris and ulnar half of flexor digitorum profundus - LOAF of hand -- Lateral two lumbricals -- Opponens pollicus -- Abductor pollicis brevis -- Flexor pollicis brevis
Sensation
- Palmar aspect of thumb, index and lateral half of ring fingers
Lesions:
- At wrist (carpal tunnel)
- pen touch test to assess for weakness of abductor pollicis brevis (get patient to abduct thumb towards pen held by examiner)
- Palm sensation spared
- At cubital fossa
- Look for loss of flexor digitorum sublimis; get patient to clasp hands together and look for index finger sticking out
Ulnar nerve
Ulnar nerve C8-T1
Motor
Finger abduction
Finger addiction
Digit 4 and 5 flexion
- Supplies small muscles of the hand except LOAF
- Flexor carpi ulnaris
- Ulnar part of flexor digitorum profundis
Sensation
- Palmar and dorsal aspects of the little finger and medial half of ring finger
Note ulnar nerve paradox where distal lesions cause greater deformity.
Causes of a true claw hand (all fingers clawed)
- Ulnar and median nerve lesion (ulnar nerve palsy alone causes a claw like hand)
- Brachial plexus lesion (C8-T1)
- Other neurological disease, e.g. syringomyelia, polio
- Ischaemic contracture (later and severe)
- Rheumatoid arthritis (advanced, untreated disease)
Causes of wasting of the small muscles of the hands
SPINAL CORD LESION - Syringomyelia - Cervical spondylosis with compression of the C9 segment - Tumour - Trauma ANTERIOR HORN CELL DISEASE - Motor neurone disease - Poliomyelitis - Spinal muscular atrophies ROOT LESION - C8 compression LOWER TRUNK BRACHIAL PLEXUS LESION - Thoracic outlet syndromes - Trauma, radiation, infiltration, inflammation PERIPHERAL NERVE LESIONS - Median and ulnar nerve lesions - Peripheral motor neuropathy MYOPATHY - Dystrophia myotonica (forearms more affected than hands) - Distal myopathy TROPHIC DISORDERS - Athropathies - Ischaemia, inc vasculitis - Shhoulder hand syndrome
Nerve root and brachial plexus trunks
C5 and 6
- Upper trunk
- Shoulder muscles
C7
- middle trunk
- Triceps and some forearm muscles
C8 and T1
- lower trunk
- hand and some forearm muscles
Brachial plexus cords, nerves and their supplied muscles
LATERAL CORD
- Musculocutaneous, median nerves
- Biceps, pronator teres, flexor carpi ulnaris muscles
MEDIAL CORD
- Median and ulnar nerves
- Hand muscles
POSTERIOR CORD
- Axillary and radial nerves
- Deltoid, triceps and forearm muscles
Ulnar nerve vs C8 root/trunk lesion
- Sensory loss with C8 lesion extends proximal to the wrist, ulnar only supplies sensation in the wrist
- Thenar muscles involved with a C8 root or lower trunk lesion
Brachial plexus lesions: CFx
COMPLETE LESION (rare):
- LMN signs affect the whole arm
- Sensory loss (whole limb)
- Horner’s syndrome
- Often painful
UPPER LESION (Erb) C5-6
- Loss of shoulder movement and elbow flexion; hand held in waiter’s tip position
- Sensory loss over the lateral aspect of the arm and forearm
LOWER LESION (Klumpke) C8-T1
- True claw hand with paralysis of all the intrinsic muscles
- Sensory loss along the ulnar side of the hand and forearm
- Horner’s syndrome
Cervical rib syndrome: CFx
- Weakness and wasting of the small muscles of the hand (claw hand)
- C8 and T1 sensory loss
- Unequal radial pulses and blood pressure
- Subclavian bruits on arm manoeuvering
- Palpable cervical rib
Brachial plexus lesions: causes
- Inflammation, autoimmune (more common upper brachial plexus)
- Radiotherapy (more often upper brachial plexus)
- Cancer (more often lower; usually painful, weakness and sensory loss present)
- Trauma
Anal sensation
Anal sensation: S3-S5
Anal reflexes: S2-S4
Lateral cutaneous nerve of the thigh
Sensory
- Lateral aspect of thigh
No motor
Femoral nerve
Femoral nerve L2, L3, L4
MOTOR:
- Knee extension
- Absent knee jerk
SENSORY:
- inner aspect of thigh and leg
Sciatic nerve
Sciatic nerve L4, L5, S1, S2
MOTOR:
- All muscles below the knee and hamstrings
SENSATION:
- posterior thigh
- lateral and posterior calf
CFx palsy:
- Foot drop
- Knee jerk intact but ankle jerk and plantar responses absent
Common peroneal
Common peroneal L4, L5, S1
MOTOR (branch of sciatic)
- Anterior and lateral compartment muscles of one leg
CFx palsy:
- Foot drop
- Intact reflexes
- Inversion preserved
- Minimal sensory loss over the lateral aspect of the dorsum of the foot
NOTE: L5 palsy has weakness of knee flexion and loss of foot inversion as well as sensory loss in L5 distribution.
Causes of foot drop
- Common peroneal nerve palsy (most likely secondary to entrapment)
- Sciatic nerve palsy
- Lumbrosacral plexus lesion
- Peripheral motor neuropathy
- Distal myopathy
- Motor neurone disease
- Stroke, anterior cerebral artery or lacunar artery syndrome
Gait disorder: hemiplegia
Hemiplegic gait = foot is plantar flexed and the leg is swung in a lateral arc
Gait disorder: spastic paraparesis
Spastic paraparesis = scissors gait
Gait disorder: parkinson’s
Parkinson’s gait = hesistation in starting
- Shuffling
- Freezing
- Festination
- Propulsion
- Retropulsion
Gait disorder: cerebellar
Cerebellar = a wide based or reeling on a narrow base.
The patient staggers towards the affected side if the lesion is unilateral.
Gait disorder: posterior column lesion
Posterior column lesion = clumsy slapping down of the feet on a broad base
Gait disorder: foot drop
Foot drop = high stepping gait
Gait disorder: proximal myopathy
Proximal myopathy = waddling gait
Gait disorder: prefrontal lobe (apraxic)
Prefrontal lobe (apraxic) = feet appear glued to floor when erect, but move more easily when the patient is supine
Special gait movements
Walk on toes = not possible if S1 lesion
Walk on heels = not possible if L4 of L5 lesion causing foot drop
UMN lesion CFx
UMN lesion = lesion at level above anterior horn cell (e.g. cerebral cortex, internal capsule, brainstem, spinal cord)
CFx:
- Upper limb drift
- Hyperrelfexia
- Extensor (upgoing) plantar response
- Pyramidal weakness (UL flexors strong, LL extensors strong)
- No muscle wasting
- Increased tone / spasticity (due to destruction of the corticoreticulospinal tract)
Causes of UMN lesions
VASCULAR: thrombosis, embolism, haemorrhage. Thrombosis of internal carotid artery (may hear bruit).
COMPRESSIVE/INFILTRATIVE: tumours, false localising signs from raised ICP (typically see 6th nerve palsy due to 6th nerves long path).
DEMYELINATING DISEASE: MS
INFECTION: HIV
Stroke: MCA CFx
Main branch (middle third of hemisphere):
- UMN face, arm>leg signs
- Homonymous hemianopia
- Aphasia or non-dominant hemisphere signs
- Sensory loss
Perforating artery (internal capsule):
- UMN face
- UMN arm>leg
Stroke: PCA CFx
Infarction of thalamus and occipital cortex:
- Homonymous hemianopia
- Examine for occipital and temporal lobe dysfunction
Stroke: ACA CFx
- UMN leg?arm
- Cortical sensory loss leg only
- Urinary incontinence
Arteries and stroke patterns
Anterior cerebral artery = leg>arm involvement
Penetrating branches of MCA = lacunar infarct
Internal carotid / MCA = aphasia or non-dominant hemisphere dysfunction, hemiplegia contralaterally to lesion, homonymous hemianopia.
Posterior cerebral artery = homonymous hemianopia, no hemiplegia
Basilar artery = quadriplegia
Penetrating branches of basilar artery to brainstem = brainstem infarct
PICA (posterior inferior cerebellar artery) = laterally medullary syndrome (ipsilateral facial sensation changes, contralateral body sensory deficits)
LMN lesions: CFx
- Weakness (may be more pronounced distally>proximally, all muscles equally involved)
- Muscle wasting
- Normal tone
- Reduced reflexes with normal or absent plantars
- Fasciculations may be present
LMN lesions
LMN lesion = interruption of reflex arc, thus lesion of the spinal motor neurones, motor root or peripheral nerve
Motor neurone disease
- Unknown pathophys but pathology in anterior horn cell,s motor nuclei of the medulla and descending tracts
CFx:
- Combination of UMN and LMN signs
- Fasiculations almost always present
- Muscle stretch reflexes usually present until late in disease
- No objective sensory changes
Peripheral neuropathy: CFx
CFx:
- Distal part of nerves involved first due to distance from the cell bodies
- Can be loss of sensation or motor function
- Typically symmetrical glove and stocking loss to all modalities
- Peripheral weakness may be present if motor nerve involvement
- If motor without sensory involvement reflexes may be reduced but should not be absent
Peripheral neuropathy: causes
DRUGS: e.g. isoniazid, vincristine, phenytoin, nitrofurantoin, cisplatinum, heavy metals, amiodarone.
ALCOHOL: with or without B1 deficiency
METABOLIC: diabetes, chronic renal failure
GUILLIAIN BARRE SYNDROME
MALIGNANCY: e.g. lung ca, leukaemia, lymphoma
VITAMINS: B12 deficiency, B1 deficiency, B6 excess
CTD / VASCULITIS: PAN, SLE
HEREDITARY: hereditary motor and sensory neuropathy
OTHER: amyloid, HIV
Motor peripheral neuropathy: causes
- Guillian Barre syndrome, chronic inflammatory polyradiculoneuropathy
- Hereditary motor and sensory neuropathy
- Diabetes mellitus
- Other: acute intermittent porphyria, lead poisoning, diphtheria, multifocal conduciton block neuropathy
Painful peripheral neuropathy: causes
- Diabetes mellitus
- Alcohol
- Vitamin B1 or B12 deficiency
- Carcinoma
- Porphyria
- Arsenic or thallium poisoning
Guillain Barre syndrome: CFx
- Flaccid proximal and distal muscle paralysis that ascends from the lower to upper limbs
- Wasting rare
- Sensory loss minimal or absent
- Sphincters not affected (cf: transverse myelitis)
Mononeuritis multiplex: def
MM = separate involvement of more than one peripheral or cranial nerves by a single disease
Mononeuritis multiplex: causes
ACUTE:
- Polyarteritis nodosa
- Diabetes
- CTD: rheumatoid arthritis, SLE
CHRONIC:
- Multiple compressive neuropathies
- Sarcoidosis
- Acromegally
- HIV
Causes of thickened peripheral nerves
Assoc with peripheral nerve leisons, peripheral neuropathy or mononeuritis multiplex.
Causes:
- Acromegaly
- Amyloid
- CIDP
- Leprosy
- Hereditary motor and sensory neuropathy
- Sarcoidosis
- Diabetes mellitus
- Neurofibromatosis
Spinal cord lesions: CFx
Spinal cord lesion causes LMN AT THE LEVEL of the lesion and UMN BELOW LEVEL of lesion.
Examples:
- C5: LMN weakness and wasting of rhomboids, deltoids, biceps and brachioradialism. UMN affecting the rest of UL and LL.
- C8: LMN weakness and wasting of instrinsic muscles of the hand. UMN signs in LL.
- T10/T11: loss of lower abdominal reflexes and upward displacement of umbilicus. UMN in LL.
- L5-S1: LMN weakness of knee flexion and hip extension (S1) and abduction (L5) plus calf and foot muscles. Knee jerks present, no ankle jerks or plantar responses. Anal reflex present.
- S3-S4: no anal reflex, saddle sensory loss, normal lower limbs.
Causes of spinal cord compression
Spinal cord lesion causes LMN AT THE LEVEL of the lesion and UMN BELOW LEVEL of lesion.
VERTEBRAL: - Spondylosis - Trauma - Prolapse of a disc - Tumour - Infiltration OUTSIDE DURA: - Lymphoma - Infection, e.g. abscess WITHIN DURA BUT EXTRAMEDULLARY: - Tumour, e.g. meningioma, neurofibroma INTRAMEDULLARY: - Tumour, e.g. glioma, ependymoma - Syringomyelia - Haematomyelia
Spinal cord syndromes: brown sequard syndrome
Brown sequard = half cord (coronally) affected (partial unilateral cord lesion)
CFx:
- Loss of pain and temperature sensation on the opposite side to the lesion
- Loss of vibration and proprioception on the same side of the lesions
- UMN BELOW the hemisection on the same side as the lesion, LMN AT the level of the hemisection on the same side
Causes:
- MS
- Angioma
- Trauma
- Myelitis
- Post radiation myelopathy
Spinal cord syndromes: subacute combined degeneration of the cord (Vit B12 deficiency)
CFx:
- Posterior column loss symmetrically-> ataxic gait
- UMN signs in LL symmetrically
- Absent ankle reflex but knee reflex may be exaggerated or absent
- Peripheral sensory neuropathy
- Optic atrophy
- Dementia
Important patterns of abnormal sensation
Total unilateral loss of all sensation = thalamus or upper brainstem lesion
Pain and temperature loss on one side of face and opposite side of body = lateral medullary syndrome (medulla involving descending nucleus of spinal tract of 5th nerve and ascending spinothalamic tract)
Bilateral loss of all sensation below a defined level = spinal cord lesion
Bilateral loss of only pain and temp below a defined level = anterior spinal cord lesion
Unilateral loss of pain and temp below a defined level = brown sequard
Loss of pain and temp over several segments but normal above and below = intrinsic spinal cord lesion near centre anteriorly (e.g. syringomyelia)
Loss of sensation over many segments but sacral sparing = intrinsic cord compression
Saddle sensory loss = cauda equina lesion (touch preserved in conus medullaris lesions)
Loss of position and vibration sense only = posterior column lesion
Glove and stocking loss = peripheral neuropathy
Loss of sensation over a well defined area of body part = posterior root lesion (if pure sensory) or peripheral nerve
Causes of dissociated sensory loss: spinothalamic loss only
Spinothalamic loss only:
- Syringomyelia
- Brown sequard syndrome (contralateral leg)
- Anterior spinal artery thrombosis
- Lateral medullary syndrome (sensory loss contralateral to other signs)
- Small fibre peripheral neuropathy (diabetes, amyloid)
Causes of dissociated sensory loss: dorsal colummn loss only
Dorsal column loss only:
- Subacute combined degeneration of the cord
- Brown sequard (ipsilateral leg)
- Spinocerebellar degeneration, e.g. Friedreich’s ataxia
- MS
- Tabes dorsalis
- Peripheral neuropathy (e.g. diabetes, hypothyroidism)
- Sensory neuropathy (dorsal root ganglionopathy which may be caused by carcinoma, DM or sjogren’s syndrome)
Syringomyelia: CFx
Syringomyelia = central cavity in spinal cord
CFx:
- Loss of pain and temp over neck, shoulders and arms (like a cape)
- Amytrophy (atrophy and areflexia) of the arms
- UMN signs in lower limb
Causes of proximal muscle weakness
- MYOPATHY
- NEUROMUSCULAR JUNCTION DISEASE e.g. myasthenia gravis
- NEUROGENIC: MND, polyradiculopathy, kugelberg-welander disease
Kugelberg-Welander disease = proximal muscle wasting and fasiculation due to anterior horn cell disease. Autosomal recessive.
Causes of myopathy
- HEREDITARY MUSCULAR DYSTROPHY
- CONGENITAL MYOPATHIES
- ACQUIRED MYOPATHIES (PACE)
- Polymyositis or dermatomyositis
- Alcohol, AIDS (HIV infection)
- Carcinoma
- Endocrine, e.g. hyperthyroidism, hypothyroidism, Cushing’s syndrome, acromegaly, hypopituitarism
- Periodic paralysis (hyperkalaemic, hypokalaemic or normokalaemic)
- Osteomalacia
- Drugs (clofibrate, chloroquine, steroids, zidovudine)
- Sarcoidosis
Causes of proximal myopathy with a peripheral neuropathy
- Paraneoplastic syndrome
- Alcohol
- Hypothyroidism
- Connective tissue disease
Causes of extensor plantar response plus absent knee and ankle jerks
- Subacute combined degeneration of the cord (B12 deficiency)
- Conus medullaris lesion
- Combination of upper motor neurone lesion with cauda equina compression or peripheral neuropathy, such as a stroke in a diabetic
- Syphilis
- Friedreich’s ataxia
- Motor neurone disease
- Diabetes mellitus
- Human T cell lymphotrophic virus infeciton
Causes of muscle weakness
- Peripheral nerve lesions
- Mononeuritis multiplex
- Peripheral neuropathy
- Spinal cord disease
- Myopathy (no sensory loss)
Signs of proximal myopathy
- Proximal muscle wasting
- Proximal muscle weakness
- Reflexes may be reduced
- Acquired or genetic
Signs of distal myopathy
- Always genetic
- - If distal limbs affected consider hereditary motor and sensory neuropathy
Types of muscular dystrophies
DUCHENNE’S (psuedohypertrophic)
- Affects only males (sex-linked recessive)
- Calves and deltoids: hypertrophied early, weak later
- Proximal muscle weakness: early
- Dilated cardiomyopathy
# BECKER
- Affects only males (sex-linked recessive)
- Similar features to Duchenne’s but less heart disease, a later onset and less rapid progression
# LIMB GIRDLE
- Males or females (autosomal recessive), onset in the third decade
- Shoulder or pelvic girdle affected
- Face and heart usually spared
# FACIOSCAPULOHUMERAL
- Males or females (AD)
- Facial or pectoral weakness with hypertrophy of deltoids
# Dystrophia myotonica (AD)
- AD
- Frontal baldness
- Expressionless triangular facies
- Atrophy of the temporalis muscle and partial ptosis
- Difficulty releasing hands post contraction
- Cataracts
- Atrophy of sternomastoid
- Cardiac failure
- Proximal muscle wasting and weakness
Dystrophia myotonica CFx / Ex
FACE: frontal bossing, expressionless triangular facies, atrophy of the temporalis muscle
EYES: partial ptosis, cataracts / lens disease
NECK: atrophy of sternomastoid, weak neck flexion with normal extension
UPPER LIMBS: shake hands and test for percussion myotonia (tapping over thenar eminence causes contraction and then slow relaxation of abductor pollicus brevis), arm wasting, UL weakness (forearms affected first), slow to release hand grip. No sensory changes
CHEST: gynaecomastica, cardiomyopathy
TESTES: atrophy
LOWER LIMB: tibial nerves affected first
ASK: test urine for sugar as assoc with T2DM
Hereditary motor and sensory neuropathy (Charcot Marie Tooth) CFx
- Pes cavus (short arched feet)
- Distal muscle atrophy due to peripheral nerve degeneration
- This dose not usually extend above the elbows or above the middle third of thigh - Absent relfexes
- Slight or sensory loss in the limbs
- Thickened nerves
- Optic atrophy, Argyll Robertson pupils
Myasthenia gravis CFx
- Muscle power decreases with use
- Little muscle wasting and no sensory change
TEST:
- Oculomotor muscles by getting patient to sustain upgaze for one minute, look for progressive ptosis
- Peek sign: test for orbicularis oculi weakness, ask pt to close eyes, if positive within 30 seconds the lid margin will begin to separate showing the sclera.
- UL proximal girdle, ask pt to hold arms above the head and repeatedly press the abducted arms down until they weaken. Power will decrease with repeated muscle contraction.
Look for thymectomy scar
Signs of cerebellar disease
- Occur on the same side of the lesion as most cerebellar fibres cross twice in the brainstem (on entry and exit to the cerebellum)
CFx
- Jerky horizontal nystagmus
- Explosive, jerky or loud speech with irregular separation of syllables (get pt to say Bristish Constitution)
- UL drift due to hypotonia of the agonist muscles (hypotonia due to loss of a facilitatory influence on the spinal motor neurones)
- Intention tremor (increases as target is approached, due to loss of cerebellar connections in the brainstem)
- Dysdiadochokinesis
- Truncal ataxia
- Gait-> patient will stagger towards affected side if there is a unilateral cerebellar hemisphere lesion
Causes of cerebellar disease
ROSTRAL VERMIS LESION (only LL affected) - Alcohol UNILATERAL 1. Space occupying lesion (tumour, abscess, granuloma) 2. Ischaemia (vertebrobasilar disease) 3. Multiple sclerosis 4. Trauma BILATERAL 1. Drugs- e.g. phenytoin 2. Alcohol (possibly due to thiamine connection) 3. Friedreich's ataxia 4. Hypothyroidism 5. Paraneoplastic syndrome 6. Multiple sclerosis 7. Trauma 8. Arnold-Chiari malformation 9. Large space occupying lesion, cerebellar disease MIDLINE 1. Paraneoplastic syndrome 2. Midline tumour
CFx Friedreich’s ataxia
Usually AD
- Bilateral cerebellar signs including nystagmus
- Pes cavus, cocking of the toes, kyphoscoliosis
- UMN in the limbs with absent reflexes
- Peripheral neuropathy
- Posterior column loss in the limbs
- Cardiomyopathy
- Diabetes mellitus
- Optic neuropathy (uncommon)
- Normal mentation
Causes of spastic and ataxic paraparesis (combined UMN and cerebellar signs)
Young adults:
- MS
- Spinocerebellar degeneration
- Syphilitic meningomyelitis
- Arnold-Chiari malformation or other lesion at the craniopsinal junction
Later life:
- MS
- Syringomelia
- Infarction (upper pons or internal capsule on one side, ataxic hemiparesis)
- Lesion at the craniospinal junciton (e.g. meningioma)
Parkinson’s disease
Extrapyramidal disease with degeneration of the substantia nigria and its pathways leading to dopamine deficiency and an excess of cholinergic transmission
CFx:
GENERAL:
- Mask like facies with few spontaneous movements
GAIT (ask patient to rise from chair, walk, turn, quickly stop and start):
- Shuffling gait (small steps with lack of arm swing.), difficulty initiating walking and difficulty stopping.
- Bradykinesia (decrease in the speed and amplitude of complex movements); can test finger tapping and twiddling (rotating hands in front of the body)
TREMOR:
- Asymmetrical resting tremor; characteristic movement is pill rolling
- Tremor decreases with finger-nose testing
TONE:
- Increased / cogwheel ridigity
FACE:
- Glabellar tap (continues to blink when forehead tapped)
SPEECH:
- Soft and monotonous
EYES:
- Weakness of upward gaze (if marked rigidity and paralysis of gaze consider PSP)
BP:
- Orthostatic hypotension
WRITING:
- Micrographia
Causes of non-physiological tremor
- Parkinsonian (resting tremor)
- Postural/action tremor (present throughout a movement)
- Idiopathic
- Anxiety
- Drugs
- Familial
- Thyrotoxic - Essential / familial
- Intention tremor (cerebellar disease, increases towards target)
- Midbrain tremor (abduction-adduction movements of upper limbs with flexion-extension wrists (usually associated with intention tremor)
Causes of chorea
- Drugs (excess levodopa, phenothiazines, OCP, phenytoin)
- Huntington’s disease (AD)
- Sydenham’s chorea (rheumatic fever) and other post infectious (rare)
- Senility
- Wilson’s disease
- Kernicterus
- Vasculitis or CTD, e.g. SLE (very rare)
- Polycythemia (very rare)
Types of dyskinesia
Dyskinesia = extrapyramidal movement disorders
Chorea = lesion of the corpus striatum causing non-repetitive, abrupt, involuntary jerky movements.
Hemiballismus = unilateral wild throwing movements of the proximal joints. Due to a subthalamic lesion on the contralateral side.
Dystonia = slow sinuous distal writhing movements that are present at rest due to involuntary abnormal posture with excessive co-contration of antagonist muscles. Due to a lesion of the outer segment of the putamem.
Pseudoathetosis = athetoid movements in the fingers in patients with severe proprioceptive loss
Relevant afferent pupillary defect
Affected side dilates when light shone in (on repeated testing)
Causes: Pathology after optic chiasm - retinal artery occlusion - large retinal attachment - retinal vein occlusion - optic nerve (optic neuritis, MS, compression)
Causes of a predominately sensory neuropathy
- Diabetes mellitus
- Carcinoma (lung, ovary, breast. May be neuronopathy, length dependemt)
- Paraproteinaemia
- Vitamin B6 intoxication
- Sjogrens syndrome
- Syphillis
- Vitamin B12 deficiency
- Idiopathic
Nerve conduction for peripheral neuropathy
Demelinating E.g. diabetes, paraprotein, CMT, CIDP - decreased velocity - increased distal latency - normal amplitude
Axonal
E.g. diabetes mellitus, toxins, metabolic, paraneoplastic
- decreased amplitude
- velocity normal >70%
