A77-14 From Mucus Plugging to Motor Neuron Disease: A Case of Amyotrophic Lateral Sclerosis

Abstract Introduction This case involves a 65-year-old male with recurrent mucus plugging and pneumonia who was eventually diagnosed with amyotrophic lateral sclerosis (ALS). Description of Case This is a 65-year-old male with past medical history of asthma that presented to the pulmonology clinic for worsening shortness of breath and a persistent cough. Initial pulmonary function testing (PFT) revealed mild airflow obstruction and air trapping. Over time, his dyspnea on exertion progressed to the point of hospitalization. Imaging demonstrated right-sided mucus plugging along with faint ground-glass opacities. Despite long-term antibiotic therapy and compliance with his medications, the patient required multiple hospitalizations for recurrent mucus plugging and pneumonia. Bronchoscopy cultures consistently grew Rothia mucilaginous and Mycobacterium gordonae. In addition to oxygen requirements progressively increasing, he developed asymmetric upper extremity weakness and changes in voice quality. Unfortunately, his respiratory failure became so severe that intubation was necessary. Neurology was consulted and they noticed fasciculations in the proximal left arm and atrophy of the left first dorsal interossei muscle. A comprehensive neuromuscular work-up, including antibody panels for myasthenia gravis and Lambert-Eaton syndrome, was negative. The electromyography however showed an active denervating disorder of motor neurons, consistent with ALS. Due to persistent hypoxia and recurrent mucus plugging, a percutaneous tracheostomy was performed, and he is now ventilator dependent. Discussion Bulbar onset ALS is an uncommon presentation of ALS onset. In limb onset ALS, the majority of cases, patients initially present with limb weakness in one extremity. It can occur at any adult age, but most commonly begins between ages 55-75. This case was unique because the first noticeable symptom was this patient’s shortness of breath caused by a mucus plug. The classic bulbar ALS symptoms are dysarthria, dysphagia, and weakened jaw muscles which he did not have any of these initially. The recurrent mucus plugging may have reflected an ineffective cough or airway clearance due to motor neuron dysfunction of the respiratory muscles. There is currently no cure for ALS, but there are treatments that can slow down disease progression. This patient was started on one of these treatments called Riluzole. Its mechanism of action is it reduces damage to motor neurons by decreasing glutamate activity, a neurotransmitter that can be toxic in excess. This case highlights a patient with an initially non-focal exam who was later diagnosed with ALS, highlighting the importance of keeping ALS in the differential to enable earlier treatment. This abstract is funded by: None