PNS

Question 1

Guillian-Barre syndrome

Answer 1

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

Question 2

Morphology of GBS

Answer 2

inflammation of Peripheral N caused by lymphocytes and macrophages

Segmental de/re/ axonal damage

Both cranial nerves and spinal

Question 3

GBS clinical

Answer 3

ascending paralysis - lower limb, upper limb, face

Loss of DTR

Question 4

Diagnose GBS

Answer 4

CSF = high protein, but no cells

Question 5

Treatment GBS

Answer 5

Plasmapharesis

Question 6

Leprosy, the two types

Answer 6

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

Question 7

Leprosy morphology and clinical

Answer 7

Morphology:
Demyelinization, remyelinization and axonal damage. Advanced stage - nerve thickening

Clinically :
symmetric polyneuropathy involving pain fibers–> loss of sensation–> cause ulcers

Question 8

Charcot-marie-tooth disease-I description

Answer 8

Hereditary Motor and Sensory Neuropathy Type I ( HMSN 1)

Most common - hereditary neuropathy & neuropathy in children.

AD inheritance

Question 9

Morphology of HMSN

Answer 9

Demyelinization and re-myelinization –onionbulbs involving distal nerves ( hypertrophic neuropathy)

Demyelination of the posterior column of the spinal cord

Question 10

Clinical features of charcot marie tooth

Answer 10

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

Question 11

‘Werdnig-Hoffman disease” cause?

Answer 11

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 )

Question 12

Pathology of Werdnig-hoffman disease?

Answer 12

Selective loss of neurons in the ant horn of the spinal cord

Biopsy – Muscle fibre atrophy -Panfascicular

Question 13

Pathogenesis of charcot marie?

Answer 13

Mutation – involves genes involved in formation and maintenance of myelin
Affects both sensory & motor functions of the extremities

Question 14

Clinical presentation of Werding Hofman

Answer 14

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.

Question 15

What is the difference between dystrophy and myopathy?

Answer 15

Dystrophies are inherited disorders beginning in childhood-

histologically muscle fibers degenerate and are replaced by fibrofatty tissues

Question 16

Duchenne Muscular dystrophy(DMD) and Beckers Muscular Dystrophy(BMD) are both caused due to a mutation in

Answer 16

Dystrophin

X-linked recessive

Question 17

Clinical findings of Duchenne’s muscular dystrophy

Answer 17

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

Question 18

Myotonic Dystrophy is described as

Answer 18

Impaired relaxation of muscles – cannot release the hand after hand shake

chronic, slowly progressing, highly variable inherited multisystemic disease

Question 19

Pathogenesis of Myotonic dystrophy

Answer 19

Pathogenesis :
Triplet repeat expansion of CTG>50 in Ch -19 gene - Dystrophia-Myotonia protein kinase (DMPK)
Autosomal dominant inheritance

Question 20

Clinical findings of myotonic dystrophy

Answer 20

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.

Question 21

Malignant Hyperthermia (malignant hyperpyrexia) is described as

Answer 21

Rare clinical syndrome triggered by anesthetic agents like halothane and succinyl choline

Question 22

Malignant Hyperthermia (malignant hyperpyrexia) is caused by

Answer 22

Mutation – Genes involving voltage gated calcium channel(Ch-1)

Question 23

Clinical findings of Malignant Hyperthermia (malignant hyperpyrexia)

Answer 23

Hypermetabolic state – Tachypnea, Tachycardia, muscle spasm, hyperpyrexia

Question 24

Treatment and diagnosis of Malignant hyperthermia?

Answer 24

Biopsy of muscle showing contraction on exposure to anesthetic agent

Treatment – Dantrolene Sodium( muscle relaxant)

Question 25

3 types of Congenital myopathies

Answer 25

Central core disease – AD
- May present with “malignant hyperthermia”
Nemaline “Rod” Myopathy – AR
Centronuclear Myopathy – X-linked form

Question 26

Clinical findings of Congenital Myopathies?

Answer 26

Clincial- Early onset – generalised muscle weakness & hypotonia - “Floppy babies” or may have severe joint contractures – Arthrogryposis

Question 27

Mitochondrial Myopathies clinical

Answer 27

Proximal Muscle weakness, external opthalmoplegia

neurological symptoms (mitochondrial encephalopathies), cardiomyopathy, lactic acidosis

Question 28

Mitochondrial Myopathies morphology

Answer 28

Collection of the mitochondria in the subsarcolemmal region - “Ragged red fibres” – Gomoris trichrome stain
“Parking lot inclusions” - EM

Question 29

3 types of Inflammatory myopathies are?

Answer 29

Dermatomyositis (children or adults)- bilateral proximal muscle weakness

Polymyositis (adults)- bilateral proximal muscle weakness

Inclusion body myositis (adults>50yr)- asymmetric distal muscle

Question 30

Inflammatory myopathies are caused due to?

Answer 30

antibody directed against t-RNA synthetase called anti-Jo-1

40% of the Pts with dermatomyositis have underlying internal malignancy

Question 31

Inflammatory myopathies are?

Answer 31

Auto-immune, seen more in females

Question 32

Dermatomyositis clinical

Answer 32

Skin & Muscle involvement

• Lilac colored rash in the upper eyelid & periorbital oedema
• “Grotton lesion” – scaling patches on Knuckles and elbow
• Symmetric proximal muscle weakness
• Dysphagia [oropharyngeal & esophageal muscles involved]

Question 33

Dermatomyositis pathogenesis

Answer 33

Immunological mechanism- Immune complexes in walls of intramuscular blood vessels
?Microvascular injury – T cells, antibodies complement deposits and ischemic injury

Question 34

Dermatomyositis Histopathology

Answer 34

Perivascular infiltrates of lymphocytes and plasma cells extending in between muscle fibers.

Question 35

Polymyositis clinical

Answer 35

Clinical: Like dermatomyositis

Absence of skin lesions

Question 36

Polymyositis histology

Answer 36

Histology: Mononuclear inflammation and necrosis within muscle fibers (CD8+ T lymphocytes in endomysium)

Question 37

Inclusion Body Myositis clinical

Answer 37

Clinical :
> 50 yrs
Distal muscles affected; asymmetricalextensors of the knee & flexors of the wrist

Question 38

Inclusion Body Myositis histology

Answer 38

Histology: Peculiar vacuoles stain positve for amyloid