12-phase flow (12)

1. 1FRAME
   Determine presentation type — VOC / ACS / sequestration / aplastic / stroke / priapism / chronic visit (ASH 2020)
   inputs: scd_genotype
   advance: Presentation type assigned
2. 2ENTRY
   Triage vital signs, pain score, oxygenation, fever (NHLBI 2014; ASH 2020)
   inputs: spo2, temperature
   advance: Triage complete
3. 3CONTEXT
   Capture genotype, prior crises, transfusion history, hydroxyurea use, vaccinations, pregnancy (ASH 2020; NASCC 2024)
   inputs: scd_genotype, prior_stroke, iron_overload
   advance: History complete
4. 4RED_FLAGS
   Bayesian pivots — FEVER in SCD: functional asplenia makes the pre-test sepsis prior high → empiric anti-pneumococcal coverage + cultures BEFORE attributing to VOC (PROPS rationale, Gaston NEJM 1986 PMID 3086721, infection ↓84% with prophylaxis). ACS pivot: NEW pulmonary infiltrate + hypoxia/respiratory symptoms = ACS (a leading SCD cause of death) — NOT uncomplicated VOC. Stroke; priapism >4h; splenic sequestration (acute splenomegaly + rapid Hb drop + reticulocytosis); aplastic crisis (Hb drop + LOW retic + parvovirus B19); multi-organ failure (ASH 2020; NHLBI 2014)
   inputs: temperature, spo2
   actions: workup.sickle_cell_crisis
   advance: Emergency stabilized
5. 5INITIAL_WORKUP
   CBC + retic + smear; CMP; LDH + bili; type & screen + extended phenotype; CXR if respiratory; CT/MRI head if neuro; UA; cultures if febrile (ASH 2020; NHLBI 2014)
   inputs: cbc_with_diff, reticulocyte_count, cxr
   actions: panel.cbc
   advance: Workup sent
6. 6BRANCHING_WORKUP
   TCD as the stroke-screening calculator → treat-threshold: time-averaged mean velocity ≥200 cm/s = abnormal → chronic transfusion (first-stroke risk ↓~92% — STOP, Adams NEJM 1998 PMID 9647873); 170-199 conditional (re-screen); <170 normal. Echo + RHC for pulm HTN; iron studies + LIC MRI for chelation; ferritin trend (NHLBI 2014)
   advance: Phenotype-specific workup complete
7. 7DIFFERENTIAL
   Crisis types (VOC / ACS / sequestration / aplastic / hemolytic / stroke / priapism / nephropathy / pulm HTN / AVN) (ASH 2020)
   advance: Crisis type or chronic complication identified
8. 8RISK_STRATIFICATION
   Severity tier + readmission risk + indication for chronic transfusion vs hydroxyurea vs gene therapy (ASH 2020; NHLBI 2014)
   advance: Risk profile + DMT plan
9. 9TREATMENT
   Acute: hydration (avoid over-aggressive), opioid PCA, O2 if hypoxic, incentive spirometry, empirical abx if febrile, exchange transfusion for severe ACS/stroke. Chronic disease-modifying: hydroxyurea is the FOUNDATION — median painful crises ↓~44%, ACS/transfusions ↓~50%, long-term mortality ↓~40% (MSH, Charache NEJM 1995 PMID 7715639); L-glutamine adjunct — fewer crises/ACS over 48 wk (BEACON Niihara NEJM 2018 PMID 30021096); chronic transfusion for primary stroke prevention (TCD ≥200, STOP); curative gene therapy exa-cel/Casgevy ~97% VOC-free ≥12 mo + lovo-cel/Lyfgenia (FDA Dec 2023; CLIMB SCD-121 Frangoul NEJM 2024 PMID 38661449). NOTE: voxelotor WITHDRAWN worldwide Sep 2024 (excess deaths/VOCs — do NOT use); crizanlizumab CAVEAT — STAND phase-3 failed, EU/UK revoked, US-only with questioned benefit.
   inputs: spo2
   actions: workup.sickle_cell_crisis
   advance: Treatment plan executed
10. 10DISPOSITION
    Inpatient for ACS/stroke/sequestration; ICU for severe ACS or multi-organ; hem clinic outpatient (ASH 2020)
    advance: Disposition set
11. 11MONITORING
    Daily Hb + retic during admission; HbS% on chronic transfusion; TCD annually peds (Adams NEJM 1998 STOP); ferritin q3m on chronic transfusion; eGFR for SCD nephropathy (ASH 2020; NHLBI 2014)
    inputs: cbc_with_diff
    actions: panel.cbc
    advance: Monitoring schedule documented
12. 12FOLLOWUP
    Health maintenance per NASCC 2024: vaccinations (penicillin prophylaxis ages <5), TCD, retinopathy screen, baseline echo, contraception/pregnancy planning, cognitive assessment, transition to adult care
    advance: Maintenance plan documented