88 diseases causing muscle hypotonia (guillain barre, werdnig hoffman, DMD, CP

Question 1

what is GBS

Answer 1

acute postinfectious segmental demylinating polyneuropathy characterized by symmetric and ascending flaccid paralysis.
(more common in adults)

Question 2

what triggers GBS

Answer 2

URI 1-4wks before onset

fluvaccination is rare

Question 3

common infectious agents linked to GBS

Answer 3

bac
-Campylobacter jejuni!! most common is campylobacter enteritis

-Mycoplasma pneumoniae

VIRAL

• Cytomegalovirus
• Epstein-Barr virus

Question 4

PP of GBS

Answer 4

molecular mimicary of pathogenic agens causing cross rxn w/ schwann cell mylein d/2 sim struc

Humoral response( b cells a.bodies) causing segmental inflamm and destruction of the axon’s yelin sheath

reduces the spped & quality of neuronal transmissions

Question 5

types of GBS 4

Answer 5

Acute inflammatory demyelinating polyneuropathy
-linked to C.jejuni

Chronic inflammatory demyelinating polyneuropathy (CIDP)
-lasts 2 months

Miller-Fisher syndrom
-Affects CRANIAL NERVES

Multifocal motor neuropathy (MMN)

Question 6

sx of GBS

Answer 6

begins w/ back and limb pain and parasthesias

ASCENDING BILATERAL FLACCID PARALYSIS
socks & gloves

reduced/ absent reflexes

LANDRY paralysis (resp muscles)

affects ANS
-constipation/ voiding

Question 7

dg of GBS

Answer 7

LP
-increased proteins and wbc in csf

electroneurograph shows lowered nerve conduction velocity

Question 8

rx of GBS

Answer 8

supportive
-monitor respiratory and carduac func

• IV immunoglobulins in severe forms
• plasmapheresis( filtere plasma from blood and remove toxic subs in this case auto ab’s)

Question 9

prognosis

Answer 9

schwann cells evetually perform remylination of axons

5% die d/2 respiratory paralysis

Question 10

what is spinal muscular atrophy

Answer 10

group of autosomal recessive motor neuron diseases caused by apoptosis of lower motor neurons due to deletion of the survival motor gene on chromosome 5

severity depends on the number of defective SMN2 genes available in the genotype

Question 11

PP oof SMA

Answer 11

involves the bulbar and lower motor neurons

SMN is involved in motor neuron stim and innihibyd apoptosis

lack increases apoptosis of motor neurons and causes poor development of the motor unit causing atrophy of the muscles but with preserved sensory neuron function

eye movement preserved and CN 3,4,6 PRESERVEED

Question 12

types of SMA

Answer 12

type 1a- severe and hypotonia occurs in utero

type 1b Werdnig-Hoffman disease!!!!!
-severe
-

type 2

• imdt
• 718months
• kiphoscoliosis

type 3
-mild
18months

type 4

• adult (10-30 years)
• normal life

Question 13

werdnig hoffman sx

Answer 13

onset of 6 months

• symmetrical muscle weakness
• proximal muscles > distal
• pradaoxical breathing d/2 weakness of intercostal muscles
• absent DTR
• weak cry
• FASCICULATIONS
• dysphagia

loss of motor milestone: cant sit up / cant keep head up

life expectancty of 2 years

Question 14

most common cause of death in SMA

Answer 14

resp failure and pneumonia

Question 15

dg of SMA

Answer 15

genetic testing

electromyography

muscle biopsy to show atrophy

Question 16

dx of SMA

Answer 16

polio

other muscluar atrophies (DMD/BECKER)

Question 17

rx of SMA

Answer 17

definitive
-intrathecal NUSINERSEN( increases the amount of functioning SMN2/ reduces bkdwn)

• resp support
• rehab

Question 18

progressive muscular dystophies (DUCHENNE/ BECKER)

Answer 18

x linked recessive progressive diseasees d/2 mutaton of the dystrophin gene

dmd; 2-5 years
bmd; 15y/o

Question 19

PP of dmd

Answer 19

dystrophom seucres cytoskeleton of myocytes to the ECM via actin fillaments

mutaions cause distubance of signal PW, leads to necrosis of myocytes and replacement of connective tissue w. fat tissue leading to PSEUOHYPERTROPHY

Question 20

sx of DMD

Answer 20

PSUDOHYPERTROPHY of calf

reuced reflexes

gower/s sign

TRENDELENBURG SIGN(waddle gait)

cant walk by 12yo

heart

• dilated cardiomyopathy
• arrythmua]-respiratory inssuf

Question 21

becker;s

Answer 21

same as DMD but slower /milder as only partial mutation occurs

Question 22

dg of dmd

Answer 22

Blood tests: ↑↑ creatine kinase

Genetic analysis: detect dystrophin gene mutation

Muscle biopsy
if genetic analysis is -inconclusive
-muscle necrosis
-absent/ reduced dystrophin

Question 23

dx of DMD

Answer 23

SMA

polymyositis 
-Muscle biopsy
Only performed if genetic analysis is inconclusive
-dxw/ increased LDH 
biopsy shows inflamm infiltrate

Question 24

rx od=f dmd

Answer 24

no cure
DMD-glucocorticoids

phhysiotherrapy
ventilation support

Question 25

DMD prog

Answer 25

30 yrs life expectancy d/2 cardiac / pulmonary complications

Question 26

BMD prog

Answer 26

40-50yr usually cardiogenic cause of death