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NEUROPATHIES (GUILLAIN BARRE SYNDROME (acute inflam) (CLINICAL FEATURES…
NEUROPATHIES
GUILLAIN BARRE SYNDROME (acute inflam)
INCIDENCE
2 per 100 000 per year
occurs 1-3 weeks after viral or other infection/immunisation
AETIOLOGY
May follow a viral infection - VZV, mumps, CMV. Also assoc with Mycoplasma, Campylobacter, antitoxins, trauma, surgery, rarely assoc with malig disease and immunodeficiency.
both antibody and cell-mediated reactions to peripheral nerve myelin are involved
some pts prod antibodies to myelin glycoproteins or gangliosides, others develop a T cell-mediated assault on myelin basic protein
segmental demyelination => secondary axonal damage - if process severe.
perivascular infiltration with lymphocytes occurs within periph nerves and nerve roots
lymphocytes and macrophages release cytotoxic substanes [cytokines] = damage Schwann cell/myelin.
when axon damage and nerve cell death occur, regeneration can't take place
CLINICAL FEATURES
Sensory symptoms predominate at the beginning
parasthaesia of feet then hands
pain (esp back) occasionally an initial symptom
weakness develops next - various presentations - maximal 3 wks after onset
tendon reflexes are absent or depressed
Severe - resp and bulbar involvement
tracheostomy/ventilation needed in 20% of cases
facial weakness in 50%
papilloedema may occur when CSF protein is markedly elevated (blocked arachnoid villi?)
Autonomic involvement
tachycardia
fluctuating bp
retention of urine
variants are common - 20% of cases
acute motor axonal neuropathy (AMAN) - often after campylobacter infection
antibodies associated: anti-GD1a and GM1
acute motor, sensory axonal neuropathy (AMSAN)
Acute snesory neuropathy assoc with anti-GD1b
IX
CSF
cells usually absent, but in 20% up to 50cells/mm^3 may be found
protein elevated, often not until 2/3 wks
NCS
early in illness may be normal
findings of multifocal demyelination soon develop
slowing of motor conduction
conduction block
prolonged distal motor latencies
Ancillary Ix [to identify any precipitating infection
viral and bacterial studies
electrolytes checked for ISADH and immune complex glomerulonephritis
CLASSIFICATIONS
ACUTE (days to 4 weeks)
diptheria
Cranial nerve onset. Mixed motor/sensory
Demyelinative. No inflammatory infiltration.
Porphyria
Motor (may begin in arm). autonomic disturbance. minimal sensory loss.
Axonal
inflammatory [GBS]
predominantly motor. Distal or proximal. Autonomic disturbance.
demyelinative with perivascular lymphocytic infiltration
SUBACUTE -occasionally chronic [months and years] - ASYMMETRICAL + MULTIFOCAL
infections
leprosy
spectrum from paucibacillary (Few organisms with intense inflam) to multi bacillary (many organism with little inflam)
sensory neuropathy, often multifocal; assoc depigmentation
HIV
range of assoc. neuropathies
vasculitic disorders
polyarteritis nodosa; wegner's granulomatosis; churg-strauss syndrome
vasculitis with wallerian degeneration in distal nerves
usually presents with mononeuritis multiplex or an asymmetrical sensorimotor neuropathy. often painful
non-systemic vasculitis
as above without systemic features
SUBACUTE AND CHRONIC [MONTHS AND YEARS] SYMMETRICAL
Metabolic and endocrine disorders
hypothyroidism - distal sensorimotor
acromegaly - distal sensorimotor
Uraemia - distal sensorimotor, axonal degeneration
Diabetes - most commonly distal sensorimotor
nutritional deficiencies
Vit B1 (thiamine) - includes alcoholic neuropathy
predominantly sensory, burning feet. weakness may develop. autonomic involvement common but mild.
axonal degeneration with segmental demyelination
B12 deficiency
predominantly sensory; may be associated spinal cord involvement
malignant disease
paraneoplastic
axonal; may be associated antibodies (anti-Hu)
sensory or sensorimotor
infiltrative
More common with lymphoma
mutlfocal, often a polyradiculopathy
paraprotein associated
monoclonal gammopathy (igG, igA, IgM)
thickened nerves with amyloid deposition and small fibre neuropathy
sensorimotor neuropathy often with autonomic involvement. may present as multiple mononeuropathies
inherited neuropathies
charcot-marie-tooth disease
refsum's disease
phytanic acid storage disorder, sensorimotor neuropathy with ichthyosis, retinitis pigmentosa and deafness
drug induced
oncology drugs
adriamycin; cisplatin; taxanes; vincristine
HIV drugs
didanosine; stavudine;zalcitabine
antibiotics
metronidazole; ethambutol;isoniazid; nitrofurantoin; dapsone
Others
Amiodarone; gold; phenytoin
Toxin induced
solvents
heavy metals
lead, arsenic, thallium
IX in pt with distal symmetrical sensorimotor neuropathy