Plasma Cell Disorders

Question 1

What is MGUS?

Answer 1

Monoclonal Gammopathy of Undetermined Significance

Unregulated proliferation of plasma cells —> asx

Can progress to MM but not always

Complications: MM, amyloidosis, light chain deposition disease

No treatment, just monitoring

Positive SPEP but everything else would be normal, BM <10% plasma cells

Question 2

What is Multiple Myeloma?

S&S

Patho

Answer 2

Neoplastic proliferation of plasma cells & monoclonal immunoglobulin (single antibody)

OLD CRABS

• OLD: incidence increases with older age
• C: calcium elevated
• R: renal failure
• A: anemia
• B: bone lytic lesions

Patho:

• BM infiltrations ~ leukopenia, thrombocytopenia, anemia
• Increased osteoclasts activity = hypercalcemia
• Lytic bone lesions
• Antibody (immunoglobulin): 1) increases viscosity of blood, 2) increases risk of bleeding (covers platelets), 3) cause kidney damage via deposition & blocking of renal tubules by Bence June Proteins

Question 3

What would you find on investigations for MM?

Answer 3

• hypercalcemia
• normocytic, normochromic anemia, thrombocytopenia, leukopenia
• Elevated Cr, BUN if advanced
• SPEP: M proteins
• UPEP: light chains in urine (Bence Jones proteins)
• BM biopsy: >10% plasma cells
• X-ray: multiple round lytic bone lesions in skull, long bones, spine
• CT/MRI: bone lesions, lesions in spleen and lymph node
• Smear: Rouleaux formation
• FISH: fluorescent in situ hybridization: chromosomal mutations

Question 4

How does a pt present with MM?

Answer 4

B sx: night sweats, unexpected weight loss, fever, fatigue

Hypercalcemia sx: constipation, nausea, weakness, arrhythmia, neurological sx: blurred vision, anxiety, confusion, hallucinations

Bone lesions sx: bone pain, fractures pathological

Foamy urine ~ proteins in your urine (Bence Jones)

Frequent infections