Todayโs path rounds is on ๐ก๐๐ฉ๐๐ญ๐ข๐ ๐ฅ๐ข๐ฉ๐ข๐๐จ๐ฌ๐ข๐ฌ! Somewhat inspired by a case I had this week 
๐๐ก๐๐ญ ๐ข๐ฌ ๐ก๐๐ฉ๐๐ญ๐ข๐ ๐ฅ๐ข๐ฉ๐ข๐๐จ๐ฌ๐ข๐ฌ?
Hepatic lipidosis is basically when there is accumulation of ๐ญ๐ซ๐ข๐ ๐ฅ๐ฒ๐๐๐ซ๐ข๐๐๐ฌ (the smallest component of fat) within the liver cells.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
Any species can get this, but cats in particular are very susceptible to it. The classic presentation of a hepatic lipidosis case is an obese female cat, that has some kind of stressor (e.g. moving, introduction of a new pet or family member, being accidentally locked somewhere without food etc) causing them to not eat.
๐๐ก๐ฒ ๐ข๐ฌ ๐๐๐๐ฎ๐ฆ๐ฎ๐ฅ๐๐ญ๐ข๐จ๐ง ๐จ๐ ๐ญ๐ซ๐ข๐ ๐ฅ๐ฒ๐๐๐ซ๐ข๐๐๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
On its own, this is not that big of a deal. In fact, one of the main functions of the liver is helping with triglyceride processing. However, very high amounts of triglycerides makes the cells more susceptible to disease, reduces their life-span and can impair their ability to repair themselves. So if another โsecondaryโ problem comes along that also affects the liver, suddenly the liver has a BIG problem! Some examples of โsecondaryโ problems are starvation, kidney disease, intestinal disease, tumours, diabetes, and more.
Without being treated, the mortality rate of hepatic lipidosis is very high. However with treatment, there is a good prognosis if it is caught early.
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
In cats, the accumulation of triglycerides likely has many contributing factors. Here are the two related factors we often think about:1) During periods of ๐๐ง๐จ๐ซ๐๐ฑ๐ข๐ (animal is not eating), the body needs to retrieve fat out of storage in order to keep up with energy requirements. Remember how the liver helps with triglyceride processing? This means when all of that fat is pulled out of storage, the liver can get overwhelmed trying to keep up with all that processing! Thus, triglycerides start to accumulate within the liver cells, because they arenโt getting processed fast enough.2) Once the triglycerides are within the liver cells, the cell packages them into nice bundles called ๐ฏ๐๐ซ๐ฒ ๐ฅ๐จ๐ฐ-๐๐๐ง๐ฌ๐ข๐ญ๐ฒ ๐ฅ๐ข๐ฉ๐จ๐ฉ๐ซ๐จ๐ญ๐๐ข๐ง๐ฌ (VLDLs). In order to make these nice packages, the liver cells need proteins, energy, and other components. If any of those โsuppliesโ are low, which can also be caused by anorexia, then the cell canโt package things, causing triglycerides to accumulate.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Cats presenting in a veterinary clinic will often have vomiting, anorexia, weakness and ๐ฃ๐๐ฎ๐ง๐๐ข๐๐ (yellowing of the tissues). Jaundice is a consequence of the liver cells not being able to excrete ๐๐ข๐ฅ๐ข๐ซ๐ฎ๐๐ข๐ง, a yellow pigment that is formed when red blood cells are recycled or removed. Without the liver cells processing bilirubin to remove it from the blood, it accumulates in the tissues giving them a yellow tinge. On an ultrasound, the clinician may be able to see an enlarged liver, and on bloodwork, the liver values will be significantly elevated. At necropsy, the liver appears larger, yellow, and is more easily broken than a normal liver. They can also have more rounded edges than normal livers, and can feel kind of greasy. On histology, you can see large, clear ๐ฏ๐๐๐ฎ๐จ๐ฅ๐๐ฌ (basically big storage bags within the cell) within the liver cells, which is where the triglycerides are stored.
๐๐ก๐จ๐ญ๐จ๐ฌ
1) A very yellow liver in its normal position in the abdomen.
2) The ๐๐ซ๐๐ง๐ข๐๐ฅ (head-side) surface of a very yellow liver after being removed from the abdomen.
3) The ๐๐๐ฎ๐๐๐ฅ (tail-side) surface of a very yellow liver after being removed from the abdomen. The green thing is the gall bladder!
4 and 5) The microscopic view of hepatic lipidosis. So many bubbles of triglyceride!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 3. Sixth Edition.
Photos 1 and 3 courtesy of University of Calgary Veterinary Medicine Diagnostic Services Unit.
Photos 2, 4 and 5 courtesy of Noahโs Arkive.
