Background

The incidences of wasp stings are frequently reported in rural areas. The outcomes can range from a mild local anaphylactic reaction to a severe systemic reaction, like multiple organ dysfunction syndrome (MODS) [1, 2]. The severe wasp sting injuries have been occurring more often in countries including India, Vietnam, Thailand, Malaysia, and China [2, 9, 10]. In contrast to the occasional incidence in previous reports, the wasp stings have been occurring more frequently in China, causing a considerable mortality among victims [3, 11]. Patients with wasp stings reported in developed countries were usually suffered from a single sting, and an anaphylactic reaction is the main clinical feature of such patients. In China, however, patients were attacked by a crowd of wasps, resulting in severe hemolysis and rhabdomyolysis that greatly injured the kidneys [3]. Blood purification therapy is thus often applied to these patients. The current study showed that the three treatment strategies (HD, CVVH/HD, and SLED/HD) could provide a similar mortality and recovery rates. A previous case report described the successful outcomes after using CVVH to treat MODS secondary to wasp attacks [12]; nevertheless, a meta-analysis study did not find the survival advantage of using CVVH over HD to treat MODS patients with acute renal failure [13]. Our study also suggested that the use of SLED, CVVH, or HD provided similar clinical outcomes when treating patients with wasp sting induced MODS.

Renal failure is frequently observed in patients with wasp sting. These patients usually presented acute tubular necrosis or acute interstitial nephritis [14], and oliguria is rapidly observed with electrolyte imbalance. Blood purification treatment is thus important of these patients. Among the different blood purification methods, CVVH provided several advantages, including the improved hemodynamic stability that will allow better clearance of small−/macro-molecule of metabolites and recovery of renal function. On the other hand, HD has advantages of flexibility, cost-effectiveness, and is effective in removing small molecules such as potassium. It is also beneficial for reducing bleeding caused by anticoagulation. For critically ill patients, there has been no consensus on the ideal treatment that should be used, but combination treatment strategy has been suggested [15]. SLED provides advantages of both CVVH and HD. It is administered using conventional dialysis technology but over a prolonged period, thereby allowing for gradual removal of fluid with less hemodynamic perturbation [16,17,18]. For patients with critical acute kidney injury requiring renal replacement, the use of SLED and CVVH provides similar outcome in terms of overall mortality and renal function recovery [18].

The safety profiles of patients treated with SLED/HD or CVVH/HD were similar, in which there were no adverse events reported during the blood purification process. In addition, no significant difference was found between the two groups entering polyuria stage and the time when Scr returned to normal, indicating both of the blood purification methods could promote the recovery of renal function at about the same time. In comparison between SLED/HD group and HD group, patients in the SLED/HD group required a shorter time period to enter into the polyuria stage and had the Scr returned to normal level, also the incidence of hypotension was reduced. This could be due to the prolonged treatment time. Indeed, a study showed that the prolonged HD treatment could increase the clearance of urea and provide a more stable hemodynamic, when compare to the conventional HD [19]. Overall, the use of SLED/HD or CVVH/HD could provide a similar efficacy in renal function recovery.

The release of large amount of inflammatory mediators may contribute to the development of MODS [3, 20]. We found that on Day 3 of the treatment, patients in the SLED/HD group had a lower APACHE II score and a lower level of WBC when compared to the HD group, suggesting patients treated with SLED had a better improvement in general health condition and inflammatory reactions.

The cost of the treatment is an important factor when considering a treatment, especially for patients in rural area. It is well known that the expense of SLED treatment is higher than that of the HD. However, we found that in the current study the expenses are comparable between SLED/HD group and HD group. Both of these treatments had a lower cost than the CVVH/HD. The patients treated with SLED/HD required a shorter time period to enter into the polyuria stage and had a reduced number of treatments when compared to that of the HD group. Both of these factors contributed to the reduced cost of SLED treatment.

Conclusion

The current study had small sample size and was retrospective in nature. A further study with a randomized control group is needed to validate the results. In summary, the use of SLED, CVVH or HD in treating MODS secondary to wasp stings provided a similar survival and recovery outcome. However, when compared to HD treatment, the use of SLED could provide a better recovery of renal function and improvement of general health condition at a reasonable cost. As such, we recommend the use of SLED as a treatment strategy for patients with MODS induced by wasp stings.