View source for Systemic lupus erythematosus

==Background==
*Autoimmune disorder affecting all systems
*Also consider drug induced lupus

===Epidemiology===
*Female:Male 10:1
*Peak in 20s-30s
*More common in Black patients

==Clinical Features==
[[File:Lupusfoto.jpg|thumb|Typical "butterfly" malar rash.]] 
[[File:PMC3410306 AD2012-834291.004.png|thumb|Palatal ulcer in SLE]]
[[File:PMC3410306 AD2012-834291.005.png|thumb|Subacute cutaneous SLE]]
SLICC Classification Criteria 2012 <ref>Lisnevskaia L, et al. Systemic Lupus Erythematosus. Lancet. 2014 May 29. Epub ahead of print.</ref>
Requirements: >4 of the following criteria (at least 1 clinical and 1 laboratory) OR biopsy proven lupus nephritis with 
positive ANA or Anti-dsDNA
*Clinical criteria
**Malar [[rash]], bullous lupus, photosensitivity
**Discoid rash, hypertrophic lupus
**Oral ulcers or nasal ulcers
**Non-scarring alopecia
**Synovitis
**Serositis
**[[glomerulonephritis|Nephritis]]
**Cerebritis, myelitis, neuropathy
**[[Hemolytic anemia]]
**[[Leukopenia]] or lymphopenia
**[[Thrombocytopenia]]

*Immunological criteria
**ANA
**Anti-dsDNA
**Anti-Sm
**Antiphospholipid antibody
**Low complement C3, low C4
**Direct Coombs' test in the absence of haemolytic anaemia

Organ system affected:
*Cardiopulmonary
**[[Pneumonia]]
***Cover for ''[[Listeria]]'' and ''[[Pseudomonas]]''
**CAD
***More common and more complications post-PCI
**[[PE]]
**[[Pericarditis]]
**[[Endocarditis]]
***Infectious and Libman-Sachs

*Neuropsychiatric/[[Altered mental status]]
**Non-convulsive [[status epilepticus]]
**CNS [[vasculitis]]
**[[Stroke]]
**[[Encephalitis]]
**[[Meningitis]]

*Musculoskeletal
**[[Arthritis]]
***Usually symmetric
***Consider [[septic arthritis]] if there is a single inflamed joint
****Cover for [[Salmonella]] in addition to standard coverage

*GI
**Lupus enteritis (mesenteric [[vasculitis]])
***Most common cause of acute [[abdominal pain]]
**[[Pancreatitis]]
**[[PUD]]

*Dermatologic
**Malar [[rash]] across bridge of nose
**Discoid rash, erythematous with scale

*Renal
**Usually a [[glomerulonephritis|nephritis]]
**Can cause a glomerulonephrosis

==Differential Diagnosis==
*[[Rheumatoid arthritis]]
*[[Sjögren Syndrome]]
*[[Dermatomyositis]]
*[[Polymyositis]]
*[[Stevens Johnson Syndrome and Toxic Epidermal Necrolysis|Stevens-Johnson syndrome]]
*[[Stevens Johnson Syndrome and Toxic Epidermal Necrolysis|Toxic Epidermal Necrolysis]]
*[[Septic Arthritis]]
*[[Lyme Disease]]
*[[Vasculitis]]
*[[Acute Rheumatic Fever]]
*[[Toxic Shock Syndrome]]
*[[Thrombotic Thrombocytopenic Purpura (TTP)|TTP]]
*[[Idiopathic Thrombocytopenic Purpura|ITP]]
*[[DIC]]

{{Differential Diagnosis Polyarthritis}}

{{Glomerulonephritis causes}}

==Evaluation==
Undiagnosed
*CBC
*Chem 10
*Urine pregnancy
*ANA
*ESR
*[[Urinalysis]]
*Bedside [[echocardiography]] if ill or hypotensive
*(Consider anti-DNA, anti-Smith, anti-Nuclear, anti-phospholipid, C3,C4, direct Coombs')

Flare
*Bedside echo if ill or hypotensive
*CBC
*Chem
*[[Urinalysis]]
*Urine pregnancy
*As directed by organ system involved

Drug Induced Lupus
*Anti-histone-Ab positive 95% of the time
*Make sure to review medications
**High risk:
***[[Procainamide]] (antiarrhythmic)
***[[Hydralazine]] (antihypertensive)
**Moderate to low risk:
***Infliximab anti (TNF-α)
***Etanercept anti (TNF-α)
***[[Isoniazid]] (antibiotic)
***[[Minocycline]] (antibiotic)
***[[Pyrazinamide]] (antibiotic)
***[[Quinidine]] (antiarrhythmic)
***D-[[Penicillamine]] (anti-inflammatory)
***[[Carbamazepine]] (anticonvulsant)
***[[Oxcarbazepine]] (anticonvulsant)
***[[Phenytoin]] (anticonvulsant)
***Propafenone (antiarrhythmic)
***[[Chlorpromazine]] (antipsychotic)

===[[Fever]] in SLE===
*Must differentiate disease activity (flare) from infection

Risk Factors for Infection <ref>Cuchacovich, R., & Gedalia, A. (2009). Pathophysiology and clinical spectrum of infections in systemic lupus erythematosus. Rheumatic diseases clinics of North America, 35(1), 75–93. doi:10.1016/j.rdc.2009.03.003</ref>
*[[Neutropenia]]/Lymphopenia
*Hypocomplementemia
*Immunosuppressive therapy (especially [[azathioprine]] <ref>Zhou, W. J., & Yang, C.-D. (2009). The causes and clinical significance of fever in systemic lupus erythematosus: a retrospective study of 487 hospitalised patients. Lupus, 18(9), 807–812. doi:10.1177/0961203309103870</ref>)

Studies
*CRP: sensitivity 100%, specificity 90% >1.35mg/dL <ref>Kim, H.-A., Jeon, J.-Y., An, J.-M., Koh, B.-R., & Suh, C.-H. (2012). C-reactive protein is a more sensitive and specific marker for diagnosing bacterial infections in systemic lupus erythematosus compared to S100A8/A9 and procalcitonin. The Journal of rheumatology, 39(4), 728–734. doi:10.3899/jrheum.111044</ref>
*PCT: sensitivity 75%, specificity 75% <ref>Scirè, C. A., Cavagna, L., Perotti, C., Bruschi, E., Caporali, R., & Montecucco, C. (2006). Diagnostic value of procalcitonin measurement in febrile patients with systemic autoimmune diseases. Clinical and experimental rheumatology, 24(2), 123–128.</ref>

==Management==
*Inflammatory complications
**[[Methylprednisolone]] 1-2mg/kg in most cases
*Infectious
**Stress dose [[steroids]] with [[hydrocortisone]] 100mg IV Q8hr if on or recently on steroids
*Dermatologic
**[[Hydrocortisone]] 1% cream
*If drug induced lupus, stop medication and consider alternative

==Disposition==
*Suspected new diagnosis can have out patient workup if well appearing
*Mild flairs can have expedited out patient management
*Musculoskeletal symptoms can usually be managed as out patients
*[[Chest pain]] requires urgent [[ACS]] evaluation
*Infections usually require admission for [[antibiotics]] and systemic [[corticosteroids]]


==Medication Dosing==
{{MedicationDose
| drug = Methylprednisolone
| dose = 1-2mg/kg IV
| route = IV
| context = Acute SLE flare management
| indication = Systemic lupus erythematosus
| population = Adult
}}

==See Also==
*[[Arthritis]]
*[[Fever and Rash]]
*[[Lupus Anticoagulant]]
*[[Pericarditis]]
*[[Pericardial Effusion and Tamponade]]
*[[Acute Renal Failure]]
*[[Adrenal Crisis]]

==References==
<references/>

[[Category:Rheumatology]]