12-phase flow (12)

1. 1FRAME
   Adult opportunistic Pneumocystis jirovecii pneumonia in HIV + non-HIV immunocompromised hosts; ABPA / bacterial CAP / viral pneumonitis covered by sibling engines
   inputs: immunocompromise
   advance: scope confirmed (immunocompromised + compatible pneumonia)
2. 2ENTRY
   Recognize subacute progressive dyspnea + dry cough + fever + exertional desaturation + bilateral GGO in immunocompromised host (IDSA OI; ATS 2006 workshop)
   inputs: immunocompromise, spo2
   advance: compatible presentation + immunocompromise documented
3. 3CONTEXT
   HIV CD4 + viral load OR transplant type + immunosuppression intensity OR malignancy/chemo OR chronic steroid ≥20 mg pred-eq ≥4 wk OR biologic; prophylaxis status; adherence; sulfa allergy
   inputs: pjp_prophylaxis_status, cd4_count, sulfa_allergy_or_baseline_meds
   advance: host phenotype + prophylaxis history captured
4. 4RED_FLAGS
   Respiratory failure (PaO2 <60 mmHg, SpO2 <90% on room air), impending intubation, pneumothorax, hypotension → ICU + STAT empiric TMP-SMX + steroids if HIV+ severe
   inputs: spo2, rr
   advance: red flags acted on; empiric TMP-SMX initiated within 1 h if high suspicion
5. 5INITIAL_WORKUP
   HRCT chest (bilateral perihilar GGO); serum β-D-glucan (high NPV); LDH; ABG with calculated A-a gradient; BAL with silver/IFA/PCR (induced sputum lower yield); HIV testing if unknown serostatus; CD4 if HIV+; CMV co-infection screen if transplant
   inputs: hrct_chest, abg, ldh, serum_beta_d_glucan
   actions: panel.inflammation, panel.abg, panel.cbc
   advance: imaging + mycology + ABG support diagnosis; do NOT delay empiric therapy for confirmation
6. 6BRANCHING_WORKUP
   CMV PCR / antigen, fungal serology (cryptococcal Ag if HIV+CD4<100), Aspergillus galactomannan in transplant, mycobacterial workup if compatible; echocardiogram if pulmonary hypertension; G6PD if salvage regimen anticipated
   inputs: g6pd
   advance: co-infections + alternative diagnoses mapped
7. 7DIFFERENTIAL
   CMV pneumonitis (especially transplant); bacterial CAP (atypical for PJP — lobar consolidation, lymphadenopathy, effusion); tuberculosis; invasive aspergillosis; mTOR-inhibitor pneumonitis (sirolimus/everolimus); pulmonary edema; COVID-19 pneumonia; lymphocytic interstitial pneumonia
   inputs: hrct_chest
   advance: plausible mimics excluded or co-managed
8. 8RISK_STRATIFICATION
   Severity stratification: severe = PaO2 <70 mmHg OR A-a gradient ≥35 mmHg OR mechanical ventilation OR ICU (Bozzette 1990 + NIH Consensus 1990 thresholds for adjunctive steroids in HIV); non-HIV mortality higher independent of severity (Wang 2021 meta-analysis)
   inputs: abg, spo2
   actions: calc.ckd_epi_2021
   advance: severity assigned; steroid indication evaluated
9. 9TREATMENT
   Empiric TMP-SMX 15-20 mg/kg/day TMP-component IV/PO divided q6-8h × 21 d (HIV) or 14-21 d (non-HIV per protocol); adjunctive prednisone 40 mg BID×5d → 40 mg daily×5d → 20 mg daily×11d in HIV PJP with PaO2 <70 OR A-a ≥35 (Bozzette 1990; NIH Consensus 1990) started within 72 h of TMP-SMX; non-HIV adjunctive steroids controversial — many use Bozzette-style if severe; salvage primaquine + clindamycin (preferred) OR pentamidine OR atovaquone (mild only); ART deferral 2 wk OK in HIV; sulfa allergy → primaquine + clindamycin
   inputs: creatinine, lft, sulfa_allergy_or_baseline_meds
   actions: panel.renal, panel.lft
   advance: empiric TMP-SMX initiated within 1 h of suspicion + steroid decision made within 72 h in HIV severe
10. 10DISPOSITION
    ICU if PaO2/FiO2 <200, vasopressors, mechanical ventilation, pneumothorax; otherwise ward; outpatient only if mild + reliable follow-up
    inputs: spo2
    advance: level-of-care determined; oxygen + monitoring plan set
11. 11MONITORING
    Daily K/Cr/CBC/LFT × first week then 2-3×/wk during TMP-SMX (BM suppression, AKI, hyperkalemia, hepatotoxicity); clinical response by day 4-8 — paradoxical worsening with steroids common day 3-4; reassess at 5-7 d for treatment failure → switch regimen; oxygenation trend
    inputs: creatinine, lft
    actions: panel.renal, panel.cbc, panel.lft
    advance: response evident or salvage triggered by day 5-7
12. 12FOLLOWUP
    Secondary prophylaxis: HIV TMP-SMX 1 SS daily OR DS thrice weekly until CD4 >200 ×6 mo on ART; transplant per institutional protocol; reinforce primary prophylaxis triggers (CD4 <200, ≥20 mg pred-eq ≥4 wk, biologics, lymphoma); ART initiation if HIV-naive (2-wk delay OK); pulmonology if persistent lung impairment
    advance: secondary prophylaxis prescribed + chronic immunosuppression plan reconciled