Correct!
5. All of the above
Exogenous lipoid pneumonia (ELP) results from repeated episodes of aspiration or inhalation of animal fat or mineral or vegetable oils over an extended period. ELP
typically occurs in older debilitated patients with neurological or esophageal disease but can occur in patients without a predisposing anatomic or functional abnormality in swallowing. Patients are frequently asymptomatic with cough and dyspnea being the most common symptoms when present. ELP is uncommon with autopsy series reporting a frequency of only 1.0–2.5% (2).
Parenchymal abnormalities are dependent on the type, amount, frequency, and length of time of aspirated or inhaled oils or fats. Animal fats are hydrolyzed by lung lipases into free fatty acids that trigger a severe inflammatory reaction. The fatty acids either remain in the alveolar spaces or are phagocytosed by macrophages that then migrate to the interlobular septa leading to fibrosis. In contrast, mineral oil and vegetable-based oils tend to cause minimal to mild inflammatory reactions.
The radiologic manifestations are variable (table 1).
The pathology of ELP is also variable but giant cell granulomas, alveolar and interstitial fibrosis, and chronic inflammation are often observed. Alveoli may be filled in by lipid-laden macrophages with almost normal alveolar walls and septae. Advanced lesions show larger vacuoles and inflammatory infiltrates of the alveolar walls, bronchial walls, and septae.
Our patient was reassured and advised to discontinue the mineral oil. Several years later he was alive and doing well.
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