12 - Haematological 1 Flashcards
How do haematological malignancies arise?
- Too much proliferation
- Cells don’t differentiate
- Cells do not apoptose
What is the main cause of morbidity and mortality in haematological malignancy?
Immunosupression due to both disease and treatment
What is myeloma?
> Malignant disorder of plasma cells (mature B lymphocytes)
- Second most common haematological malignancy
- Excess secretion of a monoclonal antibody
What is the definition of the following:
- Multiple myeloma
- Monoclonal gammopathy of undetermined significance (MGUS)
- Smouldering myeloma
Multiple myeloma: myeloma affects multiple areas of the body
Monoclonal gammopathy of undetermined significance (MGUS): excess of a single type of antibody or antibody components without other features of myeloma or cancer. May progress to myeloma so routine monitoring
Smouldering myeloma: progression of MGUS with higher levels of antibodies. It is premalignant and more likely to progress to myeloma than MGUS. Waldenstrom’s macroglobulinemia is a type of smouldering myeloma where there is excessive IgM specifically.
What is the structure of an antibody?
Made by B cells/plasma cells
Light chains: kappa or lambda
Heavy chains: IgG, IgA, IgE, IgD, IgM
What is the pathophysiology of multiple myeloma?
- Mutation in one of the plasma cells so divides uncontrollably and produces monoclonal antibodies
- Imunoglobulins in a patient with myeloma one of the types of immunoglobulin (A, G, M, D or E) will be significantly abundant. Usually IgG. They are called monoclonal paraprotein.
- “Bence Jones protein” found in urine in myeloma as they are subunits of the light chains
- Step one is development of MGUS, then step two is progression from MGUS to smouldering myeloma then to MM
What is the issue with MM?
- Infiltration of bone marrow by B cells causing bone marrow suppression
- Excess monoclonal antibodies/light chain secretion
What are the 5 key features/clinical presentations of MM?
CRABBI
- C – Calcium (elevated)
- R – Renal failure
- A – Anaemia (normocytic, normochromic) from replacement of bone marrow
- B – Bone lesions/pain
- B - Bleeding
- I - Infection
What are some myeloma defining events?
Myeloma can present with hyper viscosity symptoms, especially if Walden’s myeloma. What are some of the symptoms of this?
What is the cause of hypercalcaemia and bone pain in multiple myeloma?
Myeloma Bone Disease
- Increased osteoclast activity and suppressed osteoblast activity due to cytokines released from plasma cells and stromal cells in contact witht the plasma cells
- Abnormal bone metabolism is patchy, meaning that in some areas the bone becomes very thin whereas others remain relatively normal. Leads to weak points that can cause pathological fractures
- All the osteoclast activity causes a lot of calcium to be reabsorbed from the bone into the blood
What sites does myeloma bone disease tend to occur?
- Skull
- Spine
- Long bones
- Ribs
What are plasmacytomas?
Individual tumours made up of the cancerous plasma cells
Can occur in the bones, replacing normal bone tissue OR in soft tissue
Why does renal disease occur in myeloma?
- High levels of immunoglobulins can block flow through tubules
- Hypercalcaemia impairs renal function
- Dehydration
- Medications used to treat conditions such as bisphosphonates can be harmful to the kidneys
What may bone marrow suppression due to replacement of bone marrow by plasma cells cause in MM?
- Anaemia
- Recurrent or persistent bacterial infection: immune dysfunction and hypogammaglobulinaemia due to suppression of normal plasma cell function
Why is there hyper viscosity of blood in MM and what are the complications this can cause?
Large amounts of immunoglobulins (proteins) in the blood causing the plasma viscosity to be significantly higher
- Easy bruising
- Easy bleeding
- Reduced or loss of sight due to vascular disease in the eye
- Purple discolouration to the extremities
- Heart failure
How may MM present symptom wise? (apart from CRAB symptoms)
- Hyperviscosity syndrome: easy bruising/bleeding, blurred vision, headaches, dyspnea
- Spinal cord compression symptoms
- Peripheral neuropathy/radiculopathy
- Splenomegaly/hepatomegaly
- Fever
- Lymphadenopathy
What are some risk factors for myeloma?
USUALLY PRESENTS AGED 70
- Older age
- Male
- Black African ethnicity
- Family history
- Obesity
What is the criteria for screening for MM?
Anyone over 60 with bone pain (particularly back) or pathological fractures
Consider in:
- Unexplained bone pain (and pathological fractures)
- Fatigue
- Symptoms of hypercalcaemia: bone pain, abdo pain, constipation, confusion, polyuria
- Weight loss
- Symptoms of cord compression: back pain, new leg weakness, bladder/bowel dysfunction
- Symptoms of hyperviscosity: headache, blurred vision, shortness of breath, mucosal bleeding
- Recurrent infections
What investigations are done as part of screening for myeloma?
- FBC (low WCC in myeloma)
- Calcium (raised in myeloma)
- ESR (raised in myeloma)
- Plasma viscosity (raised in myeloma)
If any of these are positive or myeloma is still suspected do an urgent serum protein electrophoresis, a urine Bence-Jones protein test, serum free light chains
How do the following tests help to screen for MM?
- Serum protein electrophoresis
- Urine Bence-Jones protein
- Serum free light chains
Protein electrophoresis
Separates proteins into different bands using an electric current. The distance individual proteins travel is dependent on their shape, size and electrical charge
Immunofixation then fixes protein in place using antbodies
Urine Electrophoresis and Serum Free Light Chains
Protein electrophoresis assumes that all myelomas secrete an intact antibody. In fact, around 20% of myelomas only secrete light chains
SFLCs looks at amount of light chain unbound to heavy chains within blood. Light chains are secreted in healthy individuals as plasma cells produce more light chains than heavy chains. Therefore, it is the ratio between the light chains kappa and lambda, which is the most important factor. An elevated ratio is suggestive of myeloma and needs further work-up.
What is the diagnostic test for myeloma?
Bone Marrow Aspiration and Trephine Biopsy
Number of plasma cells in sample will be significantly raised
What is a prognostic marker for MM?
B2M
What other investigations need to be done once myeloma is diagnosed with biopsy?
Need these investigations for diagnostic criteria
Assess for bone lesions: PET-CT (skeletal survey will not pick up lytic lesions)
Assess for organ damage: FBC, U+Es, Bone profile
Staging: beta-2 microglobulin, albumin