INTRODUCTION Granulomatous inflammation is a distinctive ...

Despite the lower sensitivity of CT scan, it would be still appropriate and useful as a screening test
for patients with suspected CNS toxoplasmosis, as only about 3% of cases will have normal scan at
the time of presentation. MRI need only be used when the CT scan is negative for a lesion or when
it reveals a solitary lesion (Porter and Sande, 1992).
Treatment
Patients with ring-enhancing brain lesions on CT scan or MRI along with positive IgG antibody to
T gondii, should receive empiric therapy. A clinical and radiological response to the specific
therapy will support the diagnosis of Toxoplasmosis. Patients who fail to show a radiographic or
clinical response within 2 weeks of therapy should have a brain biopsy performed. If the biopsy
confirms Toxoplasmosis, a switch to an alternative therapy should be considered (Luis, 2006).
Initial Therapy should be continued for at least 6 weeks, and the preferred regimen is
Pyrimethamine 200 mg po as a loading dose, followed by 50 mg (< 60 kg body weight) to 75 mg
(>60 kg) po qd, plus leucovorin (folinic acid) 10–20 mg per day (can increase = 50 mg) po qd, +
sulfadiazine 1000 (< 60 kg) to 1500 mg (= 60 kg) po q 6h.
Alternative regimen includes Pyrimethamine + leucovorin (as above) + clindamycin 600 mg IV or
po q6h (preferred alternative), or another regimen of TMP-SMX (5 mg/kg TMP and 25 mg/kg
SMX) IV or po bid.
Maintenance (suppressive) therapy should be lifelong in immunocompromised patients unless
immune reconstitution occurs and is composed of Pyrimethamine 25 – 50 mg po qd + leucovorin
10–25 mg po qd, + sulfadiazine 500–1000 mg po q6h (preferred). With an alternative regimen (the
relapse rate on these regimens is approximately 25%) Clindamycin 300–450 mg po q6–8h +
pyrimethamine + leucovorin dosed as above (Luis, 2006)
Echinococcus infection
Human infection with the different echinococcal species is termed hydatid disease (Eckert et al.,
2001). The word hydatid Refers to the fluid-filled larval forms found in the intermediate hosts
(hydatid is derived from a Latin hydatis, or drop of water). Echinococcus granulosus causes cystic
hydatid disease, which is characterized by cystic lesions found mainly in the liver or lungs.