Approach to cancer

Question 1

How can paraneoplastic syndromes present?

Answer 1

Hypercalcaemia, hypoglycaemia, hyperoestrogenism, hyperhistaminaemia, hypergastrinaemia

Question 2

Explain hypercalcaemia as a PNS

Answer 2

Tumour produces a hormone which mimics PTH causing an increase in serum calcium.
Neoplastic ddx: lymphoma, anal sac adenocarcinoma, osteosarcoma.
Non-neoplastic ddx: hypoadrenocorticism, primary CRF, vit D toxicity, lab error
CS: PUPD, v+, constipation, anorexia, tremors, muscle weakness

Question 3

Explain hypoglycaemia as a PNS

Answer 3

CS: seizure/collapse
Neoplastic ddx: insulinoma, hepatic neoplasm
Non-neoplastic ddx: hypoadrenocorticism, hepatic dz, sepsis, pregnancy

Question 4

Explain hyperoestrogenism as a PNS

Answer 4

Males, associated with sertoli cell tumour
Either retained testicle or one enlarged (tumour) and once small (effects of oestrogen)
CS: attractive to other male dogs, pendulous prepuce, bilateral symmetrical alopecia, reduced libido
Oestrogen suppresses the bone marrow and can cause anaemia, thrombocytopenia, leukopenia (bacteraemia, haemorrhage)

Question 5

What immune mediated syndromes can neoplasia cause?

Answer 5

Neuropathies, IMHA, IMTP, myasthenia gravis (thymoma, actyl choline autoantibodies)

Question 6

What other haematological effects can neoplasms have?

Answer 6

Anaemia of chronic disease, DIC, increased/decreased/normal cell count, vasculitis

Question 7

How can a tumour cause hyperviscosity syndrome?

Answer 7

Primary polycythaemia (increase in RBC production)
Secondary polycythaemia in response to hypoxia
Increased proteins in blood (overproduction of IgG)