Patients with chronic neurologic disorders may present to the emergency department with complications of their underlying medical conditions. Emergency management of these disorders often centers on evaluation of potential respiratory complications and an assessment for appropriate inpatient or outpatient management of acute illness or exacerbation of chronic disease.
AMYOTROPHIC LATERAL SCLEROSIS
Patients with amyotrophic lateral sclerosis (ALS) experience progressive muscle atrophy and weakness. Limb spasticity, hyperreflexia, and emotional liability are common symptoms of upper motor neuron demyelination, while lower motor neuron dysfunction can cause muscle weakness, atrophy, fasciculations, dysarthria, dysphagia, and difficulty with mastication. In the early phase of disease, symptoms may be asymmetric. Respiratory muscle weakness causes progressive respiratory difficulty that presents as dyspnea with exertion or at rest. Sensory and cognitive function is often spared, although up to 15% of patients may also develop dementia and Parkinsonism.
Diagnosis and Differential
The diagnosis early in the course of illness can be challenging, which contributes to a median time to diagnosis of 14 months. Clinicians may suspect ALS when signs are found of upper and lower motor neuron dysfunction without other central nervous system dysfunction. Other diagnoses to consider that may have ALS-like symptoms are systemic illnesses such as diabetes, thyroid and parathyroid dysfunction, vitamin B12 deficiency, heavy metal toxicity, vasculitis, and CNS tumors.
Emergency Department Care and Disposition
A new diagnosis of ALS is uncommon to make in the emergency department. Stable patients with suspicious symptoms should be referred for appropriate testing by a neurologist if an initial workup does not reveal an emergent cause of neurologic symptoms.
Patients with a known diagnosis of ALS may present for emergency care with complications such as respiratory failure, aspiration pneumonia, choking episodes, or traumatic injuries.
Optimize pulmonary function based on an individual patient's respiratory status and comorbidities using interventions such as nebulizer treatments, steroids, antibiotics, and intubation, as indicated. While a blood gas may not reliably predict impending respiratory failure, a forced vital capacity <25 mL/kg or 50% decreased from predicted normal increases the likelihood of pneumonia and respiratory failure in these patients.
Patients with pneumonia, inability to handle secretions, respiratory distress, or need for ventilator support should be admitted to an appropriate level of inpatient care.
Myasthenia gravis is an autoimmune disorder of the neuromuscular junction that is characterized by muscle weakness and fatigue. Most patients have weakness of proximal extremity muscles, neck extensors, and facial or bulbar muscles. Ptosis and diplopia are common presenting symptoms, and symptoms typically worsen as the day progresses and improve with rest. Severe respiratory muscle weakness causing respiratory failure is characteristic of a myasthenic crisis.
Diagnosis and Differential