pulmonary alveolar phospholipoproteinosis; alveolar proteinosis; pulmonary surfactant metabolism dysfunction; inborn error of pulmonary surfactant metabolism
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Etiology
- 95% idiopathic
- excessive production of alveolar surfactant &/or diminished clearance of surfactant by alveolar macrophages
- genetic
Epidemiology
- rare
- affects mostly young adults
- male:female ratio 3:1
Pathology
- alveoli contain PAS+ granular eosinophilic material
- alveolar material is largely dipalmitotyl lecithin
Genetics
- autosomal recessive
- associated with defects in CSF2RB
- associated with defects in SFTPB (type 1)
- associated with defects in SFTP (type 2)
- associated with defects in ABCA3 (type 4)
Clinical manifestations
- initial febrile episode
- disease-free interval of weeks to months after initial febrile episode (2-12 months)
- progressive dyspnea
- productive cough
- diffude crackles, bilateral
- low-grade fever
- chest pain
- weight loss
- autosomal recessive form fatal
Diagnostic procedures
- pulmonary function testing:
- restrictive pattern
- decreased DLCO
- bronchoscopy
- bronchioalveolar lavage
- respiratory cultures are negative
- lung biopsy
- alveoli filled with lipoproteinaceious material
- bronchioalveolar lavage
Radiology
- chest X-ray
- alveolar infiltrates in the lower 2/3 of lungs
- may resemble pulmonary edema
- costophrenic angles are spared
- high-resolution computed tomography (HRCT)
- characteristic 'crazy paving' pattern[2]
- thickened septal lines with ground-glass opacities
- characteristic 'crazy paving' pattern[2]
Complications
- Nocardia infection
Differential diagnosis
(similar histopathology)
Management
- whole lung lavage to remove intra-alveolar material[3]
- spontaneous resolution occurs in 1/3 of patients
More general terms
Additional terms
- bronchoalveolar lavage (BAL)
- Nocardia
- periodic acid Schiff base (PAS)
- pulmonary surfactant-associated protein B; SP-B; 18 kD pulmonary-surfactant protein; 6 kD protein; pulmonary surfactant-associated proteolipid SPL(Phe) (SFTPB, SFTP3)
References
- ↑ Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 756
- ↑ 2.0 2.1 Medical Knowledge Self Assessment Program (MKSAP) 14, American College of Physicians, Philadelphia 2006
- ↑ 3.0 3.1 Abdelmalak BB, Khanna AK, Culver DA, Popovich MJ. Therapeutic Whole-Lung Lavage for Pulmonary Alveolar Proteinosis: A Procedural Update. J Bronchology Interv Pulmonol. 2015 Jul;22(3):251-8 PMID: https://www.ncbi.nlm.nih.gov/pubmed/26165897