Systemic Lupus Erythematosus (SLE) Guide: ANA-10 Rule, EULAR/ACR Criteria, and Treat-to-Target Plan

1. Diagnosis & Classification (2019 EULAR/ACR)

Step	How to Apply at the Bedside	Key Numbers & Rules
Entry criterion	Confirm ANA by indirect immunofluorescence (HEp-2) or a solid-phase equivalent ≥ 1 : 80 on ≥ one occasion.	If the ANA screen is negative, SLE cannot be classified—stop.
Weighted domains (take the highest item in each domain)	Clinical • Fever 2 • Alopecia 2 • Oral ulcers 2 • Subacute/discoid rash 4 • Acute malar rash 6 • Arthritis 6 • Serositis—pleural/pericardial effusion 5 or pericarditis 6 • Neuro—delirium 2 / psychosis 3 / seizure 5 • Haematology—leucopenia 3 / thrombocytopenia 4 / autoimmune haemolysis 4 • Renal—proteinuria > 0.5 g/d 4 / class II–V LN 8 / class III–IV LN 10 Immunological • Antiphospholipid antibodies—LA +, ACL ≥ 40 GPL, or anti-β2GP1 ≥ 40 U = 2 pts • Complement—low C3 or C4 = 3 pts; low both = 4 pts • Anti-dsDNA 6 pts or anti-Sm 6 pts	≥ 10 total points, including ≥ 1 clinical item, confirms SLE.

Bedside mnemonic – “10-POINT LUPUS” • P Positive ANA (entry) • O Oral ulcers • I Immune antibodies • N Nephritis • T Thrombocytopenia – keep adding manifestations until you reach 10 points.

2. Activity & Damage Staging

Domain	Instrument & Timing	Interpretation
Global activity	SLEDAI-2K – score at every visit	0-4 = low, 5-12 = moderate, ≥ 12 = high
Organ activity	BILAG-2004 – grade each organ (A = severe, B = moderate, C = mild)	Any “A” flare mandates urgent therapy.
Cumulative damage	SLICC/ACR Damage Index (SDI) – yearly	Each permanent item (≥ 6 mo) adds 1; SDI ≥ 3 predicts reduced survival.

3. Investigation Checklist — LUPUS-MAP

L – Lab baseline	CBC, renal & liver panel, ESR/CRP, fasting lipids/glucose
U – Urinalysis & protein	Dipstick + microscopy every visit; 24-h or spot UPCR for protein burden
P – Panel antibodies	Anti-dsDNA & complements at each flare; full aPL profile once
U – Ultrasound/echo	Renal US; echocardiogram if serositis or pulmonary pressures suspected
S – Safety screen	HBV, HCV, HIV, IGRA before steroids/biologics
M – Multiplex imaging	Renal biopsy if UPCR > 0.5 g/g or active sediment
A – Atherosclerosis	BP, BMI, QRISK/Framingham – SLE doubles CV risk
P – Pregnancy	Document aPL status, ensure disease quiescence ≥ 6 mo, stop teratogens

4. Management — 2023 EULAR Treat-to-Target Ladder

Severity / Organ	Preferred Induction	Escalate or Add-On	Treatment Target
Universal	Hydroxychloroquine (HCQ) 200–400 mg/day (adjust if eGFR < 30); baseline + annual OCT	—	All SLE patients unless contraindicated
Mild (rash, arthralgia)	HCQ ± NSAID; prednisone ≤ 7.5 mg/day	MTX or AZA if persistent	SLEDAI ≤ 4, pred ≤ 5
Moderate (polyarthritis, serositis)	Pred 0.3–0.5 mg/kg taper + MMF 1 g bid or MTX	Belimumab 10 mg/kg IV q4 w / 200 mg SC weekly	Steroid-free low activity by 6 mo
Severe major-organ (neuro, cytopenia)	IV methyl-pred 500–1000 mg × 3 days + MMF 2–3 g/day or Euro-Lupus CYC 500 mg q2 w × 6	Rituximab 1 g × 2 or Anifrolumab 300 mg q4 w if refractory	SLEDAI < 6; pred < 7.5 mg
Lupus nephritis III–V	MMF 2–3 g/day + steroid pulses or low-dose CYC	Voclosporin 23.7 mg bid or Belimumab add-on	UPCR < 0.7 g/g by 12 mo
Refractory / emerging	Consider Anifrolumab (non-renal), Obinutuzumab, CAR-T trials	—	Personalised target

Glucocorticoid rules – Pulse only for organ-/life-threatening disease; aim maintenance ≤ 7.5 mg/day and taper to zero when SLEDAI ≤ 4 for ≥ 6 months.

Drug-safety pearls

Drug	Key Toxicity	Practical Monitoring
HCQ	Retinal toxicity	OCT baseline then q 12 mo
Cyclophosphamide	Haemorrhagic cystitis, infertility	MESNA + hydration; fertility counselling
Belimumab	Depression/suicide risk	Mood surveillance
Voclosporin	GFR decline, hypertension	Scr & BP monthly

5. Shared-Care Matrix — Generalist vs Rheumatologist

Task	Primary-care / Internal Medicine	Requires Rheumatology
Initial suspicion, ANA screen, basic labs	✓	Confirm classification & scoring
Manage mild cutaneous/arthralgia on HCQ ± NSAID	✓	DMARD initiation & titration
Vaccinations, BP & lipid control, bone health	✓	—
Pregnancy planning, aPL screen	Coordinate with obstetrics	Adjust immunosuppression; high-risk antenatal care
Any renal, neuro-psych, cytopenic, serositis flare	Start IV steroid, urgent labs	Biopsy & immunosuppressive strategy
Access to biologics / voclosporin trials	—	✓ centre-based
Formal SLEDAI/BILAG/SDI review, steroid taper decisions	Shared (if trained)	Lead escalation

Bottom line: Every SLE patient should be co-managed—generalists excel in early recognition and comorbidity prevention, rheumatologists steer immunomodulation and organ-specific care.

6. 60-Second OSCE Script — Putting It All Together

Diagnosis: “Ms B has ANA 1:640, malar rash (6 pts) + arthritis (6 pts) + low C3/C4 (4 pts) = 16 pts ⇒ definite SLE.”
Activity: SLEDAI-2K = 12 (high); BILAG A in renal; SDI 0.
Investigations: Complete LUPUS-MAP including renal biopsy—expect class III LN.
Treatment plan: Pulse methyl-pred + MMF 2 g/day; HCQ 300 mg/day; target UPCR < 0.7 g/g by 12 months; add voclosporin if proteinuria plateaus at 3 months.
Follow-up: CKD screen, BP q 2 weeks, eye exam yearly, rheumatology in 1 week, contraception & pregnancy counselling.

7. Key Take-Home Messages

ANA first, 10 points next – no ANA, no SLE; hit ≥ 10 with at least one clinical manifestation.
Stage precisely – pair SLEDAI for activity, BILAG for organ flare, and SDI for irreversible damage.
LUPUS-MAP – a mnemonic that safeguards comprehensive baseline, safety, and flare work-up.
Treat-to-target – start with HCQ for all, layer steroids judiciously, and escalate early with MMF/CYC, biologics, or voclosporin to achieve low disease activity or remission and steroid minimisation.
Shared care saves lives – primary care manages comorbidities and screening; rheumatology directs immunosuppression and complex flares.

Master the ANA-10-point rule, SLEDAI/BILAG/SDI gauges, and the 2023 EULAR ladder, and you will navigate both board exams and real-world clinics with confidence.