A 29-year-old woman attends the Emergency Department after developing painful neck stiffness and facial grimacing earlier this evening.

 She reports two days of persistent vomiting and was prescribed anti-sickness tablets by her GP yesterday.

 Earlier today, while planting a shrub in her garden, she sustained a small puncture wound to her thumb, which she cleaned herself.

 Since then, she has felt “tightness in her jaw” and occasional involuntary upward rolling of the eyes.

 She denies headache, fever, or limb weakness.

Vital signs: HR 108 bpm, BP 126/78 mm Hg, RR 22 /min, SpO₂ 98 % RA, Temp 36.9 °C.

 Examination:

Mild trismus-like jaw spasm with intermittent facial contractions.

No opisthotonus or sustained rigidity.

Wound: clean, < 1 cm, non-purulent.

Neurological exam: no focal deficit, tone and reflexes normal between spasms.

 Urine β-hCG: previously “equivocal” in GP clinic; repeat pending.

Your registrar notes the striking facial posturing and wonders if this could represent functional seizure !

Based on the presentation and clinical context, what is the most likely diagnosis?