Lupus nephritis overview

# Overview
Systemic lupus erythematosus (SLE, or lupus) is an autoimmune disease. In patients with an autoimmune disease, the immune system cannot tell the difference between harmful substances and healthy ones.  As a result, the immune system attacks otherwise healthy cells and tissue. The history of lupus erythematosus can be divided into three periods: classical, neoclassical, and modern.

# Historical Perspective
Lupus Nephritis was first discovered by Osler and Jadassohn, two physicians, in 1948 by the discovery of the LE cell in 1948. The word "lupus" means wolf in Latin, as the destructive injuries SLE causes brought to mind wolf bites. The history of lupus erythematosus can be divided into three periods: classical, neoclassical, and modern. The classical period mostly refers to ancient history, when there was no exact definition of the disease. During the neoclassical lupus era, scientists investigated the manifestations of lupus and worked to define the disease's action. Modern history is mostly focused on a microscopical understanding of the disease and pathogenesis of SLE.

# Classification
Lupus nephritis may be classified according to the Renal Pathology Society/International Society of Nephrology (RPS/ISN) classification which includes minimal mesangial lupus nephritis (class I), mesangial proliferative lupus nephritis (class II), focal lupus nephritis (class III), diffuse lupus nephritis (class IV), lupus membranous nephropathy (class V) and advanced sclerosing lupus nephritis (class VI)

# Pathophysiology
Systemic lupus erythematosus (SLE, or lupus) is an autoimmune disease.  This means there is a problem with the body's immune system. Normally, the immune system helps protect the body from harmful substances.  But in patients with an autoimmune disease, the immune system cannot tell the difference between harmful substances and healthy ones.  As a result, the immune system attacks otherwise healthy cells and tissue.

# Causes
There are no established direct causes of systemic lupus erythematosus. Common contributory factors in the development of systemic lupus erythematosus include geneticpredisposition, auto-immune diseases, and use of drugs. Less common factors include environmental factors and exposure to ultraviolet (UV) light.

# Differentiating Hereditary pancreatitis from Other Diseases
Lupus nephritis must be differentiated from other glomerular diseases that may cause hematuria, proteinuria, or renal failure. The various types of glomerular diseases should be differentiated from each other based on associations, presence of pitting edema, hemeturia, hypertension, hemoptysis, oliguria, peri-orbital edema, hyperlipidemia, type of antibodies, light and electron microscopic features. The following table differentiates between various types of glumerular diseases.

# Epidemiology and Demographics
The incidence of lupus nephritis is 34 to 51 percent in Blacks, 31 to 43 percent in Hispanics, 33 to 55 percent in Asians, and 14 to 23 percent in Whites. In 2005, Incidence was fiund to be 5.1 (Overall), 1.9 (Adult men), 8.2 (Adult women).The incidence of Lupus nephritis increases with age upto 50 years; the median age at diagnosis is 25 years.Chronic disease name is usually first diagnosed among middle age patients. African Americans have a higher frequency of developing Lupus nephritis in the United States.

# Risk Factors
Common risk factors in the development of Lupus nephritis may be occupational, environmental, genetic, and viral.

# Screening
According to the United States Preventive Services Task Force, screening for systemic lupus erythematosus is not recommended.

# Natural History, Complications, and Prognosis
Common complications of Lupus nephritis include microscopic hematuria, nephrotic syndrome, celluar casts, elevated creatinine and destruction of more than 50% of glomeruli.

# Diagnosis

## Diagnostic study of choice
In SLE, nephritis we suspect renal involvment by an abnormal urinalysis and/or increased serum creatinine. Histopathologic findings on renal biopsy confirm the diagnosis.

## History and Symptoms
As a manifestation of SLE, Lupus nephritis shares most of the symptoms with SLE. A positive history of familial lupus, skin rashes (especially photosensitive skin rashes), arthritis, and fatigue may be suggestive of systemic lupus erythematosus. The most common symptoms of SLE include constitutional symptoms like fatigue, fever, myalgia, and weight changes. The organ-specific symptom mostly occur with disease progression. SLE may show a variety of symptoms in different organs depending on its complications. eg.g Foamy urine.

## Physical Examination
In the earlier stages of the disease, patients appear well, while in the late stages of the disease, patients are clearly ill with multi-organ involvement. The patient may show a wide range of skin manifestations including urticaria, bullous lesions, malar rash, and scarring alopecia. The patient may develop nasal and oral ulcers. Arthritis may lead to a decreased range of motion, joint effusion, and arthralgia. Neurological manifestations including psychosis, cognitive impairment, and hallucinations, may also be present.

## Laboratory Findings
Laboratory findings consistent with the diagnosis of systemic lupus erythematosus include autoantibody elevation of ANA, anti-dsDNA antibody, anti-SM antibody, and antiphospholipid antibodies, and a decrease in complement levels. Nonspecific laboratory findings include mild pancytopenia, elevated levels of creatinine and proteinuria due to renal failure (secondary to nephritis), elevated levels of ESR and CRP as acute phase reactants, decreased level of complements, and positive direct Coombs test.

## Electrocardiogram
The most common and important ECG findings associated with systemic lupus erythematosus (SLE) include sinus tachycardia, ST segment changes, and ventricular conduction disturbances. Other ECG findings are related to late complications of SLE and may range based on the complication.

## X-ray
On X-ray imaging, systemic lupus erythematosus (SLE) may be characterized by different features regarding the present complication. The most common characteristic findings of SLE in X-ray include thumb printing sign in the abdominal X ray, blunting of the costophrenic angle due to pleural effusion, cardiomegaly, hepatomegaly, osteoprosis, tenosinovitis, and other manifestations based on the complications.

## CT scan
On abdominal CT-scan, systemic lupus erythematosus (SLE) may be characterized by hepatosplenomegaly, pancreatic parenchymal enlargement, and ascites. On cardiac CT-scan, SLE may be characterized by enhancement of the thickened pericardium. On brain CT-scan, SLE may be characterized by brain atrophy, stroke patterns like cortical hypodensity, and increased attenuation of the cortex.

## MRI
On abdominal MRI, systemic lupus erythematosus (SLE) may be characterized by hepatomegaly, pancreatic parenchymal enlargement, and hypervascularity of mesentery. On cardiac MRI, SLE may be characterized by mitral leaflet thickening, pericardial thickness, and pericardial effusions. On brain MRI, SLE may be characterized by white matter lesions, changes in blood circulation of the brain, and patchy areas of enhancement. On musculoskeletal MRI, SLE may be characterized by intramuscular edema, proliferative tenosynovitis, and bone marrow edema.

## Other Imaging Findings
Another imaging modality that can be used for the diagnosis of systemic lupus erythematosus complications is the double-contrast technique for gastritis evaluation. Another imaging technique that can be helpful in the diagnosis of SLE complications, especially early manifestations, is the Technetium-99m scan. It can be used in different ways, including bone scintigraphy and bone scans to evaluate early and late bone complications, and for early evaluation of other organ complications including cardiac, hepatobiliary, and pulmonary complications.

## Other Diagnostic Studies
Renal biopsy may be helpful in the diagnosis of Lupus nephritis.

# Treatment

## Medical Therapy
The mainstay of therapy for systemic lupus erythematosus (SLE) is to control disease activity and prevent organ damage. The treatment of choice for systemic lupus erythematosus (SLE) varies based on the severity of the disease and symptoms. Generally, all the patients with any type of SLE manifestation should be treated with hydroxychloroquine regardless of the level of their disease. Other pharmacologic medical therapies for SLE include glucocorticoids like oral prednisone or intravenous methylprednisolone, NSAIDs like celecoxib, and immunosuppressive therapy with mycophenolate, cyclophosphamide, or rituximab, particularly in severe cases. Cutaneous lupus erythematosus (CLE), if presented separately without any other system involvement, can be treated with topical corticosteroids. Other organ-related complications of SLE should be treated separately.

## Surgery
Surgical intervention is not recommended for the management of systemic lupus erythematosus.

## Primary Prevention
There is no established method for the primary prevention of systemic lupus erythematosus.

## Secondary Prevention
Secondary prevention strategies following systemic lupus erythematosus include using aspirin, ACE inhibitors, and statins to reduce atherosclerotic diseases, and using cancer screenings.