Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 59, Num. 2, 2011, pp. 273-275

Neurology India, Vol. 59, No. 2, March-April, 2011, pp. 273-275

Case Report

Brainstem involvement in subacute sclerosing panencephalitis

Pawan Sharma¹, Dileep Singh¹, Maneesh Kumar Singh¹, Ravindra Kumar Garg¹, Neera Kohli²

¹ Department of Neurology, Chhatrapati Shahuji Maharaj Medical University, Uttar Pradesh, Lucknow, India
² Department of Radiodiagnosis, Chhatrapati Shahuji Maharaj Medical University, Uttar Pradesh, Lucknow, India

Correspondence Address: Ravindra Kumar Garg, Department of Neurology, Chhatrapati Shahuji Maharaj Medical University, Uttar Pradesh, Lucknow - 226 003, India, garg50@yahoo.com

Date of Submission: 13-Dec-2010
Date of Decision: 13-Dec-2010
Date of Acceptance: 13-Dec-2010

Code Number: ni11073

PMID: 21483132

DOI: 10.4103/0028-3886.79146

Abstract

Keywords: Encephalopathy, measles, pons

Introduction

Subacute sclerosing panencephalitis (SSPE) is a progressive, devastating brain disorder caused by persistent mutant measles virus infection. The diagnosis is based on characteristic clinical findings, abnormality in electroencephalography (EEG) abnormality and the elevated anti-measles antibodies titer in the cerebrospinal fluid. ^[1],[2]

The parieto-occipital region of the brain is most frequently and severely affected. ^[3] The basal ganglia, cerebellum, spinal cord and corpus callosum are less commonly affected. In later stages of the disease, cerebellum and brainstem are affected. Brainstem involvement is uncommon, and usually there is involvement of other regions of the brain. ^[4],[5] Here we describe an unusual patient of SSPE with dominant brainstem involvement.

Case Report

A 15-year-old boy was apparently normal 1 year ago, when he had 1 episode of tonic-clonic seizures. After the seizures, family members noticed that he started taking less interest in studies, and his school performance declined gradually over a period of 6 months. The relatives also noticed changes in his behavior in the form of decreased interest in playing games and taking more time in replying to simple questions. He also did not interact normally with friends and family members. He could independently perform his daily activities until 10 days back, when he had 3 episodes of generalized tonic-clonic seizures. He also developed fever of mild-to-moderate grade after episodes of seizures. He did not regain consciousness after the last episode of seizure and was brought to our hospital in an unconscious state. He had normal birth history and had normal motor and mental developments. He was not immunized against measles and had history of measles at 1½ years of age. The parents were nonconsanguineous, and his three siblings were in good health. On neurological examination, he was stuporous with a Glasgow Coma Scale score of 9/15. The pupils were normal in size and reacting to light. The deep tendon reflexes were brisk, and plantar response was extensor bilaterally. There were no signs of meningeal involvement. Other neurological and systemic examinations were unremarkable.

Routine blood investigations, including hemogram, and urinalysis were normal. The cerebrospinal fluid analysis revealed opening pressure of 10 cm of water with 8 lymphocytes, 50 mg/dL proteins and 68 mg/dL sugar (corresponding blood sugar was 90 mg/dL). Bacterial and Lowenstein-Jensen media cultures of cerebrospinal fluid were negative. In cerebrospinal fluid, Mycobacterium tuberculosis polymerase chain reaction, Herpes simplex 1 and 2 polymerase chain reaction and cryptococcal antigen were negative. Cerebrospinal fluid anti-measles antibody titers were elevated (1/512 titer by particle agglutination test; 1/128 titer, normal). EEG showed generalized periodic high-amplitude sharp and slow wave complexes [Figure - 1]. Magnetic resonance imaging (MRI) of the brain revealed extensive involvement of the brainstem. There were T2 and FLAIR hyperintense signals involving pons and middle cerebellar peduncle [Figure - 2]. Subtle asymmetrical T2 hyperintensities were also seen on left parieto-occipital cortex [Figure - 3]. Marked atrophy of fronto-temporal region was also present [Figure - 2]. The patient was treated with intrathecal interferon-alpha (IFN-α), sodium valproate and clonazepam. There was no significant change in his mental status at the 2-month follow-up.

Discussion

Typical clinical picture of declining mental status, seizures, myoclonus with characteristic EEG pattern, raised anti-measles antibody titers in cerebrospinal fluid (CSF) and presence of cortical atrophy with subtle signal changes in parieto-occipital region on MRI suggest a diagnosis of SSPE. However, prominent brainstem involvement on MRI, as described above, has not been commonly described in SSPE.

The various MRI abnormalities described in SSPE include asymmetric, focal regions of signal changes (hyperintense on T2-weighted/ FLAIR image and hypointense or isointense on T1-weighted image) involving cerebral cortex, subcortical predominantly periventricular white matter, basal ganglia, thalamus and corpus callosum. The cerebellum and brainstem may be involved in late stages. ^{[2],[4],[6],[7]} The correlation between MRI findings and clinical severity is not exactly known. ^[8] Tuncay et al. described that asymmetric cortical and subcortical involvements were initial neuroimaging manifestations. Later on, cortical atrophy and the involvement of multifocal deep white matter became the most prominent findings. ^[2] Lesions in SSPE usually start appearing in the occipital region and then progress to involve frontal cortex; and subsequently subcortical white matter, brainstem and spinal cord get involved. ^[7]

Brainstem neuroimaging changes in SSPE are very uncommon. ^[5],[9] In our case, signal changes were predominantly seen in pons and middle cerebellar peduncles. Yilmaz et al. have reported brainstem involvement in 2 cases of typical SSPE. ^[10] They demonstrated a substantially large focal lesion about in the pons in a 9-year-old girl with typical symptoms of SSPE; and a hyperintense lesion in the pons and peduncle of cerebellum on T2-weighted image in other patients of SSPE. Kalane et al. reported brainstem changes in a child with SSPE, with brain MRI showing extensive brainstem and cerebellum involvement with additional lesion in the basal ganglia. ^[11]

Brainstem involvement is rarely described in SSPE, leading to unfamiliarity and sometimes to erroneously reporting of neuroimaging by a radiologist unaware of the clinical history, as in the case described by Kalane et al., where low-grade glioma was initially reported. ^[11] On of the basis of these cases, we would like to stress that brainstem involvement may be seen in patients with SSPE; sometimes, without the involvement of other areas of the brain. Therefore, one should be aware of such extensive brainstem and cerebellum neuroimaging involvement in SSPE. SSPE should be kept in mind when dominant brainstem abnormalities are seen on neuroimaging.

References

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