Myeloma and Paraproteins Flashcards
(27 cards)
what test is doen for possible myeloma?
serum electrophoresis
what is true about MGUS
50% have lytic bone disease, anaemia, hypercalcaermia or renal failure
what are the different types of heavy chains?
Gamma – IgG Alpha – IgA Mu – IgM Delta – IgD Epsilon - IgE
what is the function of each heavy chain
IgM - Initial phase of antibody production, Exists as a pentamer – highest molecular weight
IgG - Most prevalent antibody subclass (75% of total)
IgA - Mucous membrane immunity
IgE - Parasite immune responses, hypersensitivity
what is the fab and fc region?
fab - variable, defines target binding. Fc - constant, defined by heavy chains
what is a paraprotein and what does it tell us?
unique monocloncal population present in the blood or urine, if it is present it tells us that there is a monocloncal proliferation of a B lymphocyte/plasma cell somewhere in the body.
outline the process of serum electrophoresis
seperates protein based on its size and charge, Forms a characteristic pattern of bands of different widths and intensities based on proteins present
what does electropheoresis assess
antibody diversity, identifies Paraprotein
what does immunmofixation assess?
Identifies what class of paraprotein is present (i.e. IgG, IgM)
what does a IgM paraprotein indicate?
Lymphoma - mature b cell
what does IgG, IgA paraproteins indicate?
myeloma - mature plasma cells
what is MGUS (monoclonal gammopathy of unknown significance)
a monocloncal paraprotien without other features of myeloma
what is MYELOMA
Neoplastic disorder of plasma cells, resulting (usually) in excessive production of a single type of immunoglobulin (paraprotein) (a clone of cancerous plasma cells which fill the bone marrow and produce only a single immunoglobulin type)
Peaks in 7th decade
Ethnicity – commoner in black population than white
Clinical manifestations may result from direct effect of plasma cells, or effect of paraprotein
what what are the CRAB features?
CRAB – hyperCalcaemia, Renal failure, Anaemia, Bone disease
how may anaemia form in there patients?
tumour infiltration - renal impairment - cytokine mediated anaemia
explain how bone is effected?
osteoclasts stimulated by myeloma cytokines, also hypercalcaemia is caused by excess calcium is released into blood from bone.
explain why patients may present with confusion
hyperviscocity, hypercalcaemia, infection.
what are the other features of myeloma?
bone disease lytic bone lesions pathological fractures cord compression hypercalcaemia bone marrow failure esp. anaemia Infections
why are the kidneys commonly effected in myeloma?
excess of light chains produced (Bence jojnes proteins) these proteins are deposited in the kidney interfereing with its function.
what are the effects of the paraprotein?
Renal failure – cast nephropathy: Immunoglobulin deposition and blockage of renal tubules.
Hyperviscosity - Syndrome caused by increased viscosity in blood, impaired microcirculation and hypoperfusion. Commonest clinical feature is bleeding – retinal, oral, nasal, cutaneous. Can also cause cardiac failure, pulmonary congestion, confusion, renal failure.
Hypogammaglobulinaemia - Impaired production of normal Immunoglobulin. Tendency to infection.
define amyloidosis…
Amyloidosis
Group of diseases characterised by deposition of fibrillar protein
Morphological appearances, physical structure are similar
Biochemical or protein composition can vary.
(crystalline protein structure)
what can amyloidosis cause?
Nephrotic syndrome Cardiac failure (LVH) Carpal tunnel syndrome Autonomic neuropathy Cutaneous infiltration
Dx of myeloma?
Myeloma is diagnosed by finding excess plasma cells in the bone marrow - pye: IgG, IgA and light chain
Must comprise > 20% of total bone marrow cell population
on cxr skull has a perrper pot appearance, fbc - low hb, uande - high creatinine, serum electrophoresis - monoclonal immunoglobulins.
how common are paraproteins?
Paraproteins are common
3-4% of population over age of 75
The vast majority have nothing wrong with them
This is termed monoclonal gammopathy of uncertain significance (MGUS)
