MM / call

Question 1

Cauda equina Sx

Answer 1

• acute (<24h; rarely subacute or chronic)
• LMN signs: weakness/paraparesis in multiple root distributions, reduced reflexes
• urinary retention (or –> overflow incontinence), fecal incontinence (loss of anal sphincter tone)
• sensory: low back pain radiating to legs, aggravated by Valsalva & sitting, relieved by lying down; bilat sensory loss or pain; saddle anesthesia; sexual dysfunction (late finding)

Question 2

What is multiple myeloma?

Answer 2

cancer of plasma cells: produce monoclonal immunoglobulin, invade and destroy adjacent bone tissue

Question 3

What are the most common presenting features of multiple myeloma?

Answer 3

bone pain and anaemia.

May also be IDed via Ix of fatigue, infections, hypercalcaemia, or renal impairment.

Question 4

Clinical manifestations of multiple myeloma

Answer 4

CRAB:

• Calcium (hypercalcemia)
• Renal disease
• Anemia
• Bone pain

Question 5

Why is calcium elevated in multiple myeloma?

Answer 5

Plasma cells secrete osteoclast activating factor, leading to increased resorption & hypercalcemia

Question 6

Why does anemia occur in multiple myeloma?

Answer 6

Bone marrow is infiltrated by plasma cells, so it is less able to produce RBCs

Question 7

Why does renal disease occur in multiple myeloma?

Answer 7

Light chains (of Ig) deposit in tubules (aka "light chain nephropathy" or "myeloma kidney"
(other kinds of kidney issues can happen: type 2 renal tubular acidosis, secondary amyloidosis, hypercalcemia)

Question 8

Why does bone pain occur in multiple myeloma?

Answer 8

• lytic bone lesions
• spinal cord compression (if tumour infiltrates from vertebrae)
• infections (plasma cells produce Ig that’s not useful for infections: impairs immunity)

Question 9

What is the epidemiology of multiple myeloma?

Answer 9

average about 3 in 100 000. Increased frequency with age; median age of Dx is about 68.
M:F is 1.6:1
Black:white is 2:1
(BMJ: black men 2x white men, black women 3x white women)

Question 10

What is lenalidomide?

Answer 10

Immunomodulator, used to treat multiple myeloma; inhibits hematopoetic cell proliferation. Also inhibits proinflammatory cytokines (altering immune response).

Question 11

What are the diagnostic criteria for multiple myeloma?

Answer 11

1. serum or urinary monoclonal protein
2. presence of clonal plasma cells in bone marrow (>60% without “CRAB”) or a plasmacytoma
3. presence of end-organ damage related to plasma cell dyscrasia, such as:
   ◆ increased serum Ca2+
   ◆ lytic bone lesions
   ◆ anemia
   ◆ renal failure

Question 12

What bloodwork abnormalities are seen in multiple myeloma?

Answer 12

CBC: Normocytic normochromic anaemia
Lytes: elevated Ca2+
Creatinine, urea: elevated (renal)
Serum albumin

Question 13

What is the prognosis of multiple myeloma?

Answer 13

Incurable; 3-7y. Newer therapies are improving prognosis but not by a whole lot.
ISS stage I: median 62mo
ISS stage II: median 44mo
ISS stage III: median 29mo
Staging is based on serum beta2-microglobulin and serum
albumin

Question 14

What do people with MM die from?

Answer 14

Seems like (based on complication list in BMJ):

• renal failure
• infection
• less commonly: cardiac failure (CHF or ischemic; amyloid deposits in heart)

Question 15

What is a Bence-Jones protein?

Answer 15

only part of an immunoglobulin; in MM, sometimes only these parts are made instead of full Ig

Bence Jones proteinuria: “free monoclonal kappa (κ) or lambda (λ) light chains in the urine”

Question 16

What makes multiple myeloma different from Waldenström macroglobulinemia?

Answer 16

Waldenström macroglobulinemia (IgM myeloma):

• rare type of B cell lymphoma
• often presents with hyperviscosity (IgM stick together –> ischemia)
• can be asymptomatic; may alternately have fatigue, freq infections, pancytopenia–> easy bleeding, hepatosplenomegaly, lymphadenopathy

Question 17

What makes multiple myeloma different from MGUS?

Answer 17

Monoclonal Gammopathy of Undetermined Significance (MGUS):
- no end-organ damage
- less than 10% plasma cells on bone marrow biopsy
The risk of MGUS progressing to multiple myeloma is 1% a year. No treatment, but monitoring required (labs)