Content area
Full Text
Abstract Central nervous system involvement due to toxoplasmosis in an immunocompetent host is rare. We describe MRI features in two immunocompetent patients with of cerebral toxoplasmosis and compare these with those for the immunocompromised host.
Keywords Toxoplasmosis * Brain * Magnetic resonance imaging
Introduction
Symptomatic central nervous system (CNS) toxoplasmosis rarely develops during primary infection in normal hosts [1]. Several reports of acute toxoplasmosis in normal hosts have appeared since 1975 [2, 3, 4], The acquired CNS infection can present as meningocncephalitis during primary infection in an immunocompetent host or as an intracerebral mass lesions or encephalitis in immunocompromised hosts [1]. CNS toxopiasmosis has increased dramatically and is one of the most common and most important opportunistic infections in patients with the acquired immune deficiency syndrome (AIDS). It has a prevalence of 3-40%, depending on the seroprevalence [5]. More than 95% of toxoplasma encephalitis in patients with AIDS is due to reactivation of a chronic latent infection [6].
Imaging in toxoplasma encephalitis in the immunocompromised is well documented [7, 8, 9]. We present MRI features in two immunocompetent patients presenting with toxoplasma encephalitis. To the best of our knowledge, this is the first report in the English-language literature describing the MRI features of diffuse toxoplasma encephalitis in immunocompetent patients.
Case reports
Case 1
A 22-year-old man, previously in good health, presented with fever, headache and mild weakness on the left, followed by gradual loss of consciousness. Examination revealed left hemi paresis with grade 2-3 on the Medical Research Council 0-5 scale. Routine blood tests revealed mild leucocytosis (8100/mm^sup 3^). 10.2 gm% haemoglobin and erythrocytic sedimentation rate 36 mm in the first hour. Blood tests were negative for HIV-II and HIV-II by two enzyme-linked immunosorbent assay (ELISA) screening kits. Other routine tests were normal. Cerebrospinal fluid (CSF) showed mild pleocytosis and elevated protein levels of 112 mg dl. IgG-antibody titre to toxoplasma gondii measured with ELISA was high in serum (1:163) and CSF (1:68).
MRI showed a large haemorrhagic lesion in the right parietal region with perifocal oedema and mass effect (Fig. 1a. b). Multiple lesions which gave high signal on T2-weighted images were also seen in the left cerebral hemisphere and cerebellar hemispheres (Fig. 1c). The lesions gave low signal or were isointense on...