Ch 5 - EDX: Peripheral Polyneuropathy Flashcards
What can be affected in peripheral polyenuropathies?
Myelin and/or axons of peripheral nerves
What is the presentation of a diffuse peripheral polyenuropathy?
Essentially involves all nerves in a length-dependent fashion to a relatively equal extent
What is the presentation of a multifocal peripheral polyenuropathy?
Involves one or multiple nerves in an asymmetric or patchy distribution
How are peripheral polyneuropathies classified?
Acquired or Inherited
What are categories of inherited peripheral polyneuropathies?
– Hereditary Motor and Sensory Neuropathies (HMSN)
– Hereditary Sensory and Autonomic Neuropathies (HSAN)
– Hereditary Motor Neuropathies (HMN)
What is the MC inherited peripheral polyneuropathy?
HMSN (Charcot-Marie Tooth) disease
What is HMSN (Charcot-Marie Tooth) disease caused by?
Duplication mutation of the PMP-22 gene
What are MCC of acquired peripheral polyneuropathies?
DM (MC)
AIDP
Medications
What is the classic triad of clinical presentation of general peripheral polyneuropathies?
– Sensory changes in a stocking/glove distribution
– Distal weakness
– Diminished/absent MSR
How do inherited peripheral polyneuropathies typically present?
– Sensory loss
– Ataxia
– Increased incidence of muscle cramping
How do acquired peripheral polyneuropathies typically present?
– Burning
– Pain
– Paresthesias
What will be seen on NCS in demyelinating injury?
Prolonged distal latency
Slowed conduction velocity
Conduction block
Increased temporal dispersion
What will be seen on EMG in demyelinating injury?
No fibrillation potentials or positive sharp waves
Myokymic discharge
Decreased recruitment
What will be seen on NCS in axonal injury?
Reduced SNAP/CMAP amplitude
Near-normal distal latency
Near-normal conduction velocity
What will be seen on EMG in axonal injury?
(+) Fibrillation potentials (+) Positive sharp waves Decreased recruitment Increased duration and amplitude Polyphasic potentials
What are NCS findings in acquired neuropathy?
+ Conduction block
Focal CV slowing
Inc temporal dispersion
What are NCS findings in hereditary neuropathy?
- Conduction block
Diffuse CV slowing
Normal temporal dispersion
What are systemic sx of small fiber neuropathy?
Orthostatic BP Dry scaly skin Dry eyes Dry mouth Burning pain in extremities ABN pinprick sensation
Norepinephrine is the primary neurotransmitter for ____.
Postganglionic sympathetic adrenergic nerves
What is the sympathetic skin response used for?
Evaluating the unmyelinated, sympathetic nerve fibers of the PNS
What does loss of sinus arrhythmia with cardiovagal innervation studies mean?
Represents denervation process
What are types of demyelinating motor PN?
Multifocal motor neuropathy
What is the pattern of inheritance for CMT?
Autosomal dominant
What is the age of onset for CMT?
Early childhood in first 2 years
Describe the motor loss in CMT.
- Slow progressive distal motor>sensory ABN
- Distal>proximal weakness
- Intrinsic foot and lower anterior leg
Describe the sensory loss in CMT.
Lower>upper limbs
ABN vibration and proprioception
Stocking/glove
Describe clinical characteristics of CMT
Pes cavus
Hammer toes
Champagne bottle leg
Hypertrophy of peripheral nerves (greater auricular nerve)
What is Roussy-Levy syndrome?
CMT associated with an essential tremor
What is seen on nerve biopsy in CMT?
Onion bulb formation from focal demyelination, then remyelination
What is seen on NCS in CMT?
SNAP: ABN CMAP: ABN, CV decreased 70% No temporal dispersion or conduction block
What is the etiology of AIDP/GBS?
Possible viral attack on the myelin and Schwann cells
What is the onset of AIDP/GBS?
1–4 weeks post illness, vaccination, or surgery
What is the 1st sign of AIDP/GBS?
Ascending sensory abnormalities
Describe CN involvement in AIDP/GBS.
Most common: CN VII
CN I and II unaffected
What are variants of AIDP/GBS?
Miller-Fisher syndrome
Pure sensory
What are signs of AIDP/GBS?
Ascending sensory ABN and weakness
ABN reflexes
Resp/autonomic failure
What is the first EDX sign of AIDP/GBS?
ABN F wave
What EDX findings are associated with poor prognosis of AIDP/GBS?
CMAP: Amp <20% of normal NCV <40% of normal F wave: Absent EMG: ABN activity (axonal involvement)
What is the etiology of CIDP?
Possible immune mediated response
What is the onset of CIDP?
Any age, peaks at 50 to 60 years of age
What is the clinical presentation of CIDP?
Relapsing/remitting Sensory ABN Symmetric proximal>distal weakness ABN reflexes Less CN involvement
What is the etiology of Hansen’s disease?
Mycobacterium Leprae
What is the MC neuropathy world-wide?
Hansen’s disease (Leprosy)
What is the clinical presentation of Hansen’s disease (Leprosy)?
Sensory ABN
Wrist drop
Foot drop
Facial palsy
What is seen on nerve biopsy in Hansen’s disease (Leprosy)?
Foamy histiocyte invasion
What is the etiology of porphyria?
Defect heme
synthesis
What is the clinical presentation of porphyria?
Female>male Lower limb pain/weakness Back/ABD pain Seizures Mental status changes Reaction to barbiturates, sulfa
What are lab features of porphyria?
Deep red urine
What is the clinical presentation of lead toxicity?
Progressive UE weakness Radial neuropathy ABD discomfort Blue lines in gums Blindness Epilepsy Encephalopathy (child)
What are lab features of lead toxicity?
Blood/urine: Lead
Basophilic stippling
in RBCs
x-ray lead lines
What is the clinical presentation of lead toxicity?
Lower limb
paresthesias and
weakness
ABN MSR
What is the clinical presentation of dapsone toxicity?
Ascending foot and
hand neuropathy
Methemoglobinemia
What is axonal AIDP associated with?
CMV and C. jejuni
infection
Which form of AIDP has a poor prognosis?
Axonal worse than demyelinating
What is the inheritance pattern of HMSN II and CMT II?
Autosomal dominant
What is the clinical presentation of HMSN II and CMT II?
Onset 2nd decade Weakness ABN MSR Less foot involvement Tremor Ataxia
What is seen on nerve biopsy in HMSN II and CMT II?
No onion bulb formation
What is the clinical presentation of Cis-platinum?
Painful parasthesia in hands and feet Nephrotoxicity Ototoxicity Myelosuppression GI complaints
What is seen on nerve biopsy in Cis-plantinum, Friedreich’s ataxia, Sjogren’s syndrome and pyirdoxine toxicity?
Abnormal large axons
What is the inheritance pattern of Friedreich’s ataxia?
Autosomal recessive
What is the onset of Friedreich’s ataxia?
2 to 16 yo
What is the clinical presentation of Friedreich’s ataxia?
ABN sensation Weakness ABN MSR Limb and trunk ataxia Optic atrophy Dysarthria Cardiomyopathy Kyphoscoliosis Pes cavus
What is the clinical presentation of Sjogren’s syndrome?
Dry eyes
Dry mouth
Keratoconjunctivitis
Associated w/ RA
What is the clinical presentation of Pyridoxine (B6)?
ABN sensation
Gait disturbances
+ Lhermitte’s sign
Sx improve w/ stopping drug
What dose of Pyridoxine (B6) causes toxicity?
> 600 mg/day
What is the clinical presentation of ETOH toxicity?
Sensory ABN Wrist/foot drop Korsakoff’s psychosis Wernicke’s encephalopathy \+/- myopathy
What is seen in nerve biopsy of ETOH toxicity?
Wallerian degeneration
What is the etiology of neuropathy with ETOH toxicity?
Malnutrition or direct
nerve injury
What is the etiology of neuropathy with amyloidosis?
Amyloid deposition in DRG
What is the clinical presentation of amyloidosis?
Sensory ABN Weight loss Hepatomegaly Purpura Nephrotic syndrome CHF
What seen on tissue biopsy in amyloidosis?
(+) birefringence with Congo red staining
What is the clinical presentation of sarcoidosis?
Low birth weight Fatigue Bilateral hilar adenopathy Uveitis CN involvment
What are lab findings in Sarcoidosis?
Inc ESR
Nerve biopsy: sarcoid tubercles
What are the types of neuropathy associated with DM?
Polyneuropathy
Mononeuropathy
Autonomic disorders
Amyotrophy
What is seen on nerve biopsy in DM?
Small and large fiber ABN
What is the neuropathy presentation in uremia?
- Sensory ABN
- Hypersensitive to touch
- Restless leg syndrome
What is seen on nerve biopsy in uremia?
Paranodal
demyelination
Axon loss
What is multifocal motor neuropathy (MMN)?
Immune-mediated disorder causing inflammatory demyelination and remyelination
What is the clinical presentation of multifocal motor neuropathy (MMN)?
Slowly progressing focal weakness Fasciculations and cramps Atrophy and myokymia Asymmetric red MSR Sensation is normal Resembles motor neuron disease (MND)
What is seen on nerve biopsy in multifocal motor neuropathy (MMN)?
Endoneurial edema Lymphocytic inflammation
Red myelin density
Onion bulb formation
What are lab findings in multifocal motor neuropathy (MMN)?
Inc anti-GM1 antibody titers
What is multifocal motor neuropathy (MMN) defined by on EDX?
Multifocal motor conduction block. More than one site of CB can occur in a single motor nerve
What is seen on EMG in multifocal motor neuropathy (MMN)?
ABN spontaneous activity, including fasciculations and myokymic discharges
What are differences in weakness between MMN and MND?
In MMN activity is confined to the muscles of clinical weakness and MND it is diffusely distributed.
What are differences in nerve patterns between MMN and MND?
In MMN activity can be traced back to peripheral nerve territories and MND it can be traced to a spinal segmental pattern.
What are the categories of HIV-related neuropathy?
-Distal Symmetric Polyneuropathy Inflammatory -Demyelinating Polyneuropathy -Mononeuropathy Multiplex -Progressive Polyradiculopathy -Autonomic Neuropathy
What is affected in Distal Symmetric Polyneuropathy?
Sensory and automonic fibers
Motor in advanced cases
What is the etiology of Mononeuropathy Multiplex?
Thrombosis of the vasa nervorum leads to multiple lesions in various nerves
What is affected in Mononeuropathy Multiplex?
Primarily axonal loss with relative myelin sparing
What is the etiology of progressive polyradiculopathy in HIV?
Cytomegalovirus
What is the clinical presentation of progressive polyradiculopathy in HIV?
Severe asymmetrical
pain, numbness, and motor deficits in the legs. Bowel/bladder dysfunctions