multiple myeloma Flashcards
definition of multiple myeloma
Haematological malignancy characterized by proliferation of plasma cells resulting in bone lesions and production of a monoclonal immunoglobulin (paraprotein, usually IgG or IgA).
plasma cells are the effector cells of the specific humoral immune response
aetiology of multiple myeloma
unknown
postulated viral trigger
Chromosomal aberrations are frequent, certain cytokines (e.g. IL-6) act as potent growth factors for plasma cell proliferation.
Associated with ionizing radiation, agricultural work or occupational chemical exposures (benzene).
transformation is because of genetic aberrations that accumulate from a pre-malignant condition - monoclonal gammopathy undetermined significance - always
epidemiology of multiple myeloma
2nd most common haematological malignancy
Annual incidence is 4 in 100,000,
prevalence is increasing
70yrs - incidence increase with age
men more
Afro-Caribbeans>white people>Asians.
sx of multiple myeloma
may be asymptomatic
bone pain
- in back/ribs/pelvic (prox skeleton)
- sudden and severe if caused by pathological fracture or vertebral collapse
infections - often recurrent - from immunoparesis and neutropenia from disease and chemo
general
- tiredness
- thirst
- polyuria
- nausea
- constipation
- mental change - from hypercalcaemia
hyperviscocity
- bleeding
- headaches
- visual disturbance
sx of hypercalcaemia - fatigue, constipation, confusion
sx of anaemia
signs of multiple myeloma
pallor
tachycardia
flow murmur
signs of HF
dehydration
purpura
hepatosplenomegaly - not according to lecture
macroglossia
carpal tunnel syndrome
peripheral neuropathies
renal impairment
cachexia
Ix for multiple myeloma
blood
blood film
bone marrow aspirate and trephine
chest, pelvic or vertebral XR
skeletal imaging, whole body MRI, skeletal survey
possible renal biospy
screening:
- serum or urine electrophoresis (do for all >50 with new back pain)
- B2 microglobin - prognostic
blood results in multiple myeloma
FBC - normochromic, normocytic anaemia
thrombocytopenia
neutropenia
high ESR CRP (can have normal CRP) because a lot of Ig
normal AlkPhos
high urea and creatinine
high Ca
serum Ig, serum free light chains - can have light chain only myeloma so need to look for SFLC or bence jones proteins
blood film in multiple myeloma
rouleaux formation with bluish background because of increased protein
pancytopenia
serum or urine electrophoresis
Serum paraprotein - ie monoclonal immunoglobin (two-thirds IgG, one-third IgA)
If IgG – increase in IgG and suppression of normal Ig – immune paresis
serum free light chains
Bence–Jones protein - free light chains in urine - k or y in 70% cases
bone marrow aspirate and trephine in multiple myeloma
increased plasma cells (large cells with a perinuclear halo, eccentric nuclei, blue cytoplasm) - usually >20%
chest, pelvic or vertebral XR in multiple myeloma
osteolytic punched out lesions without surrounding sclerosis eg pepper pot skull - from increased osteoclast activation from signalling by myeloma cells
pathological fractures
vertebral collapse
fractures
osteoporosis, osteopenia
(CT/MRI to detect lesions not seen on XR)
in pic - plasmocytoma in sternum
what is a plasma cell dyscrasia
eg myeloma
abnormal proliferation of single clone of plasma or lymphoplasmacytic cells = secretion of Ig or an Ig fragment = dysfunction of many organs especially the klidneys
Ig is seen as a monoclonal band, or paraprotein, on serum or urine electrophoresis
classification of plasma cell dyscrasias
based on Ig
- IgG in 2/3
- IgA in 1/3
- few IgM or IgD
other Ig levels are low - immunoparesis = increased suseptibility to infection
in 2/3 urine contains Bence Jones proteins - free Ig light chains of kappa or lambda, filtered by the kidney
how does myeloma cause renal impairment
light chain deposition
light chains have toxic and inflammatory effect on the proximal tubule cells
damage is mainly caused by the precipitation of light chains in teh distal loop of henle
deposits may be AL-amyloid = nephrotic syndrome
monoclonal immunoglobulins also disrupt glomeruli
diagnostic criteria for myeloma
have high index of suspicion
eg in bone pain, or back pain that isnt improving
check blood film and electrophoresis
criteria:
- monoclonal protein band in serum or urine elctrophoresis
- increased plasma cells on marrow biopsy
- evidence of end-organ damage from myeloma
- hypercalcaemia
- renal insufficiency
- anaemia
- bone lesions - XR of spine, chest, skull, pelvis, +- Tc-99m MIBI and PET