Hello - thanks for asking your question.
Although I am an internal medicine physician, please see your primary
care physician for specific questions regarding any individual cases –
please do not use Google Answers as a substitute for medical advice.
I will be happy to answer factual medical questions.
Serum alkaline phosphatase is derived predominantly from the liver and
bones, although other sources may contribute to serum levels in some
settings. Alkaline phosphatase levels also vary with age. Rapidly
growing adolescents can have serum alkaline phosphatase levels that
are twice those of healthy adults because of leakage of bone alkaline
phosphatase into blood. Also, the normal serum alkaline phosphatase
gradually increases from age 40 to 65, particularly in women. The
normal alkaline phosphatase for an otherwise healthy 65-year-old woman
is more than 50 percent higher than a healthy 30-year-old woman.
Thus, it may be normal for the alkaline phosphatase to be high in
growing children. From UptoDate, here is a suggested evaluation of an
elevated alkaline phosphatase:
"The first step in the evaluation of an elevated alkaline phosphatase
is to identify its source . . . a (serum) GGT should be obtained.
These tests are usually elevated in parallel with the alkaline
phosphatase in liver disorders, but are not increased in bone
disorders. An elevated serum alkaline phosphatase with a normal
5'-nucleotidase or GGT should prompt an evaluation for bone diseases."
(1)
If the GGT is elevated, then the elevated alkaline phosphatase is
presumed to be of liver origin.
From UptoDate, here are some causes alkaline phosphatase elevation:
1) Marked elevation (4 times the upper limit of normal)
- Obstructive jaundice due to cancer
- Common duct stones
- Sclerosing cholangitis
- Bile duct stricture
- Drug and toxins associated with cholestasis
- Primary biliary cirrhosis
- Liver allograft rejection
- Infectious hepatobiliary diseases seen in patients with AIDS (eg,
CMV or microsporidiosis and tuberculosis with hepatic involvement).
- Alcohol-induced steatonecrosis (rarely)
2) Moderate elevation (3 times the upper limit of normal)
Lesser increases in alkaline phosphates activity, up to three times
the upper limit of normal, are nonspecific and occur in all types of
liver disease, including viral hepatitis, chronic hepatitis,
cirrhosis, infiltrative diseases of the liver, and congestive heart
failure. Elevations in hepatic alkaline phosphatase of this magnitude
can also occur in disorders that do not directly involve the liver,
such as Hodgkin's disease, myeloid metaplasia, intraabdominal
infections, and osteomyelitis.
Two to fourfold elevations in plasma alkaline phosphatase levels have
been described in several members of a family who had no evidence of
bone or liver disease.
3) Isolated or disproportional elevation
- Partial bile duct obstruction due to gallstones or tumor.
- Early in the course of some cholestatic liver diseases such as
primary sclerosing cholangitis and primary biliary cirrhosis.
- Infiltrative diseases such as amyloidosis, sarcoidosis, hepatic
abscesses, tuberculosis, and metastatic carcinoma.
- Extrahepatic diseases such as myeloid metaplasia, peritonitis,
diabetes mellitus, subacute thyroiditis, and uncomplicated gastric
ulcer.
- Extrahepatic tumors, including osteosarcomas, lung, gastric, head
and neck, renal cell carcinoma, ovarian, uterine cancer, and Hodgkin's
disease, that secrete alkaline phosphatase (often a form known as the
Regan isoenzyme) or cause leakage of hepatic alkaline phosphatase into
serum by an unknown mechanism. (2)
Here is a suggested diagnostic approach from UptoDate:
"Initial testing should include a right upper quadrant ultrasound
(which can assess the hepatic parenchyma and bile ducts) and an
antimitochondrial antibody (AMA), which is highly suggestive of PBC.
The presence of biliary dilatation suggests obstruction of the biliary
tree. In patients with biliary dilatation or choledocholithiasis, an
endoscopic retrograde cholangiopancreatogram (ERCP) should be done to
identify the cause of obstruction and to allow for an intervention
such as stone removal or stent placement. Patients with a positive AMA
should have a liver biopsy to verify the diagnosis of PBC." (1)
To answer your question about treatment - it would depend on the cause
(as you can see, there are many). In the case of children, it is
certainly possible that the alkaline phosphatase is elevated as a
consequence of growing.
Once the cause of the elevated alkaline phosphatase has been
determined by your personal physician or gastroenterologist, I would
be happy to answer questions about treatment.
This answer is not intended as and does not substitute for medical
advice - the information presented is for patient education only.
Please see your personal physician for further evaluation of your
individual case.
Please use any answer clarification before rating this answer. I will
be happy to explain or expand on any issue you may have.
Thanks,
Kevin, M.D.
Search strategy:
No internet search engine was used in this answer. All sources are
from physician-written and peer-reviewed sources.
Bibliography:
1) Pratt. Approach to the patient with abnormal liver function tests.
UptoDate, 2003.
2) Pratt. Alkaline phosphatase and other enzymatic measures of
cholestasis. UptoDate, 2003.
Links:
Lab Tests Online - ALP
http://www.labtestsonline.org/understanding/analytes/alp/faq.html
Health A to Z - Liver Function Tests
http://www.healthatoz.com/healthatoz/Atoz/ency/liver_function_tests.html |
