Unfortunately, as of 2010, there are no reporting requirements for lupus, so the number of patients is not precisely known. The Centers for Disease Control estimate that between 322,000 to possibly over a million people in the United States were afflicted with this disease in 2008. Unlike many autoimmune disorders that involve a specific organ or tissue type, lupus can involve the kidneys, skin, joints and other organs. If lupus involves the kidneys, it is called lupus nephritis. Most of the symptoms of lupus nephritis are very similar to every other chronic kidney disease.
Proteinuria
One of the very first symptoms of renal involvement is proteinuria. Proteinuria is a condition that results when the kidneys cannot retain proteins that circulate in the blood. These proteins are spilled into the urine causing high urine protein. Patients with high urine protein often have edema because water is retained. This often shows up as puffiness around the eyes first thing in the morning. The Lupus Foundation of American explains that sometimes the edema shifts to the feet and legs as the day progresses.
Hematuria
Hematuria is the presence of red blood cells in the urine. In many instances, the red blood cells can only be seen in an urinalysis. Such hematuria is called microhematuria. In other instances, the urine may be darker than usual or may appear tea or cola-colored.
Hypertension
Hypertension, or high blood pressure is common among kidney patients--and those with lupus are no exception. As the Lupus Foundation of American points out, acetylcholinesterase, or ACE, inhibitors have the salutary effects of reducing blood pressure while simultaneously lowering proteinuria.
Low Complement
Complement is the name of one of a particular family of proteins involved in the immune response. As explained by NYU Medical Center Director H. Michael Belmont, abnormally low levels one particular complement protein called C3 are often a warning that the kidneys are affected by lupus.
Unlike the aforementioned symptoms, low levels of C3 are unique to lupus and another kidney disease called MPGN.
References
- National Institute of Diabetes and Digestive and Kidney Diseases: Lupus Nephritis
- Lupus Foundation of America: Kidney Disease
- Cerebel.org: Lupus Clinical Overview
- University of Maryland Medical Center: Lupus nephritis - Symptom
- National Institute of Diabetes and Digestive and Kidney Diseases: Hematuria
