Peripheral Nerve Flashcards
How do you classify motor and sensory nerves?
A alpha - large extrafusal motor fibres A Beta - Large sensory carrying crude touch, pressure and vibration sense A gamma - small intrafusal motor fibres A delta - fast pain, fine touch B pre ganglionic autonomic C pain, post ganglionic autonomic
What is the conduction velocity in 1A fibres?
120m/s
What is the conduction velocity in C fibres?
2m/s
All post-ganglionic autonomic fibres are which category?
C fibres
What is the difference between fasciculations and fibrillation?
Fasciculations are coarse muscle contractions that are visible to the naked eye, whereas fibrillations are not visible and require EMG to detect;
What muscles does the dorsal scapular nerve innervate?
rhomboids levator scapulae Dorsal scapula nerve C (3 for LS) 4, 5 Root
Which nerve innervates serratus anterior?
Long thoracic C5-7 Root
What is the function of supraspinatous?
shoulder abduction 15-30 degrees
What nerve innervates Supraspinatous?
suprascapular C4-6 Superior trunk
All 3 trunks in the brachial plexus form which cord?
Posterior
Which nerve innervates abductor pollicis longus?
Posterior interosseus nerve C7,8
Which nerve innervates extensor digitorum?
Posterior interosseus nerve C7,8
What root levels supply Posterior interosseus nerve?
C7,8
Which peripheral nerve innervates brachioradialis?
Radial C5,6
Which peripheral nerve innervates biceps brachii?
Musculocutaenous C5,6 Lateral cord
How do you differentiate brachioradialis motor function from biceps brachii?
Biceps tested with hands supinated brachioradialis with thumbs pointing up (pronated)
Which muscle in the upper limb receives innervation from all 3 trunks?
Triceps (C6,7,8)
Which muscles are innervated by anterior interosseous nerve?
Radial part of FDP (1+2) Flexor pollicis longus pronator quadratus
What sign do you look for with AIN palsy?
OK sign
What muscles does the median nerve innervate?
LOAF Pronator teres, flexor carpi radialis, FDS
Which muscle controlling thumb movement is innervated by ulnar nerve?
adductor pollicis
Which thumb movement is innervated by radial nerve?
extension (extensor pollicis brevis and longus)
What is the function of superficial peroneal nerve?
Foot eversion and plantar flexion (innervates peroneus longus)
What is the function of tibial nerve?
knee, ankle and toe flexion and ankle inversion
Which muscle inverts the ankle?
Posterior tibialis
What is the motor function of deep peroneal?
ankle dorsiflexion toe extension
Which nerves form the roots of the brachial plexus?
Ventral rami of C5-T1
What do the dorsal rami of the brachial plexus supply?
paraspinal muscles
Fibrillation potentials on EMG indicate what?
Motor axon loss
When is the H reflex used?
Suspected S1 radiculopathy
What is a Martin-Gruber anastamosis?
Anastamosis between median and ulnar nerves in the forearm Classification based on the origin from the median nerve: Type a (47.3%) from the branch to the superficial forearm flexor muscles, Type b (10.6%) from the common trunk, and Type c (31.6%) from the anterior interosseous nerve. Pattern II was a duplication of Type c (10.5%)
What is Richie-Cannieu anastamosis?
Motor connections from median to ulnar in the palm. Found in 70% of patients.
Medical conditions associated with entrapment neuropathies?
Diabetes Acromegaly Hypothyroidism RA PMR Gout
What is the mechanism of entrapment in hypothyroidism?
Glycogen deposition in Schwann cells
How would you treat occipital neuralgia?
Non surgical options Analgesia (NSAIDs, neuropathic agents) TENS machine Botox Occipital nerve injections (can be done at trigger points at nuchal line or C2 nerve root blocks) Surgical options decompression at C1/2 OCF in cases of AAS If idiopathic - ONS Occipital neurectomy
Where are the 2 most common sites of median nerve entrapment?
- Carpal tunnel syndrome 2. Pronator teres syndrome
Why is sensation to the palm in tact in CTS?
Palmar cutaneous branch of median nerve comes off 5.5cm proximal to the styloid process of the radius and travels over the TCL.
What is the difference between struthers ligament and struthers arcade?
Struthers Arcade is a normal finding (and in closer proximity to the ulnar nerve) Struthers ligament bridges between medial epicondyle and supracondylar process (an anatomical variant in 0.7-2.7% population)
Commonest peripheral nerve entrapment
CTS
What proportion of patients with median or ulnar neuropathy also have a cervical radiculopathy?
70%
Treatment of CTS?
Conservative - rest, neutral position splints Carpal tunnel injections Surgical decompression
What is Kaplan’s cardinal line?
Runs from the base of the thumb web space to the hook of the hamate. The superficial palmar arch, which is vulnerable during carpal tunnel surgery, is distal to this line.
What are the 2 key branches of the median nerve coming off around the TCL?
Palmar cutaneous branch (usually proximal) recurrent motor branch (usually distal)
Where can the ulnar nerve be compressed?
- Arcade of Struthers 2. Retroepicondylar groove ‘ulnar groove’ (between medial epicondyle and olecranon 3. Cubital tunnel - distal to ulnar groove between heads of FCU under ‘Osborne’s ligament’ or cubital tunnel retinaculum 4. At the point of exit from the FCU 5. Guyon’s canal at the wrist
What is Wartenberg’s sign?
One of the earliest findings of ulnar nerve entrapment (abducted little finger due to weakness of the third palmar interosseous muscle–patient may complain that the little finger doesn’t make it in when they reach into their pocket)
What is Froment’s sign?
grasping a sheet of paper between thumb and the extended index finger results in extension of the proximal phalanx of the thumb and flexion of the distal phalanx as a result of substituting flexor pollicis longus (which is spared since it is innervated by anterior interosseous nerve) for the weak adductor pollicis
How do you grade severity of ulnar nerve injury?
Stewart classification system 1 - mild - symptoms with no atrophy or weakness 2 - moderate - detectable sensory loss, mild atrophy, power 4 or 4+ 3 - severe - constant symptoms, moderate to marked atrophy and power <4
What are the 2 most important parameters on EMG that predict a good outcome of treatment in ulnar nerve compression?
- Preserved CMAP amplitude in ulnar hand muscles 2. Conduction block with slowed conduction velocity at elbow (as this suggests demyelination rather than axonal loss)
What do you expect to see on EMG for ulnar nerve compression at elbow?
- NCV <50m/sec across elbow 2. drop of >10m/sec comparing below elbow to above elbow 3. CMAP drop >20%
Would you do a simple decompression or transpose the ulnar nerve?
For most cases, simple decompression is recommended over transposition (similar success rate with lower complication rate). Possible exceptions include: bony deformity, nerve subluxation
How do you differentiate between radial nerve injury from posterior cord injury of the brachial plexus?
Deltoid and latissimus dorsi spared in radial nerve injury
What is Saturday night palsy?
Mid-upper arm compression on radial nerve from improper positioning of arm during sleep
How do you differentiate between radial nerve palsy and C7 radiculopathy?
Triceps will be weak in C7 radiculopathy
Non-entrapment cause of wrist drop and finger extensor weakness (usually bilateral)
lead poisoning
Site of compression of PIN in forearm
Arcade of Fröhse. PIN dives into supinator through this fibrous band.
2 main branches of radial nerve
PIN superficial radial nerve
Causes of isolated axillary nerve entrapment/injury
- Shoulder dislocation 2. Sleeping in prone position with arms above the head 3. compression from thoracic harness 4. Injection injury in high posterior aspect of shoulder 5. compression in quadrilateral space (between neck of humerus, long head of triceps, teres major and minor)
How does suprascapular nerve entrapment present?
Shoulder pain Atrophy/weakness of supraspinatus and infraspinatus
Where is the site of suprascapular nerve entrapment?
suprascapular notch beneath the transverse suprascapular ligament.
What roots comprise the lateral cutaenous nerve of thigh
L2, L3
Which nerve is most susceptible to acute compression palsy?
Common peroneal
What is the innervation of pronator teres?
Median nerve (C5-T1) - mostly from C6/7 roots
In EMG what is the interference pattern?
When the EMG during contraction fully obscures the baseline. Incomplete interference is seen with motor axon loss and is the earliest change seen with EMG
What are the EMG changes seen with radiculopathy?
>day 0 = reduced interference pattern, fasciculation, prolonged H-reflex and reduced F-wave >7 days = Fibrillation potentials and positive sharp waves in the paraspinal muscles >14 days = Fibrillation potentials and positive sharp waves in the prox. limb muscles >21 days = Fibrillation potentials and sharp waves in the distal limb muscles
What is a motor unit potential?
Sum of electrical activity from muscle fibres supplied by the same motor neuron
When do F-waves appear?
25-55ms. Measured in the muscle after the stimulation whilst CMAPs are after a few ms.
What is an F-wave?
Antidromic motor neurone stimulation travels to the prox. horn and causes it to back fire. This then travels to the muscle causing a contraction in a delayed fashion. Amplitude is smaller and more variable depending on how many motor neurons are excited. It is useful for assessing proximal lesions in multiple nerve roots e.g. GBS/CIDP not isolated radiculopathy.
What is an H-reflex?
Stimulation of the tibial nerve generates a reflex arc (same as the ankle jerk) and causes gastrocnemius and soleus (triceps surae) activation. It is sensitive for S1 radiculopathy.
What causes multifocal demyelination?
Mononeuritis multiplex = paraproteinemia, diptheria and leptosy
What causes generalised demyelination?
GBD / CIDP / Lymphoma / Mulitple myeloma / Amiodarone
What causes multifocal axonopathy?
Diabetes Vasculitis HIV Sarcoid Amyloidosis Neoplasms
What causes generalised axonopathy?
Diabetes Alcohol Drugs Critical illness Multiple myeloma
What pattern of injury is seen in nerve entrapment?
Demyelination before axonal degeneration (on when severe)
What are the expected features of CTS?
Motor: Prolonged distal motor latencies (demyelination) with a reduced CMAP (axon loss) but normal conduction velocity between the elbow and the wrist. Sensory: Prolonged latencies (onset and peak) and slowed conduction velocity.
Where you measure radial nerve motor responses?
Needle or electrode over the extensor pollicus longus muscle (identified by extension of the thumb and palpating the muscle on the dorsal forearm). The radial nerve is stimulated at the lateral epicondyle.
What does the involvement of brachioradialis on EMG suggest?
Radial nerve injury proximal to the elbow (as the nerve branches to brachioradialis come off higher than the elbow)
In a suspected radial nerve injury, why test deltoid EMG?
As deltoid involvement (axillary nerve) would suggest a lesion of the posterior cord.
Why does radial nerve weakness / wrist drop cause weakness of grip?
Bow stringing effect - the hand flexors cannot work in a flexed position.
What does an absent radial nerve SNAP suggest?
That the main trunk of the radial nerve is affected not the PIN which is purely motor without a sensory component
What NCS/EMG changes occur with C6 radiculopathy?
Paraspinal muscles show acute denervation (telling you it is a radicular component). C5 muscles are unaffected i.e. rhomboids and supra/infraspinatus. Muscles with C6 input such as biceps, deltoid and brachioradialis will be weak.
How does a Martin-Gruber anastomosis present?
In patients with CTS, if they have a Martin-Gruber anastomosis, the prox latency is less than the distal latency. This is because the distal latency is slowed by demyelination at the carpal tunnel (because they have CTS). The proximal latency is short because the anastomosis allows the stimulation to travel along the ulnar nerve bypassing the slowing at the carpal tunnel and stimulates the thenar eminance.
What is the root supply to vastus lateralis?
Mostly L4 from the femoral nerve
What is the main root supply to tensor fascia lata?
Mostly L5 from the superior gluteal nerve (which also supplies gluteus medius and minimus)
Why would the CMAP for the common peroneal nerve be larger when stimulated at the knee than the ankle?
If there is an accessory deep peroneal nerve which would stimulated at the knee but not at the ankle.
What is the root supply to the adductors?
L2-4 via the obturator nerve
What root supply does the adductor reflex test?
L2-4
What root supplies inversion and eversion of the ankle?
L5. Inversion via the tibialis posterior (tibial nerve) and Eversion via peroneus longus/brevis (supfl. peroneal nerve)
What are the root values for wrist flexion and extension?
C6/7 - flexion C7/8 - extension
What are the root values for wrist extension?
C7/8
What is nerve supply to psoas?
L1-3 ventral rami
What nerve supplies sensation to the femoral triangle?
Genitofemoral nerve (L1/2)
Which part of the sciatic nerve forms the tibial nerve?
Ventral division (medial)
Which part of the sciatic nerve forms the common peroneal nerve?
Dorsal division (lateral)
What is the root supply to the pudendal nerve?
S2,3,4
How can you distinguish Guyon’s canal from cubital tunnel compression?
Guyon’s canal spares the dorsal sensation to the ulnar side of the hand (dorsal ulnar cut branch comes off 5 cm prox to Guyon’s canal) and spares the ulnar innervated muscles in the forearm e.g. flex. carpi ulnaris.
Where does common peroneal nerve entrapment occur?
Fibular tunnel - due to a fibrous band on perneous longus
What is the difference between prox. and distal tibial tarsal tunnel syndrome?
Distal involves the medial and lateral plantar nerves causing chronic heel pain. Prox. compression occurs behind the medial malleolus and causes pain in the sole of foot and toes with clawing due to weakness of the foot intrinsics. Pain worse with dorsiflexion eversion test.
What is the inverted radial reflex?
Diminished brachioradialis reflex with reflex contraction of the fingers. Suggests C5/6 pathology
What levels do the reflexes in the upper limb test?
Biceps C5 Brachioradialis / supinator C6 Triceps C7
What is the difference between a poly and mononeuropathy?
Multiple vs single nerve peripheral neuropathy resulting in weakness, sensory disturbance and abnormal reflexes.
What are the causes of peripheral neuropathies?
Mnemonic GRAND-THERAPIST: GB, Renal failure, Alcohol, Nutritional deficiencies, DM Trauma, Hereditary, Entrapment, Radiation, Amyloid, Porphyria/paraneoplastic, Infection (leprosy), Sarcoid and Toxins
What are the inherited neuropathies?
Charcot-Marie-Tooth; 7 types mostly AD. Types 1 and 2 are most common. Results in LL motor>sensory deficits. Type 1 continue to ambulate but Type 2 loose ambulation as teenagers.
What % of critical care neuropathies resolve completely?
50%
What is the classical finding of ETOH neuropathy?
Diffuse sensory loss with loss of ankle jerk
What are the causes of a brachial plexus injury?
Trauma Pancoast tumour Cervical rib (thoracic outlet syndrome) DM Vasculitis Viral Inflammatory - Parsonage-Turner syndrome
What is the presentation of Parsonage-Turner syndrome?
Intense pain with development of weakness within 2 weeks (80% had a sudden onset of weakness). 50% have a viral prodrome. 50% are confirmed to the shoulder girdle.
How can multi-level radiculopathy be distinguished from a plexopathy with EMG?
Sampling of the paraspinal muscles with EMG shows involvement with radiculopathy but not plexopathies
What causes lumbosacral plexus neuropathy?
Diabetes. Associated with tenderness over the femoral nerve. If L4 is involved (knee ext weakness) can be mistaken for femoral nerve injury. If L5 is involved (foot drop) can be mistaken for common peroneal nerve injury.
How does diabetic neuropathy present? (3 types)
Primary sensory polyneuropathy (glove and stocking) Diabetes proximal neuropathy Autonomic neuropathy (bladder dysfunction and orthostatic hypotension)
What are the features of femoral neuropathy?
Femoral nerve root supply = L2,3,4 Weakness with hip flexion and knee extension. Loss of knee reflex and numbness over the anterior thigh / medial calf. Positive femoral stretch test!
What are the causes of femoral neuropathy?
Diabetes, femoral entrapment (hernia repair), intra-abdominal tumour, retroperitoneal haematoma.
What are the monoclonal gammopathies?
Mulitple myeloma Waldenstrom’s macroglobulinaemia Monoclonal gammopathy of undetermined significance
What position causes maximal stretch of the ulnar nerve in the cubital tunnel retinaculum?
Flexion
What is a lower trunk brachial plexus neuropathy commonly mistaken with?
Ulnar neuropathy
What are amyloid deposits?
Insoluble extracellular protein aggregates that can be deposited in peripheral nerves. Occurs in 15% of patients with multiple myeloma. Causes autonomic dysfunction and symmetric dissociated sensory loss.
What neuropathies may result from groin catheter puncture haematomas?
Femoral neuropathy (hip flexion and knee ext weakness) Obturator neuropathy (adductor weakness and groin numbness) Lateral femoral cutaneous nerve (meralgia paraesthetica)
How do you treat neuropathies secondary to groin catheter puncture haematomas?
Conservative
Label the anatomy of a peripheral nerve.
With labels
Label the anatomy of a peripheral nerve.
With labels
How do you treat neuropathies secondary to groin catheter puncture haematomas?
Conservative
What are the classification systems for peripheral nerve injury?
Seddon and Sunderland classifications
What is the Seddon classification?
Neuropraxia - nerve in continuity, compression or ischaemia causing local conduction block.
Axontomesis - Complete interruption of axons and myelin sheaths. Endoneurium intact. Associated with Wallerian degeneration occurs
Neurotmesis - complete transection of the nerve with loss of continuity. Spontaneous regeneration not possible.
What is the Sunderland classification?
Ranges from 1st - 6th degree with 1st degree being a focal demyelination and 6th degree being a complete transection. Note: Sunderland 1 = neuropraxia, Sunderland 2-4 = axonotmesis and Sunderland 5-6 = Neurotmesis.
What are the causes of a brachial plexus injury?
Trauma
Traction
Cervical rib
Haematoma
What does a Horner’s syndrome in addition to a brachial plexus injury suggest?
Preganglionic injury (interruption of white rami communicans / sympathetic chain).
What does Serratus anterior (long thoracic nerve) and Rhomboid (dorsal scapular nerve) muscle weakness suggest?
The injury is proximal to the brachial plexus (preganglionic)
What is Erb’s palsy?
Waiter’s tip position with adducted and internally rotated arm, elbow extension and wrist flexion.
Caused by upper brachial plexus injury (C5/6) resulting in deltoid, biceps, supra and infraspinatus injury. Hand function is unaffected.
What is Klumpke’s palsy?
Lower brachial plexus injury (C8/T1) - look for a pancoast tumour esp if Horner’s syndrome!
Weakness and wasting of the small muscles of the hand resulting in claw deformity.
Which brachial plexus injury is seen with birth trauma?
Erb’s palsy (upper trunk C5/6)
How do you manage a brachial plexus injury due to a compressive haematoma?
Immediate exploration
How do you manage a brachial plexus injury due to a clean cut?
Tension free end to end anastomosis within 24-48 hours
How do you manage a brachial plexus injury due to a gunshot wound?
Conservative for 6 months. After that grafts or tendon transfers.
How do you manage a brachial plexus injury due to traction injury?
Do EMG at 6 months. Incomplete post-ganglionic injuries tend to improve spontaneously. If no improvement then explore and graft / tendon transfer.
How do you manage a brachial plexus injury due to a neuroma in continuity?
a. neurolysis (if SNAP intact)
b. nerve graft (if SNAP absent)
c. nerve transfer (if SNAP absent)
What are the donor sites for nerve transfers with brachial plexus injury?
Spinal accessory
Intercostal nerves to musculocutaneous
Ulnar nerve fascicles to the median nerve
AIN to the median nerve
What are the features of thoracic outlet syndrome?
Arterial - UL pallor / ischaemia
Venous - UL congestion / oedema
Nerve - Lower trunk
Muscle - Scalenus (anticus) syndrome
Is thoracic outlet syndrome more common in men or women?
Women
What investigations would you perform for suspected thoracic outlet syndrome?
EMG - confirms muscle denervation pattern. NCS may show loss of the medial antebrachial cutaneous SNAP.
MRI of brachial plexus may show a kink in the lower trunk
Cervical spine x-rays with oblique views
What is the surgical treatment for thoracic outlet syndrome?
Scalaenectomy and resection of the 1st rib
What is the surgical treatment for thoracic outlet syndrome?
Scalaenectomy and resection of the 1st rib
What investigations would you perform for suspected thoracic outlet syndrome?
EMG - confirms muscle denervation pattern. NCS may show loss of the medial antebrachial cutaneous SNAP.
MRI of brachial plexus may show a kink in the lower trunk
Cervical spine x-rays with oblique views
Is thoracic outlet syndrome more common in men or women?
Women
What are the features of thoracic outlet syndrome?
Arterial - UL pallor / ischaemia
Venous - UL congestion / oedema
Nerve - Lower trunk
Muscle - Scalenus (anticus) syndrome
What are the donor sites for nerve transfers with brachial plexus injury?
Spinal accessory
Intercostal nerves to musculocutaneous
Ulnar nerve fascicles to the median nerve
AIN to the median nerve
How do you manage a brachial plexus injury due to a neuroma in continuity?
a. neurolysis (if SNAP intact)
b. nerve graft (if SNAP absent)
c. nerve transfer (if SNAP absent)
How do you manage a brachial plexus injury due to traction injury?
Do EMG at 6 months. Incomplete post-ganglionic injuries tend to improve spontaneously. If no improvement then explore and graft / tendon transfer.
How do you manage a brachial plexus injury due to a gunshot wound?
Conservative for 6 months. After that grafts or tendon transfers.
How do you manage a brachial plexus injury due to a clean cut?
Tension free end to end anastomosis within 24-48 hours
How do you manage a brachial plexus injury due to a compressive haematoma?
Immediate exploration
Which brachial plexus injury is seen with birth trauma?
Erb’s palsy (upper trunk C5/6)
What is Klumpke’s palsy?
Lower brachial plexus injury (C8/T1) - look for a pancoast tumour esp if Horner’s syndrome!
Weakness and wasting of the small muscles of the hand resulting in claw deformity.
What is Erb’s palsy?
Waiter’s tip position with adducted and internally rotated arm, elbow extension and wrist flexion.
Caused by upper brachial plexus injury (C5/6) resulting in deltoid, biceps, supra and infraspinatus injury. Hand function is unaffected.
What does Serratus anterior (long thoracic nerve) and Rhomboid (dorsal scapular nerve) muscle weakness suggest?
The injury is proximal to the brachial plexus (preganglionic)
What does a Horner’s syndrome in addition to a brachial plexus injury suggest?
Preganglionic injury (interruption of white rami communicans / sympathetic chain).
What are the causes of a brachial plexus injury?
Trauma
Traction
Cervical rib
Haematoma
What is the Sunderland classification?
Ranges from 1st - 6th degree with 1st degree being a focal demyelination and 6th degree being a complete transection. Note: Sunderland 1 = neuropraxia, Sunderland 2-4 = axonotmesis and Sunderland 5-6 = Neurotmesis.
What is the Seddon classification?
Neuropraxia - nerve in continuity, compression or ischaemia causing local conduction block.
Axontomesis - Complete interruption of axons and myelin sheaths. Endoneurium intact. Associated with Wallerian degeneration occurs
Neurotmesis - complete transection of the nerve with loss of continuity. Spontaneous regeneration not possible.
What are the classification systems for peripheral nerve injury?
Seddon and Sunderland classifications
What neuropathies may result from groin catheter puncture haematomas?
Femoral neuropathy (hip flexion and knee ext weakness) Obturator neuropathy (adductor weakness and groin numbness) Lateral femoral cutaneous nerve (meralgia paraesthetica)
What are amyloid deposits?
Insoluble extracellular protein aggregates that can be deposited in peripheral nerves. Occurs in 15% of patients with multiple myeloma. Causes autonomic dysfunction and symmetric dissociated sensory loss.
What is a lower trunk brachial plexus neuropathy commonly mistaken with?
Ulnar neuropathy
What position causes maximal stretch of the ulnar nerve in the cubital tunnel retinaculum?
Flexion
What are the monoclonal gammopathies?
Mulitple myeloma Waldenstrom’s macroglobulinaemia Monoclonal gammopathy of undetermined significance
What are the causes of femoral neuropathy?
Diabetes, femoral entrapment (hernia repair), intra-abdominal tumour, retroperitoneal haematoma.
What are the features of femoral neuropathy?
Femoral nerve root supply = L2,3,4 Weakness with hip flexion and knee extension. Loss of knee reflex and numbness over the anterior thigh / medial calf. Positive femoral stretch test!
How does diabetic neuropathy present? (3 types)
Primary sensory polyneuropathy (glove and stocking) Diabetes proximal neuropathy Autonomic neuropathy (bladder dysfunction and orthostatic hypotension)
What causes lumbosacral plexus neuropathy?
Diabetes. Associated with tenderness over the femoral nerve. If L4 is involved (knee ext weakness) can be mistaken for femoral nerve injury. If L5 is involved (foot drop) can be mistaken for common peroneal nerve injury.
How can multi-level radiculopathy be distinguished from a plexopathy with EMG?
Sampling of the paraspinal muscles with EMG shows involvement with radiculopathy but not plexopathies
What is the presentation of Parsonage-Turner syndrome?
Intense pain with development of weakness within 2 weeks (80% had a sudden onset of weakness). 50% have a viral prodrome. 50% are confirmed to the shoulder girdle.
What are the causes of a brachial plexus injury?
Trauma Pancoast tumour Cervical rib (thoracic outlet syndrome) DM Vasculitis Viral Inflammatory - Parsonage-Turner syndrome
What is the classical finding of ETOH neuropathy?
Diffuse sensory loss with loss of ankle jerk
What % of critical care neuropathies resolve completely?
50%
What are the inherited neuropathies?
Charcot-Marie-Tooth; 7 types mostly AD. Types 1 and 2 are most common. Results in LL motor>sensory deficits. Type 1 continue to ambulate but Type 2 loose ambulation as teenagers.
What are the causes of peripheral neuropathies?
Mnemonic GRAND-THERAPIST: GB, Renal failure, Alcohol, Nutritional deficiencies, DM Trauma, Hereditary, Entrapment, Radiation, Amyloid, Porphyria/paraneoplastic, Infection (leprosy), Sarcoid and Toxins
What is the difference between a poly and mononeuropathy?
Multiple vs single nerve peripheral neuropathy resulting in weakness, sensory disturbance and abnormal reflexes.
