Case Presentation: A 65-year-old male with a past medical history significant for hypertension initially presented with episodes of double vision, fatigue and dysphagia. Physical exam was remarkable for right-sided ptosis which improved with the ice pack test. Serology was positive for anti-acetylcholine receptor antibodies. Further workup revealed a decremental response to slow (2Hz) repetitive nerve stimulation of the right spinal accessory nerve and was diagnosed with Myasthenia Gravis(MG). CT scan of the chest revealed thymoma for which the patient underwent resection and was placed on a high dose (50 mg daily) oral prednisone, in addition to mycophenolate and pyridostigmine. Four months later the patient presented to the hospital with shortness of breath. A chest X-ray revealed reticulonodular infiltrates. Further workup led to the diagnosis of histoplasmosis. Mycophenolate was then stopped and prednisone was tapered. The patient subsequently developed refractory diarrhea secondary to Cytomegalovirus (CMV) colitis. The patient continued to develop recurrent pneumococcal infections despite off immunosuppressive therapy. Eight months post discontinuation of steroids, the patient developed disseminated candidal infection. Immunological studies were remarkable for hypogammaglobulinemia IgG: 100 mg/dl (N: 700-1600). Flow cytometry revealed reduced mature circulating B cells, reduced CD4 count, and reversal of the CD4: CD8 ratio of 0.5 (N: 2.0). Subsequently, the bone marrow biopsy revealed a reduced pre-B cell lineage leading to the diagnosis of Good’s syndrome (GS). The patient was successfully treated with IVIG (1g/kg) and since then has remained stable on a monthly IVIG regimen.
Discussion: Patients with MG are commonly treated with corticosteroids, cytotoxic drugs (mycophenolate, azathioprine), alkylating agents (cyclophosphamide) and calcineurin inhibitors (cyclosporine A, tacrolimus) [9]. These immunosuppressive drugs predispose patients to infections [10]. Hence, during opportunistic infections, immunosuppressive therapy is weaned off to aid in the recovery from infections [10-11]. Recurrent opportunistic infections after the discontinuation of immunosuppressive therapy should raise the suspicion for an immunodeficiency disorder. Good’s syndrome is a rare adult-onset immunodeficiency disorder in the setting of thymoma characterized by the decrease in all types of immunoglobulin, T-cells and an abnormal CD4: CD8+ T-cell ratio [12]. The prognosis of Good’s syndrome appears to be poor. Hermaszewski et al. [13] found that only 33% of patients were alive at the end of 10 years in comparison with 97% of patients with common variable immunodeficiency. Thymoma can be associated with both MG and GS. But their concurrent existence in a thymoma patient is an extremely rare association [11]. A delay in recognizing GS can lead to an infectious catastrophe as seen in our patient.
Conclusions: Despite forming two extreme ends of the immunological spectrum, Good Syndrome and Myasthenia Gravis can co-exist in the same patient. Hence, when a patient with MG develops recurrent opportunistic infections following thymectomy, flow cytometry should be considered to rule out GS. Once their co-existence is confirmed, prompt initiation IVIG therapy is life-saving and can prevent future occurrences of opportunistic infections.