A 27-year-old Sinhalese man presented with a 2-year history of intermittent left-sided pleuritic-type chest pain which was associated with a non-productive cough and wheezing. He was previously healthy and self-employed. He did not have a family history of note and denied smoking tobacco or consuming alcohol.
He had been treated with inhaled bronchodilators, inhaled corticosteroids, and antibiotics intermittently. During evaluation, his chest X-ray revealed a pleural-based lesion along the lateral wall of his chest with lobulated inner margins in the left hemithorax (Fig. 1). Further evaluation with a contrast-enhanced computed tomography (CT) scan of his chest revealed multiple pleural-based enhancing focal lesions involving the left hemithorax with calcifications (Fig. 2). A CT-guided Tru-Cut biopsy confirmed the diagnosis of a thymoma. While awaiting thymectomy and debulking surgery, he developed diplopia with a right-sided abducens nerve palsy and partial ptosis on the same side. An MRI of his brain with orbits was normal. Repetitive nerve stimulation of facial and spinal accessory nerve-muscle pairs showed significant decrement and his acetylcholine receptor (AChR) antibody titer was 11.8 nmol/L (normal < 0.4 nmol/L), thus, confirming the clinical diagnosis of MG.
Prior to starting immunosuppressive treatment for MG, he developed fever with chills and rigors which was associated with progressively worsening difficulty in breathing and a productive cough over a period of 1 week.
An initial examination found bilateral, asymmetrical partial ptosis and a right sixth cranial nerve palsy. Demonstrable muscle fatigability was present. His neck flexion power on admission was grade 4/5. Upper and lower limb examinations were neurologically normal. However, his forced vital capacity (FVC) on admission was 1.0 liter. In addition, he had clinical features consistent with a left lower zone pleural effusion without tracheal deviation. The rest of his physical examination was normal.
Pneumonia of the lower lobe of his left lung with parapneumonic effusion and impending myasthenic crisis were diagnosed and he was commenced on intravenously administered meropenem 1 g every 8 hours, after taking blood and sputum for microbiological cultures. He was treated with orally administered pyridostigmine 60 mg 6 hourly for the fatigable weakness.
A summary of his laboratory parameters are shown in Table 1.
Table 1 Summary of the hematological and biochemical parameters His chest X-ray showed left lower zone consolidation with a pleural effusion which was confirmed on an ultrasound scan of his chest.
On day 3 of hospital stay plasmapheresis was commenced. On day 4 of hospital stay, there was worsening bulbar weakness and neck flexion and he required admission to the intensive care unit (ICU). In addition, orally administered prednisolone was commenced at 10 mg daily and increased by 10 mg per day until a dose of 60 mg daily was reached, which was then continued. His serum potassium levels, C-reactive protein, and white cell counts were monitored.
A total of five cycles of plasma exchanges were performed on an every-other-day basis and subsequently intravenous immunoglobulin at a dose of 0.4 g/kg per day for 5 days was given. Intravenously administered meropenem was continued for 14 days. He did not require endotracheal intubation or mechanical ventilation.
During the ICU stay he was detected to have low immunoglobulin G (IgG) and immunoglobulin M (IgM) levels. Flow cytometry analysis of lymphocyte subsets revealed low B cell counts (Table 2).
Table 2 Summary of the immunological parameters (peripheral blood) Good syndrome was diagnosed due to the presence of hypogammaglobulinemia and thymoma. Following completion of intravenous immunoglobulin therapy, he underwent thymectomy and debulking of thymic tumor deposits. Postoperatively, he made a good recovery without any episodes of acute weakness or the development of infections. Histology of the surgical specimens revealed type B2 thymoma with implants in his left lung and parietal pleura. His prednisolone dosage was gradually tapered to a maintenance dose of 10 mg/day without relapse of MG at 6-month follow-up.