Multiple myeloma Flashcards
Definition: Multiple Myeloma
Multiple myeloma is a cancer of plasma cells, a type of white blood cell responsible for producing antibodies. In multiple myeloma, abnormal plasma cells accumulate in the bone marrow and interfere with the production of normal blood cells.
Common Causes of Multiple Myeloma?
The exact cause of multiple myeloma is not fully understood. However, certain factors may increase the risk:
1. Genetic Predisposition: Family history of multiple myeloma or other plasma cell disorders.
2. Age: Risk increases with age, with most cases diagnosed in people over 65.
3. Race: African Americans are at higher risk compared to other ethnic groups.
4. Radiation Exposure: Higher incidence among individuals exposed to high levels of radiation
Pathophysiology of MM?
Abnormal Plasma Cells: Mutated plasma cells (myeloma cells) proliferate uncontrollably in the bone marrow.
Monoclonal Gammopathy: Production of a monoclonal immunoglobulin (M protein) by malignant plasma cells.
Bone Marrow Infiltration: Accumulation of myeloma cells in the bone marrow disrupts normal hematopoiesis (blood cell production).
Bone Destruction: Myeloma cells release substances that stimulate osteoclasts, leading to bone resorption and lytic lesions.
Epidemiology of MM?
Multiple myeloma accounts for approximately 1% of all cancers and 10% of all hematologic malignancies.
It is more common in older adults, with the median age at diagnosis around 69 years.
Men are slightly more affected than women.
Name the Risk Factors of MM (5):
1,.Age: Risk increases with age, with most cases diagnosed in people over 65.
2. Gender: Slightly more common in men than women.
3. Race: African Americans have a higher risk compared to Caucasians.
4. Obesity: Increased BMI may be a risk factor.
5. Radiation Exposure: Higher incidence among individuals exposed to high levels of radiation.
Features at clinical presentation (4)?
Bone Pain: Common symptom due to bone lesions (lytic lesions).
Fatigue: Resulting from anemia and disease burden.
Renal Dysfunction: Due to excess light
chains (Bence Jones protein) or hypercalcemia.
Infections: Increased susceptibility due to impaired immune function.
Neurological Symptoms: Rare, but can occur due to spinal cord compression or nerve compression by plasmacytomas.
What are the presenting features of MM?
History:
- Bone pain, fractures, or unexplained fractures.
- Fatigue, weakness, weight loss.
- Renal problems, recurrent infections.
Examination:
- Signs of anemia (pallor, fatigue).
- Bone tenderness or palpable masses (plasmacytomas).
- Signs of hypercalcemia (dehydration, confusion).
Multiple myeloma: Differential diagnoses (3)?
- Other Plasma Cell Disorders: Monoclonal gammopathy of undetermined significance (MGUS), solitary plasmacytoma.
- Metastatic Bone Disease: Prostate cancer, breast cancer.
- Other Hematologic Malignancies: Lymphoma, leukemia.
What are the most common clinical signs of multiple myeloma (4)?
“Crab”
Hypercalcemia
Renal dysfunction
Anaemia
Bone pain with lytic lesions.
Investigations for Multiple Myeloma?
- Laboratory Tests:
- FBC: Anaemia, thrombocytopenia.
- Serum protein electrophoresis (SPEP): Detection of M protein.
- Serum free light chain assay (FLC): Quantifies free light chains. - Bone Marrow Examination: Aspiration and biopsy to confirm plasma cell infiltration.
- Imaging: Skeletal survey (X-rays), MRI, or CT scan to detect bone lesions.
- Other Tests: Renal function tests, beta-2 microglobulin, calcium levels.
Principles of treatment and management for multiple myeloma?
Chemotherapy: Combination regimens (e.g., bortezomib, lenalidomide, dexamethasone).
Autologous Stem Cell Transplantation: High-dose chemotherapy followed by stem cell rescue.
Targeted Therapy: Proteasome inhibitors (e.g., bortezomib), immunomodulatory drugs (e.g., lenalidomide).
Supportive Care: Bisphosphonates for bone health, management of renal complications, infections, and symptoms.
