Sialolithiasis — ORE Part 1 MCQ

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ModerateOral MedicineSialolithiasisORE Part 1

A 30-year-old man presents with recurrent episodes of unilateral facial swelling related to meals. The swelling subsides spontaneously after 1–2 hours, and he reports a salty taste in his mouth when the swelling reduces. Which investigation would be most useful in confirming the diagnosis?

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Correct answer: A — Ultrasound of the submandibular gland

The clinical presentation is pathognomonic for sialolithiasis: postprandial unilateral swelling (triggered by increased salivary flow attempting to overcome the obstruction), spontaneous resolution (1–2 hours), and salty taste (saliva discharged as stone moves or passes). The submandibular gland is affected in ~80% of sialoliths due to its viscous, alkaline saliva and dependent duct anatomy. Ultrasound is the evidence-based first-line imaging: sensitivity >90% for stones >2 mm, portable, no ionizing radiation, and cost-effective. While CT (option B) provides excellent imaging and is useful for complex or hilar stones or when ultrasound is inconclusive, it involves radiation and is reserved for secondary diagnostic or surgical planning. Sialography (historical invasive method with cannulation and retrograde contrast injection) and MRI (expensive, time-consuming, not first-line) are inappropriate as primary investigations. FNA and biopsy have no role in sialolith diagnosis. Ultrasound of the submandibular gland is the standard of care in modern practice.

Reference: Meta-analysis: Utility of Ultrasonography for Diagnosis of Salivary Gland Sialolithiasis. PubMed 2022. https://pubmed.ncbi.nlm.nih.gov/35043982/; Point-of-care Ultrasound Diagnosis of Acute Sialolithiasis. PMC 2018. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5965241/; Giant Asymptomatic Submandibular Sialolith (systematic review). PMC 2025. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12651031/