Tough Question

[Medistudent1]

A 65 year-old male presents with a 4-6 month history of intermittent production of red-tinged urine. Physical exam
reveals a well nourished patient with slightly enlarged prostate and no other abnormal findings.

Initial laboratory data reveals:

-hemoglobin 18.7 g/dl (normal: 13.0-18.0 g/dL)
-hematocrit 58% (normal: 37-49%)
-BUN 10 mg/dl = urea of 3.6 mmol/L (normal: 8-25 mg/dL or 2.9-8.9 mmol/L)
-creatinine 0.8 mg/dl = 70 μmol/L (normal: 0.6-1.5 mg/dL or 52-132 μmol/L)
-calcium 12.3 mg/dl = 3.1 mmol/L (normal: 8.5-10.5 mg/dL or 2.1-2.6 mmol/L)
-urinalysis: ++ hematuria, + PMN.

The patient's lab results are most consistent with which of the following?

A. Dehydration

B. Paraneoplastic syndrome

C. Renal hematoma

D.Cystitis secondary to E. coli

E.Renal calculi

??????

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[sexyman]

goin with B- paraneoplastic syndrome from a renal cell caricinoma (causing the hematuria).

Paraneoplastic syndrome explains the increased hematocrit (epo) and the hypercalcemia (PTrP)

do you have the answer or are you asking for one? ha

 

[MedGeek12]

I think B as well

 

[Medistudent1]

I have an answer. I just wanted to hear some discussion from the forums

I give it out tomorrow

 

[lemontilt]

I say B too. The calcium suggest paraneoplastic. Just dehyd wouldnt cause the intermitten red urine. But a renal calculi would do that.

But, I d go with B.

 

[Medistudent1]

Hey Guys, Glad you are enjoying these! There are more to come!

The correct answer is Choice B.

This patient has a combination of polycythemia (erythrocytosis), hematuria, and hypercalcemia. His urea/BUN is in the normal
range and this excludes dehydration as the cause of his elevated hematocrit, and it would not explain his intermittent hematuria.

Renal hematoma generally follows trauma (non-traumatic renal hematoma can occur but it rare), and there is no suggestive history here. Like cystitis and renal calculi this diagnosis does not explain the hypercalcemia or the erythrocytosis.

The combination of laboratory findings is compatible with a diagnosis of paraneoplastic syndrome. Although hypercalcemia can
occur in many tumor syndromes, the presence of hematuria suggests that this patient may have a renal tumor, and renal cell
carcinoma (RCC) would be high up the list of differentials.

RCC originate from renal tubular epithelium and account for 95% of all renal tumors and around 2-4% of all malignancies. Around
30% of RCC patients present with metastatic disease, most often lung followed by soft tissue, bone, liver, skin and central nervous
system. 30% of RCC patients have a paraneoplastic syndrome.

There are many types of paraneoplastic syndrome, often categorized on the basis of the predominant organ system affected.

Mechanistically, they result from either:

-secretion of biologically active substances
-alterations of immunity e.g. auto-immune syndromes, immune complex disease

In some cases no mechanism can be determined. In the case of our patient, the erythrocytosis is likely the result of ectopic
erythropoietin secretion by the tumor cells. This can be found in up to 10% of cases. There are two main mechanisms for the
hypercalcemia; humoral hypercalcemia of malignancy (HHM) due to secretion of parathyroid-hormone-related-peptide (PTHrP) and
osteolytic hypercalcemia. HHM is the most common paraneoplastic syndrome in patients with RCC, occurring in 20% of cases.

Suggested References
Sacco E, Pinto F, Sasso F, et al. Paraneoplastic syndromes in patients with urological malignancies. Urol Int 2009; 83: 1-11.


More questions to come