NAC OSCE Diagnostic Investigations & Data Interpretation 3

Question 1

A 25-year-old woman presents with dysuria and urinary frequency for 2 days. Urinalysis: >10 WBC/hpf, positive nitrites, positive leukocyte esterase. Urine culture grows E. coli. She has no fever, flank pain, or comorbidities. What is the most appropriate treatment?

Accepted Answer

Oral trimethoprim-sulfamethoxazole for 3 days

Answer

Uncomplicated lower UTI in a healthy non-pregnant woman is treated with a 3-day course of trimethoprim-sulfamethoxazole (or nitrofurantoin), which is effective and minimizes antibiotic exposure.

Question 2

A 60-year-old man with COPD has an ABG on room air: pH 7.38, pCO2 52 mmHg, pO2 56 mmHg, HCO3 30 mEq/L, SaO2 87%. What is the most appropriate oxygen saturation target when initiating supplemental oxygen?

Accepted Answer

SaO2 88–92%

Answer

In COPD patients with chronic hypercapnia, the target SaO2 is 88–92% to maintain adequate oxygenation without suppressing the hypoxic respiratory drive and worsening CO2 retention.

Question 3

A 32-year-old woman at 10 weeks gestation has Hgb 92 g/L, MCV 73 fL, and serum ferritin 6 μg/L (normal >15). What is the most likely diagnosis?

Accepted Answer

Iron deficiency anemia

Answer

Microcytic anemia (low MCV) with a markedly low serum ferritin confirms iron deficiency as the cause, which is the most common nutritional deficiency in pregnancy.

Question 4

A 52-year-old man has serum creatinine 340 μmol/L, K+ 6.1 mEq/L, pH 7.29, and a renal ultrasound showing bilateral small hyperechoic kidneys. What is the most likely diagnosis?

Accepted Answer

Chronic kidney disease

Answer

Bilateral small echogenic kidneys on ultrasound indicate established fibrosis and scarring, confirming chronic rather than acute kidney disease; associated hyperkalemia and metabolic acidosis reflect reduced renal mass.

Question 5

A 67-year-old man has a PSA of 13.5 ng/mL and a digital rectal exam revealing a hard, irregular nodule on the right lobe of the prostate. What is the most appropriate next step?

Accepted Answer

Transrectal ultrasound-guided prostate biopsy

Answer

An abnormal DRE (hard nodule) plus elevated PSA constitutes a clinical indication for prostate biopsy regardless of PSA value alone, to rule out prostate cancer.

NAC OSCE Practice Test

NAC OSCE Practice Test

NAC OSCE Diagnostic Investigations & Data Interpretation 3