EpistemisAtrophy of the thenar eminence
Specialty: Musculoskeletal.
Why it occurs
- Untreated severe chronic carpal tunnel syndrome (advanced compression of the recurrent motor branch of the median nerve)
- Severe chronic C8-T1 cervical radiculopathy
- Syringomyelia or tumors of the upper cervical spinal cord
- Amyotrophic Lateral Sclerosis (ALS, classic "ape hand" or "skeleton hand" sign)
- Multifocal motor polyneuropathy
- Spinal muscular atrophy type IV in adults
Initial workup
Needle electromyography (EMG) of the thenar eminence (abductor pollicis brevis, opponens muscle) and interossei | Motor and sensory nerve conduction velocity (ENG) studies of the median, ulnar and radial nerves | Magnetic resonance imaging of the cervical spine and brain.
red flags
Bilateral thenar atrophy associated with diffuse muscle fasciculations in arms and legs, generalized cramps, progressive dysarthria and hyperactive muscle stretch reflexes (TRE) in atrophic limbs (indicates concomitant upper and lower motor neuron involvement suggestive of ALS).
Standard management
- There are no drugs that reverse atrophy in the advanced carpal tunnel, surgical decompression of the flexor retinaculum is mandatory to stop the progression; in case of ALS: Riluzole (50 mg every 12 hours orally; moderately prolongs survival by reducing glutamatergic neurotransmission).
Educational guidance for study. It is NOT a prescription recommendation. The actual choice depends on the cause, the patient, and current guidelines.
- Area
- Musculoskeletal
- Listed causes
- 6
- Treatment options
- 1