Cerebrospinal fluid pressures in subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis presenting as acute disseminated encephalomyelitis and pseudotumour cerebri

Subacute sclerosing panencephalitis (SSPE) is a chronic progressive encephalitis of childhood and young adults due to persistent measles virus infection. The usual age of onset is between 5 and 15 years. There are wide varieties of presentations of SSPE described in the literatures. Variable clinical presentations may lead to diagnostic dilemma and unnecessary investigations especially in developing countries, where the measles is quite endemic and vaccination status is not up to the mark because of poor literacy and socioeconomic status. Good clinical correlations, neuroimaging findings, EEG and cerebrospinal fluid (CSF) marker for SSPE yield the clue to diagnosis. This case illustrates a 13-year-old boy presented with short history of intellectual decline, headache, papilloedema, cranial nerve palsy, myoclonus with suggestive neuroimaging mimicking acute disseminated encephalomyelitis (ADEM) and pseudotumour cerebri. Subsequently he was diagnosed to be a case of SSPE on the basis of CSF and serum measles antibody titer.

Epidemiological Findings and Clinical and Magnetic Resonance Presentations in Subacute Sclerosing Panencephalitis

Subacute sclerosing panencephalitis (SSPE) is a rare, progressive, inflammatory neurodegenerative disease. This study investigated the relationships of clinical stage with epidemiological and magnetic resonance imaging (MRI) findings in SSPE by retrospective review of 76 cases (57 male) diagnosed by typical periodic electroencephalographic features, clinical symptoms and elevated measles antibody titre in cerebrospinal fluid. Clinical stage at diagnosis was I or II in 48 patients, III in 25 and IV in three. Prominent findings at presentation were atonic/myoclonic seizures (57.9%) and mental deterioration with behaviour alteration (30.3%). Frequent MRI findings (13 – 32 patients) were subcortical, periventricular and cortical involvement and brain atrophy; the corpus callosum, basal ganglia, cerebellum and brainstem were less frequently involved. Five patients had pseudotumour cerebri. Cranial MRI at initial diagnosis was normal in 21 patients (19 stage I/II, two stage III/IV). Abnormal MRI findings were significantly more frequent in the later stages, thus a normal initial cranial MRI does not exclude SSPE, which should, therefore, be kept in mind in childhood demyelinating diseases even when the presentation is unusual.

Cerebrospinal fluid nitric oxide levels in subacute sclerosing panencephalitis

Oxidative damage plays a role in neurodegenerative diseases. Levels of cerebrospinal fluid nitrite and nitrate levels (oxidation products that provide an indirect estimation of nitric oxide) were investigated in relation to clinical and laboratory features in subacute sclerosing panencephalitis (n = 47) and age-matched control (n = 43) groups. Significantly decreased levels of nitrite (median, 4.91 micromol/L) and nitrate (median, 6.14 micromol/L) were found in the patients. Nitrite and nitrate levels did not correlate with clinical or laboratory findings, except for presence of myoclonus. Cerebrospinal fluid nitrite levels of subacute sclerosing panencephalitis patients without myoclonic jerks were significantly higher than in those with myoclonus (median, 15.63 vs 4.34 micromol/L, respectively). The higher levels of nitrite in these patients can be explained by short disease duration and early stages of disease. Nitrate levels in subacute sclerosing panencephalitis patients with myoclonus (median, 9.26 micromol/L) were higher than in those without myoclonus (median, 4.25 micromol/L). Microbleeding resulting in conversion of nitrite to nitrate and increased production of superoxide can be suggested as possible mechanisms underlying these findings.

Pseudotumor cerebri secondary to subacute sclerosing panencephalitis

Unusual presentations are not rare in subacute sclerosing panencephalitis. Five patients initially diagnosed with pseudotumor cerebri were ultimately determined to have pseudotumor cerebri secondary to subacute sclerosing panencephalitis. The present study retrospectively reviewed 56 cases history, neurologic symptoms, and clinical and laboratory data, as well as the outcomes. On admission, five patients (group 1) presenting with pseudotumor cerebri exhibited bilateral papilledema, and in each of them cranial magnetic resonance imaging revealed small lateral ventricles, effacement of the subarachnoid space, and no mass lesion. On admission, 51 patients (group 2) had no pseudotumor cerebri findings. The year of original measles infection, the interval between measles and onset of subacute sclerosing panencephalitis, and initial neurologic symptoms were similar, but length of symptoms before diagnosis of subacute sclerosing panencephalitis was shorter in group 1, and the clinical stage of subacute sclerosing panencephalitis on admission was more advanced in group 2. Cerebrospinal fluid mean open pressure was 378 +/- 22 H(2)O in group 1 and 146 +/- 28 H(2)O in group 2; cerebrospinal fluid antibody was 2038 +/- 768 U/L in group 1 and was 664 +/- 214 U/L in group 2. Only three of the five patients with pseudotumor cerebri had typical periodic discharges on electroencephalographic examination. These findings suggest that subacute sclerosing panencephalitis can cause pseudotumor cerebri.