Pulmonary Alveolar Proteinosis
Description
● Introduction:
➣ Rosen et al. first reported it in 1958.
Pathology: Impaired gas exchange due to the buildup of amorphous, insoluble, lipoproteinaceous material in the alveoli.
➣ Etiology:
• Originally idiopathic, currently categorised as
• Idiopathic/autoimmune: most prevalent (~83%)
• Secondary: caused by silicates, aluminium, fibreglass, silica, infections (TB, Nocardia, and Pneumocystis), and haematologic cancers (~16%)
• Congenital: uncommon (~1%).
● The pathophysiology of silica-associated PAP is as follows:
➣ Inhaled fine silica → damage to the airway epithelium + accumulation of protein-lipid exudate → buildup of surfactants.
➣ Hyperplasia of type II pneumocytes → ↑ phospholipid surfactant (e.g., dipalmitoyl lecithin).
➣ Lipoproteinaceous material persists due to impaired alveolar macrophage clearance.
➣ Experiments: rats exposed to quartz dust developed silica aggregates and alveolar proteinosis with desquamative pneumonitis.
● Diagnostic features include:
➣ Milky, PAS-positive BAL fluid;
➣ Histology: Alveoli containing PAS+ proteinaceous material;
➣ Birefringent particles (silica/silicates) in polarised microscopy.
➣ Radiology: symmetrical, bilateral, perihilar infiltrations (also known as "bat-wing" patterns).
➣ A decrease in DLCO is a characteristic functional anomaly.
● Literature Review (363 instances, 1988–2014):
➣ Classification:
• Idiopathic/Autoimmune: 293 (83%)
• Secondary: 56 (16%)
• Birth defects: 3 (1%)
➣ Diagnosis: OLB, TBLB, and BAL.
➣ Treatment options include combination treatment, GM-CSF, and WLL (mainstay till 2006).
➣ Results: GM-CSF enhanced care of refractory/autoimmune PAP; high survival with WLL.
● Case Report: 52-year-old man smoker who had smoked for 60 years
➣ Two years of silica dust exposure at work (floor tile cutting, sans mask)
➣ Symptoms include a persistent cough with white sputum and progressive exertional dyspnoea (18 months). No systemic symptoms, fever, or weight loss.
➣ Examination: Fine inspiratory bibasilar rales, little dyspnoea, otherwise normal.
➣ Research:
• Blood gases: pH 7.44, PaO2 76 mmHg, and PaCO2 35 mmHg
• PFTs: limiting with 54% ↓DLCO
• CXR: Both alveolar infiltrations (distribution of butterflies, preservation of CP angles)
• Cultures negative, birefringent silicate particles, and PAS+ lipoproteinaceous material after bronchoscopy or biopsy
➣ Whole Lung Lavage (WLL) as a treatment → significant improvement in oxygenation and symptoms
● Discussion and Conclusion:
➣ Until occupational reasons are ruled out, PAP shouldn't be regarded as idiopathic. There is convincing clinical and experimental evidence of silica-induced PAP.
➣ The connection between silica exposure and secondary PAP is reinforced by this instance.
➣ Essential clinical pearl: In cases of unexplained alveolar proteinosis, always assess occupational and environmental exposure.
➣ Future care will involve environmental control and targeted immunotherapy (GM-CSF, anti-GM-CSF autoantibody treatment, and B-cell reduction).
Protocol
● Treatment:
➣ According to Ramirez, Whole Lung Lavage (WLL) has been the norm since the 1960s.
• Needs a double-lumen ET tube and general anaesthesia.
• Saline is injected or suctioned until the effluent (usually 15–20L) clears.
• The eyeball approach is employed to determine sufficiency.
➣ GM-CSF, or Granulocyte-Macrophage Colony-Stimulating Factor:
• Finding: PAP develops in GM-CSF gene/receptor knockout mice.
• Routes: systemic, subcutaneous, and breathed.
• Current strategy: save WLL for refractory patients and attempt GM-CSF first.
➣ Other alternatives (for those who are refractory) include:
• Rituximab
• plasmapheresis
• end-stage lung transplantation.
➣ Supportive:
• Steer clear of exposure to dust, silica, and harmful inhalants.
• If the cancer is secondary, treat the underlying infections.
● Problems include:
• Severe Hypoxaemia: Because of compromised alveolar gas exchange, PAP patients have low blood oxygen levels.
• Clinical manifestations of respiratory distress may include coughing, cyanosis, and increasing dyspnoea.
• Risk of Infection: Patients are more susceptible to secondary infections as a result of impaired lung clearance.
• Impaired Daily Function: Exhaustion and an inability to do daily tasks because to low oxygen levels.
● Medical Management:
➣ Lavage of the Whole Lung (WLL):
• Whole lung lavage, in which saline is infused into the lungs and subsequently expelled to eliminate the accumulated surfactant, is the main treatment intervention for PAP.
• To eliminate proteinaceous debris, saline is repeatedly injected and aspirated, one lung at a time, after the patient has typically been intubated and put under general anaesthesia.
➣ Oxygen Therapy: Until conclusive treatment is possible, more oxygen may be given to treat hypoxaemia.
➣ Monitoring and Supportive Care: Vital signs, pulse oximetry, and arterial blood gas monitoring. keeping an eye out for issues like pneumothorax or infection.
➣ Complication Treatment: When necessary, prompt therapy of infections or other problems.
● Comprehensive Nursing Management & Interventions
➣ Preparing for the procedure:
• Providing the patient and their family with information and comfort regarding the WLL procedure.
• Evaluate oxygen needs, baseline vitals, and respiratory condition.
• Assemble the tools required for airway care, lavage, and intubation.
➣ During Whole Lung Lavage:
• Help the interdisciplinary team place and keep an eye on the patient.
• Assistance with airway management (maintenance of endotracheal tubes, suctioning as necessary).
• During lavage, keep an eye on fluid input and outflow to ensure precise documentation.
• Keep an eye out for any consequences from the surgery, including fluid overload, arrhythmia, or hypoxia.
• To reduce the risk of infection, adhere to stringent aseptic procedures.
➣ Post-procedural Care:
• Continuous assessment of haemodynamic and respiratory conditions.
• Until regular gas exchange is restored, give more oxygen.
• Vigilant observation and evaluation for indications of infection or deteriorating hypoxaemia.
• To avoid atelectasis and enhance lung function, early mobilisation and incentive spirometry are used.
• Offer psychological treatment and emotional support, addressing worries and anxieties.
➣ Education and Planning for Discharge:
• Inform the patient about infection or recurrence symptoms and when to consult a doctor.
• Instruct students on how to prevent infections and recognise symptoms of respiratory distress.
• Assure outpatient follow-up for continued observation and, if necessary, repeat lavage.
Notes
For more ditails visit 10.1002/rcr2.201
