Recognizing Amyotrophic Lateral Sclerosis Early: Bilateral Internal Capsule Hyperintensities as a Diagnostic Clue
Taleen Shahrigian1, Jason Schick1, Christopher Gilbert1, Aileen Antonio2, Christopher Goshgarian1, Melanie Taylor1, Joel Phillips1
1Trinity Health Grand Rapids, 2Trinity Health Saint Mary's Hauenstein Neurosciences
Background:
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting both upper and lower motor neurons, leading to muscle weakness, spasticity, and eventual respiratory failure. Although the diagnosis is primarily clinical-based on a combination of neurological examination and electromyographic findings, neuroimaging can support evaluation by excluding mimics and identifying subtle signs of corticospinal tract involvement. Bilateral internal capsule hyperintensities, though rare, may serve as an early radiologic clue in ALS.
Results:
A 57-year-old female presented with one year of progressive bilateral lower extremity weakness and fasciculations, which were noted in all extremities on examination. Additional findings included distal right upper limb atrophic spasticity, bilateral Hoffman signs, extensor plantar responses, brisk deep tendon reflexes throughout, and a spastic gait. Brain MRI revealed T2 hyperintensities in the bilateral posterior limbs of the internal capsule extending into the upper midbrain. The combination of upper and lower motor neuron signs, along with subtle bilateral corticospinal neuroradiological findings, raised concern for ALS, leading to appropriate management.
Conclusions:
Symmetric internal capsule hyperintensities, while not commonly highlighted in ALS imaging, may indicate early corticospinal tracts involvement and serve as a subtle radiologic clue. While not definitive, these findings can raise clinical suspicion for ALS in patients with progressive motor symptoms. Early recognition of such imaging patterns, in conjunction with clinical signs, may facilitate timely diagnosis and intervention, ultimately improving care in neurodegenerative conditions like ALS.
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