A patient with a known esophageal stricture is experiencing progressive dysphagia and regurgitation of undigested food. Which diagnostic test should the nurse anticipate the healthcare provider will order to evaluate the severity of the stricture and plan further management?

Rationale:

A. Urine specific gravity reflects the kidney’s ability to concentrate or dilute urine, which can be influenced by hydration status, diuretics, or fluid intake. While it provides information about urine concentration, it is not the most accurate or reliable indicator of overall renal function, especially in chronic or progressive kidney disease.

B. Blood urea nitrogen (BUN) is influenced by many nonrenal factors, including hydration status, protein intake, gastrointestinal bleeding, and liver function. Although BUN may rise with renal impairment, it is less specific for assessing kidney function compared to creatinine.

C. Serum creatinine is the best indicator of renal function because it directly reflects the kidneys’ ability to filter waste products from the blood. Creatinine levels are less affected by diet or hydration and increase when glomerular filtration rate (GFR) declines, making it especially important in monitoring renal involvement (lupus nephritis) in clients with SLE.

D. Serum sodium reflects fluid and electrolyte balance, not kidney filtration ability. Sodium levels may remain normal even in significant renal impairment, making it an unreliable indicator of renal function.

Rationale:

A. Scheduling serological testing for Lyme disease may be part of the diagnostic process, but early testing is often unreliable because antibodies may not be detectable in the first few weeks after infection. Waiting for test results can delay treatment and increase the risk of complications.

B. Assessing for neurological involvement, such as facial palsy, is important in later stages of Lyme disease. While the nurse should monitor for these signs, it is not the immediate priority in a client with early localized disease and a characteristic rash.

C. Administering a prescribed dose of doxycycline is the most appropriate initial action. Early antibiotic treatment for Lyme disease, especially when a bull’s-eye rash (erythema migrans) is present, is critical to prevent progression to more serious systemic manifestations, including neurological, cardiac, or musculoskeletal complications. Prompt initiation of therapy is more important than waiting for confirmatory testing.

D. Initiating a discussion about safe hiking practices is valuable for health promotion and prevention, but it does not address the client’s immediate need for treatment. Education can be provided after initiating therapy.