DX: Hepatic Encephalopathy (Hyperammonemia)

Patient had chronic Hepatitis B infection with chirrosis. Ammonia levels were high and was having an hepatic failure. Patient symptoms were mild several months ago but were progressively worsening.

She was classified in Stage 3 of the West Haven criteria for Hepatic Encephalopathy

MRI findings are unspecific and we ussually see this kind of cortical T2 hyperintensities in various forms of encephalitis. It had no restriction in DWI and T1 was completely normal. Clinical history is imperative to make this diagnosis.

In this case, the characteristic imaging feature is the symmetric thalamic altered signal mainly in the pulvinar regions. Usually, hepatic encephalopathy affects globus pallidus such as this case also. Other clue is the cortical and subcortical hyperintensities that may reflect edema because of swelling of the astrocytes. These are often described that mimic ALS (Lou Gehrig's).

Here are the relevant images: (sorry the poor quality but we work with 1T Magnet).

Here is a similar case on literature:

AJNR 2010 31: 1471-1479

There is a debate on wheter ammonia levels correlate with the onset of Encephalopathy. There are plenty litereture on this subject that goes beyond the scope of this blog but it's interesting to check it out.

Here are some useful links:

http://www.ajnr.org/content/29/9/1612.full.pdf+html
http://www.ajnr.org/content/31/8/1471.full.pdf+html
http://emedicine.medscape.com/article/186101-overview
http://www.aafp.org/afp/2003/1001/p1408.html


Thank you Dr. Muñoz, Dr. Gurrala Ravikiran and Dr. Prabhu Radhan for your participation in the discussion of this case.

Until next time!