Investigation of patent foramen ovale as a mechanism for brain metastasis in patients without prior lung involvement

Purpose The mechanisms of brain metastasis are incompletely understood. Circulating tumor cells travel to the right heart and through the pulmonary circulation, where they may become lung metastases, and can circulate further to the left heart and brain. In patients who develop brain metastases without lung involvement, we hypothesized that cancer cells may travel directly from the right atrium to left atrium via a patent foramen ovale (PFO), akin to paradoxical embolism. If the prevalence of PFO is greater in these individuals compared to the general population (20–30%), PFO may play a role in brain metastasis, and prophylactic closure may provide benefit. Accordingly, we investigated the prevalence of PFO in patients with brain metastases without prior lung involvement. Methods We prospectively identified patients with brain metastases from a non-lung primary cancer with no preceding or concurrent lung involvement. Nine eligible participants underwent a transcranial Doppler study with intravenous agitated saline to assess for PFO. Results Among nine participants, primary cancers were breast (n = 6), upper gastrointestinal (n = 2), and thyroid (n = 1). A positive bubble study was identified in 2/9 (22.2%) participants: one female with breast cancer and one male with duodenal adenocarcinoma. No participants developed lung metastases on subsequent chest imaging. Conclusion In this prospective pilot study, we found a similar prevalence of PFO in patients who developed brain metastases without preceding lung involvement compared to estimates for the general population. Through a larger study is needed, the development of brain metastases in these individuals may primarily reflect tumor-specific biological factors diecting metastasis organotropism (AU)

Investigation of patent foramen ovale as a mechanism for brain metastasis in patients without prior lung involvement.

PURPOSE: The mechanisms of brain metastasis are incompletely understood. Circulating tumor cells travel to the right heart and through the pulmonary circulation, where they may become lung metastases, and can circulate further to the left heart and brain. In patients who develop brain metastases without lung involvement, we hypothesized that cancer cells may travel directly from the right atrium to left atrium via a patent foramen ovale (PFO), akin to paradoxical embolism. If the prevalence of PFO is greater in these individuals compared to the general population (20-30%), PFO may play a role in brain metastasis, and prophylactic closure may provide benefit. Accordingly, we investigated the prevalence of PFO in patients with brain metastases without prior lung involvement. METHODS: We prospectively identified patients with brain metastases from a non-lung primary cancer with no preceding or concurrent lung involvement. Nine eligible participants underwent a transcranial Doppler study with intravenous agitated saline to assess for PFO. RESULTS: Among nine participants, primary cancers were breast (n = 6), upper gastrointestinal (n = 2), and thyroid (n = 1). A positive bubble study was identified in 2/9 (22.2%) participants: one female with breast cancer and one male with duodenal adenocarcinoma. No participants developed lung metastases on subsequent chest imaging. CONCLUSION: In this prospective pilot study, we found a similar prevalence of PFO in patients who developed brain metastases without preceding lung involvement compared to estimates for the general population. Through a larger study is needed, the development of brain metastases in these individuals may primarily reflect tumor-specific biological factors diecting metastasis organotropism.

Piperacillin-induced Thrombocytopenia in a Dual Heart and Kidney Transplant Patient: A Case Report.

BACKGROUND: The present study reports a case of piperacillin-induced thrombocytopenia in a dual heart and kidney transplant patient on January 28, 2016 (taking mycophenolate mofetil and tacrolimus). Before the transplant, the patient was treated with Zosyn twice, with no reports of thrombocytopenia or allergy. However, he was diagnosed with heparin-induced thrombocytopenia and vancomycin allergy during each of those hospitalizations, respectively. Eight months after the transplant, the patient presented with infectious symptoms and was started on Zosyn. RESULTS: One day after starting Zosyn, the patient experienced a drop in platelet count from 6,000/µL from 216,000/µL. Platelets decreased as low as 1 on day 3 of hospitalization. Administration of mycophenolate mofetil, tacrolimus, Bactrim, vancomycin, Zosyn, ranitidine, and Rivaroxaban were discontinued. Platelet counts stabilized the day after Zosyn was discontinued and slowly increased after the patient was treated with 2 doses of intravenous immunoglobulin, 4 units of platelets, and a tapered dose of prednisone. CONCLUSIONS: The patient was initially diagnosed with vancomycin-induced thrombocytopenia but then tested positive for antibodies to piperacillin and negative for antibodies to vancomycin and tazobactam. The patient was discharged with a diagnosis of piperacillin-induced thrombocytopenia. This case report presents a case of piperacillin-induced thrombocytopenia, previously misdiagnosed as vancomycin-induced thrombocytopenia and heparin-induced thrombocytopenia.