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A 44-year-old man presents to the emergency department with a left-sided facial droop that began 30 hours ago and has progressed to involve the whole left side of the face. He cannot raise his left eyebrow, cannot close his left eye (the Bell phenomenon is present — the eye rolls upwards on attempted closure), and the left side of his mouth droops with drooling. He reports reduced taste on the left side of the tongue and that loud sounds are uncomfortably loud in his left ear. There are no vesicles in the ear or mouth, the ear examination is normal, facial sensation is intact, and there is no limb weakness. He is otherwise well; he has no prior similar episodes. Blood pressure 132/82, glucose normal. On the same shift, a separate 67-year-old woman is referred with three months of recurrent, 10-second bursts of electric-shock pain in the right cheek and jaw brought on by washing her face and drinking cold water, with a normal neurological examination.
Questions
a) For the 44-year-old man: state the diagnosis, the single most important bedside sign that distinguishes it from a stroke, and the grade of palsy if he has obvious asymmetry, no forehead movement and incomplete eye closure. (2 marks)
The diagnosis is acute Bell palsy (idiopathic lower motor neurone facial nerve palsy). The single most discriminating bedside sign is that the forehead is INVOLVED (he cannot wrinkle it or close the eye) — a lower motor neurone lesion. In contrast, an upper motor neurone lesion (cortical stroke) spares the forehead because the upper face has bilateral cortical innervation. With obvious asymmetry, no forehead movement and incomplete eye closure, this corresponds to House-Brackmann grade IV (moderately severe).
b) Outline the evidence-based medical management for the 44-year-old man, including drug, dose, route, timing and one mandatory supportive measure. (3 marks)
- Oral prednisolone 60 mg once daily for 5 days, then taper over 5 days (e.g., 50, 40, 30, 20, 10 mg) — started WITHIN 72 HOURS of onset (he is at 30 hours, so eligible). This improves complete recovery from about 80 percent to about 94 percent (Sullivan NEJM 2007; Madhok Cochrane 2016).
- Eye protection is mandatory: lubricating eye drops by day, and ointment plus eyelid taping or a shield at night, because lagophthalmos risks exposure keratopathy and corneal ulceration (a preventable cause of blindness). Urgent ophthalmology review if corneal exposure or ulceration.
- Antivirals (aciclovir or valaciclovir) add only marginal benefit and are not routinely required for uncomplicated Bell palsy; they would be essential if ear vesicles were present (Ramsay Hunt).
c) The man asks whether the loud, uncomfortably sharp sounds in his left ear and the loss of taste are explained. Relate these to the anatomy of the facial nerve, and name the test of lacrimation. (2 marks)
Both are explained by branches of the facial nerve affected proximal to their origin: the nerve to stapedius (which dampens the stapes) is involved → hyperacusis (loud sounds); the chorda tympani (taste to the anterior two-thirds of the tongue and salivation) is involved → dysgeusia. A lesion proximal to the greater petrosal nerve would also reduce lacrimation, assessed by the Schirmer test ('tears, tastes and taps' localises the level of the lesion within the fallopian canal).
d) For the 67-year-old woman with paroxysmal right-sided facial pain: give the diagnosis, the first-line drug with a typical dose, and two features that would mandate an MRI rather than a clinical-only diagnosis. (3 marks)
- Diagnosis: trigeminal neuralgia (classical, by ICHD-3/EAN criteria) — paroxysmal, electric-shock, unilateral V2/V3 pain lasting seconds, provoked by innocuous triggers, no deficit between attacks.
- First-line drug: carbamazepine — start 200 mg twice daily, titrate to 600 to 1200 mg/day (maximum 1600 mg/day); about 70 percent respond initially.
- Two features mandating MRI (i.e., secondary TN — MS or tumour): (i) any persisting sensory loss or neurological deficit between attacks, and (ii) onset under 40, bilateral involvement, or non-response to an adequate carbamazepine trial. For refractory but classical TN, definitive surgical options include microvascular decompression (Jannetta), gamma knife radiosurgery, or percutaneous ganglion procedures.