Proteins of many types circulate in the blood. The liver produces many of the blood proteins from building blocks absorbed through the intestine from the diet. Normally, the kidneys prevent protein losses through the urine by conserving blood proteins. Abnormalities of the liver, kidneys, intestine and traumatic fluid losses can cause abnormally low blood protein levels.
Nephrotic Syndrome
Nephrotic syndrome refers to a group of kidney disorders associated with significant protein losses in the urine. Although there are several causes of nephrotic syndrome, all are associated with an abnormality of the filtering units of the kidneys, which causes protein leakage into the urine. Heavy protein losses in the urine lead to low blood protein levels. The Merck Manual for Healthcare Professionals states kidney conditions known to cause nephrotic syndrome include membranous nephropathy, rapidly progressive and membranoproliferative glomerulonephritis, IgA nephropathy, hereditary nephritis, and congenital nephrotic syndrome.
Cirrhosis with Liver Failure
Liver failure is a leading cause of low blood protein levels. The liver manufactures albumin, which is the most abundant of the blood proteins. Insufficient albumin production by a failing liver causes a decreased blood protein level. The Merck Manual for Healthcare Professionals points out that blood albumin concentration is one of the primary criteria used to evaluate the severity of liver failure.
Drs. J. Heidelbaugh and M. Serbondy note in their article, "Cirrhosis and Chronic Liver Failure: Complications and Treatment," published in "American Family Physician" that accumulation of protein-rich fluid in the abdomen due to liver cirrhosis contributes to low blood protein. The accumulation of fluid in the abdomen is termed ascites. It occurs as blood backs up in the abdominal blood vessels due to slow passage through the scarred liver. The blood backup increases pressure in the blood vessels leading to protein-rich fluid leakage into the abdomen.
Massive Bleeding and Extensive Burns
Massive bleeding and severe burns can cause low blood protein due to overwhelming protein losses. With bleeding, the proteins are lost along with blood. In the case of massive burns, protein-rich fluid leaks from the open burn wounds. Immense amounts of fluid and protein that can be lost through burns. In a research article published in the journal "Burns," Dr. M. Lehnhardt and colleagues reported the total amount of blood proteins in the circulation is lost through fluid leakage in roughly the first 24 hours after sustaining second degree burns involving 20 percent of the body surface area.
Crohn's Disease and Celiac Disease
Crohn's disease is a chronic inflammatory condition of the intestine, which damages its absorptive surface. Celiac disease is a condition wherein a reaction to dietary gluten causes intestinal inflammation and damage. The National Institute of Diabetes and Digestive and Kidney Diseases explains that both Crohn's and celiac disease interfere with the absorption of dietary protein from the intestine, which may lead to protein malnutrition and an abnormally low blood protein concentration.
References
- Mayo Clinic: Nephrotic Syndrome
- Merck Manual for Healthcare Professionals: Nephrotic Syndrome
- Merck Manual for Healthcare Professionals: Cirrhosis
- American Family Physician: Cirrhosis and Chronic Liver Failure, Complications and Treatment
- "Harrison's Principles of Internal Medicine, 16th Edition"; Dennis L. Kasper, M.D., et al, Editors; 2004
