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xB11W3 > PBL 2 > Flashcards

PBL 2 Flashcards

1
Q

what is muscular dystrophy?

A

group of familial disorders that cause degernation of skeletal muscle fibres causing progressive weakness and loss of muscle mass

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2
Q

how are muscular dystorphies distinguishable from neuropathies?

A

as in muscular dystrophy the neuromuscular junctions are not affected

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3
Q

what are the 3 types of muscular dystrophy?

A

Duchenne’s
becker
mytonic

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4
Q

what are the 2 dystrophinopathies?

A

Duchenne’s and Becker muscular dystrophy

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5
Q

what are dystrophinopathies?

A

muscular dystrophy caused by mutations in the dystrophin gene

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6
Q

what is the genetic basis of duchenne’s muscular dystrophy?

A

X-linked recessive

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7
Q

what is the chance of a boy and a girl being affected by duchenne’s if their mother is a carrier?

A

50% for girs to be a carrier

50% for boy to be affected

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8
Q

why is Duchenne’s much more common in men?

A

because they only have a single X chromosome so the affected one will definitely be expressed unlike in females where only one X chromes gets affected

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9
Q

what is lyonization?

A

X-inactivation

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10
Q

what happens to a female if their X chromosome that is not affected by duchennes is expressed?

A

then they will be asymptomatic

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11
Q

what happens in females if more cells have the defective dystrophin gene than do not?

A

they can be manifesting carriers - show slow progressive weakness beginning in the 2nd or 3rd decade of life

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12
Q

how many times is DMD sporadic and how many times is the mother a carrier?

A

DMD is sporadic 1/3rd of the time and the mum is a carrier 2/3rds of the time

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13
Q

when will DMD clinically manifest by?

A

5 years of age

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14
Q

when will someone with DMD typically be whellchair dependant by?

A

10-12 years

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15
Q

what are symptoms of DMD?

A 
frequent falls
Gower's sign
not walking by 15 months
not speaking as well as children their age
trouble running or jumping
waddling gait
walking on toes
poor balance
walks with legs wide apart
walks with arms and shoulders held back
large calf muscles
muscle pain and stiffness
learnign disabilities
walks with chest protruded 
delayed growth
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16
Q

what are late symptoms in DMD?

A

respiratory failure due to weak diaphragm
scoliosis
dilated cardiomyopathy
arrhythmias

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17
Q

what is Gower’s sign?

A

using hands to get up from lying/sitting down due to weak muscles around hips and legs

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18
Q

why does DMD present with large calf muscles?

A

pseudohypertrophy - muscular enlargement through deposition of fat rather than muscle fibre

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19
Q

what is the life expectancy of a neonate with Duchenne’s?

A

about 27 years

20
Q

what is the pathophysiology of duchenne’s?

A

absence of dystrophin in skeletal muscles due to a mutation means we get cell membrane damage due to the protein not being able to anchor cells cytockeletons to extracellular matrix. this cell membrane damage allows Ca2+ to enter muscle cells= necrosis and allows creatine kinase to leave the muscle cell
eventually, muscles are infiltrated with fat and fibrotic tissue, leaving them weak

21
Q

whats the role of dystrophin?

A

Dystrophin-associated protein complex acts as an anchor to connect each muscle cell’s cytoskeleton with the extracellular matrix.

22
Q

how can we diagnose Duchenne’s?

A

high creatine kinase levels
mutations seen in dystrophin in DNA tests
muscle biopsy to stain for dystrophin

23
Q

what is the treatment for duchennes?

A

glucocorticoids to slow down the degeneration

physiotherapy and conditioning to improve the quality of life

24
Q

how is becker’s muscular dystrophy different to duchennes?

A

dystrophin is present but it is misshapen due to a missense mutation
symptoms appear later at 10-20 years old
intellectual disability and contractors are not as common/severe
cardiac fibrosis may be the predominant presentation

25
Q

what is myotonic muscular dystrophy?

A

the most common muscular dystrophy beginning in adulthood
it is characterized by progressive muscle wasting and weakness. People with this disorder often have myotonia and are not able to relax certain muscles after use.

26
Q

what is myotonia?

A

prolonged muscle contractions

27
Q

what is the genetic basis for myotonic muscular dystrophy?

A

autosomal dominant - only 1 copy of the gene needs to be present and is not sex linked

28
Q

what is type 1 mytotonic muscular dystrophy?

A

Steinerts disease
There is a trinucleotide repeat of CTG on DMPK gene on chromosome 19 which codes for myotonic dystrophy protein kinase = inhibition of muscle contraction

29
Q

what is more severe, type 1 or type 2 myotonic muscular dystrophy?

A

type 1

30
Q

what is type 2 myotonic muscular dystrophy?

A

tetra nucleotide repeat of CCTG on CNBP gene on chromosome 3 which codes for cellular nucleic acid binding protein

31
Q

when does type 2 myotonic muscular dystrophy present?

A

in adulthood with mild muscle weakness mostly affecting proximal muscles of thighs and hips

32
Q

what are some complications of myotonic muscular dystrophy?

A

cataracts, breathing and swallowing weakness, head, neck and facial muscle weakness, heart difficulties, insulin resistance etc…

33
Q

what is anticipation?

A

there is earlier symptom onset and greater severity with each generation

34
Q

why is myotonic muscular dsytrophy worse with each generation?

A

with each generation we get more repeats and the higher the number of repeats, the earlier and more severe the symptoms are

35
Q

outline the pathophysiology of myotonic muscular dstrophy?

A

repeat expansion causes widespread hydrogen bonding between C and G pairs which makes RNA form condensed clumps so other genes cannot be expressed normally and then egene deficiencies lead to myotonic dystrophy

36
Q

how do we diagnosi myotonic muscular dystrophy?

A

genetic testing to check for number of CTG and CCTG repeats

electromyography to assess electrical activity in muscles

37
Q

what is the treatment for myotonic muscular dystrophy?

A

there is no treatment but you can treat symptoms e..g surgery to prevent cataracts or having a cardiac pacemaker

38
Q

where does creatinine come from?

A

creatine is used in ATP formation during muscular effort and is then converted into creatinine which enters the blood stream and is excreted through the kidneys

39
Q

what is the Healthy Child Programme?

A

a universal preventative service providing families wth a programme of screening, immunisation, health + development reviews, supplementd by advice around health, wellbeing and parenting

40
Q

what should effective implementation of the healthy child programme lead to?

A

strong parent-child attachment and positive parenting
care that keeps children healthy and safe
preventing some serious communicable diseases
healthy eating and increased activity promotion to reduce obesity
readiness for schooll and improved learning
increasing breastfeeding rates
early detection for developmental delay, abnormalities, ill health and safety concerns

41
Q

what are the 4 areas of development in a child?

A

gross motor
fine motor and vision
hearing speech and language
social skills and behaviour

42
Q

how many children will be able to walk by 12 months? and by 15?

A

50 % by 12 months and 90% by 15 months

43
Q

when should you worry about developmental delay in terms of walking?

A

18 months

44
Q

what is the difference between speech and language in development?

A

speech is making sounds and language is about the content and organisation

45
Q

what are some developmental red flags?

A 
regression of skills
not fixing and following objects by 3 months
not responding to noise
not babbling by 1 years
limited use of speech at 3 years
no smile at 8 weeks
not holding objects at 5 months
early hand preference
not sitting u at 12 months
not walking by 18 months
persistent toe walking
not pointing at objects at 2 years

xB11W3 (9 decks)

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