Clinical Course of Amyotrophic Lateral Sclerosis according to Initial Symptoms: An Analysis of 500 Cases

One obstacle in early diagnosis of amyotrophic lateral sclerosis (ALS) is its vague initial presentation, which is generally classified into limb- and bulbar-dominant types and may be mistaken for other musculoskeletal conditions. We analyzed clinical data from patients in relation to their initial presentation and prognosis from symptom onset to diagnosis.

We retrospectively analyzed the medical records of patients with ALS who were admitted for pulmonary rehabilitation between January 2007 and December 2019. We collected data on time of onset, initial presenting symptoms, unnecessary operations due to misdiagnosis, and the time between symptom onset and final diagnosis of ALS.

Among 500 patients, unnecessary operations were performed in 43 patients. The median durations between symptom onset and ALS diagnosis for patients with and without operations were 11 and 9 months, respectively (p=0.008). 67.0%, 28.8%, and 4.2% of the patients presented with limb-, bulbar-, and respiratory-dominant symptoms, respectively, as initial presentations. The median ages at symptom onset were significantly different for limb-, bulbar-, and respiratory-dominant onset (57.5, 60.6, and 66.7 years, respectively; p<0.001). Compared to the other two types, patients with the respiratory-dominant onset were all male and showed higher rate of emergent endotracheal intubation before ALS diagnosis.

Inappropriate operations significantly delayed the diagnosis of ALS. Respiratory difficulty can account for a significant proportion among initial presentations in ALS. Compared to limb- and bulbar-dominant types, respiratory-dominant onset appears to show male predominance, older age at symptom onset, and poor respiratory prognosis.