RESPIRATORY FAILURE AS THE INITIAL CLINICAL MANIFESTATION OF MYASTHENIA GRAVIS IN THE INTENSIVE CARE UNIT: A CASE REPORTnia Gravis in the Intensive Care Unit: A case report

Abstract

Introduction: Myasthenia gravis is an autoimmune disorder affecting the neuromuscular junction. Regarding pathophysiology, autoantibodies target postsynaptic muscle membrane antigens, causing endplate depletion leading to muscle weakness. The clinical spectrum varies from a purely ocular form to severe general weakness affecting limb, bulbar and respiratory muscles. Myasthenic crisis, a medical emergency resulting from involvement of respiratory muscles, may manifest as the initial clinical presentation of myasthenia gravis.

Case report: Herein, we report a case of a 23-year-old male, who presented to the Emergency Department of the University Hospital of Larissa after a car accident. The patient had mild lung injury, without any neurological symptomatology. During hospitalization the patient manifested acute respiratory failure with hypercapnia leading to cardiac arrest, requiring cardiopulmonary resuscitation. The patient was intubated and admitted to the Intensive Care Unit. Despite clinical and laboratory improvement, patient had elevated carbon dioxide levels, disallowing his weaning from ventilation and oxygen supply. Patient's history revealed episodes of blepharoptosis and muscle fatiguability in the form of difficulty performing physical tasks, while neurological examination showed bulbar symptoms, facial, neck and upper extremities muscle weakness, unraveling a potential Myasthenia Gravis phenotype. Serum immunology study disclosed positive antibodies against muscle specific kinase. The patient was treated with intravenous immunoglobulin (IVIg) and then plasma exchange sessions, leading to clinical improvement.

Conclusion: Myasthenia Gravis should be suspected in case of respiratory failure and inability to wean off mechanical ventilation, especially in young adults. When treating a respiratory failure due to a potential myasthenic crisis, plasma exchange or IVIg should be carefully evaluated as an aggressive and rapid treatment option with good prognosis.