Lupus nephritis develops as a complication of systemic lupus erythematosus (SLE), commonly known as lupus. This autoimmune disease causes the immune system to attack the kidneys, particularly the area that filters blood. As a result, the kidneys become inflamed and progressively cease to function normally. It is one of the most serious complications that may arise among lupus patients.
Definition & Facts
Lupus nephritis occurs in approximately three of every 10,000 people suffering from lupus. The average age of those that develop the disease is between 20-40. It will typically appear within five years of an SLE diagnosis. Lupus nephritis is named such because it causes inflammation of the kidney’s nephrons. These structures are responsible for filtering blood.
Properly functioning kidneys are extremely important in maintaining the body’s health. They keep body fluids at proper levels, remove toxins and waste, and help control blood pressure and volume by regulating hormones. Lupus nephritis prohibits the kidneys from performing these functions.
Early diagnosis can greatly improve the outcome of treatment; however, there still may be a progressive loss of kidney function. Without treatment, lupus nephritis can lead to the need for dialysis or complete kidney failure. Though most patients do not tend to lose both kidneys, some do require a kidney transplant.
Symptoms & Complaints
Though each person may display different symptoms, often the first to be noticed is swelling in the feet, ankles, and legs (edema). This swelling typically worsens throughout the day. Swelling may also occur in the hands and face, though less commonly than in the legs and feet.
The symptoms of lupus nephritis occur along with the symptoms of active systemic lupus erythematosus such as arthritis, rash, fever, and fatigue. Other symptoms that may present themselves include urine that is foamy or frothy, an increased need to urinate during nighttime hours (nocturia), the presence of blood in the urine (hematuria), high blood pressure (hypertension), and weight gain.
Lupus nephritis damages the immune system, making it difficult for the body to differentiate between healthy and toxic substances.
The exact cause of lupus nephritis is unknown. A person’s genetic makeup is a vital component in the onset of both systemic lupus erythematosus and lupus nephritis. People who are first-degree relatives of those that suffer from systemic lupus erythematosus are at a higher risk of developing lupus nephritis.
Diagnosis & Tests
Physicians will begin the diagnosis of lupus nephritis by giving the patient a physical examination. Medical history and the presentation of symptoms will be coupled with the results of the exam. From there, the doctor will likely order tests to see how the kidneys are functioning.
Clinical urine tests can be used to look for fragments of cells called urinary casts that are normally found in the blood. These tests are also used to look for protein in the urine (proteinuria) that is accumulating in the body due to the kidneys malfunctioning.
Blood tests can be used to check creatinine levels which also indicate how well the kidneys are working. An ultrasound uses sound waves in order to process a thorough image of the kidneys. Physicians use these images to look for abnormalities in the size and shape of the kidney.
Iothalamate clearance testing uses a special dye injected into the blood in order to see how well the kidneys are filtering. Physicians can determine functionality by how quickly the dye leaves the blood. This test is the most accurate test of filtration speed.
A biopsy may be ordered to determine the amount of inflammation or scarring present in a patient. Done in a hospital setting, a long needle is used to remove a piece of the kidney tissue. This tissue is then examined under a microscope. Once a diagnosis of lupus nephritis has been made, the stage of the disease will be determined. This will fall into one of the six classes, each progressively worse.
Treatment & Therapy
There is no cure for lupus nephritis. The main goal of a treatment is to keep the kidneys functioning as normally as possible and to slow the progression of the disease for as long as possible. Just as the symptoms of lupus nephritis vary from person to person, so too do treatment plans.
Physicians will take into account the symptoms presented and the severity of the disease when formulating a course of treatment. A biopsy of kidney tissue is important in determining the stage of lupus nephritis and therefore which treatment options should be considered.
- Those with Stage 1 show little to no physical evidence of lupus nephritis.
- Stage 2 involves the treatment of the patient with corticosteroids. These drugs decrease inflammation and tend to be effective in patients with this stage of the disease.
- Stage 3 marks the early stage of advanced lupus nephritis. The outlook remains positive, though treatment will require high amounts of corticosteroids.
- Stage 4 is the advanced stage where there is a risk of developing kidney failure. Treatment for Stage 4 requires not only high amounts of corticosteroids, but also immunosuppressive drugs to reduce the immune system activity that damages the kidneys.
- Stages 5 and 6 will also follow this protocol, although the chances of recovery are considerably smaller. Along with corticosteroids and immunosuppressive drugs, medications that lower blood pressure (antihypertensives) and prevent blood clots may also be necessary.
Prevention & Prophylaxis
Regular exercise is important to maintain healthy blood pressure and cholesterol levels. It is also important to avoid toxins, especially those from smoking and alcohol consumption. Smoking cessation and abstaining from alcohol may help prevent this condition from worsening. Prescription medications and over-the-counter medications such as analgesics that may cause harm to the kidneys should also be avoided or used cautiously and in close consultation with one's health care provider.