Second edition

14.qxd 3/10/08 9:50 AM Page 507
Clinical features
Clinically (Agamanolis et al. 1979; Aicardi et al. 1977), after
an asymptomatic latent interval ranging from 1 to 6
months after a measles infection, there is a subacute onset
of delirium over days or a week or so, accompanied, variously,
by myoclonus, focal signs, and seizures, which may
be either grand mal or partial; in some cases simple partial
motor status epilepticus has been noted.
Although the CSF is generally normal, in some cases
there may be a mild lymphocytic pleocytosis or a mildly
elevated total protein; anti-measles antibodies may or may
not be present.
Course
The disease is relentlessly progressive to coma and death
within weeks to months.
Etiology
This disease probably occurs secondary to reactivation of a
defective measles virus within neurons and oligodendrocytes;
pathologically, there is very little or no inflammation,
and measles-containing inclusion bodies may be
found within both the nuclei and cytoplasm of both types
of cells (Aicardi et al. 1977; Gazzola et al. 1999).
Although most patients have been children with
leukemia, cases have occurred in adults with Hodgkin’s
disease (Wolinsky et al. 1977), adults undergoing therapeutic
immunosuppression (Gazzola et al. 1999), patients
with AIDS (Budka et al. 1996), and, rarely, apparently
immunocompetent adult patients (Chadwick et al. 1982;
Croxson et al. 2002).
Differential diagnosis
Subacute measles encephalitis must be distinguished from
other measles-related disorders. Acute measles may be
complicated by an encephalitis; however, in these cases
symptoms occur in the context of a measles rash. Acute
disseminated encephalomyelitis, like subacute measles
encephalitis, also has a latent interval but it is shorter, in
the order of weeks; furthermore, there is no myoclonus in
acute disseminated encephalomyelitis. Subacute sclerosing
panencephalitis also has a latent interval but this is much
longer, in the order of years.
Treatment
The general treatment of delirium is discussed in Section
5.3; anecdotally, ribavirin was beneficial.
14.14 Progressive rubella panencephalitis 507
14.14 PROGRESSIVE RUBELLA
PANENCEPHALITIS
Progressive rubella panencephalitis is a vanishingly rare
disorder occurring as a result of a reactivation of rubella
infection, generally in a patient with the congenital rubella
syndrome.
Clinical features
The congenital rubella syndrome is characterized by mental
retardation, microcephaly, deafness, and cataracts, and
most cases of progressive rubella panencephalitis occur in
this setting in patients aged from 4 to 19 years (Townsend
et al. 1975a; Weil et al. 1975). Rarely, progressive rubella
panencephalitis has occurred as a sequela to an uncomplicated
case of German measles in an otherwise healthy individual
(Lebon and Lyon 1974; Wolinsky et al. 1976), again
after a long latent interval.
Clinically (Townsend et al. 1975a, 1976) there is a gradual
onset of dementia, which is typically accompanied by
ataxia; seizures are uncommon and myoclonus is generally
absent.
The EEG shows generalized slowing and, in some cases,
a burst-suppression pattern may eventually appear.
Neuroimaging reveals cortical atrophy and ventricular
dilation. The CSF is generally abnormal, with a lymphocytic
pleocytosis, an elevated total protein, oligoclonal
bands, and anti-rubella antibodies.
Course
This is a relentlessly progressive disease; spasticity and
quadriparesis eventually appear and death occurs after
8–10 years.
Etiology
Pathologically (Townsend et al. 1975a, 1976, 1982; Weil et al.
1975; Wolinsky et al. 1976), there is a widespread perivascular
inflammatory response, with prominent demyelinization
and gliosis; although rubella virus may be found in
neurons, there are no inclusion bodies. Furthermore,
immunoglobulin deposits are found on cerebral vessels.
Differential diagnosis
When the syndrome occurs in the setting of the congenital
rubella syndrome, there is little doubt as to the diagnosis.
When, however, it occurs in an otherwise healthy child or
adolescent, consideration may be given to subacute sclerosing
panencephalitis, which is distinguished by prominent
myoclonus.