Case report: spontaneous pregnancy following thymectomy for myasthenia gravis associated with premature ovarian failure

Clinical characteristics and relationship between myasthenia gravis and premature ovarian failure: report of two cases

Myasthenia gravis (MG) and premature ovarian failure (POF) are rare. MF and POF greatly affect patients’ health. Combined occurrence of MF and POF in young women can have serious consequences. We report two cases of MG with POF. Case 1 was a 20-year-old woman who presented with myasthenic crisis and menopause in September 2015 and November 2015, respectively. The patient’s estradiol and follicle-stimulating hormone levels were abnormal. She was administered plasmapheresis and methylprednisolone pulse therapy. She improved and was discharged with normal restoration of menstruation after 3 months. Case 2 was a 21-year-old woman who had right eyelid droop and double vision in June 2014. She presented with menstrual disorder and menopause in August 2014 and September 2014, respectively. Estradiol and follicle-stimulating hormone levels were abnormal. She underwent progesterone therapy. She was admitted to hospital again in March 2016 with a myasthenic crisis. She received methylprednisolone pulse therapy and underwent thymectomy, but menstruation was not restored. In conclusion, there is comorbidity of POF in MG, and there is a close relationship between these two diseases. MG may subsequently lead to development of POF, and timely immunotherapy for MG may normalize POF.

Resolution of autoimmune oophoritis after thymectomy in a myasthenia gravis patient

Myasthenia gravis (MG) is an autoimmune disorder characterized by autoantibodies against acetylcholine receptors. MG is generally an isolated disorder but may occur concomitantly with other autoimmune diseases. We describe an eighteen-year-old girl with MG who was admitted to our clinic with secondary amenorrhea and diagnosed as autoimmune oophoritis. Since her myasthenic symptoms did not resolve with anticholinesterase therapy, thymectomy was performed. After thymectomy, her menses have been regular without any hormonal replacement therapy. To our knowledge, this is the first report on a patient with autoimmune ovarian insufficiency and MG in whom premature ovarian insufficiency resolved after thymectomy, without hormonal therapy.

Premature ovarian failure

Premature ovarian failure (POF) causing hypergonadotrophic hypogonadism occurs in 1% of women. In majority of cases the underlying cause is not identified. The known causes include: (a) Genetic aberrations, which could involve the X chromosome or autosomes. A large number of genes have been screened as candidates for causing POF; however, few clear causal mutations have been identified. (b) Autoimmune ovarian damage, as suggested by the observed association of POF with other autoimmune disorders. Anti-ovarian antibodies are reported in POF by several studies, but their specificity and pathogenic role are questionable. (c) Iatrogenic following surgical, radiotherapeutic or chemotherapeutic interventions as in malignancies. (d) Environmental factors like viral infections and toxins for whom no clear mechanism is known. The diagnosis is based on finding of amenorrhoea before age 40 associated with FSH levels in the menopausal range. Screening for associated autoimmune disorders and karyotyping, particularly in early onset disease, constitute part of the diagnostic work-up. There is no role of ovarian biopsy or ultrasound in making the diagnosis. Management essentially involves hormone replacement and infertility treatment, the only proven means for the latter being assisted conception with donated oocytes. Embryo cryopreservation, ovarian tissue cryopreservation and oocyte cryopreservation hold promise in cases where ovarian failure is foreseeable as in women undergoing cancer treatments.

Myasthenia gravis and premature ovarian failure

We describe a patient who developed seropositive myasthenia gravis 16 years after she was diagnosed with autoimmune premature ovarian failure with antibodies to the receptor for follicle-stimulating hormone (FSH). Although thymectomy led to improvement of her myasthenic symptoms, menses did not resume. Such combined seropositivity for antibodies to acetylcholine and ovarian hormone receptors in a patient with myasthenia gravis and premature ovarian failure may reflect common disease mechanisms, although the precise pathogenesis of these disorders remains ill-defined.