Alveolar Proteinosis (diff names)

last updated: April 11, 2016

 

General

a syndrome caused by defects in the generation or degeneration of surfactant that lead to abnormal accumulation of surfactant-derived components (proteinaceous material) in the alveoli and terminal bronchioli

 

Architecture of lung untouched, normal intraalveolar septum

 

Golgi: involved in secretory pathway

 

Rare, mostly men, 72% smokers, make predominance lost with nonsmokers; smoking accelerates the disease progression

 

3 classifications

  • Congenital

    • deficiency beta surfactant protein

  • Primary (acquired) (autoimmune)

    • mostly (90% of cases)

    • more patchy, crazy paving

  • Secondary

    • associated with certain systemic diseases

 

“With the benefit of hindsight”

 

1990s: mice deficiency in GM-CSF autoantibodies

 

Symptoms

  • Dyspnea

  • resting dyspnea?

  • Weight loss

  • Fever

  • Clubbing ?

 

Physiology

Surfactant recycled by macrophages and type II cells

 

 

Pathophysiology

GMCSF from type II cells allows maturation of the macrophages

  • antibodies to the GMCSF does not allow it to bind to its macrophage receptor and younger foamy macrophages

  • defect in the breakdown of surfactant

 

Diagnosis

  • Latix agglutinin test for GMCSF (BAL levels correlate better)

    • Milky, waxy, foamy macrophages (also think usually amiodarone)

    • PAS+ pink stain inside the cell

  • PFT: restrictive pattern, low DLCO

  • X-ray: widespread patchy airspace disease more at bases

  • CT: crazy paving pattern (not specific)

 

Treatment

  • Whole lung lavage

    • double lumen tube

    • 1L saline instilled with percussion (about 30L per lung)

    • many bottles

    • Looks like a paper weight in snow storm when shaken

    • usually lavaged once is enough (on average lasts about 15 months)

    • usually symptoms get better few days after 2nd lavage

    • usually not diuresed afterwards

    • Duke does lavage under hyperbaric chamber

  • GMCSF

    • given for autoimmune disease usually

    • usually if becomes refractory to whole lung lavage

  • Plasmapheresis, retuximab, etc not really done yet; steroids have been shown to be detrimental

 

Reference

... but I would more especially commend the clinician who, in acute diseases, by which the bulk of mankind are cutoff, conducts the treatment better than others.
 
Hippocrates, 400 BC