Myeloma Flashcards
What is the pathophysiology of myeloma?
Myeloma is a plasma cell dyscrasia. Malignant proliferation of a single clone of plasma cells accumulating in the bone marrow, leading to overproduction of Ig or Ig fragments causing organ dysfunction.
How is myeloma classified?
Based in Ig product - it is usually IgG (2/3) or IgA.
Why does myeloma increase susceptibility to infection?
Immunoparesis: levels of Igs other than the one undergoing malignant proliferation (eg IgG) are low; also neutropaenia from cell crowding and treatment.
What are Bence Jones proteins?
In 2/3 of patients with myeloma, urine contains Bence Jones proteins, which are free Ig light chains of kappa (K) or lambda (λ) type, filtered by the kidney.
Describe the epidemiology of myeloma.
Peak age 70 years More common in afro-caribbeans
Give 4 signs of end-organ damage in myeloma.
CRAB HyperCalcaemia Renal impairment - decreased urine output Anaemia, neutropaenia or thrombocytopaenia (marrow infiltration, same as leukaemia) Bone lesions
Why can myeloma cause backache and pepperpot skull?
Myeloma cells signal increased osteoclast activity which causes osteolytic bone lesions which cause backache, pathological fractures and vertebral collapse. This causes pepperpot skull - small holes in the skull.
Why can myeloma cause hypercalcaemia and what are 4 signs of hypercalcaemia?
Myeloma cells signal increased osteoclast activity, causing hypercalcaemia which causes ‘bones (fractures), stones (kidney stones), groans (abdominal pain) and psychic moans (depression)’.
Other than hypercalcaemia what can cause renal impairment in myeloma?
Light chain deposition (20% of myelomas). Damage is mainly caused by precipitation of light chains in the distal loop of Henle. Monoclonal Igs also disrupt glomeruli.
What type of anaemia occurs in myeloma?
Normocytic normochromic anaemia.
What would bloods show for myeloma?
FBC: Marrow infiltration: anaemia, neutropaenia, thrombocytopaenia. ESR: raised Urea and creatinine: raised Hypercalcaemia (40%)
What would bone marrow biopsy show for myeloma?
Many plasma cells with abnormal forms
What would blood film show for myeloma?
Rouleaux formation of red cells. This means stacks or aggregations of RBCs because of the discoid shape.
What would be seen on X ray for myeloma?
‘Punched out’ lesions eg pepperpot skull, vertebral collapse, fractures.
What is electrophoresis?
Separation of macromolecules by their charge. Lots of differently charged molecules give a diffuse smear while lots of similarly charged molecules give a band. Therefore it is used to diagnose myeloma, where there is a monoclonal Ig which shows as a band.
