questions 6

Systemic Lupus Erythematous

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Topic updated on 12/10/17 2:40pm

Snapshot
  • A 46-year-old African American woman with history of systemic lupus erythematosus presents with increasing fatigue, arthralgias, rash, and hematuria. She reports that she had previously been on hydroxychloroquine with success but had not seen a physician in 5 years. Physical exam shows a malar rash on her face. Laboratory exam reveals a highly positive antinuclear, anti-double-stranded DNA, and anti-Smith antibodies. She also has low complement levels. She is restarted on hydroxychloroquine and steroids.
Introduction
  • Clinical definition
    • systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by acute flares, commonly presenting with rash, joint pain, and fever
      • multiple organ systems are involved, including renal, neurologic, dermatologic, cardiovascular, and hematologic
  • Epidemiology
    • demographics
      • more common in female patients of reproductive age
      • African American, Asian, or Hispanic descent
    • risk factors
      • family history
      • oral contraceptive use
      • hormone replacement therapy
      • other autoimmune diseases
  • Pathogenesis
    • unknown but thought to be an interaction among immune dysfunction, genetic factors, and environmental factors
      • autoantibodies precipitate immune complexes in multiple organs, including kidneys, skin, and brain
      • polyclonal activation of B cells with the production of autoantibodies against DNA
      • complement factors and cytokines also play a key role
      • environmental triggers include sunlight (photosensitive rash), infection, and drugs
        • hydralazine
        • isoniazid
        • procainamide
  • Associated conditions
    • antiphospholipid syndrome
      • increased risk of thrombosis
      • increased risk of atherosclerosis
    • lupus nephritis
      • anti-DNA immune complexes deposition in glomeruli
      • nephritic or nephrotic syndrome
        • diffuse proliferative is the most common and most severe type
    • drug-induced lupus
      • typically positive for antinuclear and antihistone antibodies
      • typically without renal or neurologic involvement
      • complement level is typically normally
    • Libman-Sacks endocarditis (LSE)
      • noninfectious endocarditis characterized by thrombi on the mitral or aortic valves (LSE in SLE)
    • Raynaud phenomenon
    • neonatal lupus erythematosus
      • associated with patients with anti-Ro or anti-La antibodies
      • neonates present with rashes and congenital heart block
  • Prognosis
    • often have recurrent flares
Presentation
  • Symptoms 
    • constitutional symptoms
      • fatigue, fever, or weight loss
    • arthralgias
    • serositis  
      • pericarditis, pleural effusion, or myocarditis
  • Physical exam
    • cutaneous findings
      • malar rash (raised or flat erythematous butterfly rash on cheeks/nose and spares nasolabial fold)
      • discoid lesions (erythematous raised plaques with keratotic scale and follicular plugging)
      • photosensitive rash
      • oral ulcers
    • neurologic findings
      • behavioral changes
      • stroke
      • seizures
      • headaches
      • chance in psychiatric status
    • renal findings
      • hematuria
      • proteinuria
Studies
  • Labs
    • antibodies
      • antinuclear antibody (ANA)
        • best initial test
        • high sensitivity but low specificity
      • anti-double-stranded DNA (dsDNA) antibody 
        • often rises during flares
        • high specificity but low sensitivity
        • poor prognostic factor
        • often indicates renal disease
      • anti-Smith antibody (antibody to snRNPs)
        • high specificity (more than anti-dsDNA) but low sensitivity
      • anti-Ro and anti-La
        • also seen in Sjögren syndrome
        • associated with higher risk of neonatal lupus erythematosus in pregnant women
      • antihistone antibody
        • high sensitivity for drug-induced lupus
    • ↓ complement levels during a flare
      • ↓C3, C4, and CH50
    • ↑ erythrocyte sedimentation rate
    • pancytopenia
      • leukopenia, thrombocytopenia, or hemolytic anemia
    • elevated partial thromboplastin time (PTT) 
      • lupus anticoagulant increases the risk for thrombi and miscarriages 
      • associated with antiphospholipid syndrome
  • Urinalysis
    • proteinuria or hematuria may indicate renal disease
  • Making the diagnosis
    • based on clinical presentation and laboratory studies
    • diagnosis confirmed with 4 or more criteria from RASHNIA4
      • Renal disease
      • Arthralgias
      • Serositis
      • Hematologic abnormalities
      • Neurologic abnormalities
      • Immunologic derangements
      • Antinuclear antibodies
      • 4 types of rashes
        • malar  
        • discoid
        • photosensitive
        • oral ulcers
Differential
  • Acne rosacea
    • distinguishing factors
      • erythematous papules and pustules on face without nasolabial sparing
      • no other systemic findings
  • Sarcoidosis
    • distinguishing factors
      • adenopathy
      • restrictive lung disease
      • skin findings of lupus pernio, rather than malar rash, discoid lesions, or ulcers
Treatment
  • Management approach
    • antimalarials are often used alongside steroids for acute flares
    • management is often dictated by specific organ involvement
  • Conservative
    • use sunscreen and avoid sun exposure
      • indications
        • for all patients
  • Medical
    • non-steroidal anti-inflammatory drugs (NSAIDs)
      • indications
        • arthralgias
    • antimalarials
      • indications
        • dermatologic findings and joint pain
        • often used in conjunction with other medications, including steroids
      • drugs
        • hydroxychloroquine
        • chloroquine
      • side effects
        • risk of retinopathy
    • steroids
      • indications
        • acute flares
      • drugs
        • prednisone
    • immunosuppressants
      • indications
        • patients not responsive to steroids
        • patients unable to tolerate steroid taper
        • lupus nephritis
      • drugs
        • azathioprine
        • methotrexate
        • mycophenolate
          • for patients with lupus nephritis
        • cyclophosphamide
          • for patients with lupus nephritis
    • belimumab
      • indications
        • patients not responsive to steroids or other immunosuppressants
      • mechanism
        • inhibits B-cells
Complications
  • Causes of death in SLE
    • infections
    • renal disease
    • cardiovascular disease
      • leading cause of death in these patients
      • includes Libman-Sacks endocarditis, hypertension, and cardiac tamponade
  • Thrombosis


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Qbank (2 Questions)

TAG
(M3.RH.3) A 29-year-old woman with a 3-year history of systemic lupus erythematosus (SLE) presents to her rheumatologist for routine follow up. Her course has been complicated by lupus nephritis (baseline creatinine 1.1 mg/dL) and she has been on stable doses of methotrexate and hydroxychloroquine for the last 2 months following a flare. Which of the following lab values can be used to best monitor this patient's disease? Topic Review Topic

1. Anti-nuclear antibody
2. Anti-dsDNA antibody
3. Anti-Smith antibody
4. Anti-RNP antibody
5. CH50 level

PREFERRED RESPONSE ▶
TAG
(M2.RH.9) A 24-year-old African-American woman presents to her primary care physician complaining of weakness and malaise. She complains that she has unintentionally lost 10 pounds of weight in 2 weeks. Upon further questioning, it is found that she gets a painful rash on her face when she goes outside in the sun. Figure A is noted upon physical examination. Her hemoglobin level was found to be 8.1 g/dl. What is most likely to be found on laboratory testing? Topic Review Topic
FIGURES: A          

1. Positive anti-ds-DNA antibodies
2. Positive anti-La antibodies
3. Positive anti-centromere antibodies
4. Positive anti-cardiolipin antibodies
5. Positive anti-ganglioside antibodies

PREFERRED RESPONSE ▶
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