Myasthenia Gravis Can Develop in Patients with Systemic Lupus Erythematosus, Case Study Says

Although rare, myasthenia gravis can develop in patients with systemic lupus erythematosus, according to a case study.

The study, “Systemic Lupus Erythematosus and Myasthenia Gravis: A Rare Association,” was published in The Indian Journal of Nephrology.

Systemic lupus erythematosus (SLE) and myasthenia gravis (MG) are two autoimmune diseases that predominantly affect young women. SLE is the most prevalent form of lupus, a chronic autoimmune disease characterized by behavioral and psychological symptoms including pain, fatigue, depression, and impaired cognition.

SLE and MG can coexist or precede each other, but their occurrence in the same patient is rare. In the study, researchers report the case of a patient who developed MG while being treated for lupus nephritis, a type of kidney inflammation, and one of the most frequent and severe symptoms of SLE.

Initially, the 38-year-old woman was diagnosed with SLE after showing symptoms that included breathlessness, oliguria (decreased production of urine), and swelling. The lower production of urine, a sign of kidney malfunctioning, led to further analysis. Clinicians found she had proteinuria (an abnormal amount of protein in the urine), hematuria (presence of blood in the urine), and the presence of antinuclear antibody antibodies, those that react against proteins found in the cell’s nuclei.

While an ultrasonogram of the abdomen showed normal-sized kidneys, a renal biopsy confirmed lupus nephritis.

The patient was treated with corticosteroids, including methylprednisolone for three days, followed by oral prednisolone for eight weeks, and monthly infusions of cyclophosphamide, an immunosuppressant medicine used to treat a variety of conditions, including lupus nephritis.

She also received hydroxychloroquine, a standard treatment in SLE, and anti-hypertensives.

Because of renal failure, the patient underwent twice-weekly hemodialysis. After three months, she had difficulties opening her eyes. Nerve conduction tests showed a decrease by 15% to 25% of facial muscle control but her limb muscles remained unaffected. These symptoms suggest MG despite the patient being negative for anti-acetylcholine receptor antibodies.

After treatment with Mestinon (pyridostigmine) twice daily, her clinical symptoms improved within 48 hours. Her renal failure also improved, although slowly, and she was dialysis-free after four months.

The patient is currently taking oral prednisolone and CellCept (mycophenolate mofetil), an oral immune-suppressing treatment developed by Genentech which is commonly used to treat MG patients.

At her last follow-up, her blood analysis was normal, and she hadn’t developed any eye symptoms.

Overall, “the association between SLE and MG is complex,” the researchers wrote, adding that in MG patients who underwent thymectomy — removal of the thymus gland — signs of SLE warrant further clinical evaluation.

“In lupus patients complaining of decreased muscle strength and fatiguability, the possibility of MG should be ruled out,” they concluded.