A 51-year-old woman developed an unusual gait related to "calf stiffness." After several months of progressive weakness, she developed a right foot drop. Within 15 months, she also described difficulty in writing, weakness of the right hand and arm, and diffuse muscle twitching with painful muscle cramps. Assessment confirmed weakness of all limbs, more marked on the right side, with muscle atrophy. Reflexes were hyperactive and fasciculations were observed in the right leg.
Within two years, the patient became severely disabled because of generalized weakness. She experienced no sensory problems, intellectual deterioration or skin breakdown in spite of her degree of immobility. Difficulty in swallowing necessitated the use of a gastrostomy tube for feeding. The patient died of respiratory failure approximately three years after reporting the initial symptoms.
* ALS = amyotrophic lateral sclerosis; LMN = lower motor neuron; UMN = upper motor neuron; EMG = electromyographic.
• Definite ALS
-LMN and UMN signs in three to four regions
-Evidence of progression
• Probable ALS
-LMN and UMN signs in at least two regions with UMN above LMN signs and evidence of progression • Possible ALS
-LMN and UMN in one region
-UMN in two regions
-LMN above UMN signs
-LMN and UMN signs but no evidence of progression
• Suspected ALS
-LMN signs in two to three regions
• Findings inconsistent with diagnosis of ALS
• Neuroimaging, EMG, clinical or other evidence of an alternative disease explaining signs or symptoms • Lack of progression to other body regions
• Cognitive decline
• Sphincter abnormalities
• Sensory dysfunction
• Visual decline