Balamuthia Mandrillaris Amoebic Encephalitis Clinically Mimicking as Myasthenia Gravis Exacerbation: A Diagnostic Challenge

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This paper reports a diagnostic challenge in a 70-year-old immunocompromised man with myasthenia gravis (MG) who developed persistent diplopia and headache that were initially treated as an MG exacerbation after prednisone was added. Over 10 days, his symptoms worsened with progressive vision loss, increasing weakness, intermittent shortness of breath, and a transient episode of right-hand numbness; MRI showed multiple ring-enhancing intracranial lesions highly suggestive of infection, but an extensive infectious workup was inconclusive and empiric antibiotics did not resolve the uncertainty. The definitive diagnosis came after clinical deterioration, brain biopsy, and subsequent PCR confirmation that the cause was Balamuthia mandrillaris amoebic encephalitis. The authors emphasize the limitation that rare intracranial infections can closely mimic MG flare-ups and that failure to recognize this can have fatal consequences, with MG context complicating timely diagnosis. The paper does not explicitly discuss endometriosis or adenomyosis; it was included in the corpus via a keyword match in the upstream search index.

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Abstract

The case is a 70-year-old immunocompromised male with a history of myasthenia gravis (MG). He presented with new-onset, persistent diplopia and headache unresponsive to prior therapy, initially suspected to be a recurrent MG exacerbation, for which oral prednisone was added to his treatment. The patient's condition worsened over the 10-day period following the clinic visit, with ongoing vision loss, increasing weakness, and intermittent shortness of breath. During this period, he also experienced a transient episode of right-hand numbness, which resolved spontaneously. He was admitted for suspected recurrent MG; neurology raised concerns about an alternative underlying process and ordered a magnetic resonance imaging (MRI) scan, which revealed multiple ring-enhancing lesions highly suggestive of an intracranial infection. Empiric antibiotics were initiated, but an extensive infectious disease workup was inconclusive. He was discharged in stable condition, with a brain biopsy and follow-up MRI scheduled for further evaluation. Five days later, he returned to the emergency department with decreased level of consciousness, fever, and confusion. He underwent a brain biopsy, which revealed evidence of an amoebic infection. In the subsequent days, his condition deteriorated rapidly, and he passed away on the same day that a diagnosis of Balamuthia mandrillaris infection was confirmed via PCR on a brain tissue sample. This case highlights significant diagnostic challenge in MG patients, where rare infections can closely mimic disease flare-ups. As demonstrated in our case, failing to recognize infections can lead to severe consequences. In MG patients with worsening, treatment-resistant symptoms and atypical presentations, MRI is strongly recommended.
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Full text loading... Abstract The case is a 70-year-old immunocompromised male with a history of myasthenia gravis (MG). He presented with new-onset, persistent diplopia and headache unresponsive to prior therapy, initially suspected to be a recurrent MG exacerbation, for which oral prednisone was added to his treatment. The patient's condition worsened over the 10-day period following the clinic visit, with ongoing vision loss, increasing weakness, and intermittent shortness of breath. During this period, he also experienced a transient episode of right-hand numbness, which resolved spontaneously. He was admitted for suspected recurrent MG; neurology raised concerns about an alternative underlying process and ordered a magnetic resonance imaging (MRI) scan, which revealed multiple ring-enhancing lesions highly suggestive of an intracranial infection. Empiric antibiotics were initiated, but an extensive infectious disease workup was inconclusive. He was discharged in stable condition, with a brain biopsy and follow-up MRI scheduled for further evaluation. Five days later, he returned to the emergency department with decreased level of consciousness, fever, and confusion. He underwent a brain biopsy, which revealed evidence of an amoebic infection. In the subsequent days, his condition deteriorated rapidly, and he passed away on the same day that a diagnosis of Balamuthia mandrillaris infection was confirmed via PCR on a brain tissue sample. This case highlights significant diagnostic challenge in MG patients, where rare infections can closely mimic disease flare-ups. As demonstrated in our case, failing to recognize infections can lead to severe consequences. In MG patients with worsening, treatment-resistant symptoms and atypical presentations, MRI is strongly recommended. - Received: - Version Posted:

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