Primary Lateral Sclerosis Clinical Presentation

Updated: Sep 06, 2019
  • Author: Carmel Armon, MD, MSc, MHS; Chief Editor: Nicholas Lorenzo, MD, CPE, MHCM, FAAPL  more...
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Primary lateral sclerosis (PLS) usually presents with gradual-onset, progressive, lower-extremity stiffness and pain due to spasticity. Onset is often asymmetrical. Affected individuals typically have no family history of similar disorders.

As PLS progresses, patients may develop balance problems and have a tendency to fall. Axial muscle involvement may result in lower back and neck pain, which may aggravate back or neck pain from other causes (eg, degenerative disc disease, osteoporosis).

As the upper extremities become involved, patients may have difficulties with activities of daily living (ADLs). Involvement of the organs of speech may result in spastic dysarthria (which initially may be mild).

Swallowing and breathing may be compromised late in the disease.


Physical Examination

Signs of upper motor neuron dysfunction may include limb and trunk spasticity, pathologic spread of deep tendon reflexes, clonus, pathologic reflexes (such as Babinski sign), and spastic dysarthria.

Signs of involvement of other systems should not be present. In particular, no cerebellar findings, involuntary movements, sensory findings, findings suggesting lower motor neuron dysfunction (such as fasciculations), visual findings, or bladder dysfunction should be observed.