Background: Diaphragm palsy is common in the advanced stages of motor neuron disease and is a primary cause of fatal outcome However, respiratory failure is a presenting symptom of motor neuron disease in only a small number of patients.
Case report: We present the case of a patient with dyspnea and orthopnea followed by subacute respiratory failure due to bilateral diaphragm paralysis as the first manifestation of amyotrophic lateral sclerosis.
Conclusions: Failure of respiratory muscle function can be the first symptom of motor neuron disease, and may precede clinical manifestation in voluntary motor units in ALS. Therefore, in cases of unexplained acute respiratory failure or when respiratory support must be continued for no clear reason, a motor neuron disease such as amyotrophic lateral sclerosis, which leads to respiratory muscle weakness and diaphragm paralysis, should be taken into consideration.