Ocular Myasthenia Gravis Associated with Autoimmune Hemolytic Anemia and Hashimoto's Thyroiditis

Abstract

We studied a patient with ocular myasthenia gravis, autoimmune hemolytic anemia, and Hashimoto's thyroiditis. This case suggests that these disorders may be related. A 62-year-old Japanese woman was referred to our clinic with a one-month history of bilateral blepharoptosis. She had a history of autoimmune hemolytic anemia, and had been treated with 5 mg of prednisolone per day for three years. On examination, mild anemia and bilateral minimal diffuse thyroid enlargement with a hard surface were noted. Results of neurologic examination were normal. Marked bilateral blepharoptosis without ophthalmoplegia was present. The pupils were isocoric and reactive. Results of motor examination of all extremities were normal. A single dose of 2 mg of edrophonium chloride administered intravenously immediately reversed the blepharoptosis. Results of laboratory examinations included normal electrolyte levels and liver function tests, and the total bilirubin level was 2.0 mg/dl (indirect bilirubin was 1.9 mg/dl). Results of complete blood cell counts were as follows: white blood cell count, 3,100/mm3; red blood cell count, 3.26 x 106/mm3; hemoglobin, 10.1 g/dl; and platelet count, 1.19 x 104/mm3• The antibody tests demonstrated a microsomal antibody of 1:1,600 and a thyroglobulin antibody of 1:1,600. The thyroid stimulating hormone level was 32 ILM/ml (normal, <10 ILM/ml). The T4, T3, and free T4 values were 7.4 ug/dl (normal, 5.0 to 13.0 ILg/dl), 100 ng/l (normal, 70 to 190 mg/l), and 0.7 ng/dl (normal, 1.1 to 2.0 ng/dl), respectively. Results of both the direct and indirect Coomb's tests were positive. The measurement of anti-acetylcholine receptor antibody titer in the blood was 0.02 pmol/ml (normal, <0.5 pmol/ml). On electromyography, typical waning waves were noted in the orbicularis oculi. Results of computed tomography of the brain were normal. No detectable thymoma was observed in the overall body computed tomographic scan. A diagnosis of ocular myasthenia gravis was made on the basis of the ocular signs, positive edrophonium chloride test, and electromyographic findings, although the antiacetylcholine receptor titer was not increased. Diagnosis of autoimmune hemolytic anemia was based on mild anemia, increased level of indirect bilirubin, and positive direct and indirect Coomb's tests. Physical examination showed minimal diffuse thyroid enlargement with a hard surface. Laboratory studies showed normal values of T3 and T4, an increased level of thyroid stimulating hormone, and decreased free T4• Positive thyroglobulin and microsomal thyroid antibodies were present. These findings were compatible with a diagnosis of Hashimoto's thyroiditis, although no biopsy of the thyroid gland was performed. It is well known that myasthenia gravis is found in association with other autoimmune diseases, and four cases of myasthenia gravis associated with autoimmune hemolytic anemia have been reported.I A combined occurrence of myasthenia gravis and Hashimoto's thyroidits is rare.' Moreover, myasthenia gravis, autoimmune hemolytic anemia, and Hashimoto's thyroiditis occurring together is an unusual constellation of autoimmune disorders. Since myasthenia gravis is associated with many autoimmune diseases, we suggest that full antibody testing be performed on a patient with this disease.