Neuromuscular I

Question 1

giant axonal neuropathy (GAN)

Answer 1

autosomal recessive disorder that manifests in early childhood. Predominantly axonal Sensorimotor neuropathy, corticospinal tract involvement with upper motor neuron signs, and optic atrophy leading to vision loss.

Neuropath large focal axonal swelling that contains tightly packed disorganized neurofilaments. GAN gene that encodes for gigaxonin

Question 2

Refsum’s disease (RD)

Answer 2

autosomal dominant peroxisomal disorder. Fatty acid metabolism, leading to accumulation of an intermediate in this pathway, phytanic acid. retinitis pigmentosa (with night blindness and visual field constriction), cardiomyopathy, and skin change. Large-fiber sensorimotor neuropathy, hearing loss, anosmia, ataxia, and cerebellar signs
Rx reduce dietary intake of phytanic acid

Question 3

F wave obtained by?

Answer 3

after supramaximal stimulation of a motor nerve.

Question 4

Significant axon loss lesions?

Answer 4

produce reductions in action potential amplitudes and tend to have preserved or mildly reduced conduction velocities

Question 5

NCS modalities?

Answer 5

sensory and motor conduction studies.

Question 6

Sensory NCS

Answer 6

stimulating a sensory nerve while recording the transmitted potential at a different site along the same nerve. Three main measures can be obtained: SNAP amplitude, sensory latency (onset and peak), and conduction velocity.

Question 7

SNAP

Answer 7

amplitude (in microvolts) represents a measure of the number of axons conducting between the stimulation site and the recording site.

Question 8

Sensory latency

Answer 8

(in milliseconds) is the time that it takes for the action potential to travel between the stimulation site and the recording site of the nerve.

Question 9

conduction velocity

Answer 9

is measured in meters per second and is obtained dividing the distance between stimulation site and the recording site by the latency: Conduction velocity = Distance/Latency.

Question 10

Motor NCS

Answer 10

are obtained by stimulating a motor nerve and recording at the belly of a muscle innervated by that nerve

Question 11

Motor CMAP

Answer 11

CMAP is the resulting response, and depends on the motor axons transmitting the action potential, status of the neuromuscular junction, and muscle fibers.

Question 12

CMAP/SNAP interpretation

Answer 12

prolonged latencies and slow conduction velocities correlate with demyelination, decrease in the amplitudes correlates with axon loss lesions.Low amplitudes can result from demyelinating conduction block when the nerve stimulation is proximal to the block.

Question 13

F-wave

Answer 13

F-wave is obtained after supramaximal stimulation of a motor nerve while recording from a muscle.travels antidromically (conduction along the axon opposite to the normal direction of impulses) along the motor axons toward the motor neuron, backfiring and then traveling orthodromically (conduction along the motor axon in the normal direction) down the nerve to be recorded at the muscle.

Question 14

H-wave

Answer 14

H-reflex is the electrophysiologic equivalent of the ankle reflex (S1 reflex arc) and is obtained by stimulating the tibial nerve at the popliteal fossa while recording at the soleus. The electrical impulse travels orthodromically through a sensory afferent, enters the spinal cord, and synapses with the anterior horn cell, traveling down the motor nerve to be recorded at the muscle.

Question 15

Large polyphasic motor unit potentials (MUPs)

Answer 15

seen in acute neuropathic lesions, but rather in chronic ones.

Question 16

Insertional activity

Answer 16

is recorded as the needle is inserted into a relaxed muscle. It is increased in denervated muscles and myotonic disorders, and is decreased when the muscle is replaced by fat or connective tissue and during episodes of periodic paralysis

Question 17

Spontaneous activity

Answer 17

is assessed with the muscle at rest, and examples include fibrillation potentials, fasciculation potentials, and myokymia and myotonic potentials. All spontaneous activity is abnormal.

Question 18

Voluntary contraction

Answer 18

MUPs are obtained while the needle is inserted into the muscle during voluntary contraction. Characteristics include recruitment pattern and MUP morphologic features, such as duration, amplitude, and configuration.

Question 19

Recruitment

Answer 19

is a measure of the number of MUPs firing during increased force of voluntary muscle contraction

Question 20

Axon loss lesions

Answer 20

reduced recruitment is characterized by a less-than-expected number of MUPs firing more rapidly than expected.

Question 21

Myopathic processes

Answer 21

Early or rapid recruitment occurs in myopathic processes with loss of muscle fibers, in which an excessive number of short-duration and small-amplitude MUPs fire during the muscle contraction.

Question 22

Poor voluntary effort or with CNS disorders

Answer 22

causing weakness, recruitment is reduced with normal MUPs firing at slow or moderate rates, sometimes in a variable fashion

Question 23

neuropathic disorders with denervation and reinnervation

Answer 23

MUPs disclose increased duration and amplitude, and may be polyphasic

Question 24

myopathic disorders

Answer 24

MUPs are of reduced duration and amplitude, and may also be polyphasic.

Question 25

Radiculopathy NCS?

Answer 25

normal SNAPs despite sensory symptoms, because SNAPs are recorded distal to the lesion, in the postganglionic projections from the dorsal root ganglion. Thus radiculopathies are usually diagnosed with the needle EMG component rather than the NCS component of the electrodiagnostic study.

Question 26

Radiculopathy path?

Answer 26

occurs from an intraspinal canal lesion resulting in damage of the preganglionic fibers. The cell body in the dorsal root ganglia and the postganglionic fibers remain unaffected, and therefore, even though sensory symptoms are prominent, the SNAPs are normal.

Question 27

axon loss radiculopathy

Answer 27

injure motor fibers in the intraspinal canal region affecting the respective myotome. This leads to denervation, with fibrillation potentials seen 3 weeks after the onset of motor axon loss, decreased recruitment, and 3 to 6 months later, large and polyphasic motor unit potentials (MUPs). The presence of these large and polyphasic MUPs is dependent on reinnervation and collateral innervation, typically occurring in a proximal to distal fashion, with proximal muscles more successfully reinnervated as compared to distal muscles.

Question 28

SFEMG

Answer 28

highly sensitive but not specific for MG, being frequently abnormal in other neuromuscular junction

Question 29

Type 1 muscle fibers

Answer 29

also called slow-oxidative, have slow ATPase activity and large oxidative capacity, with large numbers of mitochondria. They are red in color and small in diameter.

Question 30

Type IIa fibers

Answer 30

fast oxidative glycolytic fibers, and have fast ATPase activity, with high glycolytic capacity and moderate oxidative capacity. These fibers are fast and resistant to fatigue.

Question 31

Type IIb fibers

Answer 31

fast-oxidative-glycolytic fibers, and have fast ATPase activity, with high glycolytic capacity but low oxidative capacity. These fibers are fast and fatigable. Their color is pale and diameter is large.

Question 32

Demyelination cardinal features

Answer 32

conduction velocity is reduced (normal >50 m/s), peak latency is prolonged (normal is <4 ms) and CMAP amplitude dispersion

Question 33

CIDP dx

Answer 33

CIDP is the diagnosis when symptoms progress or relapse beyond 8 weeks.

Question 34

Peripheral nerve injury severity

Answer 34

can range from focal demyelination to axonal injury and finally nerve transection with discontinuity of the nerve. Electrophysiologic studies can help determine the degree of injury.

Question 35

Focal nerve injury

Answer 35

segmental demyelination, which is characterized by the presence of slowing at a specific site, or the presence of a conduction block, which is a decrease in the CMAP amplitude with proximal stimulation as compared to distal stimulation, without significant temporal dispersion.

Question 36

Axon loss lesion

Answer 36

Wallerian degeneration, which is typically completed in 7 to 10 days from the injury. After 10 days, the distal axon degenerates and can no longer conduct.Once denervation occurs, spontaneous muscle activity appears on EMG, manifested by fibrillation potentials, which usually appear after the third week from the injury.

Question 37

GBS resp vitals

Answer 37

negative inspiratory force of less than −30 cc H2O or vital capacity of less than 15 to 20 mL/kg support elective endotracheal intubation.

Question 38

Brachial plexus

Answer 38

C5 to T1 nerve roots

Question 39

Roots

Answer 39

Two nerves that innervate the upper extremity branch off the nerve roots themselves. The dorsal scapular nerve, which innervates the rhomboids and levator scapulae, arises from the C5 nerve root. The long thoracic nerve, which innervates the serratus anterior, arises from the C5 to C7 roots.

Question 40

Trunks

Answer 40

The ventral rami of the C5 to T1 nerve roots join to form the trunks of the brachial plexus. The upper (or superior) trunk, formed from the C5 and C6 nerve roots, gives off two branches: the suprascapular nerve, which innervates the supraspinatus and infraspinatus, and the nerve to subclavius. The point where the C5 and C6 nerve roots meet is called Erb’s point. The middle trunk is formed from the C7 root. There are no branches from the middle trunk. The lower (inferior trunk) is formed from the C8 and T1 roots. There are no branches from the inferior trunk. The trunks then divide into anterior and posterior divisions.

Question 41

Cords

Answer 41

lateral cord gives rise to the lateral pectoral nerve, which innervates the pectoralis major. The lateral cord ends as two nerves, the median nerve and the musculocutaneous nerve. posterior cord ends as two nerves, the axillary nerve and radial nerve. The medial cord gives fibers to the median nerve and then continues as the ulnar nerve

Question 42

familial amyloid polyneuropathy (FAP) type 1

Answer 42

polyneuropathy, autonomic features, and a family history.

Question 43

familial amyloid polyneuropathy (FAP) type 2

Answer 43

carpal tunnel, a family history of carpal tunnel, mild predominantly sensory polyneuropathy, and absence of prominent autonomic features.

Question 44

FAP 4

Answer 44

corneal dystrophy being a prominent early feature. In later life, cranial neuropathies and skin changes occur; cranial nerves VII, VIII, and XII are commonly affected.

Question 45

FAP 3

Answer 45

FAP3 is similar to FAP1 in clinical manifestations, but with earlier renal involvement and more gastrointestinal involvement, with a higher incidence of duodenal ulcers.

Question 46

FAP pathology

Answer 46

mutations in transthyretin, a plasma protein that is synthesized predominantly in the liver and transports thyroxine and other proteins.

Question 47

Autonomic dysfunction resulting from diabetic neuropathy

Answer 47

resting tachycardia or bradycardia, loss of the respiratory variability of the heart rate, loss of the normal tachycardic response, orthostatic hypotension, and increased risk of silent myocardial infarction. Gastrointestinal abnormalities, Neurogenic bladder, impotence

Question 48

Charcot–Marie–Tooth disease

Answer 48

hereditary sensorimotor neuropathies or peroneal muscular atrophy. group of inherited peripheral neuropathies. The CMTs can be divided into demyelinating, axonal, and combined demyelinating and axonal forms.

Question 49

(CMT) 1

Answer 49

MT1A is due to a duplication in the peripheral myelin protein 22 (PMP22) gene on chromosome 17 related to myelin synthesis. hammertoes, high-arched feet, palpably enlarged nerves, two decades of life and include slowly progressive weakness, muscle atrophy, kyphosis. CMT 3 presents in infancy.

Question 50

Median nerve arm

Answer 50

is derived from the lateral and medial cords. innervates pronator teres, flexor carpi radialis, and flexor digitorum superficialis. median nerve is prone to injury with supracondylar fractures.

Question 51

Median nerve forarm

Answer 51

In the forearm, the median nerve gives off the anterior interosseous nerve that innervates flexor digitorum profundus to the second and third digits, flexor pollicis longus, and pronator quadratus

Question 52

Median nerve wrist

Answer 52

Before entering the carpal tunnel, the median nerve gives off the palmar cutaneous sensory nerve, a pure sensory nerve. The median nerve then passes through the carpal tunnel and gives off the thenar motor branch, which innervates abductor pollicis brevis and opponens pollicis. The median nerve also innervates the first and second lumbricals.

Question 53

Ulnar nerve

Answer 53

provides innervation to many intrinsic hand muscles.

Question 54

Lumbar plexus

Answer 54

is formed by contributions from T12 to L4 and gives rise to three major and three minor nerves. Three minor nerves are the iliohypogastric, ilioinguinal, and genitofemoral. Three major nerves are the femoral, obturator, and lateral femoral cutaneous

Question 55

Genitofemoral N.

Answer 55

L1 and L2.

Question 56

Lateral femoral cutaneous nerve

Answer 56

L2 and L3

Question 57

Femoral nerve

Answer 57

L2, L3, and L4

Question 58

Obturator nerve

Answer 58

originates from the anterior divisions of L2, L3, and L4 and divides into an anterior and a posterior division.

Question 59

lumbosacral trunk

Answer 59

is a structure that originates from L4 and L5 and joins the sacral plexus to form the sciatic nerve

Question 60

Sacral plexus

Answer 60

originates from the L4-S4 nerve roots, with L4 and L5 provided by the lumbosacral trunk The anterior divisions of L4-S3 contribute to form the tibial division of the sciatic nerve. The posterior divisions from L4-S2 contribute to the common peroneal division of the sciatic nerve.

Question 61

superior gluteal nerve

Answer 61

originates from L4, L5, and S1 and innervates the gluteus medius, gluteus minimus, and tensor fasciae latae.

Question 62

Pudendal nerve

Answer 62

originates from S2, S3, and S4 and provides sensory innervation to the perineal region and perianal region through the inferior rectal nerve, perineal nerve, and dorsal nerve of the penis or clitoris

Question 63

hereditary neuropathy with liability to pressure palsies (HNPP)

Answer 63

autosomal dominant predominantly demyelinating hereditary neuropathy with incomplete penetrance and is caused by a deletion in the peripheral myelin protein 22 gene (PMP22). Present with recurrent episodes of focal mononeuropathies or plexopathies of the upper or lower limbs; the peroneal nerve is most commonly affected, followed by the ulnar nerve

Question 64

Hereditary neuralgic amyotrophy (Parsonage–Turner)

Answer 64

recurrent upper extremity mononeuropathies

Question 65

Sciatic nerve

Answer 65

originates from the L4-S3 roots. Superior gluteal nerve innervates the gluteus medius, minimus, and tensor fasciae latae. The inferior gluteal nerve innervates the gluteus maximus

Question 66

Sciatic nerve transitions to ?

Answer 66

tibial nerve medially and the common peroneal nerve laterally. short head of the biceps femoris is supplied by the common peroneal division which is above common site of compression.

Question 67

Peroneal nerve

Answer 67

Superficial peroneal nerve gives off branches to the peroneus longus and brevis, which permit foot eversion. The deep peroneal nerve supplies the tibialis anterior, extensor hallucis, extensor digitorum longus and brevis, and peroneus tertius.

Question 68

Deep peroneal nerve lesion

Answer 68

Foot drop with inability to dorsiflex the foot without impairing eversion of the foot. Preservation of foot inversion distinguishes peroneal neuropathy from L5 radiculopathy, in which the tibialis posterior muscle innerverated by tibialis N.

Question 69

Femoral nerve injury

Answer 69

weakness in hip flexion and knee extension, loss of the patellar reflex, and sensory findings in the anteromedial thigh and medial leg.

Question 70

Weak hip flexion?

Answer 70

Iliopsoas intrapelvic injury rather than an inguinal injury.

Question 71

obturator nerve injury

Answer 71

adductor weakness suggests involvement L2-L4 radiculopathy or a lumbar plexopathy.

Question 72

Anti-Hu

Answer 72

sensory neuronopathy (dorsal root ganglionopathy) in setting of SCC

Question 73

Anti-Yo

Answer 73

is present in ovarian carcinoma and manifests with cerebellar degeneration

Question 74

Anti-Ri

Answer 74

is associated with opsoclonus–myoclonus with or without ataxia in the setting of neoplasms of the lung or breast.

Question 75

Anti-MAG

Answer 75

antibodies against myelin-associated glycoprotein and are associated with demyelinating neuropathy in the setting of MGUS

Question 76

Sural nerve

Answer 76

tibial nerve gives off the sural nerve that provides sensory innervation to the lateral aspect of the leg and foot

Question 77

Tibial nerve at level of thigh?

Answer 77

division of the sciatic nerve, and at the level of the thigh, it provides innervation to the semimembranosus, semitendinosus, and long head of the biceps femoris

Question 78

Tibial nerve distal to popliteal fossa?

Answer 78

continues down the leg innervating the gastrocnemius, soleus, tibialis posterior, flexor digitorum longus, and flexor hallucis longus and splits up into sural nerve

Question 79

Tibial nerve at the ankle?

Answer 79

tibial nerve passes under the flexor retinaculum through the tarsal tunnel and gives three terminal branches: (1) calcaneal, (2) medial plantar, and (3) lateral plantar.

Question 80

Tarsal tunnel neuropathy?

Answer 80

entrapment neuropathy of the tibial nerve at the level of the tarsal tunnel will not produce weakness on plantarflexion. This entrapment neuropathy may manifest with burning pain in the plantar region, worse with standing and walking, with sensory deficits in the sole and sometimes atrophy in this area.

Question 81

multifocal motor neuropathy (MMN)

Answer 81

purely motor demyelinating neuropathy that presents with asymmetric weakness from involvement of individual peripheral nerves, hypo- or areflexia in the distribution of affected nerves, and no sensory manifestations. Anti-GM1 antibodies
Rx IVIG, not plasmapharesis or steroids

Question 82

Ulner nerve

Answer 82

continuation of medial cord. C8 and T1 fibers. branches to flexor carpi ulnaris and then flexor digitorum profundus to the fourth and fifth digits. Deep motor branch innervates hypothenar eminence muscles: abductor digiti minimi, flexor digiti minimi, and opponens digiti minimi

Question 83

CMT4

Answer 83

autosomal recessive forms of Charcot–Marie–Tooth

Question 84

S1 radiculopathy

Answer 84

pain radiating from the buttock down the posterior thigh, posterior leg, and lateral foot, with sensory impairment in this dermatomal region, especially the lateral foot and fifth toe. weakness is plantarflexion and toe flexion, and the ankle deep tendon reflex will be reduced or absent. H-reflex is commonly reduced or absent.

Question 85

ulnar neuropathy at or above the elbow

Answer 85

loss of fine motor coordination due to weakness of the third and fourth lumbricals, palmar/dorsal interossei. Claw hand, with the fourth and fifth digits hyperextended at the metacarpophalangeal joint and partially flexed at the interphalangeal joint and fourth lumbricals as well as the interossei and flexor digiti minimi are weak

Question 86

Ulnar nerve compression at the wrist/Guyon’s canal

Answer 86

Involvement of flexor carpi ulnaris and flexor digitorum profundus. CMAP amplitudes would be abnormally low with stimulation at the wrist, and a reduction in CMAP amplitude would not occur with more proximal stimulation.

Question 87

Diabetic amyotrophy

Answer 87

polyradiculoneuropathy. Onset occurs during adjustment of insulin treatment, or associated with episodes of hypo- or hyperglycemia. Develop weakness and eventually atrophy, which involve the pelvic girdle and thigh muscles.

Question 88

Radial nerve

Answer 88

continuation of the posterior cord. C5, C6, C7, and C8 fibers. brachioradialis (a forearm flexor), and extensor carpi radialis longus and brevis. Distal to the elbow, it bifurcates into the posterior interosseous nerve innervates extensor carpi ulnaris, extensor digitorum communis, extensor digiti minimi, abductor pollicis longus, extensor pollicis longus and brevis, and extensor indices.

Question 89

Foot drop

Answer 89

Foot drop can be seen with common or deep peroneal lesions, as well as with sciatic nerve lesions, L5 radiculopathies, and plexopathies. weak dorsiflexion and eversion points toward a common peroneal nerve injury. short head of the biceps femoris is spared suggests lesion is distal

Question 90

lateral femoral cutaneous nerve

Answer 90

L2 and L3, and is purely sensory

Question 91

Small-fiber neuropathy

Answer 91

preservation of vibratory sense and proprioception, as well as deep tendon reflexes/strength

Question 92

posterior interosseous nerve palsy

Answer 92

pure motor nerve. Caused by diabetic mononeuropathy and posterior interosseous nerve compression (such as due to lipomas or nerve sheath tumors) or can be seen in Parsonage–Turner syndrome. Weakness of wrist extension in an ulnar direction

Question 93

L2-L3-L4 radiculopathies vs lumbar plexopathy vs femoral nerve neuropathy

Answer 93

In radiculopathies, the SNAPs are normal, whereas in plexopathies, they are abnormal. Paraspinal fibrillations are seen in radiculopathies, but not in plexopathies. In femoral neuropathy, the manifestations should be restricted to the distribution and muscles supplied by this nerve.

Question 94

Neuralgic amyotrophy or Parsonage–Turner syndrome

Answer 94

can occur following surgery, vaccination, or systemic viral illness; acute onset of severe shoulder and arm pain, which then resolve, with subsequent occurrence of weakness potentially affecting any part of brachial plexus

Question 95

median nerve palsy at the level of the antecubital fossa

Answer 95

Intact strength of the ulnar nerve–innervated muscles indicates it is not a medial cord lesion

Question 96

Ischemic monomelia

Answer 96

during placement of arteriovenous shunts for dialysis, is painful and causes circumferential sensory loss in multiple nerve distributions

Question 97

anterior interosseous nerve syndrome.

Answer 97

pure motor branch of the median nerve and innervates flexor digitorum profundus to the second and third digits, flexor pollicis longus, and pronator quadratus

Question 98

Demyelination on EMG

Answer 98

Typically show prolonged or abnormal distal latencies and slow conduction velocities, with abnormal late responses, which are the F-response and the H-reflex. Reduction in CMAP amplititude. Also motor conduction block

Question 99

Pronator teres syndrome

Answer 99

compression of the median nerve as it passes between the two heads of pronator teres. pronator teres strength is intact and excludes a complete median nerve palsy at the elbow.

Question 100

radial neuropathy at the axilla.

Answer 100

Loss of sensation over the posterior arm (posterior cutaneous nerve), weakness of the triceps. prolonged crutch use, or with prolonged pressure otherwise on the axilla, as occurs in “Saturday night palsy,”

Question 101

radial neuropathy at the spiral groove

Answer 101

Intact strength of the triceps and intact sensation on the posterior aspect of the arm support that the lesion is distal to origin of the posterior cutaneous nerve to the arm and branches to triceps

Question 102

Jugular foramen syndrome,

Answer 102

compressive lesions of the foramen magnum, such as metastases or schwannomas. Vagus/glossopharyngeal nerves, spinal accessory nerve

Question 103

cervical plexus

Answer 103

ventral rami of C1 to C4. levator scapula (C3 and C4). greater/lesser occipital nerves

Question 104

multifocal acquired demyelinating sensory and motor neuropathy (MADSAM)

Answer 104

demyelinating neuropathy with evidence of conduction block, presenting with asymmetric motor and sensory symptoms. Subacute progression usually starts off in the upper limbs –> lower limbs. anti-GM1 antibodies are not present.
Rx Steroids

Question 105

superficial sensory radial neuropathy or Wartenberg’s syndrome

Answer 105

compression or irritation of superficial sensory radial neuropathy due to tight handcuffs or watches, venipuncture, or surgery

Question 106

musculocutaneous neuropathy

Answer 106

continuation of the lateral cord and carries predominantly C5 and C6 fibers. innervates the brachialis muscle and the biceps brachii, which flex the forearm at the elbow. sensory innervation to the lateral half of the forearm via the lateral antebrachial cutaneous nerve, but this nerve does not provide any sensation below the wrist

Question 107

Small-fiber neuropathy dx

Answer 107

diagnosis include quantitative sudomotor axon-reflex test (QSART), thermoregulatory sweat test (TST), and skin biopsy. EMG/NCS are normal because these tests evaluate the integrity of large nerve fibers.Small fibers include myelinated A-δ and unmyelinated C-fibers

Question 108

QSART

Answer 108

evaluates postganglionic sympathetic cholinergic sudomotor function, and is performed by stimulation of sweat glands by iontophoresis of acetylcholine

Question 109

thermoregulatory sweat test (TST)

Answer 109

assesses the pattern of sweating and dysfunction of sweating by placing the patient in a warming chamber while covered by a reactive powder that changes color with sweat. In small-fiber neuropathy with distal involvement, abnormal sweating is typically detected in hands and feet but not in the trunk.

Question 110

Axillary neuropathy

Answer 110

fractures at the surgical neck of the humerus and with anterior shoulder dislocations. axillary nerve is a continuation of the posterior cord, and carries predominantly C5 and C6 fibers.

Question 111

Fabry’s disease

Answer 111

X-linked disorder that results from a deficiency in the enzyme α-galactosidase A, a lysosomal enzyme. Commonly involved organs include the kidneys, heart, and skin. small-fiber neuropathy and autonomic neuropathy.

Question 112

suprascapular nerve entrapment

Answer 112

shoulder pain, and weakness of the supraspinatus, which abducts the arm, particularly during the first 30 degrees of abduction, and infraspinatus, which externally rotates the shoulder when the elbow is flexed and fixed at the patient’s side.

Question 113

thoracodorsal nerve

Answer 113

arises from the posterior cord and innervates the latissimus dorsi, which acts to adduct the arm.

Question 114

thoracoabdominal polyradiculopathy

Answer 114

long-standing diabetes, and presents with pain and dysesthesias, patchy sensory and motor changes in thoracic and abdominal nerve root territories, usually unilateral but may be bilateral.

Question 115

neurogenic thoracic outlet syndrome

Answer 115

compression on the C8 and T1 nerve roots. brachial plexus passes through the scalene triangle, which is formed by the anterior scalene, middle scalene, and first rib. Causing weakness of intrinsic hand muscles and sensory loss in a C8 and T1 distribution

Question 116

hereditary sensory and autonomic neuropathy (HSAN) type 1

Answer 116

Starts in adulthood. including pain, sensory loss, and autonomic features with little motor involvement. The main autonomic manifestation is hypohidrosis

Question 117

HSAN2

Answer 117

infancy, and is characterized by generalized loss of sensation and insensitivity to pain, leading to significant risk of mutilation to the hands, feet, lips, and tongue. Autonomic symptoms are not prominent

Question 118

HSAN3 (familial dysautonomia)

Answer 118

autosomal recessive HSAN with prominent autonomic features. With emotional stimulation, there is hyperhidrosis, skin flushing, and hypertension. Other autonomic features include absence of lacrimation.

Question 119

HSAN4

Answer 119

congenital insensitivity to pain. insensitivity to pain, leading to repeated injury and self-mutilation. Cognitive delay is also present, as are significant behavioral problems including hyperactivity. Autonomic features include anhidrosis, leading to heat intolerance and frequent fevers.

Question 120

primary erythromelalgia

Answer 120

episodes of severe burning and erythema of the distal extremities, precipitated by exposure to either heat or cold. sodium channel SCN9A gene, which results in hyperactivity of the dorsal root ganglia.

Question 121

lower trunk lesion

Answer 121

lead to weakness in ulnar and median nerve–innervated muscles.weakness of intrinsic hand muscles and sensory loss on the medial forearm and hand. Sensory loss occurs in a C8 and T1 distribution; the medial arm, innervated predominantly by T1 and T2, often has preserved sensation.

Question 122

lateral cord lesion

Answer 122

weakness of musculocutaneous-innervated muscles as well as C6- and C7-innervated median nerve muscles

Question 123

acute intermittent porphyria (AIP)

Answer 123

Common triggers include medications, menstruation, and alcohol exposure. With exposure to these triggers, activity of the hepatic enzyme ALA synthase increases, leading to overproduction of heme precursors. Neuropsychiatric symptoms including psychosis occur, and seizures. Wrist drop. During an attack, elevated levels of porphobilinogen and aminolevulinic acid are detectable in the urine and serum.

Question 124

L5 radiculopathy

Answer 124

pain from the buttock radiating down the lateral thigh, anterolateral leg, and dorsum of the foot, with sensory impairment in this dermatomal region extending to the big toe. The weakness is prominent on toe extension and ankle dorsiflexion, as well as inversion and eversion of the foot. foot drop is a frequent manifestation that may be seen with L5 root lesion and common peroneal neuropathy distinguishing the two is NCS. Superficial peroneal SNAPs are abnormal in common peroneal nerve lesions, but normal in L5 radiculopathies.