Epidemiology
- Incidence: rare disorder
- Familial Clustering: present in >50% of cases
- Especially clusters in siblings
- Age: most cases are diagnosed in 20’s-40’s
- Has been reported in all age groups though
- Sex
- Female>male in familial cases
- Female=male in sporadic cases
Physiology
- Accumulation of hydroxyapatite (calcium and phosphorous) crystal concretions (0.01-3 mm) in alveolar spaces (probably due to some inborn error of caclium metabolism)
- Over time, alveolar walls become fibrotic
Diagnosis
- CXR/Chest CT Pattern
- Early: characteristic diffuse bilateral calcific alveolar infiltrates (with air bronchograms) with lower lobe predominance
- “Vanishing heart phenomena”: due to microliths adjacent to heart border
- “Black and white” pleural-related lines (pathognomonic): white thick line at subpleural area adjacent to black pleural line (a Mach band)
- Chest CT: lower lobe and subpleural predominance of intra-alveolar calcified nodules, pleural calcifications may be seen
- Later: ILD, evidence of pulmonary hypertension
- Early: characteristic diffuse bilateral calcific alveolar infiltrates (with air bronchograms) with lower lobe predominance
- PFT’s: usually normal until late in course, when restriction with decreased DLCO occurs
- FOB: TBB may aid in confirming diagnosis
- Bone Scan: may aid in confirming diagnosis
- Serum Calcium and Phosphorous: normal
- CBC: polycythemia (occurs late in course, associated with hypoxemia)
Clinical
(may be asymptomatic even with extensive CXR abnormalities)
- Interstitial Lung Disease (see [[ILD-Etiology]])
- Clubbing
- Cough and dyspnea: occur late in course
- Expectorated Microliths: occurs infrequently
- Crackles: occur with later development of ILD
- Cor Pulmonale (see [[Pulmonary HTN-Etiology]])
Treatment
- Supportive treatment:
- Whole Lung Lavage: not useful
Prognosis
- Progression is variable
References
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