1. DISEASES OF PERIPHERAL NERVESDR
BASHAR SHAKER
DISEASES OF PERIPHERAL NERVES

2. Numerous inherited and acquired pathological processes may affect the nerve roots (radiculopathy), the nerve plexuses (plexopathy) and/or the individual nerves (neuropathy).

3. Cranial nerves 3-12 share the same tissue characteristics as peripheral nerves elsewhere and are subject to the same range of diseases. Nerve fibres of different types (motor, sensory or autonomic) and of different sizes may be variably involved. Disorders may be primarily directed at the axon, the myelin sheath (Schwann cells) or the vasa nervorum

4. PATTERN OF INVOLVMENT
Mononeuropathy Simplex=Single Nerve Mononeuropathy Multiplex=Several Nerves Randomly &Noncontiguously Polyneuropathy( Peripheral Neuropathy)=Dysfunction of Numerous Peripheral Nerves at the Same Time leading to predominantly distal & symmetrical deficit usually affecting lower more than upper limbs

5. Types &Causes of peripheral neuropathy

6. Diseases of Peripheral Nerves
SYMPTOMS &SIGNS
1.Sensory Disturbances
A.Numbness, Hyperpathia, Impaired Sensation &
SPONTANEOUS PAIN esp. in SMALL FIBER
involvement ;D. M. , Porphyria, AIDS, Alcoholic,
Entrapment …..
B. Dissociated Sensory Loss
Small Fib. Pain &Temp.
Large Fib. Touch, Vib. & Position

7. 2. MOTOR DEFICITS
Weakness , Wasting , Fasciculation
Diminished or Absent Reflexes
i.e. LMNL
3.AUTONOMIC DISTURBANCES
Post. Hypotension, Coldness, Imp. Sweating, Impotence….esp. GBS, Diabetes, Renal Failure, Porphyria….
4. ENLARGED NERVES
Leprosy, Amyloidosis, HSMN, Refsum Dis., Acromegaly..

8. Causes of P. N . 1. Inflammatory: GBS , CIPD
2. Metabolic &Nutritional :D.M. ,Uremia, Liver Failure, Hypothyroidism, Acromegaly, B12 Deficiency….
3.Infectious &Granulomateous:AIDS, Leprosy, Diphtheria, Sarcoidosis…
4.Vasculitis: PAN, SLE, Rh.Arthritis…
5.Neoplastic &Paraneoplastic
6. Drugs &Toxins:Alcohol, INH, Vinicristine, Phenytoin, Heavy Metals….
7.Hereditory:HSMN, HSN, Refsum Disease,Porphyria..
8. IDIOPATHIC

9. Drugs causing peripheral neuropathy
Amiodarone , statins , hydralazine
Cardiovascular agents
Cisplatine , thalidomide , vincristine
Chemotheraputic agents
Chloramphenicol , INH , ETB , nitrofurantoin , metronidazole
Anti-infective agents
Gold , disulfiram , pyridoxine , tacrolimus , colchicine , phenytoin
Others

10. EVALUATION OF PATIENTS
TIME COURSE=Acute; Inflamm., Infectious, Toxins…
Chronic;Hereditory, Metabolic…
AGE= Early; Hereditory
Late; Metabolic, Neoplastic
OCCUPATION= Exposure to toxins
MEDICAL HISTORY
DRUGS
FAMILY HISTORY

11. DIFFERENTIAL DIAGNOSIS
Diseases of muscles &n.m. junction
normal sensation& tendon reflexes
Diseases of spinal cord
pyramidal signs &sensory level below the lesion
Radiculopathies
dermatomal &myotomal distribution

12. INVESTIGATIONS CONFIRM DIAGNOSIS EMG = DENERVATION
ENG &NCV = Demyelination or Axonal Degeneration
REVEAL UNDERLYING CAUSE

13. INVESTIGATION OF PERIPHERAL NEUROPATHY

14. INVESTIGATION OF PERIPHERAL NEUROPATHY

15. TREATMENT UNDERLYING CAUSE NURSING CARE ? ULCERS &CONTRACTURES
RESPIRATORY MONITORING &MANAGEMENT
CARE OF SKIN &NAILS
RELIEF OF PAIN ----Lancinating Pain--PHENYTOIN
CARBAMAZEPINE
MEXILETINE
Constant Pain----AMITRIPTYLINE
GABAPENTINE

16. GUILLIAN BARIE SYNDROME ACUTE ASCENDING POLYRADICLONEUROPATHY
This syndrome of acute paralysis develop in 70 % of patients 1-4 weeks after respiratory infection or diarrhoea (particularly Campylobacter).
In Europe and North America, acute inflammatory neuropathy is most commonly demyelinating ( AIDP ).
Axonal variants ,either ( AMAN ) or (ASMAN) are more common in China and Japan .

17. There is a predominantly cell-mediated inflammatory response directed at the myelin protein of spinal roots , peripheral and extra-axial cranial nerves , triggered by molecular mimicry between epitopes found in the cell walls of some microorganisms and gangliosides in the schwann cells and axonal membranes .

18. The resulting release of cytokines blocks nerve conduction and is followed by a complement – mediated destruction of the myelin sheath and the associated axon

19. Clinical features
Distal paraesthesia and limb pains precede a rapidly ascending muscle weakness from lower to upper limbs , more marked proximally than distally. Facial and bulbar weakness commonly develops , and respiratory weakness requiring ventilatory support occurs in 20 % of cases . In most patients weakness progresses for 1-3 weeks but rapid deterioration to respiratory failure can develop within hours

20. On examination there is diffuse weakness with widespread loss of reflexes.
An unusual axonal variant described by Miller Fisher comprises the triad of ophthalmoplegia , ataxia and areflexia .
Overall, 80% of patients recover completely within 3-6 months, 4% die, and the remainder suffer residual neurological disability which can be severe. Adverse prognostic features include older age, rapid deterioration to ventilation and evidence of axonal loss on EMG.

21. Investigations
The CSF protein is abnormal at some stage of the illness, but may be normal in the first 10 days. There is usually no rise in CSF cells ( lymphocytosis of > 50/ml suggests an alternative diagnosis ). Electrophysiological studies are often normal in the early stages but show typical changes after a week or so , with conduction block and multifocal motor slowing , sometimes most evident proximally as delayed F-waves.

22. Management
During the phase of deterioration , regular monitoring of respiratory function ( vital capacity and arterial blood gases) is required, as respiratory failure may develop with little warning and require ventilatory support. Ventilation may be needed if the vital capacity falls below 1L , but ventilation is more often required because of bulbar weakness leading to aspiration.

23. General management to protect the airway and prevent pressure sores and venous thrombosis is essential . Corticosteroids have been shown to be ineffective . Plasma exchange and intravenous immunoglobulin therapy shorten the duration of the illness ,reduce severity and improve prognosis provided treatment is started within 14 days of the onset of symptoms .

24. Chronic demyelinating polyneuropathy
It is either hereditary or immune-mediated. Charcot-Marie-Tooth (CMT) disease which is of many types ;the most commom % is the autosomal dominant one causing distal wasting (inverted champagne bottle or stork leg ) often with pes cavus and a predominantely motor involvement

25. Chronic demyelinating polyneuropathy
Presents with a relapsing or progressive generalized neuropathy. Sensory,motor or autonomic nerves can be involved but the signs are predominantely motor . Multifocal Motor Neuropathy MMN is a variant with motor involvement only .

26. CIDP
CIDP usually responds to immunosuppressive treatment ;corticosteroids , methotrexate or cyclophosphamide OR to immunomodulatory treatments (plasma exchange or IVIg ),which is the best of patients with MMN . About 10 % of patients with acquired demyelinating polyneuropathy have an abnormal serum paraprotein , sometimes associated with a lymphoproliferative malignancy .

27. DIABETIC NEUROPATHY
AMYOTROPHY = PAIN &WEAKNESS WITH ATROPHY PELVIC GIRDLE &THIGH MUSCLES WITH ABSENT KNEE REFLEX &LITTLE SENSORY LOSS
MONONEUROPATHY = ACUTE PAINFUL CRANIAL NERVES
BOTH HAVE GOOD PROGNOSIS

28. Entrapment neuropathy
Focal compression or entrapment is the usual cause of mononeuropathy . However , some patients present with what initially appears to be a single nerve lesion and then go on to develop multiple nerve lesions.This is termed mononeuritis multiplex .

29. Symptoms and signs
Area of sensory loss
Muscle weakness/muscle-wasting
Symptoms
Nerve
Lateral palm and thumb, index, middle and medial half 4th finger
Abductor pollicis brevis
Pain and paraesthesia on palmar aspect of hands and fingers, waking the patient from sleep. Pain may extend to arm and shoulder
Median
(at wrist) (carpal tunnel syndrome)
Medial palm and little finger, and medial half 4th finger
All small hand muscles, excluding abductor pollicis brevis
Paraesthesia on medial border of hand, wasting and weakness of hand muscles
Ulnar
(at elbow)

30. Muscle weakness/muscle-wasting Symptoms Nerve
Area of sensory loss
Muscle weakness/muscle-wasting
Symptoms
Nerve
Dorsum of thumb
Wrist and finger extensors, supinator
Weakness of extension of wrist and fingers, often precipitated by sleeping in abnormal posture, e.g. arm over back of chair
Radial
Nil or dorsum of foot
Dorsiflexion and eversion of foot
Foot drop, trauma to head of fibula
Peroneal
Lateral border of thigh
Nil
Tingling and dysaesthesia on lateral border of the thigh
Lateral cutaneous nerve of the thigh (meralgia paraesthetica)

31. In an entrapment neuropathy, pressure initially damages the myelin sheath, and neurophysiology will show slowing of conduction over the relevant site. Sustained or severe pressure damages the integrity of the axons, demonstrable as loss of the sensory action potential distal to the site of compression.

32. Certain conditions increase the propensity to develop entrapment neuropathies. These include acromegaly, hypothyroidism, pregnancy, any pre-existing mild generalised axonal neuropathy (e.g. diabetes), and oseophytes. Patients with multiple recurrent entrapment neuropathies, especially at unusual sites, should be screened for autosomal dominant hereditary neuropathy with liability to pressure palsies (HNPP) .

33. Unless axonal loss has occurred, entrapment neuropathies will recover, provided the pressure on the nerve is relieved, either by avoiding precipitating activities or limb positions, or by surgical decompression.

34. Entrapment neuropathy CTS
MEDIAN N. COMPRESSION AT THE WRIST
IDIOPATHIC, PREGNANCY, TRAUMA, ARTHRITIS, MYXOEDEMA, ACROMEGALY, TENOSYNOVITIS……
PAIN, NUMBNESS IN MEDIAN N. DISTIBUTION ?SHOULDER
> AT NIGHT
WEAKNESS & ATROPHY OF THENAR MUSCLES
TINEL SIGN , PHALEN MANEUVER
Rx LOCAL STEROIDS, WRIST SPLINT, SURGERY

35. Cranial nerves may also be the target of entrapment neuropathy.
An isolated lesion of one 8th cranial nerve usually indicates compressive pathology such as acoustic neuroma in or near the cerebellopontine angle.
Isolated lesions of the 9th , 10th , 11th , and 12th cranial nerves are uncommon.

36. Common causes of damage to cranial nerves 3 , 4 , 6
Associated features
Nerve(s) involved
Common pathology
Site
Contralateral pyramidal signss
Ipsilateral LMN7th palsy
Other brainstem / cerebellar sign
3 (midbrain )
6 (ponto-medullary junction)
Infarction
Hemorrhage
Demyelination
Intrinsic tumour
Brainstem
Meningism , features of primary disease course
Papilloedema
Features of SOL
Pain
Features of SAH
8,7,5 nerve lesions
Ipsilateral cerebellar signs
Other features of trauma
3,4 and/or 6 6
3 (Uncal herniation)
3(posterior communicating)
6 (basilar )
Meningitis
Raised ICP
Aneurysms
Cerebello-pontine angle tumours
Trauma
Intrameningeal

37. Common causes of damage to cranial nerves 3 , 4 , 6
Associated features
Nerve(s) involved
Common pathology
Site
May be 5th neve involvement also
Pupil may be fixed ,mid-position
(sympathetic plexus affected)
3,4 and /or 6
Infection/thrombosis
Carotid artery aneurysm
Caroticocavernous fistula
Cavernous sinus
May be proptosis , chemosis
Tumours(sphenoid wing meningeoma )
Granuloma
Superior orbital fissure
Pain
Pupil often spared in vascular 3rd nerve palsy
Vascular(e.g. diabetes,vasculitis)
Infections
Tumour
Trauma
Orbit

38. Syndromes of lower cranial nerves lesions outside the brainstem
cause
Site of lesion
Cranial nerves involved
Syndrome
Metastases
Neurinoma
Meningeoma
Epidermoid
Carotid body tumour
Jugular foramen
(inside skull)
9th,10th,11th
Vernet
Same
outside skull near foramen magnum
9th,10th,
11th, 12th
Collet-Sicard

39. Syndromes of lower cranial nerves lesions outside the brainstem
Cause
Site of lesion
Cranial nerves involved
Syndrome
Carotid dissection
Metastases
Neurinoma
Posterior pharangeal space near carotid artery
9 ,10, 11, 12, horner syndrome
Villaret
Meningeoma
Epidermoid
Skull base
Hypoglossal canal 12
Isolated 12th

40. Trigeminal neuropathy
Isolated trigeminal sensory neuropathy is rare. It causes unilateral facial sensory loss and is associated in some patients with scleroderma, Sjögren's syndrome, or other connective tissue disorder. Patients with trigeminal neuralgia don’t have sensory loss on examination unless there have been operative procedures on the nerve . Reactivation of varicella zoster virus in the trigeminal nerve cause herpes zoster most frequently in the ophthalmic division and is followed in about one third of patients by postherpetic neuralgia .

41. Facial nerve palsy
Idiopathic facial nerve palsy or Bells palsy is a common condition affecting all ages and both sexes .The lesion is within the facial canal and may be due to reactivation of latent herpes simplex virus 1 infection .Symptoms usually develop subacutely over a few hours , with pain around the ear preceding the unilateral facial weakness. Patients often describe the face as numb but there is no objective sensory loss (except possibly to taste).

42. Hyperacusis can occur if the nerve to stapedius is involved , and there may be diminished salivation and tear secretion . Examination reveals an ipsilateral lower motor neuron facial nerve palsy . Vesicles in the ear or on the palate indicate that the facial palsyis due to herpes zoster rather than Bells palsy .

43. Prednisolone mg daily for a week speeds recovery if started within 72 hours.Artificial tears and ointment prevent exposure keratitis and the eye should be taped shut overnight. About 80% of patients recover spontaneously within 12 weeks. A slow or poor recovery is predicted by complete paralysis, older age and reduced facial motor action potential amplitude after the first week. Recurrences can occur but should prompt further investigation. Aberrant re-innervation may occur during recovery, producing unwanted facial movements (e.g. eye closure when the mouth is moved) or 'crocodile tears' (tearing during salivation).

44. Hemifacial spasm
This usually presents after middle age with intermittent twitching around one eye, spreading ipsilaterally over months or years to affect other parts of the facial muscles. The spasms are exacerbated by talking or eating, or when the patient is under stress. The cause, as with trigeminal neuralgia, is probably an aberrant arterial loop irritating the nerve just outside the pons. The facial nerve should be imaged to exclude a structural lesion, especially in a young patient. Drug treatment is not effective but injections of botulinum toxin into affected muscles help, although these usually have to be repeated every 3 months or so. Occasionally, microvascular decompression is necessary.

45. Brachial Plexopathy
Trauma usually damages either the upper or the lower parts of the brachial plexus. Lower parts of the brachial plexus are vulnerable to infiltration from breast or apical lung tumours (Pancoast tumour) and may be damaged by therapeutic irradiation. The lower parts of the plexus may also be compressed by anatomical anomalies at the thoracic outlet, which may be accompanied by circulatory changes in the arm due to subclavian artery compression.

46. Physical signs in brachial plexus lesions

47. Brachial Plexopathy
An acute brachial plexopathy of probable inflammatory origin may present with 'neuralgic amyotrophy'. In this syndrome, a period of very severe shoulder pain precedes the appearance of a patchy upper brachial plexus lesion, often affecting the long thoracic nerve which produces winging of the scapula. Recovery occurs over months and is usually complete.

48. Lumbosacral plexopathy
Lumbosacral plexus lesions may be caused by neoplastic infiltration or compression by retroperitoneal haematomas in patients with a coagulopathy. A small vessel vasculopathy can produce a lumbar plexopathy, especially in elderly patients when it may be the presenting feature of type 2 diabetes mellitus ('diabetic amyotrophy') or a vasculitis. This presents with painful wasting of the quadriceps with weakness of knee extension and adduction, and an absent knee reflex.

49. MOTOR NEURONE DISEASE
DEGENERATION OF MOTOR NEURONS IN SPINAL CORD MOTOR NUCLIE OF LOWER CRANIAL NERVES ,
ONSET YEARS, > IN MALES, 2/ ,
SPORADIC, %FAMILIAL ( AUT. DOM. ) CHR 15
CAUSE : UNKNOWN
?AUTOIMMUNE
INCREASED OFR FORMATION
REDUCED NEUROTROPHIC FACTORS
EXCITOTOXINS

50. CLINICAL TYPES &FEATURES A
CLINICAL TYPES &FEATURES A. PROGRESSIVE BULBAR PALSY = LMN CRANIAL NERVES B.PSEUDOBULBAR PALSY = UMN CRANIAL NERVES C.SPINAL MUSCULAR ATROPHY = LMN SPINAL CORD AHC D. PURE LATERAL SCLEROSIS = UMN IN LIMBS E. AMYOTROPHIC LAT. SCLEROSIS = MIXED C. & D MAY BE WITH A. & B. NO EXTRA OCULAR MUSCLES INVOLVEMENT NO SPHINCTER INVOLVEMENT NO SENSORY DEFICIT NORMAL CSF EMG Rx = RILUZOLE 100mg /day may slow progression & reduce mortality. It is GLUTAMATE ANTAGONIST . Side effects = fatigue, dizziness, GIT diturbance, raised liver enzymes. Anticholinergics for drolling of saliva Physiotherapy FEEDING = Semisolid diet, NG tube, Gastrostomy. Tracheostomy Prognosis = Bad especially in Bulbar type Progressive &fatal in 3 -5 years

51. MND IN CHILDREN
INFANTILE = WERDING HOFFMANN DIS. ONSET AT 3 MONTHS , DEATH
AT 3 YEARS, AR , DIFFICULT SUCKING , SWALLOWING&
VENTILATION, ATROPHY & FASCICULATION OF TONGUE &
LHMB MUSCLES, NO SENSORY DEFICIT , NO Rx
INTERMEDIATE = CHRONIC W-H-DISEASE
AR, 2nd of 1st year, LESS BULBAR INVOLVEMENT ,
> BENIGN, SLOWLY PROGRESSIVE , KYPHOSCOLIOSIS
&CONTRACTURES , SURVIVE TO ADULTHOOD
JUVENILE = KUGELBERG – WELANDER DISEASE
AR, COULD BE AD OR X – LINKED
ONSET AT CHILDHOOD OR EARLY ADOLESCENCE
MORE IN PROXIMAL MUSCLES , LITTLE BULBAR INVOLV.
DISABILITY IN EARLY ADULT LIFE
NO Rx

52. SYRINGOMYELIA CAVITATION OF SPINAL CORD
COMMUNICATING = CENTRAL CANAL &THE CAVITY
NON – COMMUN. = CYSTIC DILATATION OF SPINAL CORD
CLINICALLY = DISSOCIATED SENSORY LOSS
WEAK. & WASTING OF MUSCLES ; CERVICAL &T 1
PYRAMIDAL SIGNS &SPHINCTER DIST. BELOW
NECK & RADICULAR PAIN
HORNER SYNDROME
SYRINGOBULBIA
MAY BE ASSO. WITH TUMOR, TRAUMA , ARACHNOIDITIS OR ANMALIES LIKE ARNOLD – CHIARI MALFORMATION
Rx = DECOMPRESSION OF DISTENDED SYRINX

53. SUBACUTE COMBINED DEGEN. OF THE CORD
B12 DEFICIENCY
PARASTHESIA &WEAKNESS OF THE EXTREMITIES = PERIPHERAL
NERVES
SPASTIC PARAPARESIS = PYRAMIDAL FIBERS
SENSORY ATAXIA = POSTERIOR COLUMN TRACT
LHERMITTS SIGN
SCOTOMAS = OPTIC ATROPHY
BEHAVIOURAL OR PSYCHIATRIC SYMPTOMS
ANEMIA MEGALOPLASTIC NOT NECESSARILY PRESENT
Rx B12I. M. …….