Extras on Lung Cancer

Question 1

Pancoast tumour:

What is it?

S+S:

• Why does it cause pain?
• Why does it cause small muscle wasting in the hand?

Answer 1

Apical lung cancer, usually squamous

Compression of C8-T2 nerves - shoulders, arm, and hand

T1 compression

Question 2

Pancoast tumour:

Why does Horner’s syndrome occur?
What are the 4 symptoms of Horner’s syndrome?

What else may it compress leading to distended neck veins?

Answer 2

Compression of sympathetic ganglion

Miosis
Ptosis
Exophthalmos
Anhidrosis

SVC obstruction

Question 3

Lambert-Eaton Myasthenic Syndrome (LEMS):

It is a autoimmune destruction of presynaptic voltage-gated calcium channels (VGCC) in the neuromuscular junction, leading to reduced ACh release.

Why is this linked to lung cancer?

Answer 3

Linked to SMALL CELL LC as there is a cross-reaction with the tumour antigen so body attacks tumour but also attacks the VGCC as the antigens are similar.

Question 4

Lambert-Eaton Myasthenic Syndrome (LEMS):

S+S:
- Knowing what it is, list some symptoms you think may occur?

How does it differ from Myasthenia Gravis?

Why does it continue after the removal of the tumour?

Answer 4

Weakness - starting in proximal legs 
Areflexia - no reflexes 
ANS dysfunction - dry mouth and postural hypotension 
Dysphagia and dysarthria 
Diplopia and ptosis 

Strength and reflexes INCREASE with repetition

Continuous presence of autoantibodies

Question 5

Lambert-Eaton Myasthenic Syndrome (LEMS):

Investigations:

• What is tested for in the serum?
• What can be done to look at electrophysiology? - 3
• Why is CXR done?

Answer 5

Autoantibodies for VGCC.

AChR Ab suggests MG

EMG
Nerve conduction studies
Low-frequency repetitive nerve stimulation

To look for small cell lung cancer - may be how this presents first

Question 6

Lambert-Eaton Myasthenic Syndrome (LEMS):

Management:

What does amifampridine do?

What is given in severe disease? - THINK ABOUT HOW THE DISEASE HAPPENS

Answer 6

It is a potassium channel blocker which leads to presynaptic membrane depolarisation and VGCC opening which improves symptoms

Immunosuppression (e.g. steroids), IVIG or plasma exchange

Question 7

SVC obstruction:

What causes this apart from lung cancer?

S+S:

• Main symptom
• Main signs
• Why may they get SOB, wheeze or stridor?

Pemberton’s sign is done to look for SVC obstruction. What is done?

Answer 7

Lymphoma, germ cell tumours, intravascular devices

Engorged veins in chest and arms

Raised JVP
Swollen face, neck or arm

Tracheal compression 
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Lifting both arms up
Elbows touch ears 
Holding for 1 minute

Question 8

SVC obstruction:

Investigations - 2

Management:

• Why are steroids given?
• What is done to open up SVC if Rx of cancer ineffective?

Answer 8

CXR and CT chest
Venography
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To reduce tumour burden in patients with steroid-responsive malignancies such as lymphoma or thymoma. Steroids are also helpful in reducing laryngeal oedema, which may result from the administration of radiation therapy.

SVC stenting