Fig. 45.5A,B. Intracranial calcifications in congenital toxoplasmosis. (A) Posterior-anterior and (B) lateral views of the skull showing scattered bilateral calcific flecks, nodules and linear streaks in frontal and parietal lobes of an infected infant.
Fig. 45.6A,B. Congenital toxoplasmosis with intracranial hyrocephalus. The grossly dilated lateral ventricles are outlined with air on (A) AP and (B) lateral radiographs after pneumoencephalography. There is spreading of the cranial sutures due to increased intracranial pressure. There is extensive calcification lining the walls of the dilated lateral ventricles, mimicking exactly the intracranial calcifications seen in cytomegaloviral infections. AFIP 220250.
Toxoplasmosis is probably the commonest cause of scattered intracranial calcifications in the neonate. Only infections acquired in utero will lead to intracranial calcification in the child.
was initially described as a cause of encephalomyelitis in 1937. Some
five years later, radiographic findings were described in ten patients.
In nine of these patients, there was diffuse intracerebral calcification,
usually occurring as tiny 2-mm foci within the cortex or as linear streaks,
particularly in the basal ganglia or thalamus. There may also be increased
intracranial pressure and hydrocephalus. In a series of patients reported
by Feldman, the incidence of intracranial complications in patients
with clinical and serological evidence of toxoplasmosis was 59%. Intracranial
calcifications were found in 32% of another series of patients reported
by Couvreur and Desmonts in 1962, many of whom had milder and subclinical
disease. Eighty-seven percent of cases had intracranial calcifications
in a further series reported by Francois and De Witte.
also considerable variation in the type of calcification. Most calcifications
are bilateral; they may be small 1 to 2-mm punctate flecks, slightly
larger 3 to 4-mm nodules, curvilinear streaks, or plaques (Fig. 45.5).
In general, meningeal calcifications are plaque-like and bilateral,
whereas those in the cerebral cortex tend to be punctate deposits or
nodules. Those in the basal ganglia or thalamus are more often striated
or curvilinear. The calcifications may be randomly scattered through
the brain parenchyma; most often they are present in the parietal region,
but they also may be found in specific cerebral structures such as the
choroid plexus, the ependyma, the meninges or the caudate nucleus and
thalamus. Calcification within the caudate nucleus usually involves
the head of the nucleus and is always bilateral and often symmetrical.
The frontal lobes are often involved but temporal and occipital calcifications
are less common. Calcifications which can be seen on imaging are extremely
rare in the infratentorial region, although the cerebellum, fourth ventricle,
and aqueduct are frequently involved histopathologically. Calcifications
which are ependymal or subependymal along the dilated lateral ventricles
mimic the calcifications seen in cytomegalovirus disease (Fig. 45.6).
Copyright: Palmer and Reeder