Lecture 19+20 + DLA 22 Flashcards
calculate conduction velocity
D / T2-T1 for motor and sensory
poliomyelitis
Infection causing inflammation of the gray matter in the
spinal cord leading to paralysis.
lesions of the soma
due to virus
profound asymmetrical muscle weakness and signs of LMN lesions
clinical features of poliomyelitis
diagnosis?
extensive paralysis of the trunk may occur
muscle weakness
hyporeflexia
fasciculations
mid-cervical involvement (C3,4,5)
can diagnose by PCR
elevated WBC
elevated protein
glucose is normal
lesions of the schwann cells?
Guillain barre
diphtheria
demyelination due to autoimmune attack or toxins
lesions of the soma and or axon
Lou Gehrig’s disease
poliomyelitis
lesions of the synaptic cleft and end plate
botulism
alpha latrotoxin
beta bungarotoxin
curare
alpha latrotoxin
leads to the massive release of ACh by effecting presynaptic exocytotic proteins
beta bungarotoxin
provokes the release of ACh, then followed by the depletion of ACh by acting on proteins in nerve terminals (exocytosis)
botulism toxin
reduces the release of ACh by acting on presynaptic proteins
Curare
blocks the nAChRs
Lambert-Eaton Syndrome (LES)
A presynaptic disorder of the neuromuscular junction
the release of ACh is impacted
autoimmune disorder (Ab attack presynaptic voltage gated Ca channels)
characteristics of LES
muscle weakness
often found in those with pulmonary small cell cancers
less ACh is released
miniEPP is unchanged
reduced amplitude of EPP
‘waxing’ response is seen in EMG
therapy of LES
removal of tumor
immunosuppressive drugs
plasma exchange
give calcium gluconate to improve calcium influx
4-aminopyridine to prolong AP and improve transmitter release
Congenital Myasthenias
present at birth and show signs before the age of 2
- deficiency of ACh esterase
EPP is larger and prolonged - prolonged opening of channels
‘slow channel syndrome’
prolonged opening of ACh channel
muscle weakness and fatigue
Myasthenia Gravis
chronic autoimmune disease
antibodies to nAChR (reduced NMJ transmission)
can be genetic
symptoms:
weakness of somatic muscles
fatigue
restoration after rest (acute)
EMG of MG?
waning (smaller lines to the right)
Myotonia Congenita
mutation of the CICN1 chloride channel
the chloride channel defect leads to increased excitability
muscular hypertrophy can occur with little physical activity
Duchenne Muscular Dystrophy
X-linked recessive early childhood onset muscle weakness high CK levels calf hypertrophy
lack of dystrophin
positive manifestations of PNS disorders
an excess or distortion of normal functions
fasciculations
paresthesia
pain
negative manifestations of PNS disorders
total loss or diminution of normal function
paralysis or paresis
areflexia
anhidrosis
numbness
neurapraxia
mild injury due to transient compression of stretch
axonotmesis
injury associated with axonal degeneration
neurotmesis
injury causing complete transection of the nerve
usually due to laceration
carpal tunnel syndrome
median nerve compression at the wrist (Neurapraxia)
usually occurs in middle aged women, pregnancy, or hypothyroidism
swelling and reduction in tunnel size
Acute Peripheral Neuropathy- GBS
guillian barre syndrome (ex)
elevated protein seen in lumbar puncture
ascending motor and sensory loss
Chronic Peripheral Neuropathy- leprosy
leprosy (hansen disease)
affects the skin and peripheral nerves
wasting and muscle weakness
multi drug antibiotic treatment
Chronic Peripheral Neuropathy- lead poisonings
motor neuropathy in adults
encephalopathy in children ( 6 and younger)
bilateral focal weakness
wasting of extensor muscles of fingers, wrist, and arms
Chronic Peripheral Neuropathy- alcoholic peripheral neuropathy
reflects the neurotoxic effects of alcohol or deficiencies
sensory and motor loss, symmetrical
starts with sensory, then motor
nerve conduction is normal
Chronic Peripheral Neuropathy- DM
many diabetics develop polyneuropathy (both types)
most common is distal symmetrical polyneuropathy
numbness, tingling, pain
Charcot Neuropathic Osteoarthropathy
also known as charcot foot
usually due to diabetic neuropathy
can lead to bone destruction, subluxation, dislocation, deformity
rocker-bottom foot is seen
