PAP was first described in 1958 and is of unknown etiology. Surfactant material fills the alveoli and stains positive with periodic acid-Schiff (PAS). The course of the disease ranges from respiratory failure to spontaneous resolution. It occurs in three clinical forms: congenital, secondary and acquired; the primary acquired disorder accounts for 90% of the cases. The acquired form may be an autoimmune disease targeting GM-CSF. About 500 total cases have been recorded in the literature with only 1 previously reported case of PAP associated with pregnancy.
36 years old woman, 25 weeks pregnant, presented with a 2 week history of increasing breathlessness and cough productive of whitish sputum. Her medical history: hyperlipidemia, tobacco abuse, DM and depression; medications: insulin and trazadone. During her last pregnancy in 2007, she presented with similar symptoms at 25 weeks gestation. Her CXR and CT chest at that time showed extensive bilateral ground glass opacities. She had negative: ANA, HIV, ANCA, Cocci serology and sputum GS and cultures. Bronchoscopy and BAL revealed intense PAS staining of amorphous bodies and granular material consistent with PAP. She underwent multiple total lung lavages and subcutaneous GM-CSF. Her PAP resolved after delivery of a normal fetus. Her current presentation was similar to that in 2007. She had an increasing O2 requirement of 12L to maintain saturation over 95 %. On examination she was cyanotic and tachypnoeic. There were normal pulmonary sounds on auscultation. Basic labs were unremarkable. CXR and CT chest showed the same bilateral alveolar and interstitial opacities with interlobular thickening. A presumptive diagnosis of PAP was made. Right lung lavage under general anesthesia was modified to RML lavage as patient had severe hypoxia requiring bag ventilation. The lavage fluid was initially turbid with sediment but gradually cleared. After the procedure, the symptoms diminished and oxygen saturation improved to 97% on 4L. Her PAS stain was again positive, microbiology was negative and LDH was 198. She was started on GM-CSF. She was also given dexamethasone for fetal lung maturity anticipating delivery before term. Last known she was 36 weeks pregnant and had only required one large volume lavage in the OR as well as weekly GM-CSF. She is to follow up with the pulmonary clinic after delivery to ensure resolution of her PAP.
The pathophysiology of PAP is unclear but impairment of surfactant clearance by alveolar macrophages as a result of inhibition of the action of GM-CSF by blocking autoantibodies may underlie many acquired cases. BAL with PAS staining is sufficient to make a diagnosis. Acquired PAP has been treated successfully since the early 1960s by whole-lung lavage, and this procedure remains the standard of care today. Therapy with GM-CSF has shown promise in approximately half of those acquired cases treated, especially those with elevated LDH levels.
PAP was of insidious onset in this patient’s last 2 of her 7 pregnancies with no clear etiology, which is the first recorded case report of this kind. We can only speculate on an association between changes in the maternal levels of GM-CSF during pregnancy and post-partum, and the development and subsequent resolution of the condition. We can substantiate this by our experience of significant clinical improvement seen in this patient with GM-CSF. Large volume lavage is both diagnostic and therapeutic and remains the standard of care.
Omer Ahmed, No Financial Disclosure Information; No Product/Research Disclosure Information