Autoimmune limbic encephalitis

Case contributed by Prof. Stephen Stuckey

Presentation

Progressive confusion.

Patient Data

Age: 40 years
Gender: Female
MRI

Both mesial temporal lobes and hippocampal tails demonstrate high T2 signal, best seen on flair. 

Nuclear medicine

PET

PET demonstrates increase uptake in the limbic system. 

Case Discussion

Limbic encephalitis may be infectious (typically HSV) or autoimmune, including paraneoplastic and non-paraneoplastic causes. 

Signal change may occur in the following locations:

  • Amygdala and hippocampus
  • Insula
  • Cingulate gyrus
  • Inferior frontal lobe

On imaging, autoimmune limbic encephalitis generally affects the amygdala and hippocampus, while infectious limbic encephalitis typically involves multiple sites. 

Patchy contrast enhancement and diffusion restriction are common.

Haemorrhage suggests HSV.

In HSV, DWI changes may precede T2 signal change.

 

There are an increasing number of recognised tumours associated with paraneoplastic limbic encephalitis, including lung (classically small cell), ovarian, breast, germ cell tumours & thymic tumours.

Similarly, there are an increasing number of auto-antibodies now recognised in non-paraneoplastic limbic encephalitis. In this case, the antibody isolated was GAD.

There is a considerable overlap of antibodies in paraneoplastic/non-paraneoplastic limbic encephalitis.

 

 

 

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Case information

rID: 30363
Case created: 5th Aug 2014
Last edited: 29th Sep 2015
Inclusion in quiz mode: Included

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