Primary lateral sclerosis disorder often affects the legs first, followed by the body, trunk, arms and hands, and, finally the bulbar muscles (muscles that control speech, swallowing, and chewing). Symptoms include weakness, muscle stiffness and spasticity, clumsiness, slowing of movement, and problems with balance and speech. PLS is more common in men than in women.
Five reports that include autopsy findings in 6 patients with PLS differ in the pathologic changes they describe. Two major factors may account for the different pathologic findings. First, uncertainties exist regarding the diagnosis in some of the series. This is discussed below in regard to one of the patients in the series described by Pringle et al in 1992.
Treatment for individuals with PLS is symptomatic. Baclofen and tizanidine may reduce spasticity. Quinine or phenytoin may decrease cramps. Some patients who do not receive adequate relief from oral treatment may consider intrathecal baclofen (i.e., infusion of medication directly into the cerebrospinal fluid via a surgically placed continuous infusion pump).