Question

The findings of attenuated ulnar SNAP amp, decreased APB CMAP amp, and normal median and ulnar MNC and SNC NCV are consistent with

a) Carpal tunnel syndrome
b) Ulnar nerve entrapment
c) Radial nerve injury
d) Brachial plexopathy

Answer 1

The electrodiagnostic findings of decreased ulnar SNAP and APB CMAP amplitudes with normal median and ulnar nerve conduction velocities are indicative of ulnar nerve entrapment rather than carpal tunnel syndrome, radial nerve injury, or brachial plexopathy.

Step-by-step explanation:

The student's question is regarding the interpretation of electrodiagnostic study findings, which suggest a specific type of peripheral neuropathy. Specifically, the findings of attenuated ulnar Sensory Nerve Action Potential (SNAP) amplitude, decreased Abductor Pollicis Brevis (APB) Compound Muscle Action Potential (CMAP) amplitude, and normal median and ulnar Motor Nerve Conduction Velocity (MNC and SNC NCV) provide evidence for a diagnosis.

The correct answer to the question is ulnar nerve entrapment, which can lead to reduced ulnar SNAP amplitude. Carpal tunnel syndrome primarily affects the median nerve within the carpal tunnel, leading to symptoms in the hand and fingers, and would therefore show abnormalities in median nerve studies, not ulnar nerve studies. A radial nerve injury would not typically present with abnormalities in ulnar nerve conduction. Finally, brachial plexopathy would likely present with a wider pattern of motor and sensory abnormalities affecting multiple nerves.

Answer 2

The findings are consistent with Ulnar nerve entrapment, which refers to the compression or irritation of the ulnar nerve. Carpal tunnel syndrome primarily affects the median nerve in the wrist, while radial nerve injury and brachial plexopathy have different symptoms and affected areas.

Step-by-step explanation:

The findings of attenuated ulnar SNAP amp, decreased APB CMAP amp, and normal median and ulnar MNC and SNC NCV are consistent with Ulnar nerve entrapment.

Ulnar nerve entrapment refers to the compression or irritation of the ulnar nerve, which runs along the inner side of the arm and passes through a tunnel called the cubital tunnel. When the nerve is compressed or irritated, it can result in symptoms such as weakness, numbness, and tingling in the ulnar nerve distribution. In this case, the ulnar SNAP (sensory nerve action potential) amplitude is attenuated, indicating a problem with the nerve conduction in the ulnar nerve.

In contrast, Carpal tunnel syndrome primarily affects the median nerve in the wrist and is characterized by symptoms such as pain, numbness, and tingling in the thumb, index finger, middle finger, and half of the ring finger. Radial nerve injury usually results in motor and sensory deficits in the posterior arm, forearm, and hand. Brachial plexopathy affects the brachial plexus, a network of nerves that originates from the spinal cord and supplies the shoulder, arm, and hand.