Q448 ) A 78 year old man presents to emergency room with severe pain in his right lower extremity. Pain began after he stumbled and fell on a sidewalk. He does not report pain anywhere else and did not lose consciousness. No tingling or numbness in either extremity. He reports inability to bear weight because it is extremely painful. His past medical history is significant for coronary artery disease and hypertension. He does report about 8lbs weight-loss in the past 1 month. On examination, he is afebrile. There is tenderness in the right thigh area. Laboratory investigations reveal Hemoglobin 10.5gm%, Platelet count 110k/ul, Calcium at 10.4 mg/dl ( N = 9.0 to 10.5 mg/dl) , Serum creatinine 2.0 mg/dl, Total protein 4.5 gm/dl, Albumin 2.0gm/dl and Ferritin 200 ng/ml. Liver function tests including Alkaline phosphatase are within normal limits. Whole body bone scan is negative for any lesions. Serum protein electrophoresis is normal with out any monoclonal spike.
An x-ray of the femur is shown below :
448) Which of the following is most helpful in diagnosing this condition?
A) Colonoscopy
B) DEXA scan
C) 24 hour urine electrophoresis
D) Vitamin D level
E) Parathyroid hormone level
449) Which of the following is likely to explain the patient’s findings?
A) Metastatic colon cancer
B) Multiple Myeloma
C) Osteoporosis
D) Secondary Hyperparathyroidism
E) Metastatic Prostate cancer
Filed under: Uncategorized, USMLE Test Prep | Tagged: Archer endocrinology, archer general internal medicine, Archer oncology, USMLE STEP 3 ONCOLOGY |
Archer USMLE Step 3 Blog 
C, B.
DEXA SCAN,
Osteoporosis
most likely secondary hyperparathyrodism
w get parathyriod hormone level
ostitis fibrosa cystic
In case of RF acidosis convert non Ionized calcium into Ionized
I’m not sure about this one, he’s got anemia and weight loss and bone pain, so it wants us to think of cancer maybe. His renal failure would make us think MM, but he’s got a normal calcium level and his serum EP was normal. The bone scan would have picked up blastic lesions if it was mets from the prostate. So we can cross off that one as well. Colon cancer doesn’t really lead to lytic lesions, at least I think so. Those are more commonly due to mets MM, thyroid cancer, renal cancer, or melanoma, right? And it kind of looks like a lytic lesion on the xray, not a diffuse demineralization of the bone like for osteoporosis. This is just a guess, but maybe the dude has renal cancer? And maybe that’s why he has anemia, weight loss, renal failure, and a lytic bone met? If he did we could check the Vit D level and see if it was low from the renal failure. I’m not even sure if renal cancer can cause renal failure greatly enough to result in decreased Vit D production. But of course, there’s no option for renal cancer, and he doesn’t have any back/flank pain or hematuria. I have no idea. Dr. Red Archer, what’s the answer please?
Good thinking ! You are going in the right direction with regard to pure lyric lesion ….. So what’s your final answer ?
D and D
I want to go with multiple myeloma the most – anemia, bone pain, weight loss, lytic lesion, low albumin…But his calcium is in the normal range and his SPEP was normal. Perhaps they can be normal early on? I’m not sure. I’m not sure what a 24 urine EP is, but I think a urine protein EP is used in the workup of MM. So, I’ll go with C and then B.
PS. Nice to see the return of the Q of the W!
You guessed it right.The patient has anemia, lytic bone lesion, renal insufficiency and if you look at the corrected calcium, hypercalcemia as well. Corrected calcium is almost 12.0 . {Corrected calcium = measured calcium + 0.8(4-albumin) } . Multiple myeloma work up includes both SPEP and UPEP not SPEP alone. Question tries to confuse you giving a normal SPEP. Sometimes, SPEP can be completely normal and UPEP can come back positive for bence jones proteins or light chains. Such a condition is called light chain myeloma wherein full immunoglobulin can not be produced so often, globulins are low and you can not really see a M-SPIKE . But light chains are monoclonal and can be very toxic to kidneys leading to myeloma kidney and renal failure. Other manifestations of Myeloma include CRAB – hyperCalcemia, Renal insufficiency, Anemia and Bone lesions. A unique feature of myeloma bone lesions is that they are purely LYTIC and they do not light up on bone scan. Alkaline phosphatase is also within normal limits since there is no osteoblastic repair activity ( Hyperactivity on bone scans and elevated ALP is a feature of osteoblastic activity in the mets. Prostate cancer metastases are usually blastic and they produce super bone scans. Osteoporosis does not explain anemia, lytic lesion and renal insufficiency. Primary hyperparathyroidism can cause hypercalcemia and diffuse osteoporosis but not lytic lesion.
Oh! The corrected calcium level! Never really understood it before, but now that you put it in context it makes more sense! The light chain myeloma variant is a nice twist too, I wasn’t familiar with that before. Nice case Dr. Red.
Thank you…more than knowing about light chain myeloma, this question is to stress on the point that both SPEP and UPEP must be done before you exclude myeloma
I never new how to apply these concepts as I studied a lot the Ca metabolism .. not too long a go.
Thank you
A,A
448- 24 hours Urine electrophoresis
449- multiple myeloma
for448 answer A
For 449 answwer A
DD
htn can coz renal damage ,,,dec vit d
I’m voting Multiple Myeloma still – in spite of negative SPEP – C,B
A,A
C,B. Multiple myeloma
Want to revise this. Negative SPEP and paraprotein gap (2.5 g/dl WNL) r/o MM or MGUS. This seems to be 2ry hyperparathyroidism due to chronic RF (Cr=2), presenting with bone pain. Serum Ca++ can be NL. Check serum PTH might help.
Your prior answers were correct
Let me repeat or emphasize, what Dr Archer has said above, twice (For those of us who keep answering AA or DD). My dear esteemed colleagues, O guild of vehement researchers!, I am one of your own!, so pls believe me!
When you see a negative serum protein electrophoresis, please don’t automatically mentally exclude multiple myeloma; Please you MUST do 24 hr urine protein electrophoresis if you suspect MM, even to the slightest bit.
In our patient in this question, CRAB – the classical pneumonic for MM is red herring! We must check urine. CRAB – is ‘high Calcium, Renal failure, Anemia, Bone lesion’
SUMMARY: 10% of MM patients ( 1 in 10 patients) do NOT have an M protein spike in their serum but they have Bence Jones proteins in their urine. Do 24 hour Urine electrophoresis to confirm your clinical suspicion. Pls do this religiously when you have Suspicious MM, it will guarantee that we don’t miss 1 out of 10 patients with MM. Thank you.
Reference:
http://www.aafp.org/afp/2005/0101/p105.html
You could also do a bone marrow biopsy looking for greater than 10% plasma cells. This is the most specific test for myeloma.
D and d
448=c
449=b
Dr Archer is correct, urine electrophoresis must be done together with serum measurement to detect for urinary monoclonal light chain proteins or bence jones proteins, this is also confirmed in Dr Conrad Fischers Usmle step 3 review text book. Bone scans are only positive for blastic lesions including paget’s disease and bony mets especially from prostate, and breast, lymphoma and medulloblastoma. Primary bone tumors also have lytic bone lesions.