====== Toxoplasma gondii ======

{{rss>https://pubmed.ncbi.nlm.nih.gov/rss/search/1vQeViLvBNI_iNiX7r5ocm4EbyX5nCtYibiyQJ62QvoJXHEMCh/?limit=15&utm_campaign=pubmed-2&fc=20230112025140}}

[[Toxoplasma]] gondii is an obligate intracellular protozoan that is ubiquitous but does not cause clinical [[infection]] except in [[immunocompromised]] hosts. Histologic features: [[necrosis]] containing 2–3 nm tachyzoites (cysts).

In [[AIDS]] patients: [[Toxoplasma gondii]] is a common [[pathogen]], and initial [[empiric therapy]] with
[[sulfadiazine]] + [[pyrimethamine]] + [[leucovorin]] is often used.
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Epidemiologic evidence suggests a protective effect of [[Toxoplasma]] gondii infection against [[multiple sclerosis]] (MS) development; however, inconsistent findings have been reported in this regard. Therefore, Rostami et al. performed an updated [[meta-analysis]] of [[observational]] studies to investigate the association of To. gondii infection with MS development. They searched all articles published in [[PubMed]], [[Scopus]], [[Embase]], and [[Web of Science]] databases as of 20 December 2021. A random-effects meta-analysis model was used to generate the pooled OR at 95% CIs. The heterogeneity between studies was assessed using I2 and Cochran's Q statistics. Moreover, the likelihood of publication bias was determined by Egger's regression test. A total of 11 studies were eligible for meta-analysis, including 1172 MS cases and 1802 controls. Our findings indicated that 29.8% (95% CI 22.8 to 37.2%) of MS patients were seropositive for To. gondii infection, compared with 34.2% (95% CI 21.9 to 47.6%) of control subjects. The estimated pooled OR was 0.79 (95% CI 0.49 to 1.26), suggesting a non-significant negative association between To. gondii infection and MS development (p>0.05). The current study does not support the significant protective role of To. gondii infection on MS development. The findings imply that further well-designed epidemiological and mechanistic studies are warranted to ascertain the possible association between To. gondii infection and MS and to exclude the potential [[confounder]]s
((Rostami A, Riahi SM, Mollalo A, Razavian I, Akbari N, Marhoommirzabak E, Mahjour S, Sartip B, Arshadi M, Razavian E, Ardekani A. Does latent Toxoplasma infection have a protective effect against developing multiple sclerosis? Evidence from an updated meta-analysis. Trans R Soc Trop Med Hyg. 2022 Jun 13:trac053. doi: 10.1093/trstmh/trac053. Epub ahead of print. PMID: 35696089.)).

===== Diagnosis =====

[[CT]]/[[MRI]] findings in [[toxoplasma abscess]]

1. most common findings: large area (low density on CT) with mild to moderate [[edema]], [[ring enhancement]] with [[IV]] [[contrast]] in 68% compatible with [[abscess]] (of those that did not ring-enhance, many showed [[hypodense]] areas with less [[mass effect]], with slight enhancement adjacent to the lesion), well-circumscribed margins
((Jarvik JG, Hesselink JR, Kennedy C, et al. Acquired Immunodeficiency Syndrome: Magnetic Resonance Patterns of Brain Involvement with Pathologic Correlation. Arch Neurol. 1988; 45:731–736))

2. most commonly located in [[basal ganglia]] are also often subcortical

3. often multiple (typically > 5 lesions
((Sadler M, Brink NS, Gazzard BG. Management of Intracerebral Lesions in Patients with HIV: A Retrospective Study with Discussion of Diagnostic Problems. Q J Med. 1998; 91:205–217))) 
and bilateral

4. usually with little to moderate [[mass effect]]
((Ciricillo SF, Rosenblum ML. Use of CT and MR Imaging to Distinguish Intracranial Lesions and to Define the Need for Biopsy in AIDS Patients. J Neurosurg. 1990; 73:720–724))
(in [[basal ganglia]], may compress [[third ventricle]] and [[Sylvian aqueduct]], causing [[obstructive hydrocephalus]])

5. most patients with [[toxoplasmosis]] had evidence of [[cerebral atrophy]].
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[[Stereotactic biopsy]] guidelines:

a) if multiple [[lesion]]s are present, choose the most accessible lesion in the least [[eloquent]] brain
area, or the lesion not responding to treatment

b) [[biopsy]] the center of non-enhancing lesions or the enhancing portion of ring-enhancing
lesions

c) recommended studies on biopsy: histology; immunoperoxidase stain for Toxoplasma gondii;
stains for TB and fungus; culture for TB, fungi, pyogens

===== References =====