The first question is really, "What is this thing called, NAFLD?"
"Non-Alcoholic Fatty Liver Disease"
So, this is a disease that occurs when fat is deposited in the liver
without other causes of fatty liver identified, and I'll go into some of the specifics a little bit later.
So, you know, how would you know if you have NAFLD? I mentioned, again, it's a silent epidemic.
Well, it's because many patients will have no symptoms at all, up to 77 percent in fact.
If they do have symptoms, they may not be very helpful in terms of guiding us as physicians, or
other health care providers to the fact that fatty liver may be present.
Fatigue is very, very common; present in 50 to 75 percent of patients with fatty liver.
But the problem is, is that fatigue is a common feature of many different diseases.
So, if someone says they're fatigued
that unfortunately doesn't help me because there's a huge, long list of things that can cause fatigue and fatty liver is one of them.
The other reason why fatigue is an important feature of fatty liver is that sleep apnea
is very common in our patients with fatty liver as well, and that can certainly contribute to daytime fatigue.
If symptoms are present, right-sided abdominal pain may be present, and that's because that's where your liver is
and we think that the reason why patients will have pain in the setting of fatty liver
is that as the fat deposits it can actually stretch out the lining, or the capsule, of the liver.
And that's really where the nerves are in the liver, they're not on the inside, they're really on the outside,
sensing problems with the, with the external parts of the liver.
But what I always tell my patients is that just because you have pain and you have an established diagnosis of fatty liver
that does not necessarily mean that your liver disease is getting worse.
It doesn't mean that because you have pain
that your liver is sicker than someone who doesn't have pain. Pain is something I think we really still don't understand very well.
But for, again, for whatever reason some patients with fatty liver will have the pain.
In part, related to the stretch of the capsule of the liver.
Other things that might make you suspicious of having fatty liver is the presence of risk factors and I've already mentioned the high
prevalence of fatty liver in patients who are obese, or have diabetes.
Lab testing may also clue you, or your health care providers into the fact that fatty liver may be present
with the liver enzymes, specifically ALT and AST,
being elevated and usually
ALT will be higher than the AST.
One thing to be aware of is that
as Hepatologists, as liver specialists, we kind of use a different range for normal liver enzymes than your local lab might.
And I'll explain why that is, it's not that we're just, you know, crazy, and setting a really low threshold.
It's that when the labs actually develop what their normal values are
they derive that from the general population that's actually getting their blood drawn.
Now I've told you about a third of the U.S. population has fatty liver disease,
so if they're deriving their "normals" from this abnormal population
you can see how that can really skew the "normal values" to being higher than they probably should be.
A normal ALT, just so you know, for a woman should be less than 20 to 25;
and for a man should be less than 30 to 35. And I've seen some
local labs say that an ALT of 60 is normal and that's absolutely not true for a woman.
That's, you know, close to three times upper limit of normal.
So other things that can clue you into the presence of fatty liver is
the appearance of fat on ultrasound, MRI, or CT Scan and this is also how a lot of patients will come to our attention.
That they complain, "I have pain on my right side."
Appropriately, their primary care doctor will get an imaging study and then they see, "Oh, the liver looks like it has fat in it."
And that's what usually initiates a referral over to my clinic.
So,
you would think because fatty liver is so common
I haven't told you about the consequences yet, but just thinking that there are populations that are likely to have fatty liver, should we screen?
If you look at the guidelines from the U.S., which is the American Association for the Study of Liver Disease, ASLD,
they don't recommend screening.
The recommendations are a little bit vague in that they suggest a high level of suspicion in high risk patients.
They kind of stop short of saying that we should be screening these patients.
And part of this is related to cost. If you're thinking about screening, you know, the at-risk U.S. population,
which is probably, you know, again, about a third of the U.S. population, that can be quite costly.
And if you don't yet have treatments that are cost-effective
in reducing serious liver-related problems, or liver-related death,
then the screening may not make sense. Though I suspect in the coming years that this may change.
The European guidelines, this is the European Association for the Study of the Liver, they, they're a little bit more prescriptive. They say
you should screen all patients with obesity, or metabolic syndrome, by checking liver enzymes and ultrasound.
I think this is a little bit overkill.
I think we really should be focusing on our highest risk patients
which tend to be patients with diabetes, because they are the ones that are most likely to have
advanced liver disease in the setting of fatty liver.
I think it's premature to say we should screen everybody who is obese, and everybody that has
a metabolic syndrome problem, such as high blood pressure, high cholesterol, but again, that may change.