Brainstem involvement in subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis and brain stem involvement: a rare combination

Subacute sclerosing panencephalitis (SSPE) is a progressive lethal neurological inflammatory disease due to persistent, wild measles virus infection in the central nervous system that is seen most frequently in children and young adolescents. Atypical presentations are seen in up to 10% of cases. Most frequently and severely affected region in the brain is the parieto-occipital region of the brain. Less commonly involved organs are the cerebellum, basal ganglia and corpus callosum. Brainstem involvement is rare and usually occurs when other areas of brain are involved along with it. Here, we describe an unusual male patient of 15 years age, having SSPE with MRI of brain showing extensive involvement of brainstem with no significant involvement of other cortical structures of the brain. It is very rarely described in SSPE, but one should be vigilant about such involvement of brainstem and cerebellum, and SSPE should not be missed when brainstem hyperintensities are seen in MRI brain with or without other region of the brain to avoid misdiagnosis.

Atypical adult-onset subacute sclerosing panencephalitis

Although subacute sclerosing panencephalitis is almost exclusively a childhood disease, it can occur in adults as well. We present an atypical case of adult-onset subacute sclerosing panencephalitis. The disease was characterized by prolonged insidious course followed by accelerated and aggressive phase, atypical EEG findings, and absence of myoclonic jerks. The diagnostic and treatment-related pitfalls are discussed.

Neurological Complications of Measles (Rubeola)

PURPOSE OF REVIEW

Owing to vaccine hesitancy, there has been a resurgence of measles infections in developed countries. Practitioners can expect to see an increase in patients with neurologic complications of measles. These devastating disorders include primary measles encephalitis, acute post measles encephalitis, subacute sclerosing panencephalitis (SSPE), and measles inclusion body encephalitis (MIBE).

RECENT FINDINGS

Although there are many unanswered questions regarding the neurologic complications of measles, recent advances have led to better understanding of the mechanism of the spread of measles within the nervous system, particularly the disruption of F protein function, which raises the possibility of treatment with fusion-inhibiting molecules. Measles and its neurological complications are preventable and must be prevented. Neurologists must educate other clinicians and the public regarding the consequences of inadequate herd immunity to measles. More effective treatments for SSPE and MIBE may be available in the near future, but currently these remain lethal diseases.

Subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis (SSPE) is a slowly progressive brain disorder caused by mutant measles virus. SSPE affects younger age groups. SSPE incidence is proportional to that of measles. High-income countries have seen substantial decline in SSPE incidence following universal vaccination against measles. SSPE virus differs from wild measles virus. Measles virus genome recovered from the autopsied brain tissues demonstrates clustered mutations in virus genome particularly in the M gene. These mutations destroy the structure and functioning of the encoded proteins. Complete infectious virus particle has rarely been recovered from the brain. Human neurons lack required receptor for entry of measles virus inside the neurons. Recent in vitro studies suggest that mutations in F protein confer hyperfusogenic properties to measles virus facilitating transneuronal viral spread. The inflammatory response in the brain leads to extensive tissue damage. Clinically, SSPE is characterized by florid panencephalitis. Clinically, SSPE is characterized by cognitive decline, periodic myoclonus, gait abnormalities, vision loss, and ultimately to a vegetative state. Chorioretinitis is a common ocular abnormality. Electroencephalography (EEG) shows characteristic periodic discharges. Neuroimaging demonstrates periventricular white matter signal abnormalities. In advanced stages, there is marked cerebral atrophy. Definitive diagnosis requires demonstration of elevated measles antibody titers in cerebrospinal fluid (CSF). Many drugs have been used to stabilize the course of the disease but without evidence from randomized clinical trials. Six percent of patients may experience prolonged spontaneous remission. Fusion inhibitor peptide may, in the future, be exploited to treat SSPE. A universal vaccination against measles is the only proven way to tackle this menace currently.

Subacute Sclerosing Panencephalitis of the Brainstem as a Clinical Entity

Subacute sclerosing panencephalitis (SSPE) is a rare progressive neurological disorder of early adolescence caused by persistent infection of the measles virus, which remains prevalent worldwide despite an effective vaccine. SSPE is a devastating disease with a characteristic clinical course in subcortical white matter; however, atypical presentations of brainstem involvement may be seen in rare cases. This review summarizes reports to date on brainstem involvement in SSPE, including the clinical course of disease, neuroimaging presentations, and guidelines for treatment. A comprehensive literature search was performed for English-language publications with keywords “subacute sclerosing panencephalitis” and “brainstem” using the National Library of Medicine PubMed database (March 1981–September 2017). Eleven articles focusing on SSPE of the brainstem were included. Predominant brainstem involvement remains uncharacteristic of SSPE, which may lead to misdiagnosis and poor outcome. A number of case reports have demonstrated brainstem involvement associated with other intracranial lesions commonly presenting in later SSPE stages (III and IV). However, brainstem lesions can appear in all stages, independent of higher cortical structures. The varied clinical presentations complicate diagnosis from a neuroimaging perspective. SSPE of the brainstem is a rare but important clinical entity. It may present like canonical SSPE or with unique clinical features such as absence seizures and pronounced ataxia. While SSPE generally progresses to the brainstem, it can also begin with a primary focus of infection in the brainstem. Awareness of varied SSPE presentations can aid in early diagnosis as well as guide management and treatment.

MR imaging of adult acute infectious encephalitis

BACKGROUND

Imaging is a key tool for the diagnosis of acute encephalitis. Brain CT scan must be urgently performed to rule out a brain lesion with mass effect that would contraindicate lumbar puncture. Brain MRI is less accessible than CT scan, but can provide crucial information with patients presenting with acute encephalitis.

METHOD

We performed a literature review on PubMed on April 1, 2015 with the search terms "MRI" and "encephalitis".

RESULTS

We first described the various brain MRI abnormalities associated with each pathogen of acute encephalitis (HSV, VZV, other viral agents targeting immunocompromised patients or travelers; tuberculosis, listeriosis, other less frequent bacterial agents). Then, we identified specific patterns of brain MRI abnomalies that may suggest a particular pathogen. Limbic encephalitis is highly suggestive of HSV; it also occurs less frequently in encephalitis due to HHV6, syphillis, Whipple's disease and HIV primary infection. Rhombencephalitis is suggestive of tuberculosis and listeriosis. Acute ischemic lesions can occur in patients presenting with severe bacterial encephalitis, tuberculosis, VZV encephalitis, syphilis, and fungal infections.

CONCLUSION

Brain MRI plays a crucial role in the diagnosis of acute encephalitis. It detects brain signal changes that reinforce the clinical suspicion of encephalitis, especially when the causative agent is not identified by lumbar puncture; it can suggest a particular pathogen based on the pattern of brain abnormalities and it rules out important differential diagnosis (vascular, tumoral or inflammatory causes).

Blindness, dancing extremities, and corpus callosum and brain stem involvement: an unusual presentation of fulminant subacute sclerosing panencephalitis

A 4-year-old girl presented with acute visual loss followed 2 weeks later with loss of speech and audition, fulminant neuroregression, and choreo-athetoid movements of extremities. Fundus showed bilateral chorioretinitis. Electroencephalography showed periodic complexes. Measles antibody titers were elevated in both serum and cerebrospinal fluid, consistent with subacute sclerosing panencephalitis. Neuroimaging showed discontiguous involvement of splenium of the corpus callosum and ventral pons with sparing of cortical white matter. Our case highlights the atypical clinical and radiologic presentations of subacute sclerosing panencephalitis. Pediatricians need to be aware that necrotizing chorioretinitis in a child and/or atypical brain stem changes could be the heralding feature of this condition in endemic countries.

Fulminant subacute sclerosing panencephalitis presenting with acute ataxia and hemiparesis in a 15-year-old boy

Background

Subacute sclerosing panencephalitis (SSPE) is a delayed and fatal manifestation of measles infection. Fulminant SSPE is a rare presentation in which the disease progresses to death over a period of 6 months. The clinical features are atypical and can be misleading.

Case Report

We report herein a teenage boy who presented with acute-onset gait ataxia followed by right hemiparesis that evolved over 1 month, with left-hemispheric, delta-range slowing on the electroencephalogram (EEG). Magnetic resonance imaging disclosed multiple white-matter hyperintensities, suggesting a diagnosis of acute disseminated encephalomyelitis. He received intravenous steroids, and within 4 days of hospital admission he developed unilateral slow myoclonic jerks. Repeat EEG revealed Rademecker complexes, pathognomonic of SSPE, and an elevated titer of IgG antimeasles antibodies was detected in his cerebrospinal fluid. The disease progressed rapidly and the patient succumbed within 15 days of hospitalization. The diagnosis of SSPE was confirmed by autopsy.

Conclusions

This case illustrates the difficulty of recognizing fulminant SSPE when it manifests with asymmetric clinical and EEG abnormalities.