PNS Flashcards
(38 cards)
Guillian-Barre syndrome
Acute inflammatory Demyelinating polyradiculoneuropathy
auto-immune reaction – Cell mediated ( T cells) and circulating antibodies
Inflammation and demyelinization
Ascending weakness and paralysis
Pathogenesis: ? Viral infection, CMV, EBV, mycoplasma, ?Bacterial, Campylobacter jejuni
Morphology of GBS
inflammation of Peripheral N caused by lymphocytes and macrophages
Segmental de/re/ axonal damage
Both cranial nerves and spinal
GBS clinical
ascending paralysis - lower limb, upper limb, face
Loss of DTR
Diagnose GBS
CSF = high protein, but no cells
Treatment GBS
Plasmapharesis
Leprosy, the two types
Hansen’s disease, Infectious polyneuropathy
Tuberculoid form - involves cutaneous nerves
Lepromatous form- involves a large peripheral nerve – bacilli infect and proliferate in the Schwann cells
Leprosy morphology and clinical
Morphology:
Demyelinization, remyelinization and axonal damage. Advanced stage - nerve thickening
Clinically :
symmetric polyneuropathy involving pain fibers–> loss of sensation–> cause ulcers
Charcot-marie-tooth disease-I description
Hereditary Motor and Sensory Neuropathy Type I ( HMSN 1)
Most common - hereditary neuropathy & neuropathy in children.
AD inheritance
Morphology of HMSN
Demyelinization and re-myelinization –onionbulbs involving distal nerves ( hypertrophic neuropathy)
Demyelination of the posterior column of the spinal cord
Clinical features of charcot marie tooth
sensory and motor deficit pes cavus - high arched foot palpable peroneal N - Distal muscle weakness( below knee) Progressive muscular atrophy of the calf Foot drop
‘Werdnig-Hoffman disease” cause?
Spinal Muscular atrophy
Infantile motor neuron disease
AR diseases – Symptoms at early age 1 to 4 months and is fatal by 3 yrs; no cure for SMA yet known
Homozygous deletion of SMN1 gene( survival motor neuron gene on chr 5 )
Pathology of Werdnig-hoffman disease?
Selective loss of neurons in the ant horn of the spinal cord
Biopsy – Muscle fibre atrophy -Panfascicular
Pathogenesis of charcot marie?
Mutation – involves genes involved in formation and maintenance of myelin
Affects both sensory & motor functions of the extremities
Clinical presentation of Werding Hofman
muscle weakness
poor muscle tone : hypotonia
legs that tend to be weaker than the arms
Increased susceptibility to respiratory tract infections
developmental milestones, such as lifting the head or sitting up, can’t be reached.
What is the difference between dystrophy and myopathy?
Dystrophies are inherited disorders beginning in childhood-
histologically muscle fibers degenerate and are replaced by fibrofatty tissues
Duchenne Muscular dystrophy(DMD) and Beckers Muscular Dystrophy(BMD) are both caused due to a mutation in
Dystrophin
X-linked recessive
Clinical findings of Duchenne’s muscular dystrophy
Normal at birth.
“Waddling gait”
Difficulties in standing up- “Gowers sign”
Wheel chair bound by age of 10 – 12 yrs
Serum CK increased during first decade of life. Later Normal levels.
Pseudohypertrophy of the calf muscles – Fat & Connective tissue
20 yrs - Heart failure dt dilated cardiomyopathy and arrhythmias, respiratory infection & respiratory insufficiency- fatal
Myotonic Dystrophy is described as
Impaired relaxation of muscles – cannot release the hand after hand shake
chronic, slowly progressing, highly variable inherited multisystemic disease
Pathogenesis of Myotonic dystrophy
Pathogenesis :
Triplet repeat expansion of CTG>50 in Ch -19 gene - Dystrophia-Myotonia protein kinase (DMPK)
Autosomal dominant inheritance
Clinical findings of myotonic dystrophy
Clinical:
Congential type –Severe
Abnormality of gait, weakness of foot & intrinsic muscles of the hand
Adult onset type -Weakness, stiffness of muscles, atrophy of facial muscles and ptosis
Extramuscular manifestations: Cataract, testicular atrophy, GIT disorders, cardiomyopathy , DM, frontal balding.
Malignant Hyperthermia (malignant hyperpyrexia) is described as
Rare clinical syndrome triggered by anesthetic agents like halothane and succinyl choline
Malignant Hyperthermia (malignant hyperpyrexia) is caused by
Mutation – Genes involving voltage gated calcium channel(Ch-1)
Clinical findings of Malignant Hyperthermia (malignant hyperpyrexia)
Hypermetabolic state – Tachypnea, Tachycardia, muscle spasm, hyperpyrexia
Treatment and diagnosis of Malignant hyperthermia?
Biopsy of muscle showing contraction on exposure to anesthetic agent
Treatment – Dantrolene Sodium( muscle relaxant)
