Multiple Myeloma: An Overview

Multiple Myeloma: An Overview

Definition:-

• Multiple myeloma (MM) is a malignant bone marrow–based, plasma cell neoplasm associated with abnormal protein production.

• Multiple myeloma also called myelomatosis.

Epidemiology:-

• 1~2% of all types of malignant diseases
• ~10% of hematological malignancies.
• 15% of lymphoid malignancies.
• ~ 50 cases per million.
• Twice common in black than white people.
• Slightly more common in males than in females.
• 98% of cases occur over the age of 40 years with a peak incidence in the 7th decade.

Etiology (Causes):-

- Exact cause is unknown, but the following are suspects:

• Radiation.
• Viral infections.
• Toxins.
• Chemicals.
• Chromosomal abnormalities ( 8 % - 35 % of MM patients ).

- MM patients with chromosomal damage have a worse prognosis, a higher rate of disease acceleration, and decreased survival. 

Clinical Signs & Symptoms:-

• Fatigue: caused by anemia
• Excessive thirst and urination: caused by excess calcium.
• Nausea: caused by excess calcium.
• Bone pain in back and ribs: caused by plasma cell acceleration.
• Bone fractures: caused by calcium leeching from bones into circulation.
• Unexpected infections: caused by compromised immunity.
• Weakness and numbness in the legs: caused by vertebrae compression. 
• Renal insufficiency.(Myeloma kidney).
• Hypercalcemia.
• Amyloidosis (in 5% of cases).
• Weight loss & night sweats (in advanced cases).
• Abnormal bleeding tendency: myeloma protein may interfere with platelet function and coagulation factors
• Thrombocytopenia (in advanced cases).

Laboratory Findings:-

• Anemia (2/3 of cases). ( Normocytic normochromic anemia ).
• Leukopenia (1/3 of cases).
• Thrombocytopenia.
• ESR > 100 mm/hr.
• Blood film shows rouleaux with a bluish background staining.
• Bone marrow shows >10% plasma cells.
• ↑ Total protein.
• ↑ Uric Acid.
• ↑ LDH.
• Hypercalcemia.
• Protein electrophoresis (monoclonal spike in the gamma region).
• Bence-Jones protein (immunoglobulin light chain) in urine. (in some cases).
• Serum β₂ microglobulin (β₂M) often raised and higher levels correlate with worse prognosis.

Radiology:-

X-rays, CT scan, MRI or PET.

Prognostic Data:-

Prognostic data include:-

• Hb.
• β₂M.
• Creatinine.
• Albumin. &
• Extent of skeletal disease.

Treatment:-

• Chemotherapy.
• Supportive.
• Radiation.
• Transplantation (bone marrow; stem cell).

Prognosis:-
 

• The prognosis of MM is poor.
• Median survival of only 6 months without therapy.
• The median survival can be increased to 3 years with chemotherapy.
• Increased survival has been reported with autologous bone marrow & peripheral blood stem cell transplants.
• Infection is a major cause of death.