Neuroimaging Findings in Rabies Encephalitis.

BACKGROUND AND PURPOSE: Rabies encephalitis is a near-fatal zoonotic disease that is usually diagnosed on clinical grounds in conjunction with characteristic history. Owing to its rapidly progressive nature, imaging is seldom performed, and hence a description of imaging findings in rabies encephalitis is anecdotal and limited. METHODS: We describe MRI findings in eight confirmed rabies cases that presented to our institute over the last 21 years. RESULTS: Most of the patients' imaging patterns are in concordance with the described literature. However, we hereby demonstrate the involvement of novel structures like dentate nuclei, cranial nerves, and meninges besides the hot cross bun sign in the pons and the presence of diffusion restriction in many gray and white matter structures of the brain. CONCLUSION: Knowledge of the broad imaging spectrum of rabies may expedite the diagnosis, especially the paralytic form, which is prone to clinical misdiagnosis as Guillain-Barre syndrome or acute disseminated encephalomyelitis.

Atypical rabies encephalitis in a six-year-old boy: clinical, radiological, and laboratory findings.

A 6-year-old boy from India developed an atypical form of rabies following a stray dog bite and as a consequence of not receiving the standard World Health Organization recommended post-exposure prophylaxis for category III wounds. Serial rising rabies virus neutralizing antibody titres in serum and cerebrospinal fluid by rapid fluorescent focus inhibition test helped confirm the diagnosis of rabies. The child has survived for 4 months since the onset of illness, albeit with neurological sequelae.

Imaging findings in rabies.

A 10 year old Vietnamese girl presented with clinical features of an acute encephalitic process. A cerebral angiogram performed to rule out vasculitis showed narrowing at the supraclinoid internal carotid and terminal basilar arteries. A diagnosis of rabies was established at autopsy. Although the major blood vessels and basal meninges were normal it was possible that transient arterial spasm induced by the viral infection was responsible for the angiographic appearance. Other imaging findings in our patient are described with a brief review of the literature. This is only the second case of rabies reported in Australia. Rabies is a rare disease in the Australian community. Recently one patient with atypical clinical presentation was confirmed to have the disease only at autopsy. In the clinical work-up, various radiological examinations were performed and a range of interesting features were encountered including an abnormal cerebral angiogram. The purpose of this paper is to report on these unusual features and to review those documented in the literature.