Good's Syndrome Presenting With Weaning Failure From Ventilation and Myasthenia Gravis in a Post-Thymectomy Patient.

Good's syndrome is a rare adult-onset immunodeficiency associated with thymoma, hypogammaglobulinemia, and cellular immune dysfunction. We report a man in his 50s with a prior thymectomy who presented with recurrent pneumonia, chronic diarrhoea, and failure to wean from non-invasive ventilation. Flow cytometry revealed absent B cells and an inverted CD4/CD8 ratio, confirming Good's syndrome. He also developed myasthenia gravis, which contributed to ventilatory failure but improved with pyridostigmine. The patient responded well to monthly intravenous immunoglobulin therapy and remained clinically stable at follow-up. This case emphasises the importance of suspecting Good's syndrome in patients with thymoma and unexplained infections, as early recognition and timely immunoglobulin replacement are essential for improving outcomes.