Case 6

Roxy's CBC results show a neutrophilia with a mild left shift, which may be consistent with an inflammatory response or bacterial infection. You notice that she also has mild anemia, so you make a mental note to request a reticulocyte count. This will help characterize the anemia as regenerative or nonregenerative and help guide your differentials.

The serum chemistry profile results show a mild elevation in the blood urea nitrogen (BUN) concentration. This elevation may be seen secondary to gastrointestinal (GI) bleeding or may be postprandial if the patient is receiving a high-protein diet. In Roxy's case, however, she also has a urine specific gravity at the low end of normal, so the elevated BUN concentration may be indicative of early renal disease.

Mild hyperkalemia is present, so differentials such as hypoadrenocorticism, renal disease, GI disease, or drugs (i.e. diuretics) would need to be considered. Given that her sodium concentration is well within normal limits-we'd expect it to be lower with these differentials-and hemolysis is present, it is likely that this mild hyperkalemia is not clinically relevant.

The most striking finding on Roxy's serum chemistry profile is the hypoproteinemia. Hypoalbuminemia, specifically, is concerning because albumin provides the bulk of the colloid osmotic pressure in the vasculature, and a marked drop will result in effusions.

Two general physiologic factors can lead to hypoalbuminemia: decreased production by the liver or increased loss. In most cases, this loss may be either through the kidneys (proteinuria), through the GI tract, or via vasculitis. Hypoadrenocorticism may be associated with low albumin, but it is rarely this profound.

Roxy's urinalysis also shows that she has a 2+ proteinuria, which, considering the specific gravity and the low albumin concentration, definitely raises a red flag.

QUESTION 2

Based on the information you have so far, what would the next best diagnostic step be?

a) An abdominal ultrasonographic examination

b) A urine protein creatinine ratio (UPCR) to assess the proteinuria

c) Pre- and post-prandial serum bile acids measurements to assess Roxy's liver function

d) Fecal fat or starch analysis

e) A serum trypsin-like immunoreactivity (TLI) test

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