Dengueenzephalitis

Dengue encephalitis is a rare condition resulting from direct involvement of the central nervous system by the dengue virus.

Epidemiology

Dengue infection, and thus dengue encephalitis, predominately occurs in tropical and subtropical areas.

Clinical Presentation

Dengue encephalitis presents similar to other forms of encephalitis with non-specific symptoms such as headache, seizures and altered level of consciousness.

Pathology

Dengue virus is a mosquito-transmitted RNA virus belonging to the Flavivirus genus.  There are four serotypes, designated DENV1-DENV-4. The serotypes most commonly implicated in neurologic manifestations of dengue virus infection are DENV2 and DENV-3.

Radiographic Features

CT

• hyperattenuating intraparenchymal foci representing spontaneous macrohaemorrhages

MRI

• T2
  • hyperintense lesions involving the basal ganglia, thalami, cortical grey matter, and subcortical and deep white matter are the classical features of dengue encephalitis, usually with associated edema
  • rarely, similar lesions are found in atypical locations such as the brainstem (particularly the substantia nigra), cerebellum, and hippocampus
• DWI/ADC: affected regions demonstrate restricted diffusion in most cases
• SWI: microhemorrhages are commonly seen

Differential Diagnosis

• acute disseminated encephalomyelitis (ADEM)
  • hemorrhage is uncommon
  • the timing between the CNS manifestations and lesions and the febrile illness may assist in differentiating dengue encephalitis from ADEM - with dengue encephalitis manifesting during the febrile period and ADEM occurring after resolution of the acute illness
• Japanese encephalitis 
  • ​hemorrhagic findings, although described, are less common
• herpes simplex encephalitis
  • usually spares the basal ganglia

Siehe auch:

• Denguefieber