Chronic autoimmune disease of unknown, multifactorial etiology. It presents a challenge to emergency providers due to its diverse and sometimes life-threatening manifestations.

Affects between 20-70 per 100,000 individuals, with 90% of the cases in women, and a higher prevalence in Asian, African American, African Caribbean, and Hispanic American individuals compared with White individuals.

Can cause manifestations in virtually any organ system through inappropriate immune response to self.

Clinical Manifestations:

• Potential constitutional manifestations of SLE include fever, fatigue, weight loss. Infections are also a potential emergent complication of SLE, and providers should rule out opportunistic infections if the patient is immunocompromised, and sepsis depending on the clinical context.
• Up to 40% of SLE patients may also present with manifestations of antiphospholipid syndrome (APS), which range from sequelae of thrombosis and thromboembolism to catastrophic APS, which presents with multiple thrombotic sites and organ failure.

Physical Examination:

• A complete and thorough examination in those who you suspect a diagnosis of SLE to be present is warranted.

Investigations:

• CBC, urinalysis, creatinine, should be routinely obtained to assess for signs of increased disease activity or systemic inflammatory process.
• In patients with suspected SLE, ANA, anti-dsDNA, anti-Smith antibody, antiphospholipid antibodies (lupus anticoagulant, IgG/IgM anticardiolipin antibodies, IgG/IgM anti-beta2-glycoprotein 1), C3/C4, ESR/CRP, and urine protein to creatinine ratios should be obtained. These can be ordered with outpatient follow-up organized for evaluation of the results.
• In patients with known SLE and chest pain, ACS should be ruled out and cardiac workup is warranted including ECG, stress test and troponin.
• Diagnostic imaging is not routinely obtained but can be valuable based on the symptoms.

Diagnostic Considerations:

• In the emergency department (ED), care providers will often see patients with SLE presenting with an exacerbation or complications from the disease or their medications.
• However, patients with suspected, but no formal diagnosis of SLE may present to the ED.
• Formally, a diagnosis is made using the 1997 ACR criteria or the 2012 SLICC criteria, but diagnosis in the ED is difficult to make given the broad manifestations of the disease and the time it takes for laboratory results to return.
• A number of other diseases are often mistaken for SLE prior to diagnosis, including undifferentiated connective tissue disease, primary Sjögren’s syndrome, primary APS, fibromyalgia with positive antinuclear antibody, idiopathic thrombocytopenic purpura, drug-induced lupus, and early rheumatoid arthritis.

Many medications are known to cause lupus-like autoimmune response and may be mistaken for SLE (see table below):

• For non-infectious consequences of SLE, introduction or modulation of immunomodulating therapy is warranted.

Image from Rosen’s Emergency Medicine 9^th Edition

• For infections in SLE patients who are on chronic steroid therapy, a stress dose of glucocorticoids (i.e. hydrocortisone 50-100 mg IV every 8 hours) + appropriate antimicrobial coverage should be initiated.
• Many symptoms related to SLE are related to inflammation and are amenable to NSAIDs. In patients with CKD or peptic ulcer disease, where NSAIDs are contraindicated, alternatives include acetaminophen and narcotics.
• For drug-induced lupus, cessation of the offending agent is therapeutic, and NSAIDs/steroids can be used for symptom control.
• For acute thrombotic events, unfractionated or low-molecular-weight heparin is indicated. In catastrophic APS, in addition to glucocorticoids and anticoagulation, IVIG, plasma exchange, and cyclophosphamide can be considered.

• Non-life-threatening presentation.
• Appropriate follow-up as an outpatient is available.
• If the patient had undifferentiated chest pain with ACS ruled out in the ED, they should have expedited evaluation with a stress test in an observation unit or outpatient basis. If stress test is done in an outpatient setting, daily aspirin should be prescribed.

• Presentation of SLE flare, new thrombotic events, infection, or life-threatening presentation.

Criteria for ICU admission:

• Progressive circulatory or respiratory derangement in spite of initial resuscitation.

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2.  Clinical manifestations and diagnosis of systemic lupus erythematosus in adults. 
   Wallace, D.J. & Gladman, D.D. (2021).Retrieved December 14, 2021

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3. Drug-induced lupus.
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4. Epidemiology and pathogenesis of systemic lupus erythematosus.
   Schur, P.H. & Hahn, B.H. (2021).  Retrieved December 14, 2021
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5. Complications of systemic lupus erythematosus in the emergency department.
   Marco, J.L. & Chhakchhuak, C.L. (2018).  Emergency Medicine. 50(1),6-16.
   DOI: 10.12788/emed.2018.0075