MCQs on Other Renal Disorders

Written by Dr. Daniel Fraser (MBBS, FRACP) – Physician

Question 1

A 26-year-old man is referred for a routine medical check by his insurance company. He has no significant medical history, and physical examination is unremarkable. As part of the assessment, a urine dipstick test is performed which is only positive for 1+ proteinuria. Other parameters are all normal. Which one of the following is the most appropriate next step in management?

A) Serum electrolytes, urea, and creatinine.
B) 24-hour urinary protein assay.
C) Perform another urine dipstick in early morning.
D) Urinary albumin to creatinine ratio (ACR).
E) Urine microscopy.

Correct Answer: C) Perform another urine dipstick in early morning.

People with normal kidney function excrete less than 150 mg of protein per day in their urine, of which about 20 mg is albumin. Proteinuria on dipstick in primary care is often an incidental and transient finding. It may be due to benign causes such as exercise, posture (orthostatic proteinuria), pregnancy, UTI, or acute febrile illness. Even alkaline urine, hematuria, semen, or leukocytes can cause false-positive results.

Orthostatic proteinuria, commonly seen in young adults, is absent in the morning and appears later in the day. Therefore, to determine if the proteinuria is transient, the most appropriate next step is to repeat the dipstick test early in the morning, ideally after the patient has been lying down overnight.

If proteinuria persists on repeated testing, further investigations should include:

Urine microscopy (option E)
Serum creatinine, urea, and electrolytes (option A)
Urinary albumin to creatinine ratio (ACR) (option D) for convenience
24-hour urinary protein (option B), which is the gold standard for quantification

However, these are not indicated as the first step in evaluating isolated, mild proteinuria detected on dipstick in an asymptomatic patient.

Question 2

A 22-year-old man presents to the Emergency Department with cough and dyspnea of one week duration, as well as fatigue, decreased urine output and dark-colored urine. Physical examination is otherwise inconclusive. Which one of the following is the single most accurate investigation to establish a diagnosis?

A) Chest X-ray.
B) Renal biopsy.
C) Anti-glomerular basement membrane antibody.
D) Urine analysis.
E) High-resolution CT (HRCT) scan of the chest.

Correct Answer: B) Renal biopsy.

This patient’s presentation with pulmonary symptoms (cough, dyspnea) and renal symptoms (oliguria, dark urine) is strongly suggestive of Goodpasture syndrome, also known as anti-glomerular basement membrane (anti-GBM) disease. This condition typically affects young males and presents with pulmonary hemorrhage and rapidly progressive glomerulonephritis.

While urine analysis and chest X-ray are important initial tests that support the presence of glomerulonephritis and pulmonary involvement, they are not diagnostic of a specific cause.

The most accurate diagnostic test for Goodpasture syndrome is renal biopsy, which shows:

Crescentic glomerulonephritis on light microscopy
Linear IgG deposition along the glomerular basement membrane on immunofluorescence (a pathognomonic finding)

Anti-GBM antibodies (option C) are also helpful and less invasive but may not be detected in all cases, and therefore renal biopsy remains the gold standard for definitive diagnosis.

HRCT (option E) may show pulmonary hemorrhage but lacks specificity.
Surgical or invasive imaging (not listed) would be inappropriate here.

Thus, renal biopsy is the single most accurate test to confirm the diagnosis of Goodpasture syndrome.

Question 3

A couple has presented to your office for infertility consultation. They have been trying to start a family for over a year. The woman’s history and examination results are normal, but the man is found to have absent vas deferens. Which one of the following would be the most appropriate advice for them?

A) They should have sperm donation.
B) The vas deferens should be fused to the ejaculatory duct.
C) Sperm aspiration and intrauterine fertilization should be tried.
D) Sperm aspiration for frozen sample and repeated tubal insemination.
E) In vitro fertilization.

Correct Answer: E) In vitro fertilization.

Explanation:
About 1–2% of infertile men have congenital absence of the vas deferens, often due to mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. These men typically present with infertility but lack other typical cystic fibrosis symptoms (such as respiratory or pancreatic disease).

The most appropriate reproductive technique is in vitro fertilization (IVF), where sperm is aspirated directly from the epididymis or testis and injected into oocytes in vitro.

Genetic screening and counselling are essential because congenital bilateral absence of the vas deferens is associated with CFTR mutations. Screening the female partner first may be more cost-effective, as a negative result significantly reduces the risk of cystic fibrosis in offspring.

Option A: Sperm donation is not appropriate when the male’s sperm can be retrieved.
Option B: Fusion of the vas deferens to the ejaculatory duct is only suitable for men who have had a vasectomy but still have intact vas deferens, not congenital absence.
Options C and D: The number of aspirated sperm is typically too low for intrauterine fertilization or repeated tubal insemination to be effective.

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4. Nephrology & Urology Module

4.1 Hematuria

4.2 Chronic Kidney Disease

4.3 Urinary Incontinence

4.4 Prostate

4.5 Renal Tumors

4.6 Other Renal Disorders

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