Primary lateral sclerosis mimicking atypical parkinsonism

Abstract

Primary lateral sclerosis (PLS), the upper motor neurone variant of motor neurone disease, is characterized by progressive spinal or bulbar spasticity with minimal motor weakness. Rarely, PLS may present with clinical features resembling parkinsonism resulting in occasional misdiagnosis as one of the atypical parkinsonian syndromes. Here we describe five patients initially referred with a diagnosis of levodopa-unresponsive atypical parkinsonism (n = 4) or primary progressive multiple sclerosis (n = 1), but subsequently found to have features consistent with PLS instead. Onset age varied from 49 to 67 years. Unilateral limb slowness or clumsiness was the initial complaint in four, and bulbar symptoms in one. Repeated finger/foot tapping was slow in all five, but without fatiguing or decrement. Spasticity with hyperreflexia, exaggerated jaw jerk and extensor plantar responses were eventually seen in all patients. Anterior horn cell involvement developed in three cases. Early gait disturbances resulting in falls were seen in all patients and none of them responded to dopaminergic medications. Two patients underwent dopamine transporter (DaT) SPECT scanning with normal results. Other features included emotional lability (n = 5) and cognitive impairment involving frontal subcortical systems (n = 1). In conclusion, these cases represent a subgroup of PLS patients in whom pyramidal slowness may be mistaken for akinesia, and spasticity misconstrued as rigidity, leading to an erroneous diagnosis of atypical parkinsonism. However, the absence of fatiguing and decrement on repeated finger/foot tapping should help to distinguish these patients from the true atypical parkinsonian syndromes.

Serum M30 levels: A potential biomarker of severe liver disease in nonalcoholic fatty liver disease and normal aminotransferase levels #

“…Whether postural abnormalities of extrapyramidal origin are a characteristic of ALS patients with stiffness or may be found in ALS patients without stiffness remains to be determined, as well as the incidence of other extrapyramidal symptoms, such as bradykinesia. However, pyramidal involvement and spasticity may cause “pseudoakinesia” (i.e., slowness of repeated movements as finger tapping without fatiguing or decrement) 37. As in our study, shortening reaction test may allow to differentiate between true parkinsonian akinesia and movement slowness of pyramidal origin.…”

Parkinsonism and motor neuron diseases: Twenty‐seven patients with diverse overlap syndromes

“…It may be difficult to distinguish the clinical features of MND in the presence of parkinsonism and vice versa. For example, eminent authorities on PD18 described five patients who had been diagnosed with atypical parkinsonism and then PLS, and concluded that PLS could account for all clinical findings. We reviewed the videos included in the publication and noted hypomimia, profound bradykinesia, stooped posture, and prominent postural instability.…”

The Stripe of Primary Lateral Sclerosis

“…1 Pure PLS represents a more benign neurodegenerative condition thought to affect only upper motor neurons and is characterized with a better prognosis than amyotrophic lateral sclerosis (ALS). 2 For the clinician, PLS is a challenging diagnosis because it can mimic several disorders such as Parkinson disease, multiple systems atrophy, corticobasal syndrome, 3 neurofilament inclusion body disease, 4 and hereditary spastic paraplegia. 5 In PLS, functional neuroimaging can highlight selective upper motor neuron degeneration in areas such as the pericentral cortex 6 or primary motor cortex.…”