Pulmonary alveolar microlithiasis

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Pulmonary alveolar microlithiasis
Synonyms	Alveolar microlithiasis
Pronounce
Specialty	Pulmonology
Symptoms	Cough, dyspnea, chest pain
Complications	Respiratory failure, cor pulmonale
Onset	Usually in adulthood
Duration	Chronic
Types
Causes	Mutations in the SLC34A2 gene
Risks
Diagnosis	Chest X-ray, CT scan, lung biopsy
Differential diagnosis	Sarcoidosis, tuberculosis, pneumoconiosis
Prevention
Treatment	Lung transplantation, supportive care
Medication
Prognosis	Variable, often poor without treatment
Frequency	Rare
Deaths

Histopathology of pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare, autosomal recessive lung disease characterized by the accumulation of small stone-like calcium phosphate microliths in the alveoli. The disease is caused by mutations in the SLC34A2 gene, which encodes a type IIb sodium-phosphate cotransporter that is expressed in the alveolar type II cells.

Symptoms

The symptoms of PAM are often non-specific and can include dyspnea (shortness of breath), cough, and chest pain. Some patients may also present with clubbing of the fingers and toes. Despite the extensive calcification of the lungs, many patients remain asymptomatic for a long period of time.

Diagnosis

The diagnosis of PAM is often made by radiography, which shows a characteristic "sandstorm" appearance due to the widespread microliths in the lungs. High-resolution computed tomography (HRCT) can also be used to confirm the diagnosis. In some cases, a lung biopsy may be necessary.

Treatment

There is currently no cure for PAM, and treatment is mainly supportive. This can include oxygen therapy for patients with severe respiratory distress, and lung transplantation in end-stage disease.

Epidemiology

PAM is extremely rare, with fewer than 1,000 cases reported worldwide. The disease affects both males and females equally, and can occur at any age, although it is most commonly diagnosed in young adults.

See also

• List of genetic disorders
• List of respiratory diseases