The objective of this case is to highlight the challenges that come along diagnosis, complication prevention, and treatment selection in treating concurrent Myasthenia Gravis and Graves’ disease.

Myasthenia Gravis is a neurological disease that occurs due to the development of autoantibodies that target postsynaptic nicotinic acetylcholine receptors at the neuromuscular junction. Symptoms include weakness and fatigue in extremities, ocular, and respiratory muscles. When diagnosing and managing a patient with Myasthenia, it is important to keep a broad differential as other diseases can mask the true diagnosis and complicate the management. One of the conditions that may impact management of MG is Graves’ disease, an autoimmune disorder characterized by the development of autoantibodies against the thyroid-stimulating hormone receptor.

We present a 37-year-old male with no past medical history who presented with progressive extremity weakness, diplopia, dysphagia, dysphonia, shortness of breath, palpitations, and insomnia. His neurologic exam showed a triple furrowed tongue, weak neck flexion and extension, fatigable weakness in the upper and lower extremities, and a positive ice pack test. Diagnostic studies were positive for elevated AchR antibody levels, low TSH and elevated T3 and T4. He was subsequently diagnosed with Myasthenia Gravis and Graves’ disease. With both diseases presenting concurrently his management was nuanced. He was treated with IVIG and steroids, then pyridostigmine. Once his respiratory status stabilized, through continuous monitoring of his negative inspiratory force levels, he was treated with cholestyramine and methimazole for his Graves’ disease.

In conclusion, this case highlights the nuanced clinical reasoning behind treatment selection when multiple autoimmune conditions, such as MG and Graves’, occur with overlapping symptoms that warrants careful management of both. It highlights diagnostic criteria, complication prevention, and treatment methods for combined diagnoses.