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Table of Contents
Year : 2020  |  Volume : 7  |  Issue : 1  |  Page : 51-54

Rhombencephalitis secondary to toxoplasma gondii infection: Case report and literature review

1 Department of Medicine, Health Sciences Center, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
2 Department of Neurology, Health Sciences Center, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil

Date of Submission02-Sep-2019
Date of Acceptance02-Oct-2020
Date of Web Publication15-May-2020

Correspondence Address:
Dr. Jamir Pitton Rissardo
Rua Roraima, Santa Maria, Rio Grande do Sul
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ami.ami_78_19

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Immunocompetent (IC) individuals with primary toxoplasmosis are usually asymptomatic. However, in some IC, toxoplasmosis can present with brainstem encephalitis. We report an adult female patient with headache associated with worsening coordination. Physical examination showed bilateral, symmetrical, and nontender cervical lymphadenopathy. Toxoplasmosis immunoglobulin G (IgG) and IgM were high, and the IgG antibody avidity pattern was low. The cerebrospinal fluid analysis was requested that revealed a positive polymerase chain reaction results for toxoplasmosis. A brain magnetic resonance imaging (MRI) showed a T1-hypointense left pontine lesion. Pyrimethamine and sulfadiazine were started. After 1 month, the patient had full recovery. Four months after, the individual was admitted due to progressive abnormal eye movements and tremor. Her neurological examinations showed ocular myoclonus and Holmes tremor. A second brain MRI showed hypertrophy of the ipsilateral inferior olivary nucleus. In the follow-up, her symptoms decreased mildly. The tremor was managed with clonazepam and levodopa. Furthermore, immune suppression investigation was negative.

Keywords: Encephalitis, myoclonus, toxoplasmosis, tremor

How to cite this article:
Rissardo JP, Caprara AL, Silveira JO. Rhombencephalitis secondary to toxoplasma gondii infection: Case report and literature review. Acta Med Int 2020;7:51-4

How to cite this URL:
Rissardo JP, Caprara AL, Silveira JO. Rhombencephalitis secondary to toxoplasma gondii infection: Case report and literature review. Acta Med Int [serial online] 2020 [cited 2022 Nov 28];7:51-4. Available from: https://www.actamedicainternational.com/text.asp?2020/7/1/51/284431

  Introduction Top

Toxoplasma gondii is an intracellular protozoan parasite that infects almost all warm-blooded animals.[1] In this context, immunocompetent (IC) individuals with a primary T. gondii infection are usually asymptomatic.[2] However, in some participants that are IC, toxoplasmosis can present with an acute systemic infection, ocular disease, or in rare situations, with brainstem encephalitis.[2],[3]

Few cases of hypertrophic olivary degeneration (HOD)

caused by rhombencephalitis associated with T. gondii infection have been reported in the literature. More specifically, to the authors' knowledge, there are two case reports of immunosuppressed (IS) individuals with toxoplasmosis who developed HOD.[3],[4] Nevertheless, this condition has not been reported in an IC participant until the present moment.

Here, we reported the case of an adult female who presented with headache and poor coordination. Cervical lymphadenopathy was observed. Laboratory results confirmed a T. gondii infection, and the patient was treated. A brain magnetic resonance imaging (MRI) revealed a lesion in the left pons. After 4 months, the patient presented with ocular myoclonus and Holmes tremor. A new brain MRI showed the left HOD.

  Case Report Top

A 50-year-old female patient presented to our hospital with a sudden onset of headache associated with worsening coordination within 5 days of onset. The patient was a previously healthy farmer, and her family history was negative for neurological diseases. On neurological examination, she was fully conscious and orientated. A mild action tremor was observed bilaterally. Laboratory tests, including complete blood cell count, sodium, potassium, glucose, urea, creatinine, bilirubin, aspartate, and alanine transaminase, were within the normal limits. A cranial computed tomography (CT) scan was normal. Supportive management was conducted.

On the 3rd admission day, the patient stated that before the onset of thefirst neurological symptoms, she had a mild fever for 3 days associated with myalgia and the appearance of persistent cervical adenopathy.

Physical examination showed the neurological findings mentioned above and revealed bilateral, symmetrical, nontender cervical lymphadenopathy. Laboratory examinations were requested: toxoplasmosis immunoglobulin G (IgG, IgM, and IgG antibody avidity pattern), hepatitis B and C (anti-HbsAg and anti-hepatitis C virus), cytomegalovirus (IgG and IgM), Venereal Disease Research laboratory, anti-HIV (1, 2), Herpes simplex virus (1, 2), Epstein–Barr (IgG and IgM), Chagas (IgG and IgM), Borrelia Burgdorferi (IgG and IgM), rheumatological diseases (anti-ribonucleoprotein, Anti-Sjögren's-syndrome-related antigen A (SSA), Anti-Sjögren's-syndrome-related antigen B (SSB), creatine phosphokinase, antinuclear antibody, and rheumatoid factor), anti-thyroid peroxidase, anti-transglutaminase, and purified protein derivative skin test.

The results were within the normal limits, except for toxoplasmosis IgG and IgM, which were high, and the IgG antibody avidity pattern that was low.

Afterward, the cerebrospinal fluid (CSF) analysis was requested, which revealed a positive polymerase chain reaction result for toxoplasmosis, 26/mm3 of white blood cells and 50 mg/dL of protein. The CSF culture and Gram stain were negative. A brain MRI showed a T1-weighted hypointense left pontine lesion with extension into the midbrain. Pyrimethamine 100 mg loading dose followed by a maintenance dose of 50 mg a day and sulfadiazine 4 g a day were started. After 1 month, the patient had a full recovery.

Approximately 4 months after, the individual was admitted due to progressive abnormal eye movements and tremors. On the neurological examination, her eye movements were pendular with an equal smooth speed in both directions; a resting and intention tremor with irregular amplitude was observed in the upper extremities, but it was worse in her left side.

Upon further questioning, the individual admitted that she had two other similar episodes, in the last month, of nausea and inability to focus her vision in a point, she thought that were normal due to working hard daily in agriculture. She only sought medical assistance this time because her symptoms remained.

Laboratorial tests and CSF analysis were within the normal limits. A cranial CT scan was normal. A second brain MRI showed hypertrophy of the ipsilateral left inferior olivary nucleus. In the follow-up, her symptoms decreased mildly, but she did not have a full recovery. The tremor was managed with clonazepam and levodopa. Furthermore, immune suppression investigation was negative.

  Discussion Top

Toxoplasmosis is an infection caused by T. gondii. In this way, contact with this obligate intracellular protozoan can occur by four pathways in humans: ingestion of contaminated food or water-containing oocysts, ingestion of undercooked meat with tissue cysts, transplacental from mother to fetus, or by organ transplantation.[1]Felidae is the only family of animals where T. gondii can complete its reproductive cycle, and the domestic cat is an important definitive host for this parasite.[1]

The most common clinical manifestation of toxoplasmosis in an IC is similar to an acute systemic reaction presenting with mild fever, headache, and persistent lymphadenopathy that is found bilateral, symmetrical, nontender, and more frequently localized in the cervical region.[2] The diagnosis in IC can be made with typical presentation and serological results of serum or CSF confirmatory for T. gondii.[2],[5] However, atypical and severe complications such as rhombencephalitis can occur, although rarely, even in IC patients.[2],[3]

The Guillain–Mollaret Triangle, also known as the dentate-rubro-olivary pathway, is composed of three corners: dentate nucleus, inferior olivary nucleus, and red nucleus.[6] In this way, a disruption in any of the three sides (tracts) that connect these corners can result in HOD.[4],[7] The clinical symptoms associated with this transsynaptic degeneration include Holmes tremor, ocular myoclonus, and palatal tremor.[6],[7] Although HOD is not always symptomatic, clinical manifestations have been reported months later of the inciting lesion in the majority of the cases.[4],[6],[7]

A presentation of toxoplasmosis with rhombencephalitis followed by HOD was rarely reported in the literature. We identified two case reports in English, and we compared them with the present case [Table 1].[3],[4] Nevertheless, the reported participants were IS, and hence, the present case is thefirst in an IC individual.[3],[4] A literature search was performed in Embase, Google Scholar, Lilacs, Medline, Scielo, and ScienceDirect, on a set of terms that included toxoplasmosis, rhombencephalitis, and HOD.
Table 1: Case report of patients with toxoplasma gondii infection who developed hypertrophic olivary degeneration

Click here to view

The literature review of Jubelt et al. about brainstem encephalitis found that toxoplasmosis only involving the rhombencephalon/brainstem, primarily involving it, or only involving it at the disease onset was very rarely reported.[8] Their study only found one case report.[8] Thus, this presentation is uncommon and the fact that it occurred in an IC individual could probably be explained by the local environmental factors.

Interestingly, on epidemiological research, we found that in thefirst semester of 2018, there was a substantial increase in the number of patients diagnosed with toxoplasmosis in the city of Santa Maria, Brazil, which is the city where the patient lives.[9] A cross-sectional study of Dal Ponte et al. using the data published in bulletins by the Municipal Health Department of the city revealed that this outbreak was the largest reported in Brazil and apparently in the world.[9] Therefore, we hypothesized that this presentation only happened because of the occurrence of the toxoplasmosis outbreak in the city of Santa Maria.

The cerebral cortex and basal ganglia are the areas that most commonly affected by T. gondii, and only fewer lesions in the cerebellum, brainstem, and spinal cord are found.[5] However, almost all the information available today about the predilection of T. Gondii for the central nervous system (CNS) derives from the studies with severely IS individuals.[5] In this context, more research is needed to elucidate the physiopathology of CNS infection by T. Gondii in IC participants. The study of Alvarado-Esquivel et al. was thefirst with IC and showed T. gondii in the neurons and astrocytes of IC individuals, but the methodology and how this observation was determined are unclearly described in their study.[5],[10] Thus, more data from IC individuals are needed to better evaluate risk factors, most common associated comorbidities, areas of CNS predilection, and prognosis of this group of individuals when they are infected with T. gondii.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Tenter AM, Heckeroth AR, Weiss LM. Toxoplasma gondii: From animals to humans. Int J Parasitol 2000;30:1217-58.  Back to cited text no. 1
O'Connell S, Guy EC, Dawson SJ, Francis JM, Joynson DH. Chronic active toxoplasmosis in an immunocompetent patient. J Infect 1993;27:305-10.  Back to cited text no. 2
Kure K, Harris C, Morin LS, Dickson DW. Solitary midbrain toxoplasmosis and olivary hypertrophy in a patient with acquired immunodeficiency syndrome. Clin Neuropathol 1989;8:35-40.  Back to cited text no. 3
Sabat S, Mannering N, Agarwal A. Hypertrophic olivary degeneration: Case series and review of literature. J Neurol Sci 2016;370:180-6.  Back to cited text no. 4
Mendez OA, Koshy AA. Toxoplasma gondii: Entry, association, and physiological influence on the central nervous system. PLoS Pathog 2017;13:e1006351.  Back to cited text no. 5
Guillain G. Deux cas de myoclonies synchrones et rythmees velo-pharyngo-laryngo-oculo-diaphragmatiques: Le probleme anatomique et phsiologique. Rev Neurol (Paris) 1931;2:545.  Back to cited text no. 6
Samuel M, Torun N, Tuite PJ, Sharpe JA, Lang AE. Progressive ataxia and palatal tremor (PAPT): Clinical and MRI assessment with review of palatal tremors. Brain 2004;127:1252-68.  Back to cited text no. 7
Jubelt B, Mihai C, Li TM, Veerapaneni P. Rhombencephalitis/brainstem encephalitis. Curr Neurol Neurosci Rep 2011;11:543-52.  Back to cited text no. 8
Dal Ponte S, Burguez D, Andrioli G. Outbreak of toxoplasmosis in the city of Santa Maria Brazil. Prehos and Disaster Med 2019;34:S74.  Back to cited text no. 9
Alvarado-Esquivel C, Sánchez-Anguiano LF, Mendoza-Larios A, Hernández-Tinoco J, Pérez-Ochoa JF, Antuna-Salcido EI, et al. Prevalence of Toxoplasma gondii infection in brain and heart by Immunohistochemistry in a hospital-based autopsy series in Durango, Mexico. Eur J Microbiol Immunol (Bp) 2015;5:143-9.  Back to cited text no. 10


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