CLINPR-100022; No of Pages 4

Clinical Infection in Practice xxx (xxxx) xxx

Contents lists available at ScienceDirect

Clinical Infection in Practice

journal homepage: https://www.journals.elsevier.com/clinpr

1 Case reports and series

2 Toxoplasmosis: An overlooked cause of confusion in a patient with myasthenia gravis

Q33Q2 Marco Lee a,⁎, Kavita Sethi b, Edward Guy c

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4 a
Harrogate and District NHS Foundation Trust, Harrogate HG2 7SX, United Kingdom
5 b
Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, United Kingdom

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6 c
Toxoplasma Reference Unit, Public Health Wales, Swansea SA2 8QA, United Kingdom
7

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8 a r t i c l e i n f o a b s t r a c t

9 19

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Article history: Background: Immunosuppressive medications are often under-recognised risk factors for toxoplasmosis in non-
10 Received 31 December 2019 HIV persons. 20
11 Received in revised form 5 February 2020 Case report: A 58-year-old male presented to our hospital with a three-day history of confusion, change in 21
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Accepted 26 February 2020 behaviour, and vomiting. Diffusion-weighted MRI revealed two frontal and one thalamic ring-enhancing lesions 22
13 Available online xxxx
associated with significant oedema, suspicious of multiple cerebral abscesses. The patient underwent surgical 23
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14
brain biopsies twice to establish the pathological diagnosis. After negative bacterial and fungal cultures and 24
37 Keywords:
38 Cerebral toxoplasmosis
16S rDNA PCR results, a suspicion of cerebral toxoplasmosis was made after noting exposure to mycophenolate
D 25
39 Toxoplasmosis mofetil (MMF) as an immunosuppressive agent for myasthenia gravis. 26
40 Toxoplasma gondii Result: The diagnosis was suggested by positive toxoplasma serum IgG, Sabin-Feldman dye test, and brain tissue 27
41 PCR. Following anti-toxoplasma treatment and cessation of MMF, the patient made a good neurological and func- 28
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Mycophenolate mofetil
42 Immunosuppressant tional recovery. 29
43 Myasthenia gravis Conclusion: This is the first described case of cerebral toxoplasmosis developing on MMF monotherapy, with six 30
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other published cases developing on MMF with other concurrent immunosuppressant medication. These few 31
descriptions suggest a rare or under-reported phenomenon. This case highlights the importance of considering 32
33
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cerebral toxoplasmosis in non-HIV persons on immunosuppressive therapy for inflammatory neuromuscular

disorders. 34
© 2020 Published by Elsevier Ltd on behalf of British Infection Association. This is an open access article under the CC 35
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36 BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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48 1. Case Full systemic enquiry revealed no other symptoms. He had no recent 63

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surgeries, dental procedures, sinusitis, otogenic infections, nor contact 64

49 A 58-year-old male presented to hospital on 18 December 2017 with with known tuberculosis cases. 65
50 a three-day history of confusion, change in behaviour, and vomiting. His Physical examination showed a normal GCS and normal neurologi- 66
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51 partner stated that he had been ‘acting strangely’ but she had not noted cal, cardiovascular, respiratory, and abdominal systems. The patient 67
52 any other specific symptoms. had good dentition and there was no rash nor peripheral stigmata of 68
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53 His background consisted of myasthenia gravis, type 2 diabetes endocarditis. The patient had no fever and was hemodynamically stable. 69
54 mellitus, and a brainstem stroke 15 months ago (evident on MRI at Admission blood tests are shown in Table 1. The high white cell and 70
55 the time). The myasthenia gravis was diagnosed 3 years previously neutrophil counts were deemed to be non-specific since the CRP was 71
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56 following presentation to the ophthalmologists with bilateral ptosis low, and the patient did not receive empirical antibiotics on 72
57 and confirmed by a positive anti-acetylcholine receptor antibody test. presentation. 73
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58 His medications consisted of MMF 1 g BD (taken for the past MRI showed two frontal and one thalamic ring-enhancing lesions 74
59 18 months), lansoprazole 30 mg OD, atorvastatin 40 mg OD, clopidogrel associated with significant oedema (Fig. 1). A normal CT chest, abdo- 75
60 75 mg OD, metformin 1 g BD, and isophane biphasic insulin 25/75 men, and pelvis made metastatic disease less likely to be the cause of 76
61 16 units OD. Prednisolone had been stopped 18 months previously these lesions. 77
62 (ceased at the time the MMF was commenced). A brain biopsy was performed on 12 January 2018 which showed 78
acute inflammation, suggestive of an abscess. Bacterial, fungal, and 79
mycobacterial direct stains and cultures were negative. A second brain 80
biopsy was performed 12 days later which showed acute inflammation 81
with necrosis, again consistent with an abscess. All cultures on this 82
⁎ Corresponding author at: Microbiology Department, Harrogate and District NHS
Foundation Trust, Lancaster Park Road, Harrogate HG2 7SX, United Kingdom. sample were again negative. 16S rDNA PCR on the sample revealed no 83
E-mail address: marco.lee@nhs.net (M. Lee). bacterial pathogens. 84

Please cite this article as: M. Lee, K. Sethi and E. Guy, Toxoplasmosis: An overlooked cause of confusion in a patient with myasthenia gravis, Clinical
Infection in Practice, https://doi.org/10.1016/j.clinpr.2020.100022
 2 M. Lee et al. / Clinical Infection in Practice xxx (xxxx) xxx

t1:1 Table 1
Q1
t1:2 Blood test results.
t1:3
Result Value Units Reference range
Hemoglobin 146 g/L 135–180
White cell count 16.68 109/L 4.0–11.0
Platelets 224 109/L 150–400
Neutrophils 13.69 109/L 2.0–7.5
Lymphocytes 1.97 109/L 1.0–4.5
Eosinophils 0.14 109/L 0.04–0.40
Sodium 136 mmol/L 133–136
Potassium 4.1 mmol/L 3.5–5.3
Urea 10.8 mmol/L 2.5–7.8
Creanine 75 umol/L 64–104
eGFR >90 mL/min/1.73m2

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Bilirubin 7 umol/L 2–21
ALT 23 IU/L <40

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Alkaline 123 IU/L 30–130
phosphatase
Albumin 39 g/L 35–50

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CRP <5.0 mg/L <5.0
HbA1c 64 mmol/mol 20–41

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HIV Negave
angen/anbody
t1:5

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*Red results indicate values outside the reference range.

85 During this time, the patient's clinical state remained unchanged. As risk factor in this patient may have led to an earlier diagnosis and re-
D 123
86 all test results were so far non-diagnostic, microbiology review was duced the need for multiple surgical biopsies. 124
87 sought, and an in-depth social history was taken. The patient is a lifelong The patient's HbA1c was 64 mmol/mol. Although type 2 diabetes 125
88 non-smoker and drinks alcohol socially. He works as a computer sys- mellitus can increase the susceptibility to various infections, seropreva- 126
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89 tems' analyst and does woodwork and makes garden furniture in his lence studies do not consistently show higher toxoplasma infection 127
90 spare time. He has lived on a farm for the past 14 years and owns rates in type 2 diabetes patients [1,2], nor a correlation with HbA1c 128
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91 three dogs and three cats. The farm has cattle, sheep, and chickens. He levels [3]. Therefore, although diabetes mellitus might have contributed 129
92 travels regularly to Australasia for holidays. His last travel was three to the patient's immunodeficiency, the evidence for increased suscepti- 130
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93 years ago on a cruise to Australia, New Zealand, Malaysia, and bility to toxoplasma reactivation from diabetes mellitus alone is not 131
94 Vietnam where he swam with turtles and dolphins. He did not engage strong. 132
95 in forest hiking nor caving and denied eating any raw or exotic foods. The global seroprevalence of toxoplasmosis is 25–30%, although it 133
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96 Following the exclusion of other likely aetiologies, the possibility of varies widely worldwide [4]. About 350 cases of toxoplasmosis are re- 134
97 cerebral toxoplasmosis was investigated in more detail. A fresh serum ported yearly in England and Wales [5], although this surveillance fo- 135
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98 sample was collected on 31 January 2018 for Toxoplasma serology cuses on the more severe clinical sequelae found within the 136
99 and the brain biopsy samples were sent to the Toxoplasma Reference immunosuppressed and pregnant populations. Thus, self-limiting flu- 137
100 Unit, Swansea, for PCR and immunohistochemical staining. Results are like and glandular fever-like symptoms in the immunocompetent are 138
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101 shown in Table 2 and Fig. 2. likely to be significantly underreported. 139

102 MMF was withdrawn immediately after the initial finding of brain This patient has two epidemiological links to toxoplasmosis. The pa- 140
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103 lesions suggestive of abscesses. Dexamethasone at tapering doses over tient lives on a farm and owns three cats. The risk factor is dependent on 141
104 6 weeks was also commenced to reduce cerebral oedema. the number of acutely infected cats and the resulting oocyst prevalence 142
105 Toxoplasma-specific treatment with pyrimethamine 200 mg stat in the environment. As waterborne transmission of toxoplasmosis is 143
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106 followed by 75 mg daily, sulfadiazine 1000 mg four times daily, and also possible, the water-based activities undertaken by the patient 144
107 folinic acid 15 mg daily was commenced for a total of 6 weeks. whilst visiting Australasian countries may also be a risk factor for ac- 145
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108 Diffusion-weighted MRI four weeks into treatment showed reduction quiring toxoplasmosis [6]. 146
109 in size of all the lesions and resolution of surrounding oedema. The pa- It is noteworthy that this patient did not have a positive test that was 147
110 tient's symptoms significantly improved, with complete resolution of considered confirmatory for cerebral toxoplasmosis. The diagnosis was 148
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111 confusion and vomiting and a return to normal function. strongly suggested by a therapeutic trial of anti-toxoplasma medication 149
112 As the patient's myasthenic ophthalmic symptoms had worsened that led to a good clinical response. For instance, the patient's IgM was 150
113 during this time, lower doses of secondary prophylaxis with pyrimeth- negative. Detection of IgM in cerebral toxoplasmosis is generally un- 151
114 amine, sulfadiazine, and folinic acid were commenced with the view helpful in cases of reactivation that occur after the acute immune re- 152
115 that further immunosuppression will be required in the future. sponse has subsided. Since reactivation of toxoplasma infection may 153
be localised within the CNS, tests on blood samples may yield negative 154
116 2. Discussion results and cannot therefore rule out the diagnosis of cerebral toxoplas- 155
mosis [7]. A positive brain biopsy PCR is not diagnostic of active toxo- 156
117 This case highlights the importance of considering reactivation of la- plasma infection, since CNS tissues are major sites of latency for 157
118 tent cerebral toxoplasmosis in patients with neurological deficits and dormant bradyzoites in those with past exposure [8]. Histology was 158
119 ring-enhancing brain lesions whilst on immunosuppressant medica- also negative, both by H&E and immunohistochemical staining. Cases 159
120 tions. The index of suspicion may have been low because the patient of cerebral toxoplasmosis missed by histology are recognised [9]. Due 160
121 was HIV-negative. As cerebral toxoplasmosis usually occurs in the im- to the high mortality of untreated cerebral toxoplasmosis, treatment 161
122 munocompromised, recognising the drug MMF as the predisposing should therefore commence despite negative clinical tests [10]. 162

Please cite this article as: M. Lee, K. Sethi and E. Guy, Toxoplasmosis: An overlooked cause of confusion in a patient with myasthenia gravis, Clinical
Infection in Practice, https://doi.org/10.1016/j.clinpr.2020.100022
 M. Lee et al. / Clinical Infection in Practice xxx (xxxx) xxx 3

Table 2 t2:1
Results of Toxoplasma-specific investigations. t2:2

Toxoplasma IgM (ELISA) Negative t2:3

Toxoplasma IgG (ELISA) Positive t2:4
Sabin-Feldman dye test Positive at 500 IU/mL t2:5
Brain biopsy toxoplasma PCR Positive t2:6
Brain biopsy H&E stained section No visible tachyzoites nor t2:7
bradyzoite-containing cysts
Brain biopsy immunohistochemical-stained No visible tachyzoites nor t2:8
section (in-situ hybridization) bradyzoite-containing cysts t2:9

medications. In addition, one case of cerebral toxoplasmosis attributed 179

to MMF has been reported to the UK MHRA Yellow Card Scheme [18]; 180
however, the underlying disease, clinical outcome, and any concomitant 181

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immunosuppressant medications are unknown. This report is the first 182
described case of cerebral toxoplasmosis developing on MMF mono- 183

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therapy, providing a stronger causal link between MMF and cerebral 184
toxoplasmosis. Prednisolone had been stopped 18 months previously 185
and the patient was solely on MMF monotherapy for myasthenia gravis. 186

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There are several proposed mechanisms by which MMF can lead to 187
cerebral toxoplasmosis. MMF can cause leukopenia and lymphopenia 188
at frequencies of ≥1/10 [19]. However, the total WBC and lymphocyte

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189
Q5
counts were normal in this patient. Another suggested mechanism is 190
that MMF selectively suppresses CD4+ T lymphocytes [20]. As control 191

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of Toxoplasma gondii relies on intact cell-mediated immunity, the risk 192
of toxoplasmosis increases with falling CD4+ T cell counts. In the HIV 193
population, there is a substantial risk of cerebral toxoplasma reactiva-
D 194
tion when CD4+ T cell counts fall below 200 cells/uL [10]. Measuring 195
the patient's lymphocyte subsets may point towards an MMF-induced 196
CD4+ lymphopenia that may have predisposed to toxoplasma reactiva- 197
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tion in this patient. 198
Hypogammaglobulinemia is also a recognised side effect of MMF 199
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[11]. Although its exact frequency is unknown, sustained 200

hypogammaglobulinemia caused by MMF may lead to recurrent infec- 201
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tions [19]. Cerebral toxoplasmosis has been described in a patient 202

with hypogammaglobulinemia and complete absence of B cells due to 203
thymoma whilst on MMF [16]. Measuring the patient's serum immuno- 204
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globulin levels may also point towards an MMF-induced 205

hypogammaglobulinemia that may have predisposed to toxoplasma 206
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reactivation. 207

4. Summary 208
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This case highlights a patient who had two brain biopsies and a de- 209
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layed diagnosis of reactivation of latent cerebral toxoplasmosis due to 210

Fig. 1. Diffusion weighted MRI head with gadolinium contrast. Left and right frontal lobe
lesions with ill-defined diffuse rim enhancement, significant oedema, and adjacent dural
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thickening. There is also an enhancing focus in the left thalamus.

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163 3. MMF as a risk factor for cerebral toxoplasmosis

164 In this case report, the drug MMF was an unrecognised risk factor for
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165 cerebral toxoplasmosis. MMF is a prodrug of mycophenolic acid, which

166 inhibits inosine monophosphate dehydrogenase, the rate-limiting en-
167 zyme that catalyzes the de novo synthesis of guanosine. MMF is a selec-
168 tive inhibitor of lymphocyte proliferation and function [11]. MMF is a
169 recognised off-label treatment for myasthenia gravis and other neuro-
170 muscular inflammatory diseases [12].
171 To date, there have been three reported cases of cerebral toxoplas-
172 mosis associated with MMF used in myasthenia gravis, one in inflam-
173 matory myopathy, one in undifferentiated connective tissue disease,
174 and one in pemphigus vulgaris (Table 3). Three of the patients
175 succumbed to the cerebral infection despite withdrawal of MMF and
176 anti-toxoplasma treatment [13,14]. The other three experienced stable Fig. 2. Haematoxylin and Eosin (H&E) stained section (400 × magnification). Acute
177 neurological outcomes with treatment [15–17]. Of note, all these pa- inflammatory cells and a small necrotic area. No tachyzoites or bradyzoite-containing
178 tients were receiving other concomitant immunosuppressant cysts were seen.

Please cite this article as: M. Lee, K. Sethi and E. Guy, Toxoplasmosis: An overlooked cause of confusion in a patient with myasthenia gravis, Clinical
Infection in Practice, https://doi.org/10.1016/j.clinpr.2020.100022
 4 M. Lee et al. / Clinical Infection in Practice xxx (xxxx) xxx

t3:1 Table 3
t3:2 Reported cases of toxoplasmosis associated with MMF.

t3:3 Site of toxoplasmosis Underlying condition Age and gender Concomitant medication Outcome References

t3:4 MMF
t3:5 Cerebral Myasthenia gravis 58 – Complete recovery with treatment This case
Male
t3:6 Cerebral Myasthenia gravis and Turner syndrome 70 Prednisolone Persistent neurological deficits with treatment [17]
Female
t3:7 Cerebral Myasthenia gravis and thymoma 54 Prednisolone Clinical stability with treatment [16]
Female IVIG
t3:8 Cerebral Myasthenia gravis 77 Prednisolone Fatal despite treatment [13]
Male
t3:9 Cerebral Inflammatory myopathy 72 Prednisolone Fatal despite treatment [13]
Female
t3:10 Cerebral Undifferentiated connective tissue disease 48 Prednisolone Fatal despite treatment [14]
Female

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t3:11 Cerebral Pemphigus vulgaris 52 Rituximab Clinical improvement [15]
Female

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t3:12 1 Cerebral [18]
t3:13 1 Myocarditis
t3:14 1 Unspecified

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211 the unrecognised predisposing risk factor of MMF monotherapy taken 7. Fricker-Hidalgo H, Bulabois C, Brenier-Pinchart M, Hamidfar R, Garban F, Brion J, et al. 243
Diagnosis of toxoplasmosis after allogeneic stem cell transplantation: results of DNA 244
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for myasthenia gravis. In our case, the patient made a good neurological detection and serological techniques. Clin Infect Dis 2009;48(2):e9-15. 245
213 recovery following a therapeutic trial of anti-toxoplasma treatment and 8. Robert-Gangneux F, Belaz S. Molecular diagnosis of toxoplasmosis in immunocom- 246
214 cessation of MMF. A detailed social, occupational, and medication his- promised patients. Curr Opin Infect Dis 2016;29(4):330–9. 247

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217 flammatory conditions, there is little understanding of the prevalence ation guidelines for the treatment of opportunistic infection in HIV-seropositive indi- 251
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Please cite this article as: M. Lee, K. Sethi and E. Guy, Toxoplasmosis: An overlooked cause of confusion in a patient with myasthenia gravis, Clinical
Infection in Practice, https://doi.org/10.1016/j.clinpr.2020.100022