Lipid-Laden Alveolar Macrophages and pH Monitoring in Gastroesophageal Reflux-Related Respiratory Symptoms

Abstract

Lipid-laden alveolar macrophages and pH monitoring have been used in the diagnosis of chronic aspiration in children with gastroesophageal reflux (GER). This study was conducted to prove a correlation between the detection of alimentary pulmonary fat phagocytosis and an increasing amount of proximal gastroesophageal reflux. It was assumed that proximal gastroesophageal reflux better correlates with aspiration than distal GER. Patients from 6 months to 16 years with unexplained recurrent wheezy bronchitis and bronchial hyperreactivity, or recurrent pneumonia with chronic cough underwent 24-hour double-channel pH monitoring and bronchoscopy with bronchoalveolar lavage (BAL). Aspiration of gastric content was determined by counting lipid laden alveolar macrophages from BAL specimens. There were no correlations between any pH-monitoring parameters and counts of lipid-laden macrophages in the whole study population, even when restricting analysis to those with abnormal reflux index expressing clinically significant GER. Quantifying lipid-laden alveolar macrophages from BAL in children with gastroesophageal-related respiratory disorders does not have an acceptable specificity to prove chronic aspiration as an underlying etiology. Therefore, research for other markers of pulmonary aspiration is needed.

Figure 1

Pearson's correlation of LLAM scoring with LLAMs (&AMs). High correlation of the percentage of fat containing AMs (LLAMs/%AMs) (from a total of 300 screened AMs) and their fat content described by the LLAMs score.

Figure 2

Scatter plots of parameters from the proximal channel of a double-channel 24 hr pH probe in the esophagus versus LLAM count (in % of 300 AMs; n = 448). (a) Total number of reflux episodes: no correlation with the percentage of fat containing AMs (LLAMs/%AMs) in the regression analysis (r = −0.042). (b) Number of reflux episodes, lasting longer than five minutes: no correlation with the percentage of fat containing AM (LLAMs/%AMs) in the regression analysis (r = −0.017). (c) Duration (minutes) of the longest reflux episode: no correlation with the percentage of fat containing AMs (LLAMs/%AMs) in the regression analysis (r = −0.022). (d) Reflux Index (percentage of time pH below 4): no correlation with the percentage of fat containing AMs (LLAMs/%AMs) in the regression analysis (r = −0.009).