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Trigeminal Neuropathy Red Flag — MFDS Part 1 MCQ

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HardHuman DiseaseTrigeminal Neuropathy Red FlagMFDS Part 1

A 66-year-old patient reports a 6-week history of progressively reduced sensation over the left lower lip and chin. There is no pain, electric-shock sensation or trigger zone. There has been no recent dental treatment, local anaesthesia or facial trauma. Intraoral examination and a diagnostic-quality panoramic radiograph show no dental or bony cause, and sensory mapping confirms hypoesthesia in the mental nerve distribution. Which diagnosis is most important to exclude?

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Correct answer: E — Malignant trigeminal neuropathy from tumour infiltration or compression

The correct answer is E. Progressive, objectively confirmed numbness of the lower lip and chin without a dental, radiographic, traumatic or iatrogenic cause is numb-chin syndrome, a focal trigeminal neuropathy. Malignant infiltration or compression of the mental, inferior alveolar or more proximal trigeminal pathway must be excluded promptly. Classical trigeminal neuralgia causes brief, electric-shock-like, triggerable pain and does not typically produce persistent sensory loss. Persistent idiopathic facial pain and burning mouth syndrome are pain or dysaesthesia disorders without this anatomically defined neurological deficit. Post-traumatic neuropathy requires a relevant preceding intervention or injury, which the stem specifically excludes.

Reference: Perez C, de Leeuw R, Escala P F, Fuentealba R, Klasser GD. Numb chin syndrome: What all oral health care professionals should know. Journal of the American Dental Association. 2023;154(1):79-93. https://www.rcseng.ac.uk/-/media/files/rcs/fds/guidelines/trigemina-neuralgia-guidelines_2021_v4.pdf