Toxoplasmic encephalitis during mycophenolate mofetil immunotherapy of neuromuscular disease

Abstract

Objective: To show that immunotherapy with medications such mycophenolate mofetil (MMF) can cause serious complications in patients with neuromuscular disorders.

Methods: Two patients with neuromuscular disorders on immunotherapy with long-term MMF who developed toxoplasmic encephalitis (TE) were included in this case series.

Results: One patient with myasthenia gravis and one patient with inflammatory myopathy on immunotherapy with long-term MMF developed severe TE. Diagnosis was based on clinical presentation, MRI brain imaging characteristics, and CSF PCR positivity for Toxoplasma gondii. Both patients were treated with pyrimethamine, sulfadiazine, and leucovorin for 2 months without clinical improvement, and both died.

Conclusions: Immunotherapy with medications such as MMF can cause devastating TE in non-HIV patients with neuromuscular disorders. Early consideration and recognition of this complication is important to possibly prevent unfavorable outcomes. The utility of screening and prophylaxis against toxoplasmosis in individuals with neuroimmunologic disorders and other autoimmune disorders who receive immunosuppressive therapy requires future study.

Figure 1. Pre- and posttreatment contrast-enhanced MRI of toxoplasmosis lesion in case 1

(A, B) Contrast-enhanced MRI demonstrated a 2.3 by 1.3 cm ring-enhancing lesion in the deep white matter of the left frontoparietal lobe. (C, D) Repeat imaging 1 month later after receiving antitoxoplasmosis treatment. A and C are MRI brain fluid-attenuated inversion recovery sequences. B and D are MRI brain T1 postgadolinium images.

Figure 2. Pre- and posttreatment contrast-enhanced MRI of second toxoplasmosis lesion in case 1

(A) Contrast-enhanced MRI demonstrated a second ring-enhancing lesion in the medial right temporal lobe. (B) Repeat imaging 1 month after receiving antitoxoplasmosis treatment.

Figure 3. Contrast-enhanced MRI of toxoplasmosis lesions in case 2

(A) MRI brain fluid-attenuated inversion recovery demonstrated multiple lesions with perilesional edema. (B) Contrast-enhanced MRI brain demonstrated multiple foci of ring-enhancing lesions in the bilateral subcortical regions.