Bilateral pseudo-internuclear ophthalmoplegia in myasthenia gravis

Myasthenia Gravis With Reversible Pyramidal Tract Damage and Pseudo Internuclear Ophthalmoplegia. A Case Report and Literature Review

Myasthenia gravis (MG) is a rare and treatable antibody-mediated autoimmune disease. Pseudo internuclear ophthalmoplegia (-INO) or pyramidal tract damage is rarely observed in MG, and there were no known cases of MG with both pseudo-INO and pyramidal tract damage. Here, we report a case of a 61-year-old female suffering from MG accompanied by pseudo-INO and pyramidal tract damage with a rapid progressive course. Her blood and cerebrospinal fluid (CSF) tests were normal, except for the presence of the anti-acetylcholine receptor antibody. CT and contrast enhancement of the chest showed a thymic involution. MRI and contrast enhancement images of the brain and whole spine were normal. Both the clinical response to the administration of neostigmine and the repetitive nerve stimulation test were positive. The motor evoked potentials at lower limb recordings were normal. According to her signs, symptoms, decrementing response on repetitive stimulation test, elevated anti-acetylcholine receptor antibody and positive response to neostigmine, the patient was diagnosed as having MG. After treatment with pyridostigmine, intravenous immunoglobulin, prednisone acetate tablets and methotrexate, all her symptoms disappeared, including pseudo-INO and pyramidal tract damage. To our best knowledge, this is the first report of a case of MG with both pseudo-INO and pyramidal tract damage. Based on our case and a review of the literature, we propose that pyramidal tract damage and pseudo-INO can be two signs of MG, and that MG can cause damage to other systems besides neuromuscular junctions.

Bilateral pseudo-internuclear ophthalmoplegia in a patient with myasthenia gravis

Purpose

To report a case of myasthenia gravis presenting with a false localizing sign, a bilateral pseudo internuclear ophthalmoplegia.

Observations

A 61 year-old male presented with a five-week history of painless binocular oblique diplopia that was associated with fatigue, vocal hoarseness and bilateral ptosis, the latter two of which worsened through the course of the day. Exam was remarkable for an apparent bilateral internuclear ophthalmoplegia (INO). MRI of the brain with and without contrast and MRA of the head and neck were within normal limits. Lab work was positive for anti-AChR binding, blocking, and modulating antibodies, as well as anti-striated muscle and anti-titin antibodies. The patient was initiated on therapy for myasthenia gravis.

Conclusion and importance

Although myasthenia gravis often presents with ptosis or diplopia, rarely patients may develop pseudo-INO secondary to extraocular muscle weakness. True INO occurs with damage to the medial longitudinal fasciculus, a myelinated tract of fibers that controls yoked horizontal eye movements. Clinicians should be suspicious of the false localizing sign of a pseudo-INO associated with myasthenia gravis when more common causes of INO have been excluded.

Muscle-specific kinase antibody positive myaesthenia gravis and multiple sclerosis co-presentation: a case report and literature review

We present the first case of simultaneous muscle-specific kinase antibody positive myaesthenia gravis and relapsing-remitting multiple sclerosis to be reported in the English literature along with the inherent diagnostic and treatment challenges. There may be an association between myaesthenia and central nervous system demyelination. We identified 72 previously published cases of myaesthenia with central nervous system demyelination. Of 19 cases of myaesthenia with relapsing-remitting multiple sclerosis, nine (47%) were acetylcholine receptor antibody negative, but there were no previously published cases with muscle-specific kinase antibody. Further research is required to clarify this association and optimal treatment in such cases.

Diagnostic confusion resolved by being upbeat

The classical stroke presentation - captured by the public health campaign mnemonic FAST (face, arm, speech, time) - does not apply in a large number of stroke cases; yet establishing a prompt diagnosis is imperative for optimal management. Here, we describe a patient with acute bulbar weakness, numbness in all extremities and an apparently normal magnetic resonance imaging (MRI) of the brain upon admission for whom even the fundamental question of whether this reflected a central or peripheral nervous system process was unclear. The critical localizing sign was upbeat nystagmus that denotes a brainstem cause. MRI of the brain in the second week confirmed a diagnosis of medial medullary infarction.

Pseudo-internuclear ophthalmoplegia as a sign of overlapping myasthenia gravis in a patient with 'intractable' hypothyroidism

We describe a 52-year-old man with a history of increasing fatigability and gait disturbances that were first attributed to hypothyroidism. On examination, he had bilateral pseudo-internuclear ophthalmoplegia with weakness of adduction and abducting nystagmus. Convergence was also impaired and he showed proximal weakness of the limb. Intravenous edrophonium almost completely abolished the nystagmus and adducting muscle weakness, and improved the strength of proximal muscles groups. The clinical response to the administration of edrophonium, the presence of AChR binding antibodes and the repetitive nerve stimulation test findings indicated that the patient had pseudo-internuclear ophthalmoplegia as a manifestation of generalized myasthenia gravis. Whereas hypothyroidism was effectively controlled with levothyroxine, his subsequent response to thymectomy, prednisolone and cholinesterase inhibitors confirmed the diagnosis of generalized myasthenia gravis.

Decompensating esophoria as the presenting feature of myasthenia gravis

Myasthenia gravis is a disease in which antibodies directed at nicotinic acetylcholine receptors are produced, leading to a deficiency of acetylcholine receptors at the neuromuscular junction. This results in impairment of muscular excitation, which appears clinically as fatigable muscle weakness. Weakness of the extraocular muscles occurs in nearly 90% of all myasthenics at disease onset, with ptosis being the most common presenting feature. Myasthenia gravis affecting one or a combination of the extraocular muscles without ptosis is less common; however, cases such as bilateral internuclear ophthalmoplegia without ptosis have been described in the literature. The authors present a case in which decompensating esophoria was the presenting feature of myasthenia gravis.

Ocular myasthenia mimicking a one-and-a-half syndrome

A 52-year-old patient developed an eye movement disorder first resembling a left internuclear ophthalmoplegia and subsequently a "one-and-a-half syndrome" as the presenting symptoms of ocular myasthenia gravis. No accompanying myasthenic features were present except for the fluctuation in the amplitude of dissociated nystagmus. This patient shows that an oculomotor disorder considered a typical pontine lesion may instead be caused by myasthenia gravis, even in the absence of other clinical and electrophysiologic features of neuromuscular deficit.