Peripheral Neuropathies
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This document discusses peripheral neuropathies and their causes and characteristics. It covers different types of neuropathies including mononeuropathies, mononeuritis multiplex, and polyneuropathies. Common causes of polyneuropathies discussed include inherited conditions, metabolic/endocrine disorders, toxins, infections, inflammation, and vitamin deficiencies. Signs and symptoms and investigative approaches are also summarized.
Peripheral Neuropathies
- 1. Peripheral neuropathies Dr. Osman Sadig Bukhari
- 2. Peripheral nerve diseases 1- Mononeuropathies 2- Multiple mononeuropathies (mononeuritis multiplex) 3- Polyneuropathies
- 3. Neuropathy = pathological processes damaging a nerve or nerves. The mechanisms of damage may be:- 1- Demyelination e.g. GB, diphth, HSMN 2- Axonal degeneration : e.g. Toxic neuropathies 3- Compression : Causes segmental demyelinatio e.g. Entrapment N. 4- Vasculopathy (infarction): Causes distal Wallerian degenerat e.g. DM, collagen diseases e.g. PAN. 5- Infiltration : e.g. leprosy, malig, sarcoidosis.
- 4. ** With axonal degen nerve conduction velocity is normal or slightly reduced & EMG shows evidence of muscle denervation. ** With demyelination conduction velocity may be slowed considerably or blocked in severe cases without accompanying muscle denerv. **- Mononeuropathy e.g. compression - Multiple mononeuropathies e.g. vasculopath infiltr, radiation - Polyneuropathies e.g. hereditary, metab toxic, GB, non metastatic manif of malig
- 5. Poly neuropathies Causes 1- Inherited neuropathies : - Charcot - Marie- Tooth disease - Dejerine- Sottas disease - Refsum,s disease - Acute intermittent porphyria - Friedreich,s ataxia
- 6. 2- Metab & endocrine: - DM - Uraemia - Chronic liver failure - Hypothyroidism - Acromegaly - Amyloidosis - Para & cryoproteinaemia
- 7. 3- Toxic neuropathies : - Alcohol - Drugs ( INH, phenytoin, vincristine, ) - Heavy metals (lead, arsenic, Hg) - Organic solvents (acryl amide, organophos)
- 8. 4- Infective: - Leprosy - Diphtheria - HIV - H. zoster
- 13. 5- Inflammatory : - Guillian – Barre’ syndrome. - Chronic demyelinating polyneuropathy - Idiopathic chronic sensorimotor neuropathy - Connective tissue diseases - Sarcoidosis - Lyme borreliosis
- 14. 6- Vitamin deficiency : - B12 - B1 - B6 - Folate - Nicotinic acid - Vit E
- 15. 7- Neuropathy associated with malignant disease 8- Neuropathy associated wz critically ill pts
- 16. Modalities of polyneuropathies - Sensory - Motor - Mixed - Autonomic
- 17. C/F of Polyneuropathies 1- Sensory dysfn: numbness, paraesthesiae, hyperaesthesia & pain starting distally and ascending proximally in gloves & stockings with impaired perception of pain, touch, temp vibration & position sense. 2- Motor dysfn : flaccid weakness most marked distally. 3- tendon reflexes : depressed or absent.
- 18. 4- Autonomic neuropathy : orthostatic hypot dysphagia, gastro paresis, gustatory sweating ( facial sweating wz anhydrosis of the feet), noct. diarrhoea, urine retention wz overflow incontinence, failure of erection, resting tachycardia, fixed HR, C/R arrest, dependant oedema wz cold feet, small non reactive pupils - Causes : - DM - GB - Acute intermittent porphyria - Amyloidosis - Drugs
- 19. Investigations : guided by sympt & signs The cause of polyneuropathy is suggested by the history including the onset, FH, PMH, DH, SH and za predominant clinical manifestations . - CBC & ESR - Renal profile & liver biochemistry - Blood glucose & thyroid fns. - ANF & RF - Plasma electrophoresis - Urinary levels of heavy metals. - CSF - CXR
- 20. - Serum lipids, lipo proteins, cry proteins - Vitamins assay - Urinary porphyrins - Genetics - Search for malig e.g. radiology, immaging, PSA, stools for occult blood, endoscopy, mamography - Nerve conduction studies - EMG - Nerve biopsy.
- 21. Inherited neuropathies 1- Charcot Marie Tooth syndrome - Mainly AD - presents in early adult life wz gait disturba or foot deformities. Slow nerve degeneratio lead to polyneuropathy wz distal weakness and wasting (inverted champagne bottle), variable sensory loss, absent kn & An jerks, high steppage gait due to foot drop - Pes cavus & claw feet +/- optic atrophy & deafness - Dis arrested in middle life. Normal life span.
- 22. 2- Dejerine Sottas disease - AR or sporadic - Progressive motor & sensory polyn with weakness, ataxia, sensory loss & depressed or absent reflexes - palpable nerves wz segmental demyelination - High CSF proteins due to obstruction by nerve roots
- 23. 3- Refsum’s disease - AD - Due to disturbance of phytanic acid metab. - Pigmentary retinal degeneration with progressive sensorimotor polyn & cerebellar signs. Auditory dysfn, cardiomyopathy and cutaneous manifestations - Marked reduction of conduction velocity - TR by restriction of phytanic acid and its precursors.
- 24. 4- Acute intermittent porphyria - Mainly motor, proximal & UL > LL - Sensory manifestations may occur - Axonal in type -High CHO diet & conc. dextrose is helpful and propranolol for tachycardia & HT.
- 25. Neuropathies associated with metab and endocrine disorders 1- Diabetes mellitus (occur singly or in combin) - Symmetric sensory or mixed polyn - Asymmetric motor radiculopathy ( diabetic amyotrophy) - Mononeuritis or mononeuritis multiplex - Autonomic
- 26. 2- Uraemia - Progressive sensorimotor polyn, LL > UL - Improves wz successful RT & to a lesser by chronic HD
- 27. Toxic neuropathies - Alcoholic polyn - Distal sensorimotor polyn frequently accomp by painful cramps, muscle tenderness and painful paraesthesia, often marked in za legs - Autonomic - May respond to B1 - Recurs or progress wz alcohol intake - Similar distal sensorimotor polyn occurs in beri beri (thiamine def)
- 28. Vitamin deficiency - Def states occur in malnutrition - preventable - potentially reversible if treated early 1- B12 def - Distal sensory polyn, sp proprioception - Absent ankle jerk - Extensor planter - Optic neuropathy - Intellectual dysfn
- 29. 2- Thiamine def ( beri beri) - polyn - cardiac failure Werneckes Korsakoff psychosis (nystagmus, ophthalmoplegia, ataxia, amnesia, confusion coma - Parental B1 for TR 3- Pyridoxine def (B6) - Mainly sensory - More common in slow acetylaters on INH. - 10mg per day for TR
- 30. Infective neuropathies 1- Leprosy - In TL leads to hypo pigmented anaethetic patches & involves peripheral nerves of predeliction which are thickened - In LL leads to gloves & stockings sensory loss - Multiple mononeuropathy 2- Diphtheric neuropathy (demyelinating) - Palatal palsy I 1-2W - Loss of accomodation in2-4W - polyn in 4-6W
- 31. 3- AIDS neuropathy - Chronic symmetric sensorimotor polyn - progressive polyradiculopathy or radiculomyelopathy ? CMV - Seropositive Pts may also develop demyeelinating polyradiculopathy and mononeuritis multiplex,
- 32. Inflammatory polyneuropathies 1- Acute post infective polyn - 1-4/52 following resp tract infection, campylobacter jejuni infection of za gut ( in 25% of cases, more severe & residual deficit), surgery & immunization - Demyelination of the spinal roots & periph N has probably immunological basis. - Patient presents wz distal weakness and numbness ascending over days to involve the face, resp muscles & bulbar muscles. - Patient may C/O back pain at za onset.
- 33. - Clinically there is muscle weakness, areflexia and variable sensory loss. Sphincters are intact & there is no sensory level. - Rapid deterioration wz resp failure may occur. - Ophthalmoplegia, ataxia & areflexia can be a presentation ( Miller Fissure) - CSF shows protein/ cell dissociation that may take 2-3 W to develop. - Nerve conduction velocity is slowed. - Investigations to search for a cause e.g CMV mycoplasma, campyl (CXR, stool culture and serology)
- 34. - DD include diphtheria, pophyria, lead N, ( pry motor N), botulism, polio & pry muscle disease - Treatment: - supportive ( ABC, nursing, physioth) - mechanical ventilation if resp paralysis occur. Monitor resp wz vital capacity. - Plasmapheresis & IV Ig if given early - Use of C/S is controversial. - complete recovery occur in 80% in 3-6 M - mortality 4% & 3% relapse. - remainder left wz disability.
- 35. Predominantly motor neuropathy 1- GB 2- Ca neuropath 3- Charcot Marie tooth disease (peroneal muscular atrophy 4- lead poisoning
- 36. Management of neuropathies 1- In 1/3 treatable cause: - toxins & offending drugs removed - Deficiencies & metab abn corrected - inflammatory causes by immunosuppression 2- In 1/3 there is identifiable cause but no TR as in hereditary 3- In 1/3 no specific cause -- Physiotherapy & occupational therapy
- 37. Mononeuropathies 1- Acute : sustained pressure e.g. tourniquet 2- Chronic: entrapment Causes according to site of compression 1- Carpal tunnel Median N 2- Cubital tunnel Ulnar N 3- Spiral groove of humerus Radial N 4- Inguinal ligament Lateral cutaneous of thigh 5- Neck of fibula Common peroneal N 6- Flexor retinaculum (tarsal tunnel) Post tibial
- 40. Mononeuritis multiplex Causes 1- leprosy (commonest) 2- DM 3- vasculitis 4- sarcoidosis 5- amyloidosis 6- malignancy 7- neurofibromatosis 8- HIV infection 9- Idiopathic multifocal motor neuropathy