Pulmonary alveolar proteinosis (PAP) is a rare respiratory disorder characterised by alveolar accumulation of surfactant-derived lipoproteinaceous material that impairs gas exchange. Three forms exist: primary (autoimmune), secondary, and congenital. Primary PAP accounts for over 90% of adult cases and is the focus of this review.
First described by Rosen et al. in 1958, PAP remains rare, with an estimated prevalence of 1–7 per million. It predominantly affects adults aged 20–50, has a male predominance (3:1), and is strongly associated with smoking.
PAP in pregnancy is exceptionally rare, with limited data to guide management. We report a case of primary PAP diagnosed in the late second trimester following incidental hypoxia during treatment for an obstructed renal stone. Diagnosis was confirmed by characteristic “crazy paving” appearance on CT imaging, bronchoalveolar lavage showing proteinaceous material, and elevated anti-GM-CSF antibodies. The patient required supplemental oxygen from 24+1 weeks until delivery at 37+5 weeks. Whole lung lavage, the gold standard therapy, was deferred until postpartum due to maternal stability and theoretical fetal risk. The pregnancy was complicated by pre-eclampsia but resulted in term delivery with favourable maternal and neonatal outcomes.
A literature review identified 12 other patients with PAP during pregnancy, including 14 pregnancies, and 15 deliveries (1 dichorionic diamniotic twins). Most cases were diagnosed preconception, allowing respiratory optimisation. Common management involved oxygen supplementation, delayed definitive treatment, and multidisciplinary input.
This case and review highlight the importance of high clinical suspicion to expedite a PAP diagnosis and individualised management in pregnancies affected by PAP.