Multiple Myeloma: Etiology, Pathophysiology

Clinical Manifestations of Multiple Myeloma

Clinical Manifestations of Multiple Myeloma can be summarized with the acronym CRAB:

• C : Hypercalcemia, primarily due to lytic bone lesions, which can lead to cardiac arrhythmias.
• R : Renal failure, often secondary to hypercalcemia as a major contributor.
• A : Anemia, typically normocytic normochromic, resulting from plasma cell infiltration of the bone marrow.
• B : Bleeding tendencies and bony lytic lesions.

Additional clinical features include:

• Normocytic normochromic anemia occurs because plasma cells invade the bone marrow, crowding out normal hematopoietic cells.
• Bleeding tendencies arise from impaired platelet production in the crowded bone marrow or from platelet dysfunction caused by abnormal antibodies.
• Bone pain or low backache is common.
• Differential diagnosis includes ruling out osteoporosis, disc prolapse, and metastatic prostate carcinoma involving the spine.
• Spinal fractures can occur, posing a risk of paraplegia due to compressive myelopathy.
• Lethargy or fatigue due to anemia may be present.
• Renal dysfunction leads to uremia, with crystalline deposits causing uremic frost after sweating, and potentially causing asterixis and metabolic encephalopathy.
• Hyperviscosity syndrome can manifest as dizziness and vertigo.
• Amyloidosis associated with multiple myeloma can lead to carpal tunnel syndrome.

Investigations

Treatment of Multiple Myeloma

Treatment for multiple myeloma involves the following medications for the induction phase:

• Steroids: Dexamethasone
• Immunomodulators: Thalidomide and lenalidomide
• Proteasome inhibitor: Bortezomib

Autologous bone marrow transplantation is considered for eligible patients. During this procedure, cancerous cells are eradicated in the induction phase using medications, and GM-CSF (granulocyte-macrophage colony-stimulating factor) injection stimulates the proliferation of normal bone marrow cells.

Are you preparing to excel in the MBBS NExT Exam 2025? Access the PW Med Ed app today to study under the guidance of leading medical experts and achieve excellent scores in your exam preparation.