Bilateral musculocutaneous neuropathy: A case report

Table 1 Electrodiagnostic study: Nerve conduction study

Nerve conduction (sensory)	Recording site	Stimulation site	Peak latency (ms)	Amplitude (μV)	Distance (cm)	Conduction velocity (m/s)	Nerve conduction (motor)	Recording site	Stimulation site	Onset latency (ms)	Amplitude (mV)	Distance (cm)	Conduction velocity (m/s)
Right median	Index finger	Palm	1.65	49.9	7	60.9	Right median	APB	Wrist	2.80	8.4
		Wrist	2.90	54.8	7	63.6			Antecubital	6.25	8.3	22	63.8
Left median	Index finger	Palm	1.60	59.8	7	63.6	Left median	APB	Wrist	2.95	8.3
		Wrist	2.80	59.7	7	66.7			Antecubital	6.50	8.3	22	62.0
Right ulnar	Small finger	Wrist	2.70	44.0	13	63.4	Right ulnar	ADM	Wrist	2.05	8.3
Left ulnar	Small finger	Wrist	2.90	37.0	14	59.6			Below elbow	5.85	8.8	23	60.5
Right lateral antebrachial	Lateral forearm	12 cm proximal	2.40	13.5	11	57.9	Left ulnar	ADM	Wrist	2.15	5.8
Left lateral antebrachial	Lateral forearm	12 cm proximal	2.60	18.8	13	63.4			Below elbow	6.00	7.4	22	57.1
Right medial antebrachial	Medial forearm	12 cm proximal	2.30	12.6	11	66.7	Right ulnar	ADM	Wrist	2.25	8.2
Left medial antebrachial	Medial forearm	12 cm proximal	2.40	19.9	12	64.9	(Post-exercise)		Below elbow	5.95	8.4	23	62.2
							Left ulnar	ADM	Wrist	2.45	8.1
							(Post-exercise)		Below elbow	6.15	9.6	23	62.2
							Right axillary	Deltoid	Erb’s point	3.65	8.6
							Left axillary	Deltoid	Erb’s point	4.05	7.2
							Right musculocutaneous	Biceps	Erb’s point	4.25	2.4
							Left musculocutaneous	Biceps	Erb’s point	4.05	1.3

ADM: Abductor digiti minimi; APB: Abductor pollicis brevis. Bold text indicates abnormal findings.

Table 2 Electrodiagnostic study: Electromyography

Muscle	Spontaneous	MUAP	Recruitment pattern	Interference pattern	Muscle	Spontaneous	MUAP	Recruitment pattern	Interference pattern
(Right)	Positive sharp wave				(Left)	Positive sharp wave
APB	None	Normal	Normal	Full	APB	None	Normal	Normal	Full
First DI	None	Normal	Normal	Full	First DI	None	Normal	Normal	Full
ECRL	None	Normal	Normal	Full	ECRL	None	Normal	Normal	Full
FCR	None	Normal	Normal	Full	FCR	None	Normal	Normal	Full
Biceps	2+	Normal	Reduced	Reduced	Biceps	2+	Normal	Reduced	Reduced
Brachialis	1+	Normal	Reduced	Full	Brachialis	1+	Normal	Reduced	Full
Infraspinatus	None	Normal	Normal	Full	Infraspinatus	None	Normal	Normal	Full
Deltoid	None	Normal	Normal	Full	Deltoid	None	Normal	Normal	Full
Triceps	None	Normal	Normal	Full	Triceps	None	Normal	Normal	Full
Cervical Paraspinal	None	NA	NA	NA	Cervical Paraspinal	None	NA	NA	NA

APB: Abductor pollicis brevis; DI: Dorsal interosseous; ECRL: Extensor carpi radialis longus; FCR: Flexor carpi radialis; MUAP: Motor unit action potential. Bold texts indicate abnormal findings.

Table 3 Electrodiagnostic study from previous hospital: Nerve conduction studies

Nerve conduction (sensory)	Recording site	Recording site	Stimulation site	Onset latency (ms)1	Amplitude (μV)	Nerve conduction (motor)	Recording site	Stimulation site	Onset latency (ms)	Amplitude (mV)	Distance (cm)	Conduction velocity (m/s)
Left median	Index finger	Index finger	Wrist	2.29	71.8	Left median	APB	Wrist	3.18	12.1
Left ulnar	Small finger	Small finger	Wrist	2.34	49.8			Antecubital	6.77	12.4	19	52.9
Left radial	Thumb	Thumb	12 cm proximal	1.82	36.3	Left ulnar	ADM	Wrist	2.24	11.0
Right medial antebrachial	Medial forearm	Medial forearm	12 cm proximal	1.93	15.9			Below elbow	5.73	11.6	19	54.4
Left medial antebrachial	Medial forearm	Medial forearm	12 cm proximal	1.61	15.8	Right axillary	Deltoid	Erb’s point	3.70	3.6
						Left axillary	Deltoid	Erb’s point	4.38	3.2
						Right musculocutaneous	Biceps	Erb’s point	5.31	3.8
						Left musculocutaneous	Biceps	Erb’s point	4.95	5.1

¹This test was performed at another hospital and latency of sensory nerve action potential was evaluated with onset latency.

ADM: Abductor digiti minimi; APB: Abductor pollicis brevis.

Table 4 Electrodiagnostic study from previous hospital: Electromyography

Muscle (Left)	Spontaneous	MUAP analysis	Recruitment pattern	Interference pattern
	Positive sharp wave
First DI	None	Normal	Normal	Full
ADM	None	Normal	Normal	Full
FCU	None	Normal	Normal	Full

ADM: Abductor digiti minimi; DI: Dorsal interosseous; FCU: Flexor carpi ulnaris; MUAP: Motor unit action potential.

Table 5 Reference values of nerve conduction studies[20]

Nerve conduction (sensory)	Onset latency (ms)	Peak latency (ms)	Amplitude (μV)
Lateral antebrachial cutaneous	1.6-2.1	2.2-2.6	12-50
Medial antebrachial cutaneous		1.7-2.6	10-30