Pathology of muscle , nerve and neuromuscular junction

Question 1

Name Auto-immune diseases

Answer 1

Lambert-Eaton syndrome
Myasthenia gravis
Polymyocitis

Question 2

What are para-neoplastic syndromes

Answer 2

Diverse range of conditions caused by a malignant tumour. Symptoms not caused by the tumours or their physical affect. Caused my chemicals or proteins being produced by the malignant cells , which can trigger auto-immune response/condition.

Question 3

Give examples of apart-neoplastic syndromes

Answer 3

1- Acanthosis nigricans - Skin 
2- Myositis - muscle 
3- Eaton-lambert, myasthenia gravis - neuromuscular junction 
4- Encephalitis - brain 
5- finger clubbing - bone/soft tissue 
6- anaemia - haematological

Question 4

What is motor neurone disease ( what it leads to , prognosis and causes e)

Answer 4

Condition of progressive degeneration of UMN and LMN. Weakness due to loss of muscle innervation.

Leads to problems such as inability to move limbs, speak , swallow , breath

Unknown cause with average prognosis of 3 years

Question 5

61 yr man with 9 month history of weakness of left arm, Muscle wasting and fasciculation’s, Diagnosed with motor neurone disease.

What is the most likely underlying cause

a) auto-immune
b) genetic
c) idiopathic
d) paraneoplastic
e) trauma

Answer 5

C) idiopathic

Question 6

61 yr man with 3 month history of weakness on left arm, Muscle wasting and fasciculation. Diagnosed with motor neurone disease

Which nerve are most commonly affected in this condition

a) UMN and LMN
b) somatic motor neurones
c) general visceral motor neurones
d) LMN
e) UMN

Answer 6

a) UMN and LMN

Question 7

Myasthenia Gravis vs Lambert-Eaton

Answer 7

MG: autoimmune disease against Calcium channels antibodies

LE: autoimmune disease against acetylcholine receptors antibodies

Question 8

67 yr woman with muscle weakness is diagnosed with Lambert-Eaton syndrome

Which underlying cancer is most likely

a) lung
b) breast
c) stomach
d) colon
e) ovary

Answer 8

e) Lung

Question 9

Do all Lambert-Eaton syndrome patients have an underlying cancer

Answer 9

No but a lot do

Question 10

67 yr woman with muscle weakness is diagnosed with Lambert-Eaton syndrome

Which underlying cancer is most likely

a) lymphoma
b) melanoma
c) small cell carcinoma
d) adenocarcinoma
e) sarcoma

Answer 10

c) SMALL CELL CARCINOMA

Question 11

67 yr woman with muscle weakness is diagnosed with Lambert-Eaton syndrome

Which serum antibody test is most likely to be abnormal

a) acetylcholine receptor
b) smooth muscle
c) calcium channels
d) mitochondrial
e) sarcolemmal

Answer 11

C) calcium channels

Question 12

44 yr woman with muscle weakness and myasthenia gravis

antibodies to which structure are most likely to be present

Answer 12

Neuromuscular junction and striated muscles.

+most specific answer neuromuscular junction

even though ACTH receptor is attached to muscle too

Question 13

44 yr woman with muscle weakness and myasthenia gravis

Which serum test is most likely to be abnormal

Answer 13

Acetylcholine receptor

Question 14

Link of MG with thymus

Answer 14

Thymus is small gland in chest , behind the sternum.

MG is autoimmune condition and in some Adult patients the thymus gland becomes hyperplastic ( enlarges ) and resembles the thymus of a child. ( Thymic hyperplasia )

If thymus is removed even though it appears normal and not hyperplasic it can still improve condition of MG patient.

Question 15

Link of MG with thymus

Answer 15

Thymus is small gland in chest , behind the sternum.

MG is autoimmune condition and in some Adult patients the thymus gland becomes hyperplastic ( enlarges ) and resembles the thymus of a child. ( Thymic hyperplasia )

If thymus is removed even though it appears normal and not hyperplasic it can still improve condition of adult MG patient.

Question 16

What is Polymyositis

Answer 16

Condition that might be auto-immune. Causing Chronic inflammation involving skeletal muscles and other muscles.

Numerous auto antibodies that are associated with polymyositis.Makes diagnosing complicated. may require muscle biopsy

Question 17

What is a histological sign of polymyositis

Answer 17

Prominent chronic inflammatory cells surrounding muscle fibres

Question 18

44 yr woman has muscle weakness and polymyositis is suspected.

Which investigation is most likely to be useful ?

a) ACTH receptor antibodies
b) muscle biopsy
c) Calcium channel antibodies
d) dystrophin gene analysis
e) manual muscle strength test

Answer 18

b) Muscle biopsy

Question 19

44 yr woman has muscle weakness and polymyositis is suspected.

Which histology would support the clinical diagnosis

a) granulomas
b) inclusion bodies
c) fatty infiltration
d) lymphocytic infiltrate
e) neutrophilic infiltrate

Answer 19

D) Lymphocytic infiltrate

Question 20

When is a muscle biopsy used

Answer 20

To diagnose Polymyositis

Question 21

12 yr body with muscle weakness and is diagnosed with Duchenne muscular dystrophy

On which chromosome is gene for this condition?

Answer 21

X

Question 22

What is Duchenne muscular dystrophy aka pseudohypertrophic muscular dystrophy ( Causes, timeline )

Answer 22

Muscular dystrophy that is a X linked recessive genetic disorder. ( only males get it , but females could be carriers and pass it down to male sons )

Patients pass before having children , become disabled young. By age of 14 muscle is filled with scar and fat tissue.

Dystrophin protein of muscle is absent in Duchenne’s

Question 23

12 yr body with muscle weakness and is diagnosed with Duchenne muscular dystrophy

which histology is most likely in his calf muscles

a) fatty infiltration
b) skeletal muscle hypertrophy
c) smooth muscle infiltration
d) neovascularisation
e) infiltrates of chronic inflammatory cells

Answer 23

a) fatty infiltration due to muscle dystrophy

Question 24

12 yr body with muscle weakness and is diagnosed with Duchenne muscular dystrophy

which is the best clinical description of this muscle enlargement ?

a) skeletal muscle hyperplasia
b) skeletal muscle hypertrophy
c) pseudohypertrophe
d) atrophy
e) lipoma

Answer 24

c) pseudohypertrophy

Not Lipoma ( tricky )