DIAGNOSIS

If toxoplasmosis is suspected, the doctor draws a blood sample and tests it
for evidence of the parasite. For people who have weakened immune systems
and are therefore more likely to develop a severe infection, a doctor may
order a magnetic resonance imaging* (MRI), a computerized tomography*
(CT) scan of the head, or rarely, a brain biopsy (removing a small sample of
brain tissue to examine) to look for signs of damage caused by the parasite.
The doctor may also suggest a visit to an ophthalmologist for an eye
exam, which may include the use of a special lamp called a slit lamp to
check for signs of the disease in the eyes. These signs may include reduced,
hazy, or blurred vision; pain when looking into bright light; eye redness;
tearing; inflammation in the back of the eye; swelling in part of the retina*;
and lesions (injuries) in the retina and/or an adjacent membrane called the
chorioid. Ophthalmologists sometimes prescribe medicine to treat an active
disease. Occasionally, an eye doctor may find signs of a prior infection with
the Toxoplasma gondii parasite during a routine eye exam, even though the
patient never experienced or noticed any symptoms. This is not a cause for
alarm, but pregnant women and those with weakened immune systems
should discuss the findings with their regular doctor to determine whether
they should take any additional precautions to prevent repeat infection.