Paraneoplastic Syndromes

Question 1

What is a paraneoplastic syndrome?

Answer 1

Syndromes caused by a cancer but not due to direct local inflammation or metastatic spread. Occur in 10% of cancer patients.

Question 2

Give 4 common cancers associated with paraneoplastic syndromes

Answer 2

Lug 
Pancreatic
Lymphoma
Breast 
Prostate 
Ovary

Question 3

What cancer types are associated with SIADH?

Answer 3

Small cell lung cancer
Pancreatic
Prostate
Lymphoma

Question 4

How does SIADH present?

Answer 4

Fatigue
Headaches
Confusion
Seizures

Question 5

What is the laboratory criteria to diagnose SIADH?

Answer 5

Hyponatraemia <130mm/L
Normal albumin and glucose
Urine osmolarity > serum osmolarity
High urinary Na+

Question 6

What is the pathophysiology of SIADH?

Answer 6

ADH secreted from well differentiated tumours. Increased ADH causes solute free water to be reabsorbed back into the bloodstream from the kidney which results in fluid retention. This results in a dilutional hyponatraemia, and high Na+ loss in the urine.

Question 7

How is SIADH managed?

Answer 7

Fluid restriction (0.5-1L/day) 
Demeclocycline (150-300mg, 8 hourly) - off label use to induce diabetes insipidus

Question 8

What is Cushing’s Syndrome?

Answer 8

Inappropriate ACTH precursor production resulting in excess cortisol

Question 9

What cancer types are associated with Cushing’s Syndrome?

Answer 9

Small cell and non small cell lung cancer
Pancreatic
Thymic
Carcinoid tumours

Question 10

How does Cushing’s Syndrome present?

Answer 10

Rapid onset
Marked weakness secondary to proximal myopathy
Hyperpigmentation
Metabolic disturbances

Question 11

How is Cushing’s Syndrome investigated?

Answer 11

24 hr urinary cortisol
Dexamethasone suppression test
ABG (metabolic acidosis)
U+Es

Question 12

How is Cushing’s Syndrome managed?

Answer 12

Anticancer therapy
Bilateral adrenalectomy
Octreotide - synthetic simvastatin

Question 13

What is the pathophysiology of paraneoplastic peripheral neuropathies?

Answer 13

Axonal degeneration or demyelination. Can be sensory, motor, autonomic or sensorimotor.

Question 14

What cancer types are associated with paraneoplastic peripheral neuropathies?

Answer 14

Small cell lung cancer
Myeloma 
Hodgkin's lymphoma 
Breast 
GI cancers

Question 15

How are paraneoplastic peripheral neuropathies investigated?

Answer 15

Nerve conduction studies
Nerve biopsy
Serum anti-Hu antibodies (maker for paraneoplastic peripheral neuropathies)

Question 16

How are paraneoplastic peripheral neuropathies managed?

Answer 16

Corticosteroids

Question 17

How does paraneoplastic cerebellar degeneration present?

Answer 17

Rapid onset and progression, prior to cancer diagnosis, bilateral cerebellar signs, late diplopia, dementia

Question 18

How is paraneoplastic cerebellar degeneration managed?

Answer 18

Steroids

Plasmaphoresis

Question 19

Which cancers are associated with paraneoplastic cerebellar degeneration?

Answer 19

Breast
Small cell lung cancer
Ovary
Hodgkin’s lymphoma

Question 20

What is Lambert-Eaton Myasthenic Syndrome?

Answer 20

Disorder of the neuromuscular junction. Reduced pre-synaptic Ca2+ dependent ACh release. Presents with proximal muscle weakness.

Question 21

What cancer types are associated with Lambert-Eaton Myasthenic Syndrome?

Answer 21

Small cell lung cancer
Breast
Thymus
GI cancers

Question 22

What is hypertrophic osteoarthropathy?

Answer 22

Painful swollen joints and finger clubbing associated with lung cancer.

Question 23

How is hypertrophic osteoarthropathy investigated and treated?

Answer 23

X-ray, bone scan

NSAIDs, corticosteroids, radiation