12-phase flow (12)

1. 1FRAME
   Adult chronic progressive fibrosing ILD — confirm UIP pattern on HRCT and adjudicate via multidisciplinary discussion (MDD: pulm + thoracic radiology + pathology) per ATS/ERS/JRS/ALAT 2022; scope excludes secondary fibrosis (CTD/drug/sarcoid), NSIP, HP
   inputs: hrct, ana_rf_ccp_myositis_panel
   advance: IPF confirmed at MDD
2. 2ENTRY
   Suspicion: progressive exertional dyspnea + dry cough + bibasilar Velcro crackles ± clubbing + restrictive PFT + ↓DLCO in patient >60 → obtain HRCT looking for UIP (ATS 2018 dx)
   inputs: age, sex
   advance: Engine entered
3. 3CONTEXT
   Smoking pack-years, occupational/environmental antigen + dust exposure, family history (familial pulmonary fibrosis / telomeropathy), autoimmune review of systems (Raynaud, sicca, mechanic hands, Gottron, arthritis), GERD, OSA, full medication review for drug-induced ILD per ATS 2018
   inputs: occupational_environmental, gerd_history, current_meds, spo2_room_air
   advance: Exposure + autoimmune + drug context complete
4. 4RED_FLAGS
   Acute exacerbation of IPF (AE-IPF — Collard 2016 PMID 27299520): acute worsening dyspnea <30 d + new bilateral GGO/consolidation on HRCT NOT fully explained by HF, fluid overload, PE or infection. Differential: (a) infection (viral PCR + bacterial + PCP if immunosuppressed); (b) PE (CTPA — D-dimer non-diagnostic in IPF → pulm.pe.core.v1); (c) cardiogenic edema (BNP, echo); (d) aspiration; (e) drug-induced ILD; (f) idiopathic AE-IPF. Also: severe resting hypoxemia (LTOT trigger SpO2 ≤88%), Group-3 PH decompensation (TTE TRV high + RV dysfunction + syncope)
   inputs: spo2_room_air
   actions: ild_acute_exac
   advance: Stabilised or escalated
5. 5INITIAL_WORKUP
   HRCT (UIP pattern grading), spirometry + DLCO, 6MWT with continuous SpO2, autoimmune serology (ANA/RF/CCP/myositis/Scl-70/Ro52), HP IgG precipitins, CBC, BMP/LFT baseline (pre-antifibrotic), BNP per ATS 2018/2022
   inputs: hrct, spirometry_dlco, six_minute_walk_test, ana_rf_ccp_myositis_panel, cbc, bmp_lft
   actions: panel.cbc, panel.lft, panel.renal
   advance: Stage-1 returned
6. 6BRANCHING_WORKUP
   If HRCT NOT definite/probable UIP → MDD ± surgical lung biopsy or transbronchial lung cryobiopsy (ATS 2018); BAL only when alternate dx (HP lymphocytosis >30%, sarcoid, infection) suspected; TTE → right heart cath if PH-ILD suspected (route pulm.pulmonary_htn_group2_to_5.v1)
   inputs: lung_biopsy, tte_for_ph
   actions: ild_acute_exac, pulmonary_nodule
   advance: MDD complete (definite UIP or biopsy-confirmed UIP)
7. 7DIFFERENTIAL
   §5.5.2 differential-as-data — IPF/UIP vs NSIP (younger, ground-glass-predominant, no honeycomb, steroid-responsive) vs chronic fibrotic HP (antigen Hx, mosaic air-trapping 3-density sign, BAL lymphocytosis >30%, IgG precipitins → reconsider HP) vs CTD-ILD (female, +ANA/RF/CCP/Scl-70/Jo-1/MDA5, extrathoracic features → rheum MDD) vs drug-induced ILD (temporal drug exposure — amiodarone/MTX/nitrofurantoin/ICI/T-DXd; reversible if stopped) vs sarcoidosis (upper-lobe, perilymphatic nodules, hilar adenopathy → pulm.sarcoidosis.v1) vs CPFE (upper-lobe emphysema + lower-lobe fibrosis, preserved spirometric volumes, severely ↓DLCO, disproportionate PH → pulm.copd.core.v1 overlap) vs asbestosis (asbestos Hx + pleural plaques). Definite-UIP HRCT has high specificity (~90-100%) for histologic UIP → biopsy can be omitted (ATS 2018 PMID 30168753)
   inputs: hrct, ana_rf_ccp_myositis_panel, hp_panel_igG
   advance: IPF confirmed at MDD or routed to sibling engine
8. 8RISK_STRATIFICATION
   GAP index (Gender, Age, FVC%, DLCO%; Ley 2012 PMID 22586007) → Stage I/II/III with 1-yr mortality 6% / 16% / 39%; rate of FVC decline (≥10% relative in 6–12 mo = progression); DLCO ≤35% / 6MWT desat <88% / PH-ILD as poor-prognosis modifiers; gate transplant referral timing
   inputs: spirometry_dlco, six_minute_walk_test, age, sex
   actions: calc.mmrc
   advance: GAP stage + progression risk documented
9. 9TREATMENT
   Antifibrotic axis — pirfenidone OR nintedanib (start regardless of FVC; choose by comorbidity/tolerability — see regimen_axes); supplemental O2 if SpO2 ≤88% rest/exertion; pulmonary rehab; vaccinations; anti-reflux CONDITIONAL (ATS/ERS 2022); EARLY lung transplant referral; AE-IPF — supportive + high-dose corticosteroid (WEAK evidence, no RCT) + treat precipitant; NO triple therapy (PANTHER harm PMID 22607134); palliative care + advance directives
   inputs: bmp_lft, spo2_room_air
   advance: Antifibrotic + supportive + transplant + palliative plan documented
10. 10DISPOSITION
    Admit if AE-IPF / hypoxemic respiratory failure (ICU + ECMO only as bridge-to-transplant in candidates — otherwise high mortality, align with goals of care); outpatient ILD/pulmonology otherwise (ATS/ERS 2022)
    advance: Disposition documented
11. 11MONITORING
    FVC q3–6 mo + DLCO q6–12 mo (progression trend drives transplant), 6MWT q6 mo, HRCT annually or per change. Antifibrotic safety: LFT monthly ×6 then q3 mo (both drugs), CBC, weight (nintedanib GI), photosensitivity counselling (pirfenidone). Track ≥10% relative FVC decline = progression trigger (ATS/ERS 2022)
    inputs: bmp_lft, spirometry_dlco
    advance: Surveillance schedule + progression thresholds documented
12. 12FOLLOWUP
    ILD clinic q3–6 mo, transplant clinic co-management, comorbidity sweep (Group-3 PH, CPFE, GERD, OSA, lung-cancer surveillance — IPF raises lung-ca risk, depression), pulmonary rehab continuity, palliative care + advance care planning (ATS/ERS 2022)
    advance: Follow-up + transplant + comorbidity + palliative loop booked