Abstract Introduction Juvenile myasthenia gravis (MG) is a rare form of the disease that can present in children. Most children, especially those under the age of 11, initially present with ocular symptoms such as ptosis and diplopia, while respiratory involvement typically emerges later in more severe disease. We present a case of a child with severe obstructive sleep apnea (OSA) who presented with recurrent episodes of acute hypercarbic respiratory failure, ultimately leading to the diagnosis of MG. Case A 7-year-old female with history of velopharyngeal insufficiency was followed in pulmonology clinic for asthma, recurrent respiratory infections, and OSA. Despite tonsillectomy, adenoidectomy, and palatoplasty, a repeat polysomnography showed severe OSA (obstructive apnea-hypopnea index of 120/hr), hypoxemia and alveolar hypoventilation. OSA was optimally managed with nocturnal bilevel positive airway pressure (BPAP). Over a four-month period, the patient experienced intermittent but progressive fatigue and increased work of breathing with poor weight gain. This was complicated by recurrent admissions for acute hypercarbic respiratory failure in the absence of identifiable triggers, with negative infectious work up and requiring escalation of respiratory support. Her symptoms and findings on exam, including truncal weakness, raised concern for hypoventilation in the setting of neuromuscular weakness. Spirometry demonstrated significant symmetric reduction in FEV1 and FVC, suggestive of a restrictive defect. Maximum inspiratory pressure (MIP) was severely reduced at 13cmH2O (25% predicted). During a hospitalization, the patient underwent extensive evaluation by neurology and genetics, ultimately leading to a diagnosis of muscle- specific tyrosine kinase (MuSK) myasthenia gravis. Initiation of treatment with pyridostigmine and prednisone led to notable improvements in her sleep symptoms, muscle strength, and weight gain. One month follow-up after diagnosis, she had improvement in MIP to 22cmH2O (42% predicted), and in FEV1 and FVC (Figure 1). Discussion This case highlights the complexity of diagnosing MG in children. The incidence of MG in pediatric populations is estimated to be approximately 1.5 cases per million children per year, and the diagnosis is complicated by the range of symptoms at presentation and a wider differential diagnosis. The initial symptoms often include extraocular muscle weakness and ptosis, with more severe presentations including respiratory symptoms. MuSK MG is a more severe subtype of MG, occurring in 10% of all cases of MG, and often presenting with earlier, more frequent, respiratory crises. This case shows the importance of considering myasthenia gravis in a pediatric patient with intermittent extreme fatigue, muscle weakness and hypoventilation. This abstract is funded by: None
Tomasek et al. (Fri,) studied this question.