JC84 (Medicine) - SLE Flashcards

1
Q

SLE

Definition

A

Chronic multisystem autoimmune disorder

Characterized by immunological disturbances resulting in excessive production of autoantibodies

Causing direct tissue damage and immune complex-mediated tissue or organ inflammation

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2
Q

SLE

Typical demographics
Genetic risk factors

A

Female: Male = 9:1
Most common in blacks, 50-70/100k in Orientals

Genetic predisposition
→ HLA-B8, DR2, DR3 or other genes that influence sex hormone status
→ complement deficiency (impaired phagocytosis)

High concordance rate in monozygotic twins
Increased risk of SLE in 1st degree relatives

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3
Q

Triggering events of SLE

A

→ Infections: EBV, parvovirus B19, rhabdovirus, HIV-1, adenovirus, salmonella

→ Drugs: Proxainamide, Hydralazine

→ Chemical agents: hydrazine, tartrazine, dyes, eosin, heavy metals (mercury, gold, cadmium)

→ Food: L-canavanine, e.g. alfalfa seeds and sprouts

→ UV light

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4
Q

List drugs that induce SLE and exacerbate SLE

A

Trigger:
 Procainamide
 Hydralazine
 Others (rare): B-blocker, quinidine, penicillamine, isoniazid, phenytoin, chlorpromazine

Exacerbate:
 Lovastatin
 Sulphonamide
 Estrogens

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5
Q

Pathogenesis of SLE

What is the role of B and T cells?

A

loss of self-tolerance in immune system secondary to predisposing genetic factors and environmental triggers

B-cell:
→ AutoAb production due to
- Reaction to self-antigens (eg. dsDNA, RNPs)
- Activation by helper T cells
→ Auto-antibodies form immune complex (consists of nuclear antigens, IgG and antinuclear antibodies)
→ deposit in tissues and organ, esp kidney, and activate complement system to cause inflammation and tissue damage

T lymphocyte changes:
→ ↓cytotoxic and suppressor T cells
→ ↑helper T cell pop’n → ↑production of autoAb

Defective phagocytosis
→ Defective phagocytosis of immune complexes or apoptotic cells

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6
Q

Name 2 classification criteria for SLE

Why are classifications useful?

A

SLICC: Consists of clinical features and immunological features

EULAR/ ACR guideline: Consists of clinical features and immunologic features

Use of classification:

  • Distinguish SLE from spectrum of autoimmune rheumatic diseases
  • No overlaping score/ double count of clinical or immunological features
  • Clearly defined cut-off for SLE
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7
Q

Precipitating factors for SLE relapse *

A

Precipitating factors for relapse:
 Drug non-compliance (most common)
 Infection
 Stress
• Physical stress including surgery
• Psychological stress
 Pregnancy
 Drug-induced
 UV light exposure

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8
Q

Constitutional symptoms of SLE *

A

Fever: only during flares, readily remits with NSAIDs, paracetamol or steroids (no remission = think infection)

Weight loss: usually only during flares

Poor appetite, malaise: continuous even when no flares

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9
Q

Musculoskeletal features of SLE *

A
  • *Arthritis**: early onset, symmetrical, migratory non-erosive polyarthritis
  • Morning stiffness: in minutes (cf >1h in RA)
  • Joint involvement: similar to RA, i.e. knees, carpal joints, PIPJ, NO DEFORMITIES
  • Deforming variant (Jaccoud arthritis)

Avascular necrosis of femoral head

Osteoporosis

Myopathy: myalgia, tenderness and weakness

Myasthenia gravis

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10
Q

Cutaneous features of SLE *

A

Photosensitivity

Cutaneous lupus erythematosus: 3 forms
- Malar/ Butterfly rash (spares nasolabial folds)
- Subacute (annular / psoriaform): non-scarring, sparing of face
- Discoid lupus erythematosus: hyperkeratosis, follicular plugging lesions, scarring alopecia if on scalp

Cutaneous vasculitis
- Telangiectasia
- Raynaud phenomenon
- Periungual erythema
- Livedo reticularis

Oral ulcers: multiple, affect different sites

Erythema nodosum

Purpuric skin rash

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11
Q

Pulmonary features of SLE *

A

Chest infection
Pleuritis: always bilateral
Interstitial lung disease (3-9%): usually non-specific interstitial pneumonia (NSIP)
→ Pulmonary embolism and infarct
→ Rare: recurrent atelectasis, acute pneumonitis, pHTN, pulmonary haemorrhage

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12
Q

Cardiac features of SLE *

A

Pericarditis ± effusion: pleuritic substernal chest pain, audible rub

Coronary artery disease

Valvular disease, e.g. Libman-Sacks endocarditis (non-bacterial endocarditis, vegetation of fibrin and immune cells)

Myocarditis, Cardiomyopathy

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13
Q

Vascular features of SLE *

A

Raynaud phenomenon: intermittent acral pallor followed by cyanosis and erythroderma

Vasculitis (11-36%): most commonly small vessels but can also involve medium/large vessels

Thromboembolic disease: both arterial and venous circulations

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14
Q

Gastrointestinal features of SLE *

A

→ Esophagus: motility disorder (40%), infective esophagitis (e.g. Candida, CMV, HSV), pill-related oesophagitis
→ Liver: asymptomatic dLFT, AI hepatitis
→ Pancreas: acute pancreatitis
→ Intestine (rare): pseudo-obstruction, protein losing enteropathy, mesenteric vasculitis

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15
Q

Ocular features of SLE *

A

Keratoconjunctivitis sicca due to 2o Sjogren
Scleritis: deep boring eye pain, acute redness and photophobia
→ Acute visual loss
→ Chronic changes: corneal deposit, maculopathy, retinal vasculopathy (cytoid bodies)

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16
Q

Renal features of SLE *

A

→ Lupus nephritis**: isolated proteinuria/haematuria, nephrotic or nephritic syndrome due to Glomerulonephritis

→ Tubulointerstitial nephritis: presenting with tubular dysfunction, eg. ↓concentration ability

→ Renal vascular disease due to immune complex deposits or microvascular thrombosis

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17
Q

Define Class I to VI of Glomerulonephritis

A

I = normal

II = Mesangial prolfieration

III = Focal proliferative

IV = Diffuse proliferative

V = membranous

VI = Sclerotic

18
Q

Neurological features of SLE *

A

Neuropsychiatric: Depression, Psychosis, Migrainous headache

Neurological:
1) Ischemia/ clot:
Cerebral ischemia
Retinopathy
Cranial/ peripheral neuropathy
Myelitis

2) Movement disorder:
Chorea
Cerebellar ataxia

3) Infection:
Meningitis and cerebral abscesses

19
Q

Haematological features of SLE *

A

Thrombo-embolism: due to Anti-phospholipid syndrome, Vasculitis, steroid use

NcNc anaemia: anaemia of chronic disease, AIHA, GI loss

Leukopenia: Neutropenia due to viral infection, immunosuppression, Anti-leukocyte antibodies

Thrombocytopenia: due to anti-platelet antibody/ ITP, APLS, medication, thrombotic microangiopathy

Pancytopenia: Sepsis, myelosuppression, thrombotic microangiopathy, hematological malignancy

Splenomegaly

20
Q

The most common causes of death in SLE **

A

Infection - most important cause in early - mid stage

Cardiovascular thrombosis - most important in late stage

21
Q

Explain why SLE patients are highly susceptible to infection

A

Intrinsic to immune system:

  • Low complement concentration
  • Anti-leukocyte antibodies
  • Poor cell-mediated immunity and defective phagocytosis
  • Poor spleen function

Extrinsic/ iatrogenic:

  • Steroid use and immunosuppression therapy
  • Uremia and nephrotic syndrome
22
Q

Antiphospholipid syndrome *

Key clinical features
Clinical diagnostic criteria

A

→ Non-superficial vascular thrombosis **Must have feature/ Definitive**

→ Adverse pregnancy outcome/ pregnancy loss

→ Persistent presence of antiphospholipid antibodies 12 weeks apart, i.e. lupus anticoagulant, anti-cardiolipin Ab, anti-β2 glycoprotein I Ab

Criteria:
Sapporo criteria: consists of Vascular thrombosis, Pregnancy loss and antiphospholipid antibodies for Dx

23
Q

Advantages of SLICC criteria over ACR criteria for classification of SLE

A

→ Allow dx solely based on biopsy-proven lupus nephritis

→ Avoid the possible duplication of highly correlated cutaneous features (e.g. malar rash and photosensitivity)

→ Include more cutaneous manifestations (e.g. SCLE), neurologic manifestations of SLE and more immunologic criteria (e.g. low complement)

→ Greater sensitivity (97% vs 83%) but lower specificity (84 vs 96%)

24
Q

Mnemonic for ACR criteria for SLE

A

Mnemonic for ACR criteria = SOAP BRAIN MD

SOAP = serositis, oral ulcer, arthritis, photosensitivity

BRAIN = blood count low, renal, ANA, immunological, neurological

MD = malar rash, discoid rash

25
Q

First line investigations for SLE **

A

□ Blood: CBC, L/RFT, ESR+/-CRP

Urine: urinalysis, microscopy, protein/creatinine ratio

□ Immune markers:
Antinuclear antibodies (ANA) for screening
Anti-ds DNA, anti-ENA, antiphospholipid Ab, C3/4 if ANA +ve or SLE highly suspected
Rheumatoid factor for r/o other AI diseases (e.g. RA, Sjogren syndrome)

Specific organ involvement e.g. CXR, ECG, renal Bx

26
Q

Anti-nuclear antibodies

Clinical use
Limitations
Accuracy
When should a positive ANA result be taken for Dx?

A

Use: Diagnosis ONLY when taken with other factors

Limitations: Titre NOT correlate with severity, False negative if severe proteinuria, Non-specific to SLE (confounding RA, Sjogren, normal population)

Accuracy: Highly sensitive, non-specific

Diagnostic when:

  • Clinical picture suggests connective tissue disease
  • Other autoantibodies are present
  • Evidence of immune complex disease
27
Q

Anti-dsDNA

Use
Accuracy

A

□ Clinical use: Diagnosis and monitoring of disease progression (esp. for lupus nephritis), Titer correlated with disease activity

□ Accuracy: high specificity to SLE, occurs in ~60% SLE patients

28
Q

Anti-ENA

  • Clinical use
  • List subtypes of Anti-ENA and their clinical use
A

Clinical use:

  • Prognosis value, Anti-Sm is diagnostic of SLE (other Anti-ENAs are not diagnostic)
  • Predict clinical manifestations

Anti-Sm - highly specific to SLE, Neurological involvement

Anti-Ro - Secondary Sjogren’s, Congenital heart block, neonatal lupus, cutanous conditions. Not specific or sensitive to SLE

Anti-RNP - Overlap features: eg. sclerodermatous skin lesions, Raynaud phenomenon, low-grade myositis. Not specific or sensitive to SLE

Anti-P - neurological diseases

29
Q

Monitoring methods for SLE **

A

Monitoring of disease activity: NO role for ANA and anti-ENA
□ Thorough clinical assessment including BP
Anti-dsDNA: +ve correlation with activity
C3/4 levels: inversely correlate with activity
Urinalysis: including protein, cells, casts
□ CBC and blood biochemistry

30
Q

General management of SLE

A

Genetic Counselling with patients, spouse, relatives
- Explain disease, drug compliance, pregnancy issues and fertility issue

Regular monitoring:
- Check BP and urine dipstick every visit with thorough PE
- Check disease activity: anti-dsDNA, C3/4, ESR, CBC, L/RFT
- Eye exam and ophthalmoscope exam

Modify risk factors:
- Smoking cessation (smoking a/w poor response to HCQ)
→ Avoid excessive sun exposure
→ Avoid potential antigenic stimuli: triggering drugs/ chemicals/ dyes…
Infection control

Supportive treatment, eg. Dialysis, RRT

31
Q

Aims of SLE treatment
Course of Tx

A
  • Target remission
  • Prevent flares
  • Prevent end-organ damage (e.g. renal disease)
  • Prevent APS
  • Limit treatment in clinically asymptomatic pt, Use lowest glucocorticoid dosage
  • Improve QoL

Course:
- Induction therapy + 3 years immunosuppressive maintenance therapy
- Anti-malarial drugs as mainstay Tx

32
Q

Define the target glucocorticoid use in SLE

A

Long term: Prednisolone <7.5mg/day
Use pulses of IV methylprednisolone for a lower starting dose and faster tapering
Early initiation of immunosuppressive drugs is better

33
Q

Define steroid dosages for different manifestations of SLE

A

Low dose (<15mg/d) for skin rashes, arthritis, serositis

Moderate dose (0.5mg/kg/d) for resistant serositis, hematologic S/S and lupus nephritis

High dose (≥1-2mg/kg/d) for severe hematologic S/S and major organ involvement

34
Q

Mainstay/ empirical medical treatment options for SLE **

A

Hydroxychloroquine (HCQ) or chloroquine (CQ)** Mainstay

Other Immunosuppressants
- Steroids
- Non-steroid: azathioprine, methotrexate, MMF
- Biologics: anti-CD20 (rituximab), anti-BAFF (belimumab)

35
Q

Hydroxychloroquine (HCQ) or chloroquine (CQ) for SLE

  • Indication
  • Dosage
  • Benefits
  • S/E
A
  • Indication: all SLE pts unless C/I
  • Dosage: <7mg/kg to avoid toxicity
  • Benefits:
    Reduce systemic complication, improve pregnancy outcome, reduce secondary infectious disease complication
  • S/E: bluish skin discoloration (esp. UV exposure), corneal deposits (reversible), bull’s eye maculopathy, RETINAL TOXICITIES
36
Q

Hydroxychloroquine (HCQ) for SLE

Major risk factors for retinal toxicities

A

Long duration of treatment
Dosage >5mg/kg/day
Chronic kidney disease
Pre-existing retinal or macular diseases

37
Q

Treatment of fever in SLE

A

→ NSAIDs, paracetamol ± low to moderate dose steroids
→ MUST r/o underlying infective or drug-related causes if unresponsive

38
Q

Treatment of Raynaud’s phenomenon

A

→ General measures

  • Avoid sudden cold exposure
  • *- Keep hands warm,** warm hands to alleviate attacks
  • *- Smoking cessation** (vasoconstricting effect of cigarettes)
  • *- Avoid sympathomimetic drugs,** e.g. decongestants, diet pills
  • *- Avoid repeated trauma** to fingertips

→ Pharmacological therapy if ineffective control

  • 1st line: slow release / long-acting CCB, e.g. nifedipine, amlodipine
  • 2nd line: sildenafil, topical nitrates, losartan or fluoxetine, Botox A injection (sympathectomy)
39
Q

Treatment for joint pain in SLE

A

→ Symptomatic relief e.g. NSAIDs, acetaminophen
→ Empirical Tx +/- immunosuppressants for refractory cases&raquo_space; Steroid, MMF, Azathioprine, Methotrexate

40
Q

Treatment of pleuritis and pericarditis in SLE

A

Pleuritis
→ NSAIDs, eg. naproxen
→ Systemic steroids: prednisolone

Pericarditis
→ Asymptomatic: conservative tx
→ Symptomatic:
- HCQ, short course NSAIDs or low to medium dose steroids
- Colchicine
- Percutaneous drainage

41
Q

Treatment of neuropsychiatric features of SLE

A

Neuropsychiatric lupus
→ Symptomatic relief: anti-convulsant, anti-psychotics, antidepressants, sedative

→ Prophylaxis for CVD: aspirin / warfarin