Risk factors associated with radiolucent foreign body inhalation in adults: a 10-year retrospective cohort study

Background Foreign body aspiration (FBA) is a serious condition with high morbidity and mortality rates. Although chest radiography is generally the first radiologic modality used in diagnosis, a substantial percentage of foreign bodies are radiolucent in adults with diagnosis challenging. Methods Retrospective review of adult patients with FBA diagnosed by flexible electronic bronchoscopy from 2012 to 2022 collecting demographics, history, hospital presentation, radiographic, and operative details. Risk factors associated with radiolucent foreign body inhalation in adults were explored using appropriate statistical methods. Results Between 1 January 2012 and 1 January 2022, 114 adult patients diagnosed with FBA were enrolled. The median age of participants was 65 years (IQR 52–74). Multidetector computed tomography (MDCT) examinations identified 28 cases (25%) showing direct visualization of the foreign body (defined as the radiopaque group) and 86 cases (75%) in the radiolucent group. Multivariable stepwise linear regression analysis showed increased odds of radiolucent foreign body inhalation in adults associated with pneumonic patches in MDCT (OR 6.99; 95% CI 1.80–27.22; P = 0.005) and plants/meat foreign bodies (OR 6.17; 95% CI 1.12–33.96; P = 0.04). A witnessed choking history (OR 0.02; 95% CI 0–0.14; P < 0.001) was a protective factor of radiolucent foreign body inhalation in adults. Conclusions Unlike radiopaque FBA, in those presenting with a suspected radiolucent foreign body aspiration, the diagnosis is far more challenging. Risk factors such as lacking a choking history, non-resolving pneumonia (pneumonic patches) in MDCT findings, and plants/meat foreign bodies may help in the early diagnosis of radiolucent foreign body inhalation in adults. Further prospective multicenter studies should be conducted to validate the findings.