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PACES 2024 > Station 3: Neuro (Upper Limbs) > Flashcards

Station 3: Neuro (Upper Limbs) Flashcards

1
Q

Unilateral hand wasting -> what to look for next?

A

Thenar wasting?

Hypothenar or intrinsic muscle wasting?

Both groups wasted?

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2
Q

unilateral hand wasting with only thenar wasting

A

Hand of Benediction sign: proximal Median nerve damage

Carpal tunnel syndrome

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3
Q

unilateral hand wasting with hypothenar/ intrinsic muscle wasting

A

usually ulnar nerve neuropathy

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4
Q

unilateral hand wasting, with intrinsic muscles, hypothenar and thenar eminence wasting

how to differentiate between C8-T1 segment vs median and ulnar neuropathy

A

finger extension should be weak in C8-T1 segment involvement

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5
Q

unilateral hand wasting, with intrinsic muscles, hypothenar and thenar eminence wasting
- causes
​

A

medial and ulnar nerve neuropathy: either simple compression, mononeuritis multiplex, multifocal motor neuropathy

C8/T1 segment: which also involves weak finger extension
- can be due to brachial plexopathy, cord involvement at C8/T1, Anterior horn cell (but with normal sensation), nerve root (associated with radicular symptoms)

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6
Q

what is the course of the radial nerve and its branches?

A

nerve roots: C5-T1
emerges from the posterior cord of the brachial plexus

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7
Q

features of a radial nerve palsy that is affected at the wrist?
ie. superficial radial nerve palsy aka Watenberg syndrome

A

the radial nerve continues as the superficial radial nerve which provides sensory innervation of the posterior aspect of the radial 3.5 digits (pure sensory)

pain and numbness over first web space dorsally (bc of overlap)
no motor weakness

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8
Q

features of radial nerve palsy injured at lower 1/3 humerus to proximal forearm?

A

posterior interosseous nerve affected (pure motor): supplies all the extensors of the forearms including APL and supinator except the extensor carpi radialis longus

Motor: finger drop
extensors of the fingers at the MCPJ affected
wrist drop not a feature as the extensor carpi radialis longus is intact

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9
Q

features of radial nerve palsy injured at middle 2/3 humerus along the spiral groove?

A

radial nerve pierces the intermuscular septum at lower third of humerus to enter the anterior compartment of arm to supply brachioradialis

Brachioradialis weak
Wrist drop
Finger drop (weak finger extensors)

triceps reflex preserved, triceps intact

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10
Q

features of radial nerve palsy injured at
upper 1/3 humerus?

A

motor:
weak triceps - elbow extension
weak brachioradialis
weak wrist extension (wrist drop)
weak finger extension (finger drop)
weak thumb extension

Reflex: triceps jerk affected

sensation: dorsum of lateral 3.5 fingers
anatomical snuffbox innervated by superifical branch of radial nerve

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11
Q

once radial palsy is detected, proceed to look for level of lesion, what to examine for?

A
  • demonstrate weakness of extension at MCPJ
  • weakness of wrist extension
  • brachioradialis
  • test triceps muscle
  • triceps jerk
  • look for reduced sensation over anatomical snuffbox
  • inspect forearm, elbow, humerus, shoulder for scars
  • test function (fine motor, coarse)

preservation of IPJ extension (lumbricals, interossei)
screen for median nerve involvement: thumb abduction, oschner’s clasping test
screen for ulnar nerve involvement: finger abduction, froment’s sign

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12
Q

causes of radial nerve palsy?

A

trauma from accident/ surgery
compression, entrapment
part of mononeuritis multiplex
lead poisoning

other causes, e.g. finger drop could be 2’ synovitis from RA

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13
Q

ix of radial nerve palsy?

A

detailed history for cause
X-ray : evaluate for fracture, tumour, healing callus

NCS, EMG to locate level of injury and to monitor recovery progress

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14
Q

management of radial nerve palsy?

A

education and counselling
PTOT: wrist splint, cock up splint for finger drops
surgical decompression of entrapment

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15
Q

prognosis of radial nerve palsy if neuropraxia with no disruption to the sheath or the axon?

A

recovery complete and rapid (weeks)

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16
Q

prognosis of radial nerve palsy if axonotmesis with disruption of axon but intach schwann sheath?

A

recovery complete but slower (1mm/day)

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17
Q

prognosis of radial nerve palsy with complete transection of the nerve?

A

recovery is incomplete

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18
Q

what is the course of the median nerve and its branches?

A

formed by lateral (C5-7) and medial (C8, T1) cords of the brachial plexus

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19
Q

features of median nerve palsy if injured at level of wrist?

A

median nerve enters the carpal tunnel and supplies LOAF (lateral 2 lumbricals, opponens policis, abductor pollicis brevis, flexor pollicis brevis) and sensory branch to the lateral 3.5 fingers
->

wasting of thenar muscles
externally rotated thumb
weak abduction of thumb
Tinel’s and Phalen’s positive in carpal tunnel

sensory loss of the lateral 3.5 fingers

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20
Q

features of median nerve palsy if injured superifically at level of forearm

A

gives off the anterior interosseous nerve in the forearm which supplies the flexor pollicis longus (flexion of the DIPJ thumb), flexor digitiorum profundus of lateral 2 fingers (flexion of DIPJ), pronator quadratus

-> AIN syndrome

no sensory loss

weak pinch sign (due to weakness of flexor pollicis longus and digitorum profundus)

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21
Q

features of median nerve palsy if injured proximally

A

median nerve supplies all the muscles of the forearm except the flexor carpi ulnaris and the ulnar half of the flexor digitorum profundus and LOAF

motor:
wasting of thenar eminence
thumb externally rotated
Hand of benediction
oschner’s clasping test
weak thumb abduction, opposition, flexion
Weak MCPJ flexion and IPJ extension by lumbricals
Weak wrist flexion by flexor carpi radialis

no reflexes affected

sensation: palm of lateral 3.5 fingers

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22
Q

median nerve palsy: how to screen for involvement of radial and ulnar nerve involvement?

A

radial nerve: test wrist and elbow extension

ulnar nerve: finger abduction, Froment’s sign

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23
Q

median nerve palsy: what to examine for to suggest underlying cause

A

Tinel’s phalens for carpal tunnel syndrome

Look for signs of scars, RA hands, acromegaly, pregnancy, hypothyroidism

Look at wrist, forearm, elbow, arm, axilla for scars

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24
Q

oschner test

A

Ochsner’s clasping test assesses the function of the median nerve for lesions in the cubital fossa or above, by testing for the function of flexor digitorum superficialis.

The patient is asked to clasp his hands together. Inability to flex the index finger confirms a lesion on that side.

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25
Q

causes of median nerve palsy?

A

trauma
iatrogenic: surgical
compression
mononeuritis multiplex
infection-leprosy
inflammatory- CIDP
ischaemic- vasculitis

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26
Q

causes of carpal tunnel syndrome

A

idiopathic
pregnancy, OCPs
endocrine- acromegaly, hypothyroidism
Hands; RA, gout, TB tenosynovitis, OA of carpus
amyloidosis, sarcoidosis

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27
Q

management of median nerve palsy?

A

education
OT, wrist splint
medications- treatment of underlying disease, IA steroid, withdrawing OCPs
surgical decompression

28
Q

what is the anatomical course of the ulnar nerve?

A

medial cord of the brachial plexus (C8, T1)

provides motor to all muscles of the hands except the LOAD, flexor carpi ulnaris and flexor digitorum profundus to 4th and 5th fingers

sensory to ulnar 1.5 fingers

29
Q

features of ulnar nerve injury at level of wrist

A

hypothenar eminence wasting
pronounced claw hand
froment’s sign positive
weakness of finger abduction
loss of sensation to medial 1.5 fingers

30
Q

features of ulnar nerve injury at forearm?

A

wasting of hypothenar muscles and small muscles of hand

less severe ulnar claw hand (Ulnar paradox)
weak DIPJ of little finger
weak flexor carpi ulnaris tendon on flexion of wrist

weak finger abduction, adduction
weak flexion of 4th and 5th fingers
Froments sign positive (weakness of adductor pollicis)

sensory loss to medial 1.5 fingers

31
Q

what is the ulnar claw hand?

A

hyperextension of the 4th and 5th MCPJ associated with flexion of the IPJs at 4th and 5th fingers

due to unopposed long extensors of the 4th and 5th fingers in contrast to the index and middle finger which are counteracted by the lumbricals which are served by the median nerve

32
Q

what is the ulnar paradox?

A

ulnar claw deformity is more pronounced for lesions distally

this is because a more proximal lesion at the elbow also causes weakness of the ulnar half of the flexor digitorum profundus, resulting in less flexion of the IPJs at the 4th and 5th fingers

33
Q

how to differentiate ulnar nerve palsy vs T1 lesion?

A

motor: in T1 lesions, thenar eminence will also be wasted

sensory: loss of T1 dermatomal distribution

34
Q

ulnar nerve palsy what to rule out?

A

rule out median nerve involvement: thumb abduction, oschners test

radial nerve involvement: wrist and elbow extension

T1 sensory loss

35
Q

ulnar nerve palsy what are some examination fingers which may suggest aetiology?

A

elbow scars, cubitus valgus deformity
compression at Guyon’s canal at the wrist (spares sensory)
Compression at cubital tunnel by 2 heads of the flexor carpi ulnaris
hypopigemented patch finger resorption, thickened nerves suggestive of leprosy

36
Q

what is Froment’s sign

A

patient asked to grasp a piece of paper between thumb and lateral aspect of index finger

the affected thumb will flex as adductor pollicis muscles are weak

37
Q

causes of ulnar nerve palsy?

A

compression or entrapment (Guyons canal at wrist, Cubital tunnel at elbow)
trauma
surgical
mononeuritis multiplex
infection- leprosy
ischaemia- vasculitis
inflammatory- CIDP

38
Q

ix of ulnar nerve palsy?

A

Bloods: HbA1c to rule out DM
X ray of elbow and wrist
KIV C spine if suspected T1 involvement
EMG and NCS to locate level of injury and monitor recovery progress

39
Q

management of ulnar nerve palsy?

A

education and avoidance of resting on elbow
PTOT
Medical- analgesia
Surgical decompression with anterior transposition of the nerve

40
Q

bilateral wasted hands with wasting of hypothenar and thenar muscles + intrinsic muscles of the hand

A

C8/T1 lesion:
Cervical spondylosis -> radicular pain
Anterior horn cell like MND or polio: No pain or sensory loss
Cord: C8/T1 myelopathy, syringomyelia, Transverse myelitis

Peripheral neuropathy:
if LL affected with glove and stocking sensory loss, then think of diffuse peripheral neuropathy

if LL ok, maybe mononeuritis multiplex (sensory loss in the pattern of nerves), multifocal motor nueropathy

41
Q

unilateral wasted hands, what possible causes

A

cervical cord
anterior horn cell: poliomyelitis
C8-T1 root lesions (cervical spondylosis)
brachial plexus (Trauma, cervical rib, tumour, radiation)
Peripheral nerve (median, ulnar, combined; asymmetric peripheral neuropathy)

42
Q

Unilateral UL weakness, UMN pattern of weakness

A

cortical
subcortical
brainstem
hemicord

43
Q

bilateral UL weakness with UMN pattern of weakness

A

spinal cord lesion
(myelopathy, compression, infarct)
bilateral brainstem
bilateral subcortical
bilateral cortical

44
Q

UL weakness, LMN pattern of weakness, proximal weakness with abnormal sensation

A

GBS CIDP
Syringomyelia

45
Q

what is syringomyelia?

A

cavity formation with presence of a large fluid filled cavity in the grey matter of the cervical spinal cord which is in communication with the central canal and contains CSF

triad of LMN weakness in ULs, dissociated sensory loss in the ULs and UMN weakness in LLs

46
Q

features of syringomyelia?

A

at the level of the syrinx:
LMN anterior horn cells affected -> flaccid weakness
dissociated sensory loss: loss of pinprick but intact sensation to vibration and propioception

below level of syrinx: affects corticospinal tracts, so spastic paraparesis of LLs

extension into cervical cord and medulla
- horner’s syndrome
- bulbar palsy (CN X-XII)
- ataxia and nystagmus (affects medial longitudinal bundle if lesion from C5 upwards)
- onion skin pattern loss of pain in the face (spinal nucleas of V CN which extens from pons to the upper cervical cord)

47
Q

causes of proximal myopathy?

A

congenital/ inherited: Myotonic dystrophy, fascioscapulohumeral dystrophy, Becker’s, LImb girdle muscular dystrophy, oculopharyngeal muscular dystrophy

endocrine/ metabolic: cushings syndrome, thyroid disease, ESRF, lactic acidosis, periodic hypokalaemic paralysis

inflammatory/ immune: poly/dermatomyositis

infection: HIV

drugs (statins, fibrates), alcohol

mitochondrial myopathy - CPEO, mcardle’s syndrome

48
Q

what special tests if suspecting myotonic dystrophy?

A

percussion myotonia of the thenar eminence

myotonic grasp

49
Q

reflexes and sensation in myotonic dystrophy?

A

reflexes reduced
sensation normal

50
Q

X linked muscular dystrophy
pseudohypertrophy of calves
Gowers sign, proximal weakness
cardiomyopathy

A

Duchenne’s, Becker’s (less severe form, later onset)

51
Q

Autosomal recessive muscular dystrophy
shoulder and pelvic girdle affected
usually 30s
sparing of face and heart

A

limb girdle muscular dystrophy

52
Q

autosomal dominant muscular dystrophy
bilateral symmetrical weakness of facial muscles and SCM with bilateral ptosis
weakness of shoulder muscles and later the pelvic girdle muscles

A

fascioscapulohumeral muscular dystrophy

53
Q

what is myotonia?

A

continued contraction of the muscles after voluntary contraction ceases, followed by impaired relaxation

54
Q

autosomal dominant disorder
myotonia, weakness, no sensory loss

A

myotonic dystrophy

55
Q

what other organ systems may be affected in myotonic dystrophy?

A

intellectual disability
cataracts
dilated CMP, conduction defects
testicular atrophy, gynaecomastia
DM
nodular thyroid enlargement

56
Q

how to ix myotonic dystrophy?

A

**confirm diagnosis: **
genetic testing
EMG - dive bomber pattern ie waxing and waning of potentials

muscle biopsy shows no inflammatory changes
muscle enzymes are normal

screen for complications:
Fasting glucose- screen for DM
ECG: conduction defect
CXR- cardiomegaly
Slit lamp for cataracts

57
Q
A
58
Q

differentials for dissociated sensory loss?

A

anterior spinal artery occlusion (Affects spinothalamic tract)

DM neuropathy, leprosy, hereditary amyloidotic polyneuropathy

59
Q

DDx for syringomyelia?

A

haematomyelia
intramedullary tumours of the spinal cord
spinal cord injuries
cranioverterbral anomalies

60
Q

associated abnormalities of syringomyelia?

A

arnold chiari malformation
bony defects around the foramen magnum
hydrocephalus
spina bifida
spinal cord tumours

61
Q

ix syringomyelia?

A

MRI spinal cord

62
Q

management of syringomyelia?

A

drainage of the syrinx to the subarachnoid space
syringoperitoneal drainage
- in AC malformation, cervical laminectomy and removal of lower central portion of the cervical bone
- intramedullary tumour excision

63
Q

what is syringobulbia?

A

syrinx in the medulla of the brainstem

usually extension of the syringomyelia but can be isolated

64
Q

features of syringobulbia?

A

horner’s
ataxia, nystagmus
Bulbar palsy
CN V, VII, IX, X
Onion skin pattern of loss of pain sensation of the face

65
Q

Huntington’s disease?

A

young adult, chorea, dementia
autosomal dominant pattern

66
Q

causes of choreathetosis?

A

Congenital: Huntington’s chorea, wilsons disease
endocrine/ metabolic: hyperthyroidism, post hyperglycaemia
inflammatory/ immune: SLE
vascular: globus pallidus stroke
infection: rheumatic fever, post encephalitis
drugs: L dopa, phenytoin, neuroleptics
toxins: CO poisoning

67
Q

extra pyramidal side effects of antipsychotics?

A

acute dystonia (oculogyric)
parkinonism
akathisia (restless legs syndrome)
tardive dyskinesia (orofacial dyskinesia)

PACES 2024 (14 decks)

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