Lanthanum masquerading as foreign body ingestion in a critically ill patient with end-stage renal disease

Medication use may affect imaging results. In this case study, we report a case of lanthanum ingestion resulting in imaging consistent with ingested metallic foreign bodies.

Hyperphosphatemia affects most patients with end-stage renal disease (ESRD) and is associated with morbidity and mortality. Lanthanum carbonate reduces daily phosphate absorption and is indicated as a non-calcium-based phosphate binder in patients with ESRD. A 58-year-old man with a medical history of stage 5 chronic kidney disease was admitted to the intensive care unit (ICU) for hyperkalemia and acute respiratory failure after a missed dialysis session. He required vasopressors, intubation, and continuous renal replacement therapy. Admission imaging demonstrated several ingested metallic foreign bodies within the colon. There was consideration of colorectal surgery and gastroenterology consultation. On the initial medication reconciliation, no medications that would have the radiographic appearance of ingested metallic foreign bodies were identified. On further review of prescription data available through the electronic medical record, it was noted that the patient had recently filled a prescription for lanthanum despite its apparent discontinuation on a previous admission. After interviewing the patient's wife, it was confirmed that the patient had continued taking lanthanum and that he was swallowing it whole and not chewing it. No consultations or interventions were performed, and the metallic foreign bodies were no longer present on further imaging after a period of 35 days.

Escalation of care was avoided in this patient due to the performance of diligent medication reconciliation and recognition of the impact of lanthanum ingestion on imaging.