Question

The client with head trauma is admitted following a motor vehicle accident. The nurse notes \(5000 \mathrm{ml}\) of dilute urinary output within 3 hours of admission. Which finding would support a diagnosis of diabetes insipidus? A. Decreased red blood cell count B. Low specific gravity of urine C. Increase blood urea nitrogen D. Increased serum creatinine level

Short answer

Answer: B. Low specific gravity of urine

Step-by-step solution

Option A: Decreased red blood cell count

A decreased red blood cell count can indicate several conditions, such as anemia or blood loss. However, it is not directly related to diabetes insipidus. Therefore, this option can be eliminated.

Option B: Low specific gravity of urine

Diabetes insipidus is characterized by the production of large amounts of dilute urine, which leads to a low specific gravity of urine. Specific gravity is a measure of the concentration of urine; a lower specific gravity indicates more dilute urine. Therefore, this option aligns with the diagnosis of diabetes insipidus and is a strong contender.

Option C: Increased blood urea nitrogen

An increased blood urea nitrogen (BUN) indicates impaired kidney function or dehydration, neither of which are specific to diabetes insipidus. While diabetes insipidus could cause dehydration, it does not affect the BUN level in a way that would support a diagnosis. Therefore, this option can be eliminated.

Option D: Increased serum creatinine level

Serum creatinine is another measure of kidney function. An increased level could indicate impaired kidney function or muscle damage, among other issues. However, it is not directly related to diabetes insipidus, so this option can be eliminated. In conclusion, the correct answer is:

Answer

B. Low specific gravity of urine