Key Points
- Confirm autoimmune PAP with GM‑CSF antibody testing.
- Whole‑lung lavage is first‑line; inhaled GM‑CSF is a validated alternative.
- Refer to centers with PAP expertise for diagnostic and therapeutic procedures.
Algorithm
- Primary survey and stabilization; focused history and exam.
- Order high‑yield tests first; escalate imaging as indicated.
- Initiate disease‑specific therapy and supportive care.
- Reassess clinical response; arrange consultation and disposition.
Clinical Synopsis & Reasoning
Progressive dyspnea with 'crazy‑paving' on HRCT suggests pulmonary alveolar proteinosis (PAP). Autoimmune PAP due to anti‑GM‑CSF antibodies is most common. Diagnostic workup includes HRCT, bronchoalveolar lavage (milky effluent with PAS‑positive material), and GM‑CSF autoantibody testing.
Treatment Strategy & Disposition
First‑line therapy is whole‑lung lavage at experienced centers. Inhaled GM‑CSF is an evidence‑supported alternative/adjunct; reserve rituximab or plasmapheresis for refractory autoimmune PAP; transplant in end‑stage disease.
Epidemiology / Risk Factors
- Epidemiology varies by setting; see citations for details.
Investigations
| Test | Role / Rationale | Typical Findings | Notes |
|---|---|---|---|
| HRCT chest | Pattern recognition | Crazy‑paving (GGO + septal lines) | — |
| Bronchoalveolar lavage | Diagnostic | Opaque/milky fluid, PAS+ | — |
| GM‑CSF antibody | Autoimmune confirmation | Positive in aPAP | Serologic test |
Pharmacology
| Medication | Mechanism | Onset | Role in Therapy | Limitations |
|---|---|---|---|---|
| Inhaled GM‑CSF | Augments alveolar macrophage function | Days–weeks | Alternative/adjunct to WLL | Cough, fever |
| Rituximab (refractory) | B‑cell depletion | Weeks | Refractory autoimmune PAP | Infection risk |
Prognosis / Complications
- Prognosis depends on timeliness of diagnosis, comorbid disease, and response to therapy.
Patient Education / Counseling
- Explain expected course, warning signs requiring urgent care, and follow‑up testing.
- Review medication use, interactions, and monitoring parameters.