CRA56 DIAMOND BRIGHT, DIAGNOSTIC BLIND: PAM MISTAKEN FOR HEART FAILURE

Jason Tan Seng Hong¹, Dyana Othman¹, Siti Nur Atiqah Alwi² Syazatul Syakirin Sirol Aflah³

¹Department of Medicine, Hospital Banting, Malaysia
²Department of Radiology, Hospital Banting, Malaysia
³Institute of Respiratory Medicine, Kuala Lumpur, Malaysia

Introduction
Pulmonary alveolar microlithiasis (PAM) is a rare, autosomal recessive lung disease marked by calcium phosphate microlith deposition in the alveoli. Often indolent and asymptomatic for years, PAM is frequently diagnosed incidentally. We report a case where PAM was discovered during admission for acute coronary syndrome (ACS), mimicking features of cardiac failure.

Case Report
A 56-year-old Malay man with underlying diabetes, hypertension, and nephrolithiasis was admitted for chest pain and diagnosed with non-ST elevation myocardial infarction (NSTEMI) based on ECG findings showing aVR ST elevation and p-pulmonale. Echocardiography revealed a reduced ejection fraction of 26%, diastolic dysfunction (grade 2), and mild pulmonary hypertension.

The patient also reported a six-month history of exertional dyspnoea. A chest radiograph showed a diffuse “sandstorm” pattern, initially interpreted as pulmonary congestion due to heart failure. However, the imaging features were atypical. High-resolution CT (HRCT) of the thorax was performed, revealing characteristic findings of PAM: diffuse calcified interlobular septal thickening, scattered micronodules, and crazy-paving appearance.

He was treated for NSTEMI and concurrently managed for PAM with supportive care and corticosteroids for suspected acute exacerbation. His clinical condition improved, and he was discharged well.

Discussion & Conclusion
This case highlights the diagnostic challenge when rare pulmonary diseases present alongside common cardiac emergencies. In this patient, radiological signs presumed to be heart failure led to the incidental diagnosis of PAM. Recognizing atypical imaging features is key to avoiding misdiagnosis. While treatment remains largely supportive, lung transplantation is the definitive therapy. The role of steroids during exacerbation remains uncertain.