The requirements of immunosuppressive therapy and clinical features in patients with myasthenia gravis who undergo thymectomy versus non thymectomy management in East Africa
Date of Award
Master of Medicine (MMed)
Dr. Dilraj Sokhi
Dr. Peter Mativo
Dr. Jasmit Shah
Internal Medicine (East Africa)
Background: Myasthenia gravis is an acquired autoimmune neuromuscular disease leading to fatigability of skeletal muscles. The thymus produces autoantibodies that target receptors to Acetylcholine or Muscle Specific Kinase. The resultant fatigability is generalized or limited to the ocular or bulbar muscles. Therapy has been targeted to reduce the autoimmune process by use of immunosuppressive agents or by thymectomy. In the African population, MG involves younger patients, more ocular involvement, is more aggressive and more resistance to immunosuppressive therapy.
Methods: We conducted a retrospective study between January 2009 and December 2019 at Aga Khan University Hospital, Nairobi. Medical records of patients with MG were obtained using the ICD 10 code search. Other methods of case finding included CARE 2000 SQL queries for patients who have had specific investigations for MG and obtaining proxy information from neurologists. Basic clinico-demographic data were recorded. Other variables such as disease exacerbation and therapies were also obtained. A Myasthenia Gravis Foundation of America post intervention status score was obtained based on the information available in the patient chart.
Results: Of 85 patients sampled, [male=56.5% (48/85); mean age 49.6 years], 30.6% (26/85) had ocular MG (MGFA class 1), and 69.4% (59/85) had generalized MG, of which (at onset) 72.8% (43/59) had mild/moderate (class II/III) disease. Mean time to diagnosis was 3.0 months. Only 36.1% (30/85) had a thymus, and were significantly more likely to have: anti-acetylcholine receptor antibodies (89.7% vs 57.4%; p=0.005); generalized MG (93.1% vs 50.0%; p<0.001); early onset of steroid use (96.6% vs 76.8%; p=0.028); and more relapses (79.3% vs 44.6%; p<0.001). Majority (29/30) underwent thymectomy, resulting in eventual dose reduction of corticosteroids and pyridostigmine and lower requirements in immunosuppressive therapy in comparison with the non thymectomy group.
Conclusion:In our study, thymectomy leads to decline in the dose requirements of pyridostigmine, steroid sparing agents and steroids at last follow up with clinical improvement.
Ochola, N. A. (2021). The requirements of immunosuppressive therapy and clinical features in patients with myasthenia gravis who undergo thymectomy versus non thymectomy management in East Africa (Unpublished master's dissertation). Aga Khan University, East Africa.