Discussion and Conclusions
We obtained two new findings from this case. First, to the best of our knowledge, this is the first case to use PDF for SCLS. Second, we determined that the substances that are therapeutic targets for SCLS are likely to be included in the medium molecule region.
We introduced PDF to treat SCLS. PDF is a blood purification method in which a dialysate is recirculated to the outside of a hollow fiber while performing plasma exchange with fresh frozen plasma (FFP) or an albumin solution using a membrane type plasma separator Evacuer🄬 Plus (Kawasumi Chemical Industry, Ltd.) EC-2A filter. PDF is said to be able to remove small and medium-sized harmful substances while retaining useful substances in the large molecule region, such as immunoglobulin and coagulation factors. Therefore, the major advantage of PDF compared to PE is that it can reduce the use of FFP (14, 15). Reducing the use of FFP can lower the cost of treatment and reduce the risk of blood transfusion complications.
In this case, PDF showed a remarkable effect, due to which we can surmise that substances within the treatment target of PDF may be the cause of SCLS. In Japan, PDF is treated as PE for insurance claims, so the use of PDFs is limited to those with PE insurance coverage. However, this patient also had myasthenia gravis and was covered by insurance for PE, due to which performing PDF was not a problem. In other circumstances, the cost can be an issue with using PDF. Therefore, unless the physician is very confident about the diagnosis, PDF should be used with extreme caution.
The findings obtained in this case can be useful to plan treatment for SCLS in future cases. If substances in the middle molecular area are responsible for increased vascular permeability, immunoglobulin and M protein will not be directly responsible. There are reports of vascular endothelial growth factor and angiopoietin 2 as substances in the middle molecular region and they reflected the clinical course(13). Together with the results of this study, it may be that such substances are the cause of SCLS.
SCLS is a rare syndrome, difficult to diagnose, and has an uncertain etiology. Although our patient did not show any hemoconcentration, she was diagnosed as having SCLS due to prominent hypotension and decrease in GEDI and hypoalbuminemia. In this case, the recurrence of sepsis could not be ruled out, but there were no major problems during surgery, the appropriate antibiotics had been administered, and blood test results had showed improvement. Finally, we could confidently diagnose SCLS based on the presence of monoclonal M protein. Other differential diseases, such as ovarian hyper-stimulation syndrome and hereditary angioedema were ruled out based on serum estradiol level and C1 esterase inhibitor level, respectively. Although there have been reports of SCLS complicated with cancer (8), the relationship between cancer and SCLS is unclear. In addition, SCLS occurring with myasthenia gravis has not been reported in the past, and it is unclear whether the two diseases are related. In this case, it was not possible to completely improve the vascular permeability. The patient may not have been completely cured due to persisting malignancy or metastasis. However, PDF may be useful in overcoming the acute phase of SCLS.
In summary, an 84-year-old woman with a history of myasthenia gravis underwent surgery for colon cancer-related perforating peritonitis. After surgery, SCLS developed and was treated using PDF. PDF was considered to be an effective treatment that covers the therapeutic target of SCLS. The use of PDF may be considered when treating the acute phase of SCLS. To the best of our knowledge, this is the first report using PDF for SCLS.