A Woman With Unilateral Facial Weakness

A 52-year-old woman presented with a 5-day history of pain in the left ear; she then had 3 days of decreased taste and facial weakness. She had no significant previous medical history. There was no history of diabetes. She drank alcohol socially.

The examination was normal except for weakness of the left orbicularis oculi, orbicularis oris, frontalis, and other left facial muscles. There was flattening of the left nasolabial fold ( Fig. 29-1 ). She also had decreased taste in the anterior left tongue. Examination of the ear was normal. Other cranial nerves were completely normal. Strength, reflexes, coordination, and sensory examinations were unremarkable. There were no Babinski signs.

What is the Most Likely Diagnosis?

The most likely diagnosis is acute idiopathic seventh nerve neuropathy, or Bell’s palsy.

What Tests Need to be Done?

A complete metabolic panel was normal, including blood sugar and erythrocyte sedimentation rate.

An EMG Test was Performed

Motor Nerve Studies

Nerve and Site	Latency(ms)	Amplitude (mV)	Conduction Velocity (m/s)
Ulnar Nerve R.	Normal ≤ 3.6	Normal ≥ 8	Normal ≥ 50
Wrist	3.4	9	–
Below elbow	7.0	9	62

Facial Nerve	Normal ≤ 2.6	Normal ≥ 2.5 ^a
Facial nerve L.	3.5	0.80	–
Facial nerve R.	3.3	4	–

a 50% reduction in amplitude compared with the opposite side is considered abnormal, if similar, waveforms.

Blink Reflex

	Ipsilateral R1 Normal ≤ 13.0 (ms)	Ipsilateral R2 ≤ 40 (ms)	Contralateral R2 ≤ 41 (ms)
Blink reflex L.	NR	NR	38
Blink reflex R.	12.0	30	NR

R1, upper limits of normal side-to-side difference is 1.2 ms. R2, upper limits of normal side-to-side difference is 5 ms.

EMG Data

Muscle	Insrt Activity	Fibs	Pos Waves	Fasc	Amp	Dur	Poly	Pattern
Orb. oculi L.	Norm	None	None	None	Norm	Norm	Few	Red
Orb. oris L.	Norm	None	None	None	Norm	Norm	Few	Red
Masseter L.	Norm	None	None	None	Norm	Norm	Few	Red
Orb. oris R.	Norm	None	None	None	Norm	Norm	None	Norm