Systemic Lupus Erythematosus

Systemic Lupus Erythematosus is an autoimmune disease that affects multiple systems of the body.

The presentation of the disease varies from patient to patient and may range from

mild cutaneous involvement to severe damage to the CNS and multiple organs.

SYSTEMIC LUPUS ERYTHMATOSUS

It is an autoimmune disease that affects multiple systems of the body. The

presentation of the disease varies from patient to patient and may range from

mild cutaneous involvement to severe damage to the CNS and multiple organs.

The exact etiology of SLE is not known. Several genetic, immunological,

endocrine and environmental factors are believed to play a very  important role in

the pathogenesis of SLE.

Etiology

SLE has multifactorial origin with an unknown exact cause. It's presumed

that SLE is caused by genetic susceptibility with an environmental

trigger. That cause defects of the immune system. vitamin D deficiency is associated with SLE.

Genetics

1. Genetics:

Genetics is believed to contribute strongly to SLE development. . More

than 50 genes are identified with association to SLE and  most  of

them code for proteins implicated in immune system. Mutations in these

genes causes deficiency of components of the immune system like the

complement proteins C1q, C1r, C1s, C4 and C2 together with TREX1 (3’-5’

Exonuclease). Some genes involved in SLE are the genes coding for HLA

class I, class II and class III genes (HLA-DRB1, HLA-DR2, HLA-DR3), IRF5-TNPO3,

ITGAM and BANK1.

Drug Induced

2. Drug Induced:

Drug Induced Lupus Erythmatosus  presents similar

symptoms like SLE but is caused by chronic drug use for treatment of long-term

illness. It doesn’t persist for long after the drugs are discontinued. Some of the

most common causes of drug induced SLE is the administration of the following

drugs: hydralazine, procainamide, quinidine, with hydralazine being the most

common cause by far. Hydralazine is useful treating hypertension and

heart failure.

Pathophysiology

SLE is a chronic condition because of type III hypersensitivity response. Reticulate

and stellate acral pigmentation with high titer of anti-cardiolipin

antibodies are an indicator of possible SLE. People with SLE have increased

polyclonal B cell activation, which results in increased B cell count. T cells

regulate the response of B-cells and infiltrate target tissues, have signaling defects ,

adhesion, co-stimulation, gene transcription, and alternative splicing. Low

complement protein C3 levels are seen in SLE.

The pathogenesis of SLE occurs by stimulation of both innate and acquired

immune systems.

In the Innate immune system, activation can either be dependent on Toll-like

receptors (TLR) or be TLR-independent. TLRs are stimulated by exposure to

extracellular DNA and RNA, along with demethylated DNA. This leads to

downstream activation of Interferon Regulatory Family (IRF-3) and further

leads to release of pro-inflammatory mediators. Neutrophils also play a role in

activation of the innate immune system by releasing their granular contents

into the extracellular space.

T cells and B cells are also involved in the pathogenesis of SLE. Expression of

Fas ligand on both cells increases and T cells are programmed to release more

cytokines for activation of B cells.

Skin lesions

1. Skin lesions are commonly seen. Red scaly patches of skin, rashes, hair

loss and mouth and nasal ulcers are common. Lesions on the skin can be

categorized into chronic cutaneous (discoid) lupus, subacute cutaneous

lupus and acute cutaneous lupus.

Joint

2.  Most common symptom is Joint pain  and is the main chief complaint

in patients with SLE.

3. Anemia is seen along with low platelet count and low WBC count in

some cases. Autoantibodies to phospholipids and cardiolipins are

detected in blood, along with prolonged partial thromboplastin time

(PTT).

Carditis

4. Any one of Pericarditis, Myocarditis or Endocarditis may be seen in SLE.

The Endocarditis in SLE is non-infectious and is called Libman-Sacks

endocarditis.

Pleuritis

5. Pleuritic pain and Pleurisy are seen in SLE, which results in reduced lung

volume.

Lupus nephritis

6. Lupus nephritis is a well-known and common complication of SLE. The

involvement may be mild subnephrotic proteinuria to severe cases with diffuse

progressive glomerulonephritis causing  chronic kidney damage. Lupus

nephritis usually seen early in  SLE disease course. New-onset

hypertension, hematuria, proteinuria, lower extremity edema, and

increased creatinine levels suggests lupus nephritis. Renal Biopsy

helps in staging the lupus nephritis and rules out other renal causes.

Neuropsychiatric syndromes

7. Neuropsychiatric syndromes can result when SLE affects the central or

peripheral nervous system. The most common neurological symptom of

SLE is intractable headaches. Other manifestations can be Mood

disorders, Cognitive Dysfunction, Cerebrovascular disease, Seizures,

Polyneuropathy, Anxiety disorder, Psychosis, Depression and so on. Rare

conditions like Guillain-Barre Syndrome and demyelinating syndrome

are also seen in SLE. Neurological disorders contribute to a significant

percentage of morbidity in patients with SLE.

Eye involvement

8. Eye involvement is seen in one-third of SLE patients. Dry eye syndrome

and Secondary Sjogren syndrome are the most common manifestations,

along with Ischemic optic neuropathy, retinopathy and glaucoma.

Abortion

9. SLE is a cause of increased rate of fetal death and spontaneous abortion

in pregnant women.

Muscle pain

10. Fatigue and muscle pain are some other complaints seen in SLE.

Treatment

There is no cure for SLE. The treatment involves preventing flares and reducing

the severity and duration of any flare-up of symptoms that is seen.

Medication for SLE

1. Medication for SLE is given to prevent and treat flares that is commonly observed.

DMARDs

Disease-modifying antirheumatic drugs (DMARDs) are given to

preventively reduce the incidence of flares.

Corticosteroids and Hydroxychloroquine

Corticosteroids and Hydroxychloroquine

are used to treat flares. Hydroxychloroquine in particular

is approved for treatment of SLE  with other drugs.

Cytotoxic drugs

2. Cytotoxic drugs like cyclophosphamide and mycophenolic acid are used

to treat Lupus Nephritis.

Lifestyle changes

3. Lifestyle changes like avoiding sunlight and avoiding activities that cause

fatigue are important.

Kidney transplantation

4. Kidney transplantation may be required for Lupus patients who have

end stage renal disease.

Pregnancy

5. Proper management of pregnancy in mothers who have SLE is

important, as infants born to such mothers are usually healthy. Women

are also advised against conception while having SLE because it can be harmful

for the baby.