Weakness beginning in the distal limbs but rapidly advancing to affect proximal muscle function (“ascending paralysis”)
immune-mediated demyelinating neuropathy
inflammation and demyelination of spinal nerve roots and peripheral nerves (radiculoneuropathy)
Infections with Campylobacter jejuni, cytomegalovirus, Epstein-Barr virus, and Mycoplasma pneumoniae
Ab to gangliosides
T cell–mediated immune response ensues, accompanied by segmental demyelination induced by activated macrophages
What are the morphoological features of GBS?
Inflammation of peripheral nerve, manifested as perivenular and endoneurial infiltration by lymphocytes, macrophages
Most intense in spinal and cranial motor roots
Segmental demyelination affecting peripheral nerves is the primary lesion, but damage to axons is also characteristic, particularly when the disease is severe
The cytoplasmic processes of macrophages penetrate the basement membrane of Schwann cells, particularly in the vicinity of the nodes of Ranvier, and extend between the myelin lamellae, stripping away the myelin sheath from the axon
What are the diagnostic findings in GBS?
Ascending paralysis (symmetric)
Sensory involvement (mainly subjective)
There is elevation of the CSF protein due to inflammation and altered permeability of the microcirculation within the spinal roots as they traverse the subarachnoid space.
NO CSF PLEOCYTOSIS
What are the nerve lesions in LL?
In lepromatous leprosy, Schwann cells are invaded by Mycobacterium leprae, which proliferate and eventually infect other cells.
There is evidence of segmental demyelination and remyelination and loss of both myelinated and unmyelinated axons.
As the infection advances, endoneurial fibrosis and multilayered thickening of the perineurial sheaths occur.
Symmetric polyneuropathy affecting the cool extremities (due to lower temperatures favoring mycobacterial growth).
Prominently involves pain fibers, and the resulting loss of sensation contributes to injury (large traumatic ulcers may develop in the extremities)
What is the feature of nerve involvement in TT?
Active cell-mediated immune response to M. leprae, with nodules of granulomatous inflammation situated in the dermis.
The inflammation injures cutaneous nerves in the vicinity; axons, Schwann cells, and myelin are lost, and there is fibrosis of the perineurium and endoneurium.
In tuberculoid leprosy, affected individuals have much more localized nerve involvement
What is the main pathogenesis in TT and LL?
LL--> schwann destruction by M.Leprae
What are the nerve lesions of diphteria?
Begins with paresthesias and weakness
Early loss of proprioception and vibratory sensation.
The earliest changes are seen in the sensory ganglia, where the incomplete blood-nerve barrier allows entry of the toxin.
There is selective demyelination of axons that extends into adjacent anterior and posterior roots as well as into mixed sensorimotor nerves
VZV occurs most frequently in ...............
thoracic or trigeminal
What is the morphology of Zoster infection?
Affected ganglia show neuronal destruction and loss, usually accompanied by abundant mononuclear inflammatory infiltrates; regional necrosis with hemorrhage may also be found.
Peripheral nerve shows axonal degenerationafter the death of the sensory neurons.
Intranuclear inclusions generally are not found in the peripheral nervous system.
True or False: IN inclusions are seen in zoster of PNS
What are the types of hereditary neuropathies?
Hereditary motor and sensory neuropathies (HMSNs)
Hereditary sensory and autonomic neuropathies (HSANs)
Familial amyloid polyneuropathies--> like HSAN+transtyrethin
3)Axonal degeneration is the primary event; 4)Regeneration and recovery are common after dialysis
Diabetic and uremic neuropathy are....................
B1 and B12 deficiency are associated with ............neuropathy
Which vitamin deficiencies cause axonal neuropathy?
Ethanol directly cause.............neuropathy
What are the direct neuropathies causes by tumors?
Brachial plexopathy from neoplasms of the apex of the lung
Obturator palsy from pelvic malignant neoplasms
Cranial nerve palsies from intracranial tumors and tumors of the base of the skull.
A polyradiculopathy involving the lower extremity may develop when the cauda equina is involved by meningeal carcinomatosis
What are the features of malignancy associated paraneoplastic neuropathy?
most common type is a sensorimotor neuropathy in lower limbs
small-cell carcinoma of the lung
inflammatory infiltrates within the dorsal root ganglia and the identification of IgG antibodies that bind a 35- to 38-kD RNA-binding protein expressed by neurons and the tumor
What is the neuropathy caused by MM?
Deposition of light-chain (AL type) amyloid in peripheral nerves
Production of monoclonal immunoglobulin that recognizes a major protein of myelin, myelin-associated glycoprotein
What is traumatic neuroma (pseudoneuroma or amputation neuroma)?
Axons, even in the absence of correctly positioned distal segments, may continue to grow, resulting in a mass of tangled axonal processes known as a traumatic neuroma (pseudoneuroma or amputation neuroma). Within this mass, small bundles of axons appear randomly oriented; each, however, is surrounded by organized layers containing Schwann cells, fibroblasts, and perineurial cells
Normal appearance of peripheral nerve (A), with all the axons aligned in a single plane with sheaths of connective tissue, as compared with traumatic neuroma (B) showing disordered orientation of axons (pale purple) intermixed with connective tissue
What are the features in CTS?
compression of the median nerve at the level of the wrist within the compartment delimited by the transverse carpal ligament
edema, pregnancy, inflammatory arthritis, hypothyroidism, amyloidosis (especially that related to β2-microglobulin deposition in individuals on renal dialysis), acromegaly, diabetes mellitus, and excessive repetitive motions of the wrist.
Symptoms are limited to dysfunction of the median nerve, including numbness and paresthesias of the tips of the thumb and first two digits.
What are other compression neuropathies?
Other nerves prone to compression neuropathies include the ulnar nerve at the level of the elbow, the peroneal nerve at the level of the knee, and the radial nerve in the upper arm; the latter occurs from sleeping with the arm in an awkward position (“Saturday night palsy”).
Another form of compression neuropathy is found in the foot, affecting the interdigital nerve at intermetatarsal sites. This problem, which occurs more often in women than in men, leads to foot pain (metatarsalgia). The histologic findings of the lesion (Morton neuroma) include evidence of chronic compression injury
What are the symptoms of C5 injury?
Pain : Neck, shoulder, scapula
Sense: Lateral arm (in distribution of axillary nerve)
Motor: Elbow and wrist extension (radial), forearm pronation, wrist flexion
What are the symptoms of C8 injury?
Pain: Neck, shoulder, medial forearm, fourth and fifth digits, medial hand
Sense: Medial forearm, medial hand, fourth and fifth digits
Motor: Finger extension, wrist extension (ulnar), distal finger flexion, extension, abduction and adduction, distal thumb flexion
What are the symptoms of T1 injury?
Pain: Neck, medial arm and forearm
Sense:Anterior arm and medial forearm
Motor: Thumb abduction, distal thumb flexion, finger abduction and adduction
What are the symptoms of L5 injury?
Symptoms: Back pain radiating down the lateral leg to foot
Signs: Decreased foot dorsiflexion, toe extension, foot inversion and eversion; mild weakness of leg abduction in severe cases
What are the symptoms of S1 injury?
Symptoms: Pain radiating down the posterior leg to foot; leg pain greater than back pain
Signs: Decreased leg extension, foot inversion, plantar flexion, and toe flexion; decreased sensation in the posterior leg and lateral foot; loss of ankle jerk
What are the symptoms of L2-4 injury?
Symptoms: Acute back pain radiating around the anterior leg into the knee and possibly foot
Signs: Decreased hip flexion, knee extension, leg abduction; decreased sensation in the anterior thigh down the medial aspect of the shin; diminished knee jerk in severe cases
What are the symptoms of S2-4 injury?
Symptoms: Sacral or buttock pain radiating down the posterior leg or into the perineum
Signs: Minimal weakness; bowel and bladder dysfunction
What are the features of mercury poisoning?
paresthesias in hands and feet that progress proximally and may involve the face and tongue. Motor weakness can also develop. CNS symptoms often overshadow the neuropathy
What is the hallmark of Lead peripheral neuropathy?
insidious and progressive onset of weakness usually beginning in the arms, in particular involving the wrist and finger extensors, resembling a radial neuropathy.
Sensation is generally preserved; however, the autonomic nervous system can be affected
Lead peripheral neuropathy is primarily......
What is the effect of arsenic on peripheral nerves?
The presenting symptoms are typically an abrupt onset of abdominal discomfort, nausea, vomiting, pain, and diarrhea followed within several days by burning pain in the feet and hands.
Examination of the skin can be helpful in the diagnosis as the loss of the superficial epidermal layer results in patchy regions of increased or decreased pigmentation on the skin
What are the features of Common peroneal injury?
Site: Fibular neck, just below the knee
Cause: Prolonged lying, leg crossing, squatting, leg cast
Symptoms: Foot drop, paresthesias and/or sensory loss over dorsum of foot and lateral shin
Signs: Weakness on foot dorsiflexion and eversion; sensory loss on dorsum of foot; reflexes normal
What are the features of deep peroneal injury?
Cause: Tight fitting shoe rim or strap
Symptoms: Ankle pain, minimal weakness and sensory loss over web space between digits 1 and 2
What are the features of Posterior tibial injury?
Site: Tarsal tunnel of ankle
Cause: Fracture or dislocation of talus, calcaneus, medial malleolus, rheumatoid arthritis, tumor
Symptoms: Aching, burning, numbness, tingling on sole of foot, distal foot, toes, and occasionally heel
Signs: Positive Tinel's sign over nerve posterior to medial malleolus; sensory loss on sole of foot; atrophy of foot muscles if severe
What are the features of Sciatic injury?
Site: Sciatic notch/gluteal region, midthigh
Cause: Trauma (hip dislocation, fracture, or replacement), prolonged bed rest, deep-seated pelvic mass, piriformis syndrome
Symptoms: Leg pain and weakness affecting most lower leg muscles
Signs: Sensory loss in peroneal, tibial, and sural territories; may spare medial calf and arch of foot; normal knee jerk; absent ankle jerk
What are the features of femoral injury?
Site: Pelvis and anterior thigh
Cause: Hip or pelvic fracture, hip replacement, lithotomy position, diabetes mellitus
Symptoms: Quadriceps weakness and sensory loss
Signs: Quadriceps weakness; sensory loss over anterior and medial thigh extending down medial shin to arch of foot; reduced or unobtainable knee jerk
What are the features of Lateral femoral cutaneous injury?
Site: Inguinal ligament (meralgia paresthetica)
Cause: Obesity, tight fitting belts, idiopathic
Symptoms: Paresthesias and pain radiating down the lateral thigh to knee
Signs: Sensory loss on lateral thigh
What is the summary of lesions seen in upper limb nerve injury?
1) Erb’s palsy------upper trunk
2) Klumpke’s palsy---- lower trunk
3) Winging of scapula----long thoracic nerve
4) Ape’ s hand---- median nerve---supracondylar fracture
5) Wrist drop------ Radial nerve---fracture of spiral groove
6) Claw hand-----ulnar nerve----- fracture of medial epicondyle
What are the branches of brachial plexus?
BRANCHES FROM ROOTS & TRUNKS
ROOTS: Dorsal scapular nerve C5, Long thoracic nerve C5,6,7
UPPER TRUNK: C5 C6 Suprascapular nerve , Nerve to subclavius
BRANCHES FROM LATERAL CORD: Lateral pectoral nerve, Musculocutaneous nerve, Lateral root of median
BRANCHES FROM MEDIAL CORD: Medial pectoral nerve, Medial cutaneous nerve of arm and forearm, Ulnar nerve, Medial root of median
BRANCHES FROM POSTERIOR CORD: Upper and lower subscapular nerves, Thoracodorsal, Axillary nerve, Radial nerve
What are the findings in upper lesions of brachial plexus?
Traction or even tearing of C5 and C6 root
Cause: Excessive displacement of head to opposite side and depression of shoulder on same side, In infants during a difficult delivery, In adults following a fall on or a blow to the shoulder
Nerves involved: Supra scapular nerve, Nerve to Subclavius, Musculocutaneous nerve ,Axillary
MUSCLES AND FUNCTIONS LOST: Lateral rotation of arm: Teres minor, Infraspinatus Abduction of shoulder: Supraspinatus, Deltoid Flexion of shoulder: corobrachialis, Biceps brachii Flexion of elbow: Brachialis, Biceps brachii Supination of forearm: Biceps brachii
ERB’S PALSY (UPPER TRUNK INJURY)• Loss of muscle function innervated by C5 and C6• Also known as waiter’s tip or policeman’s tip• Arm medially rotated, adducted, hangs by side• Forearm extended and pronated
Arm medially rotated, adducted, hangs by side• Forearm extended and pronated
What are the features of Klumpke paralysis?
Fibers of C8 and mostly T1 root are torn
Cause:Excessive abduction of arm a) Birth injury in breech delivery b) Person falling from a height clutching an object to save himself Compression of lower trunk a) Cervical rib b) Malignant mets in lower deep cervical lymph nodes
Nerves involved T1 fibers run in ulnar and median nerve
Muscles involved: All small muscles of the hand( interossei and lumbricals)
Sensory loss along the medial side of forearm
KLUMPKE,S PALSY: Clawed hand• Hyperextension of metacarpophalangeal joint----- by unopposed extensor digitorum • Flexion at interphalangeal joint by unopposed flexor digitorum superficialis and profundus
What are the symptoms of Klumpke paralysis?
Hyperextension of metacarpophalangeal joint----- by unopposed extensor digitorum
Flexion at interphalangeal joint by unopposed flexor digitorum superficialis and profundus
What are the symptoms of Long thoracic injury?
Arise from roots c5 , c6 and c7
Muscles involved Serratus anterior
Functions lost Abduction above 90 degrees
Causes:• Blows or pressure in posterior triangle of neck• In radical mastectomy
Deformity: Winging of scapula vertebral border and inferior angle of scapula unduly prominent
What are the features of axillary injury?
Arise from posterior cord of brachial plexus
Causes: a. Fracture of surgical neck of humerus, b. Inferior dislocation of shoulder joint, c. Pressure of badly adjusted crutch upward into armpit, d. Misplaced injection into deltoid
Muscles involved• Deltoid • Teres minor
Sensory loss • Upper lateral cutaneous nerve of arm• Loss of skin sensation over the lower half of deltoid muscle
What is the characteristic of radial nerve?
Largest branch of plexus•
From posterior cord
Arise in axilla ---> spiral groove -> lateral intermuscular septum -> front of lateral epicondyle -> divides into superficial and deep• Superficial --> lateral side of radial artery --> posterior surface of wrist/ Deep branch -->supinator --> neck of radius --> posterior surface of wrist
What are the branches of radial nerve?
Axilla• Posterior cutaneous nerve of ARM• Nerve to long head and medial head of triceps
Branches in spiral groove• Lower lateral cutaneous nerve of arm• Posterior cutaneous nerve of forearm• Nerve to lateral and medial head of triceps
Branches in anterior compartment of arm:• Nerve to small part of brachialis• Nerve to brachioradialis• Nerve to ECRL
Branches in cubital fossa:• Deep branch of radial nerve to ECRB, supinator and all muscles in posterior compartment of forearm• Superficial branch provides sensation to dorsum of hand and dorsum of
Branches in distal fore arm• Palmar cutaneous branch----skin on lateral side of palm
Branches in palm• Muscle of thenar eminence• First 2 lumbricals • Skin of palmar surface of lateral 3 ½ fingers• lateral 3 ½ fingers
What are the features of radial nerve injury in axilla?
Causes• Pressure of badly fitted crutch into armpit• Falling asleep with arm over the back of chair------ Saturday night palsy
Motor loss:• Extension at elbow----- paralysis of triceps and anconeus• Extension of wrist and fingers-----paralysis of extensors of wrist and all muscles of posterior compartment• Supination----can still be performed by biceps
Deformity known as WRIST DROP -----flexion of wrist as a result of action of unopposed flexors of wrist and fingers
Sensory loss• posterior surface of arm and fore arm• Dorsum of hand and dorsal surface of lateral 3 ½ fingers
What are the features of radial injury in spiral groove?
Most commonly in distal part of groove beyond the origin of nerves to triceps and anconeus and cutaneous nerves
Causes:• Fracture of shaft of humerus• Prolonged pressure on the back of arm as in• Unconscious patient by edge of operating table• Prolonged application of tourniquet in thin lean person
Motor loss:• Extension of wrist, fingers and thumb• Elbow extension is spared
Sensory loss: • Dorsum of hand and dorsum of lateral 3 ½ fingers• Sensations on posterior arm and forearm are spared
What is the major difference in radial nerve injury between spiral groove and axilla?
In spiral groove: Elbow extension and Sensations on posterior arm and forearm are spared
What are the features of median nerve?
1) Formed in axilla by lateral and medial roots from respective cords
2) Anterior compartment of arm ---- crosses brachial artery from lateral to medial
3) At elbow crossed by bicipital aponeurosis
4) Passes between 2 heads of pronator teres to enter forearm
5) At wrist at lateral border of flexor digitorum profundus6) Enter palm beneath flexor retinaculum
What are the branches of median nerve?
1) Branches in axilla and arm• no branches
2) Branches in proximal forearm• To all anterior compartment muscles except flexor carpi ulnaris and medial half of flexor digitorum profundus
3) Branches in distal fore arm• Palmar cutaneous branch----skin on lateral side of palm
4) Branches in palm• Muscle of thenar eminence• First 2 lumbricals • Skin of palmar surface of lateral 3 ½ fingers
What are the features of median nerve injury at elbow?
Cause:• Supracondylar fracture of humerus
Motor loss• Loss of pronator of forearm• Loss of long flexors of wrist and fingers except medial half of flexor digitorum profundus and flexor carpi ulnaris• Loss of flexion of terminal phalanx of thumb• Loss of thenar muscles (wasted)
Deformity:Forearm ----supinated, Wrist----flexion is weak accompanied by adduction, Fingers----no flexion of interphalangeal joint of index and middle Thumb---flexion, abduction and opposition is lost
APE’S HAND----thumb laterally rotated adducted and thenar eminence flattened
Sensory loss• Lateral side of palm• Palmar surface of lateral 3 ½ fingers• Distal part of dorsal surface of lateral 3 ½ fingers
What is the feature of INJURY TO MEDIAN NERVE AT WRIST?
Most common injury of median nerve
Causes• Due to penetrating injuries or stab wound at the wrist
Motor loss• Muscle of thenar eminence• First two lumbricals
Deformity APE’S HAND
Sensory loss • Same as in elbow lesion
What are the features of NJURY TO MEDIAN NERVE IN CARPAL TUNNEL?
Passage of long flexor tendon and median nerve
Syndrome is caused by compression of median nerve due t o reduced size of canal
Causes• Inflammation of retinaculum• Arthritis of carpal bones• Inflammation of synovial sheaths of flexor tendons
Sensory and motor Loss:• Pain and paraesthesia of lateral one and half finger• Weakness of thenar muscle
What are the features of ulnar nerve?
Arise from medial cord in axilla
Descends between axillary artery and vein
In anterior compartment of arm on medial side of brachial artery
Pierces medial intermuscular septum to enter in posterior compartment
At elbow lies behind medial epicondyle
Enter forearm between 2 heads of flexor carpi ulnaris
At wrist between tendons of flexor carpi ulnaris and digitorum profundus
Enter palm superficial to flexor retinaculum
What are the branches of ulnar nerve?
Branches in axilla or arm• No branches
Branches in proximal forearm• Nerve to FCU• Medial half of flexor digitorum profundus
Branches in distal forearm• Palmar cutaneous branch -----skin of hypothenar eminence• Posterior cutaneous branch----skin of medial third of dorsum of hand and dorsal side of medial one and half finger
Branches in palm• Superficial branch of ulnar---- skin of palmar surface of medial one and half finger• Deep branch of ulnar• All small muscles of hand except of thenar muscles and first 2 lumbricals
What are the features of ulnar nerve injury at elbow?
Most commonly injured at this site
Cause• Fracture of medial epicondyle
Motor loss• FCU and medial half of flexor digitorum profundus• Small muscle of hand are paralyzed except thenar muscles and first 2 lumbricals
Deformity• Wasting of ulnar border of forearm• Terminal phalanges of little and ring finger can not be flexed• Inability to abduct and adduct fingers• Loss of adduction of thumb• Forment’s sign flexion of terminal phalanx of thumb while attempting adduct the thumb in ulnar nerve palsy•
CLAW HAND: a. Metacarpophalangeal joints of fourth and fifth finger are hyper extended, b. Interphlangeal joint of fourth and fifth fingers are flexed • Flattening of hypothenar eminence• Hollowing between metacarpals on dorsum of hand due to paralysis of dorsal interossei
Sensory loss• Anterior and posterior surfaces of medial half of hand and medial one and half fingers
What are the features of ulnar nerve injury at wrist?
ULNAR NERVE INJURY AT WRIST• Due to superficial position
Causes• Penetrating wounds
Motor loss• Small muscles of hand except those of thenar eminence and first 2 lumbricals
Deformity• Claw hand more prominent
Sensory loss• On the medial side of palm and palmar and dorsal surface of 1 ½ fingers• Sensation on posterior medial surface of hand is intact