We analyzed data from patients with renal colic during pregnancy who were treated in our department over the past 10 years. The main feature of this study is that we specifically evaluated patients with renal colic during pregnancy with a potential need for surgical intervention. We demonstrated that the duration of pain, ureteral stone size, hydronephrosis, and fever were independent predictors for surgical intervention.
The consideration of patient factors is an important element when making treatment decisions for renal colic .In accordance with previous reports [14-16], our present analysis demonstrated that the duration of pain symptoms is a significant clinical predictor for surgical intervention. We found that patients with <4 days of pain were more likely to be treated effectively by conservative techniques, while those with ≥4 days of pain were more likely to undergo surgical intervention. In fact, it has been suggested that delayed presentation, when considered as a single factor, may reduce the likelihood of stones passing spontaneously. We consider that the duration of pain is an important predictor for surgical intervention as this is a relatively easy parameter to acquire in an era were significant emphasis is placed on imaging and laboratory findings. In addition, the intensity of pain is closely related to surgical intervention. Unfortunately, we were unable to acquire comprehensive evaluation records that related to the intensity of pain.
The occurrence of hydronephrosis in a normal pregnancy has been attributed to hormonal effects, external compression, and intrinsic changes in the ureteral wall .Pathological hydronephrosis can usually be distinguished from physiological hydronephrosis by the presence of flank pain or the radiographic or sonographic visualization of the cause of the obstruction. In the present study, the degree of hydronephrosis differed between the two groups and therefore influenced the decision as to whether to perform surgery. Furthermore, we found that patients with moderate to severe hydronephrosis are more likely to undergo surgical intervention in pregnancy.
Ureteral stone size is a well-recognized prognostic factor for the successful passage of stones and is a key factor to consider when decision making [10, 19] .The passage rates for stones < 3 mm, 3 - 4.9 mm, 5 - 6.9 mm, and ≥ 7 mm have been reported to be 50%, 13%, 10%, and 0%, respectively[ 20]. In the present study, we found that a stone size stones ≥ 8 mm is a risk factor for surgical intervention. Compared with non-pregnant women, ureteral stones are easier to pass during pregnancy due to the fact that the ureters are dilated.
Approximately 50% of pregnant women with stones will suffer from urinary tract infection and will require antibiotics. Urgent decompression of the urinary system in a febrile or septic pregnant woman, followed by a subsequent definitive solution under improved conditions, is highly recommended for such cases. In the present study, 16% of pregnant women had fever and 70% patients who had a persistently high fever underwent surgery. However, antibiotic treatment was effective for pregnant women who had not undergone surgery and had transient fever. Through ROC curve, fever can predict that 56.6% of patients will require surgery. Therefore, a persistent high fever in pregnant women with acute renal colic may result in sepsis and systemic inflammatory response syndrome, thus endangering the safety of the mother and child; surgical intervention is vital in such cases.
Our analyses ultimately allowed us to create a nomogram. Based on this nomogram, it is possible to calculate a risk score for a given patient. Thus, we can determine the probability of surgical intervention. We believe that the use of this nomogram in clinical practice may help us to guide the management of patients suffering from renal colic in pregnancy.
There are several limitations to our study that should be considered. Owing to the retrospective nature of the data acquisition, the decision to intervene surgically lacks appropriate standardization. Moreover, the decision to treat patients non-surgically was not standardized and we cannot therefore assess all of the potential factors that were involved in the decision-making process. Another limitation is that this analysis reflects our own treatment decisions that may not be in concordance with other urological centers. We are based in the South China Urology Stone Treatment Center. Many of our patients had undergone a series of interventions in an outer hospital before coming to our institution. This may have increased our rate of surgical intervention. However, none of our patients were found to have elevated levels of serum creatinine. Furthermore, except for one case, involving premature delivery after the placement of a ureteral stent, all patients were discharged from the hospital safely. Although one patient with premature birth occurred after surgery, the patient also had other important factors leading to premature birth, such as fever, pyelonephritis, which could led to adverse results .At our institution, ultrasound is the imaging study of choice. This is because ultrasound can safety evaluate stone size, stone location, and hydronephrosis in pregnancy. Although computed tomography (CT) has become the preferred imaging method for diagnosing urinary stones, we only use B-ultrasound in pregnant cases. Data from CT imaging techniques are likely to improve the estimation of calculus size and location, particularly when very small calculi are present.