PSA Block Haematoma — ORE Part 1 MCQ

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ModeratePharmacology & TherapeuticsPSA Block HaematomaORE Part 1

During administration of a posterior superior alveolar nerve block, a patient develops rapid unilateral swelling of the cheek that extends towards the lower eyelid. What is the most likely cause?

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Correct answer: D — Vascular trauma causing a haematoma

The correct answer is **A. Vascular trauma causing a haematoma**. The PSA injection is delivered in a region containing vessels, including branches of the posterior superior alveolar artery and the pterygoid venous plexus. Needle trauma can cause rapid blood extravasation, producing immediate unilateral cheek swelling that may track towards the periorbital tissues. A published PSA-block case describes facial oedema developing immediately after injection and subsequent haematoma formation. Hypersensitivity and angioedema may cause facial swelling but would not be the expected immediate, focal complication of this injection technique and are usually accompanied by wider allergic features. Subcutaneous emphysema requires air entry and typically causes crepitus. Maxillary sinus perforation does not characteristically cause abrupt external facial swelling during local-anaesthetic injection.

Reference: Marques ALN, Figueroba SR, Mafra MAT, Groppo FC. Edema and hematoma after local anesthesia via posterior superior alveolar nerve block: a case report. Journal of Dental Anesthesia and Pain Medicine. 2022;22(3):227-231. https://pubmed.ncbi.nlm.nih.gov/35693352/