01Approach to the Critical Patient/attcp44

Immediate priorities

›Airway and breathing threats

›Hypoxemic respiratory failure

›SpO2 < 88% on room air or resting hypoxemia

›PaO2 < 60 mmHg on ABG

›Increased A-a gradient disproportionate to exam findings

›Ventilatory failure

›Rising PaCO2 indicating fatigue

›Respiratory rate >= 30 per minute

›If intubation required, use lung-protective ventilation strategy

›Tidal volume 6 mL/kg IBW

›PEEP titration for oxygenation

›Superimposed infection identification

›Fever or hemoptysis in known PAP patient

›High suspicion for opportunistic organism

›Nocardia, NTM, Aspergillus, Cryptococcus, Mucor

›Broad-spectrum antimicrobials while awaiting cultures

›Include Nocardia coverage if clinically suspected

›Trimethoprim-sulfamethoxazole for Nocardia empiric therapy

Monitoring and targets

›Oxygenation targets

›SpO2 92–96% with supplemental oxygen

›Titrate oxygen to avoid hyperoxia

›High-flow nasal cannula for moderate hypoxemia

›Flow rates 30–60 L/min

›FiO2 titrated to SpO2 target

›Clinical deterioration triggers

›Escalating oxygen requirement despite supplemental therapy

02History/hx48

Presenting symptoms

›Cardinal presentation

›Progressive exertional dyspnea

›Insidious onset over weeks to months

›Often previously healthy adult aged 30–50 years

›Cough character

›Dry cough most common

›Scant white frothy sputum in some cases

›Fatigue and exercise intolerance

›Often out of proportion to clinical exam findings

›Associated constitutional symptoms

›Weight loss

›Chest heaviness

›Deconditioning

Alarm features

›Red flag symptoms

›Fever in known or suspected PAP

›Suggests superimposed opportunistic infection

›Nocardia, NTM, Aspergillus, Cryptococcus

›Hemoptysis

›Atypical for PAP itself

›Warrants evaluation for infection or alternative diagnosis

›Rapidly progressive dyspnea

›Secondary PAP in hematologic malignancy context

›Respiratory failure risk

›Digital clubbing

›Not typical of PAP; suggests alternative diagnosis

03Physical Exam/exam31

Vitals and general

›Stability snapshot

›Oxygen saturation

›May be normal at rest in mild disease

›Ambulatory desaturation on exertion

›Respiratory rate

›Tachypnea in advanced or decompensated disease

›Temperature

›Fever atypical for PAP itself; suggests superinfection

›Blood pressure

›Hemodynamic instability in severe respiratory failure

Pulmonary examination

›Auscultation findings

›Fine inspiratory crackles

›Present in minority; often clear auscultation despite extensive radiographic disease

›Clinical-radiologic dissociation is hallmark of PAP

›Absence of wheeze or bronchial breath sounds typical

›Work of breathing

›Accessory muscle use in advanced disease

›Inability to complete sentences

General inspection

›Cyanosis in advanced disease with severe hypoxemia

›Plethora from secondary polycythemia

›Chronic hypoxemia driving erythropoietin response

›Check CBC for elevated hemoglobin

›Digital clubbing

›Not typical of PAP

›If present, suggests alternative or concomitant diagnosis

04Differential Diagnosis/ddx42

Life-threatening mimics

›Pulmonary edema

›Cardiogenic: BNP elevation, bilateral Kerley lines, cardiac history

›ICD-10 J81.0

›Non-cardiogenic ARDS: Acute onset, identifiable trigger, bilateral infiltrates

›ICD-10 J80

›Pneumocystis jirovecii pneumonia

›Immunocompromised host

›HIV status, CD4 count

›Beta-D-glucan elevation

›ICD-10 B59

›Diffuse alveolar hemorrhage

›Hemoptysis with dropping hemoglobin

›Serial BAL increasingly bloody

›ICD-10 J98.09

Infectious mimics

›Community-acquired pneumonia

›Acute febrile illness with lobar consolidation

›ICD-10 J18.9

›Nocardia pulmonary infection

›Particularly relevant as PAP complication

›Cavitary lesion or nodular infiltrates

›Disseminated fungal infection

›Aspergillus, Cryptococcus in immunodeficient state

Interstitial lung disease mimics

›Organizing pneumonia

›Subacute onset, migratory consolidations

›ICD-10 J84.116

05Laboratory Tests/lt43

Diagnostic serology

›Serum anti-GM-CSF autoantibodies

›Sensitivity 100% for autoimmune PAP

›Specificity 98–100%

›Commercially available via ELISA or latex agglutination

›First-line confirmatory test for autoimmune PAP

›Serum GM-CSF levels

›Low or undetectable in autoimmune PAP

›Elevated in hereditary PAP

›Useful for subtype distinction

Biomarkers and severity markers

›LDH

›Elevated in PAP; correlates with disease severity

›Nonspecific; also elevated in PCP and other ILD

›KL-6 (Krebs von den Lungen-6)

›Elevated in PAP; correlates with severity and treatment response

›Useful for monitoring

›Surfactant proteins A and D

›Elevated in PAP

›Not disease-specific

›CEA and CYFRA 21-1

›Elevated in PAP; correlate with severity

›Not diagnostic alone

Gas exchange and hematologic assessment

›Arterial blood gas

›PaO2 as key severity marker

›A-a gradient elevation

›PaO2/FiO2 ratio for severity classification

06Diagnostic Tests/dt56

Scoring Systems

›PAP disease severity scoring

›Based on PaO2 at rest (mmHg)

›Mild: PaO2 > 75 mmHg

›Moderate: PaO2 60–75 mmHg

›Severe: PaO2 < 60 mmHg

›Additional severity parameters

›DLCO percent predicted

›Six-minute walk test distance and desaturation

›CT extent of opacification (CT grade scoring)

›Pulmonary function tests

›Restrictive pattern with reduced TLC

›Reduced FVC and FEV1 with preserved FEV1/FVC ratio

›Reduced DLCO

›Key severity and treatment response marker

›Six-minute walk test

›Functional capacity assessment

›Ambulatory desaturation detection

MRI

›Chest MRI role in PAP

›Not routinely used; HRCT preferred for lung parenchymal assessment

›Lower sensitivity for interstitial pattern characterization

›Radiation-free alternative for follow-up in select cases

›Brain MRI indications

›Suspected CNS Nocardia infection complicating PAP

›Neurological symptoms in immunocompromised PAP patient

CT

›HRCT chest (gold standard imaging modality)

07Disposition/dispo27

Admission criteria

›Inpatient admission indications

›Respiratory failure or severe hypoxemia

›Resting SpO2 < 88% on room air

›PaO2 < 60 mmHg

›Suspected superimposed opportunistic infection

›Fever with known PAP

›IV antibiotics required

›WLL procedure planning or post-WLL monitoring

›ICU or high-dependency care post-WLL

›New diagnosis requiring workup and specialist consultation

›Hemodynamic instability

ICU level care

›ICU indications

›Mechanical ventilatory support

›Vasopressor requirement

›Post-WLL monitoring in high-risk patients

›Typically 24–48 hours post-procedure

Discharge criteria

›Safe discharge parameters

›Stable oxygenation on supplemental oxygen or room air

›SpO2 >= 90% ambulatory

›No evidence of active opportunistic infection

›Pulmonology follow-up arranged within 2–4 weeks

›Inhaled GM-CSF therapy instructions provided if prescribed

Transfer considerations

›Transfer triggers

›WLL not available at current facility

08Treatment/t81

Supplemental oxygen and supportive care

›Oxygen therapy

›Supplemental oxygen for resting or exertional hypoxemia

›Target SpO2 92–96%

›High-flow nasal cannula for moderate hypoxemia

›Flow 30–60 L/min

›FiO2 titrated to target

›Non-invasive positive pressure ventilation

›CPAP or BiPAP for respiratory distress without intubation

›Mechanical ventilation for respiratory failure

›Lung-protective strategy: tidal volume 6 mL/kg IBW

›PEEP titration

First-line pharmacotherapy

›Inhaled GM-CSF therapy

›Molgramostim (inhaled)

›ERS guidelines: first-line for symptomatic confirmed autoimmune PAP

›IMPALA-2 phase 3 trial demonstrated improved pulmonary gas transfer and functional health status

›Dose: 300 mcg inhaled daily in cycles

›Well-tolerated; minimal systemic absorption

›Sargramostim (inhaled)

›Alternative inhaled GM-CSF preparation

›Used in AEROSURF and related trials

›Mechanism

›Restores alveolar macrophage surfactant clearance capacity

›Overcomes GM-CSF autoantibody neutralization at alveolar level

Whole lung lavage

›WLL indications

›Respiratory failure at diagnosis

›Preferred approach for severe presentation

›Rescue therapy for GM-CSF non-responders

›Symptomatic disease not controlled by inhaled GM-CSF

›WLL procedure details

›General anesthesia with double-lumen endotracheal tube

›Single-lung ventilation during lavage

›Warmed normal saline 37 degrees Celsius instilled per lung

›Up to 40–50 L saline per lung per session

›Lavage fluid appears progressively clearer with each aliquot

›Typically staged in two sessions

›Right lung first (larger), then left lung

›Sessions separated by 3–7 days

›Post-WLL monitoring 24–48 hours

›Approximately one-third require repeat WLL within 2–3 years

›WLL contraindications and precautions

›Severe refractory hypoxemia precluding single-lung ventilation

›Active uncontrolled infection

›Coagulopathy requiring correction first

Second and third-line therapies

›Inhaled GM-CSF post-WLL

›Prolong remission and reduce recurrence rate

›Combination strategy supported by current evidence

›Rituximab

›Third-line therapy for refractory autoimmune PAP

›Anti-CD20 monoclonal antibody depletes B cells producing anti-GM-CSF autoantibodies

›Dose: 375 mg/m2 IV weekly x 4 doses (standard regimen)

›Plasmapheresis

›Fourth-line option

›Removes circulating anti-GM-CSF autoantibodies

›Reserved for severe refractory cases

›Statin therapy

›Under investigation for cholesterol homeostasis in alveolar macrophages

›Not yet standard of care; observational data only

Secondary PAP treatment

›Treat underlying condition

›Hematologic malignancy therapy

›MDS: disease-modifying therapy per hematology

›Leukemia: induction chemotherapy

›Cessation of inhalational exposure

›Remove from occupational silica or dust exposure

›WLL for symptomatic secondary PAP

›Adjunct to treating underlying cause

Lung transplantation

›Reserved for terminal respiratory failure

›Eligible patients without contraindications

›Disease can recur in transplanted lung

›Rare indication

Opportunistic infection treatment

›Nocardia treatment

›Trimethoprim-sulfamethoxazole as first-line

›TMP 15 mg/kg/day in 2–4 divided doses IV for severe disease

›Duration 6–12 months depending on extent

›Imipenem plus amikacin for severe or disseminated Nocardia

›Aspergillus treatment

›Voriconazole first-line

›Loading: 6 mg/kg IV Q12h x 2 doses

›Maintenance: 4 mg/kg IV Q12h

›Cryptococcus treatment

›Liposomal amphotericin B plus flucytosine induction

›Fluconazole consolidation

09Special Populations/sp57

Pregnancy

›Physiologic considerations

›Respiratory alkalosis and reduced FRC in normal pregnancy

›Reduced physiologic reserve for additional hypoxemia

›PAP-related hypoxemia may worsen with pregnancy

›Fetal hypoxia risk with maternal hypoxemia

›Target maternal SpO2 > 95% to ensure fetal oxygenation

›Diagnostic approach in pregnancy

›HRCT with appropriate shielding if clinically indicated

›Fetal radiation risk low with chest CT

›Serum anti-GM-CSF antibody testing safe in pregnancy

›BAL safe under local anesthesia with minimal sedation

›Treatment in pregnancy

›WLL can be performed in pregnancy under careful anesthesia planning

›Multidisciplinary team: pulmonology, maternal-fetal medicine, anesthesia

›Left lateral decubitus positioning to avoid aortocaval compression

›Inhaled GM-CSF safety in pregnancy

›Minimal systemic absorption; limited human data

›Risk-benefit discussion with specialist

›Rituximab generally avoided in pregnancy

›B-cell depletion risk to fetus

›Oxygen supplementation to maintain SpO2 > 95%

Geriatric

›Age-related considerations

›Reduced physiologic reserve

›Lower tolerance for hypoxemia

›Impaired cough reflex increases aspiration and infection risk

›Polypharmacy and drug interactions

10Background/b65

Epidemiology

›Prevalence and incidence

›Prevalence 7–27 per million population

›Rare diffuse lung disease

›Incidence estimated 0.36–1.65 per million per year

›Autoimmune PAP accounts for > 90% of all cases

›Secondary PAP accounts for approximately 5–10%

›Hereditary and congenital PAP rare (< 2%)

›Demographics

›Peak incidence of autoimmune PAP: age 30–50 years

›Affects all races, sexes, and geographic regions

›Male predominance in smokers (4:1 ratio)

›Natural history

›Spontaneous remission in approximately 20% of autoimmune PAP

›Progressive respiratory failure in minority without treatment

›Pulmonary fibrosis develops in up to 20% and portends poor prognosis

›Mortality historically related to opportunistic infections and respiratory failure

›Smoking association

›Strong association; more prevalent in current smokers

›Mechanism unclear; may enhance autoimmunity

Pathophysiology

›Autoimmune PAP mechanism

›Neutralizing autoantibodies against GM-CSF

›Produced by B cells

›Block GM-CSF signalling in alveolar macrophages

›Impaired alveolar macrophage differentiation and function

›Failure to catabolize surfactant phospholipids and proteins

›Accumulation of lipoproteinaceous material in alveoli

11Patient Discharge Instructions/pdi37

copy discharge instructions

›Diagnosis and disease explanation

›Pulmonary alveolar proteinosis is a rare lung disease

›A protein-like substance builds up in the air sacs of the lungs

›This reduces oxygen transfer and causes breathlessness

›Treatment can effectively control or reverse this buildup

›Medications and therapy

›Inhaled GM-CSF therapy (molgramostim or sargramostim) if prescribed

›Use exactly as directed by your pulmonologist

›Do not miss doses; adherence is essential for response

›Supplemental oxygen if prescribed

›Use continuously at the prescribed flow rate

›Bring portable oxygen to all appointments and outings

›Activity and lifestyle

›Smoking cessation is essential

›Smoking worsens disease and impairs treatment response

›Ask your doctor about cessation supports

›Avoid known occupational dust exposures

›Silica, aluminum, cement dust

›Workplace modification or protective respirator required

›Gradually resume activity as tolerated after treatment

›Follow-up schedule

›Pulmonology follow-up within 2–4 weeks of discharge

›Serial pulmonary function tests and arterial blood gas monitoring

›Repeat HRCT chest to assess treatment response

›If you had a whole lung lavage procedure, repeat evaluation in 3–6 months

›Return to emergency department immediately for

›Worsening shortness of breath or new requirement for more oxygen

12References/r24

Guidelines and key sources

›McCarthy C, Carey BC, Trapnell BC. Autoimmune Pulmonary Alveolar Proteinosis. American Journal of Respiratory and Critical Care Medicine. 2022. PMID 35227171

›Core review of autoimmune PAP pathophysiology, diagnosis, and management

›Trapnell BC, Nakata K, Bonella F, et al. Pulmonary Alveolar Proteinosis. Nature Reviews Disease Primers. 2019. PMID 30846703

›Comprehensive disease primer covering all PAP subtypes

›Trapnell BC, Inoue Y, Bonella F, et al. Phase 3 Trial of Inhaled Molgramostim in Autoimmune Pulmonary Alveolar Proteinosis. NEJM. 2025. IMPALA-2 trial

›Established inhaled GM-CSF as first-line therapy for aPAP

›Trapnell BC, Inoue Y, Bonella F, et al. Inhaled Molgramostim Therapy in Autoimmune Pulmonary Alveolar Proteinosis. NEJM. 2020. IMPALA trial

›Phase 2 trial supporting inhaled GM-CSF efficacy

›Papiris SA, Kallieri M, Zompatori M, et al. Autoimmune Pulmonary Alveolar Proteinosis. Seminars in Respiratory and Critical Care Medicine. 2025. PMID 41197983

›WLL technique, post-WLL management, combination therapy

›Kumar A, Abdelmalak B, Inoue Y, Culver DA. Pulmonary Alveolar Proteinosis in Adults: Pathophysiology and Clinical Approach. Lancet Respiratory Medicine. 2018. PMID 29397349

›Clinical approach framework and diagnostic algorithm

›Jouneau S, Chauvin P, Lederlin M, Painvin B, Kerjouan M. Pharmacotherapy for Autoimmune Pulmonary Alveolar Proteinosis. Drugs. 2025. PMID 40866780

›Comprehensive pharmacotherapy review including rituximab and plasmapheresis

›Ataya A, Mathavan A, Wang TS. How I Do It: Whole Lung Lavage in Pulmonary Alveolar Proteinosis. Chest. 2025. PMID 41072904

›Procedural guidance for WLL technique

›Bonella F, Borie R. Pulmonary Alveolar Proteinosis. Clinics in Chest Medicine. 2025. PMID 41110926

›Current review of diagnosis and management

›Trapnell BC, Whitsett JA, Nakata K. Pulmonary Alveolar Proteinosis. NEJM. 2003. NEJM doi 10.1056/NEJMra023226

›Classic foundational review establishing PAP classification and pathophysiology

›Lettieri S, Bonella F, Marando VA, et al. Pathogenesis-Driven Treatment of Primary Pulmonary Alveolar Proteinosis. European Respiratory Review. 2024. PMID 39142709

›Pathogenesis-based treatment algorithm

›Ryerson CJ, Adegunsoye A, Piciucchi S, et al. Update of the International Multidisciplinary Classification of the Interstitial Pneumonias: ERS/ATS Statement. European Respiratory Journal. 2025. PMID 40774805

›PAP classification within updated ILD taxonomy

Evidence & Review

Evidence & Review