Urinary tract stones in pregnancy

Pr-AKI: Acute Kidney Injury in Pregnancy – Etiology, Diagnostic Workup, Management

Despite significant improvements in inpatient and outpatient management, pregnancy-related acute kidney injury (Pr-AKI) remains an important risk factor for early and late maternal and fetal morbidity and mortality. There is a discrepancy between the incidence of Pr-AKI in developing and in developed countries, with the former experiencing a decrease and the latter an increase in Pr-AKI in recent decades. Whereas septic and hemorrhagic complications predominated in the past, nowadays hypertensive disorders and thrombotic microangiopathy are the leading causes of Pr-AKI. Modern lifestyles and the availability and widespread use of in-vitro fertilization techniques in industrialized countries have allowed more women of advanced age to become pregnant. This has led to a rise in the percentage of high-risk pregnancies due to the disorders and comorbidities inherent to or accompanying aging, such as diabetes, arterial hypertension and preexisting chronic kidney disease. Last but not least, the heterogeneity of symptoms, the often overlapping clinical and laboratory characteristics and the pathophysiological changes related to pregnancy make the diagnosis and management of Pr-AKI a difficult and challenging task for the treating physician. In addition to general supportive management strategies such as volume substitution, blood pressure control, prevention of seizures or immediate delivery, each disease entity requires a specific therapy to reduce maternal and fetal complications. In this review, we used the current literature to provide a summary of the physiologic and pathophysiologic changes in renal physiology which occur during pregnancy. In the second part, we present common and rare disorders which lead to Pr-AKI and provide an overview of the available treatment options.

A Systematic Review of Elective Laser Therapy during Pregnancy

Introduction: Currently, lasers are used to treat many diseases and their complications. However, the use of lasers in pregnant patients is still controversial. Methods: In this review, the application of lasers in the fields of urology, surgery, obstetrics, dermatology, and musculoskeletal disorders is evaluated. The following keywords were used to search through PubMed, Google Scholar, and Scopus: pregnancy, laser, urolithiasis, endovenous laser ablation (EVLA) or treatment, leg edema, varicose vein, venous insufficiencies, hair removal, pigmentation, telangiectasia, vascular lesions, Q switch laser, diode laser, holmium, holmium-YAG laser, erbium laser and Pulsed dye laser, low-level laser therapy, high-intensity laser therapy, pain, musculoskeletal disorders, twin to twin transfusion syndrome (TTTS), amnioreduction, and safety. Results: Totally, 147 articles were found, and their abstracts were evaluated; out of 53 articles extracted, 14 articles were about dermatology, 24 articles were about urology, 12 articles were about obstetrics and gynecology, 10 articles were about musculoskeletal disorders and three articles were related to surgery. Conclusion: Laser therapy can be used as a safe treatment for urolithiasis, skin diseases, TTTS and varicose veins of the lower extremities. However, the use of laser therapy for musculoskeletal disorders during pregnancy is not recommended due to lack of evidence, and also we cannot recommend endovenous ablation.

Comparison of Conservative and Surgical Treatments in Symptomatic Pregnancy Hydronephrosis

OBJECTIVES

This study aimed to evaluate the factors affecting the treatment choice in pregnant women with symptomatic hydronephrosis.

METHODS

Hospital records of pregnant women who visited our clinic due to symptomatic hydronephrosis between December 2010 and December 2020 were analysed retrospectively. Patients were divided into 2 groups: conservative and surgical (JJ stent) treatment groups. Age, gestational week, primipara, trimester, visual analogue scale (VAS), and preterm birth rates as well as clinical, laboratory, and ultrasonography findings were compared between the groups.

RESULTS

The study included 227 pregnant women (conservative treatment group, 133; JJ stent group, 94). Age, gestational week, primipara, trimester, hydronephrosis side, fever, pyelonephritis, pyuria, preterm labour and abortion, as well as blood urea nitrogen, creatinine, C-reactive protein, and white blood cell levels did not differ significantly between the groups (p > 0.05). In the JJ stent group, VAS, creatinine value, culture positivity rate, degree of hydronephrosis, and renal pelvis anterior-posterior (AP) diameter were significantly higher than those in the conservative treatment group (p < 0.05). The cut-off value for renal pelvis AP diameter was 16.5 mm in the first 2 trimesters and 27.5 mm in the third trimester.

CONCLUSIONS

Surgical treatment should not be delayed in pregnant women who do not respond to conservative treatment and have impaired renal function and grade 3-4 hydronephrosis. Early surgical intervention is necessary in patients with a renal pelvis AP diameter of >16.5 mm in the first 2 trimesters and >27.5 in the third trimester.

Imaging during pregnancy: What the radiologist needs to know

During the last decades, there has been a growing demand for medical imaging in gravid women. Imaging of the pregnant woman is challenging as it involves both the mother and the fetus and, consequently, several medical, ethical, or legal considerations are likely to be raised. Theoretically, all currently available imaging modalities may be used for the evaluation of the pregnant woman; however, in practice, confusion regarding the safety of the fetus often results in unnecessary avoidance of useful diagnostic tests, especially those involving ionizing radiation. This review article is focused on the current safety guidelines and considerations regarding the use of different imaging modalities in the pregnant population; also presented is an imaging work-up for the most common medical conditions of pregnant women, with emphasis on fetal and maternal safety.

Safety and feasibility of percutaneous nephrolithotomy (PCNL) during pregnancy: A review of literature

OBJECTIVE

Management of nephrolithiasis during pregnancy can be challenging because of the potential risks to the mother and fetus. Diagnosis and treatment can be a dilemma owing to the anatomical and physiological changes, besides the limitation in the use of X-rays. The aim of this article was to identify any case series or case reports where percutaneous nephrolithotomy (PCNL) was used as a treatment modality for nephrolithiasis in pregnancy.

MATERIAL AND METHODS

A review of the literature was performed using Medline, EMBASE, CINAHL, and Scopus from 1990 to October 2019. A search was conducted using the following search terms: "urolithiasis," "renal stones," "stone disease," "kidney stones," "pregnancy," "pregnant," "percutaneous nephrolithotomy," "PNL," and "PCNL." The initial search strategy retrieved 52 articles, but after going through them, only 7 were suitable for inclusion in this review.

RESULTS

Overall, seven studies reported regarding 16 patients who underwent PCNL procedure during pregnancy. The patients were aged 18-34 years and had the procedure between 11 and 32 weeks of gestation. Most stones were in the renal pelvis or pelvic-ureteric junction and sized 8-40 mm, with the most common indication for the intervention being refractory pain. Most treatments used ultrasound guidance, and X-ray fluoroscopy was employed only in two cases. No complications occurred to the mother or fetus in any of the case reports, suggesting that PCNL is a safe and feasible treatment for patients with persistent symptoms when conservative treatment has failed.

CONCLUSION

All the reported cases of PCNL achieved stone-free status with no complications. Although PCNL has been evidenced to be safe, it must be performed by experienced endourologists after careful consultation with the obstetricians. Patient counseling and multidisciplinary team decision-making are paramount in such complex scenarios.

Review on diagnosis and management of urolithiasis in pregnancy: an ESUT practical guide for urologists

PURPOSE

Management of urolithiasis in pregnancy can be challenging for most urologists with diagnostic and treatment dilemma to ensure the best outcome for both mother and fetus. We wanted to review the literature for urolithiasis in pregnancy with a practical management guide for urologists.

METHODS

A non-systematic review of literature was carried out for all English language literature using Medline. To ensure a more comprehensive search, the review of diagnosis and management of pregnant patients with urolithiasis was carried out separately, by two authors independently. Due to diagnostic complexity, investigations (US, CT, MRI) carried out were assessed separately.

RESULTS

Our search included diagnostic studies such as US, CT and MRI (73, 20 and 27 articles, respectively) and management studies (55 articles in total). Details on etiology, radiation risk, safety of various diagnostic modalities, medications and treatment options are covered through an evidence-based approach. We provide a practical guide for urologists in what is clearly a stressful situation for patient and physician alike.

CONCLUSIONS

Urolithiasis in pregnancy needs a careful multidisciplinary management to achieve good outcomes for both mother and baby. Our review shows that a balanced approach for diagnosis and treatment seems to achieve the best outcomes in pregnancy.

The Efficacy and Safety of Laser Lithotripsy in Pregnancy

Introduction: The aim of our study was to assess the efficacy and safety of laser lithotripsy in pregnant patients. Methods: In this retrospective study, we reviewed the 15 pregnant women who have been treated for ureteral stones with semi-rigid ureteroscope and holmium laser at our center between Januarys 2007and April 2015. Results: The mean age of patients and mean gestational age was 29.3 years old 27.3 weeks respectively. Mean size of stones was 7.84 mm. Twelve patients had renal colic, and hematuria was found in 3 cases. Irritative urinary symptoms such as frequency and urgency detected in 6 ones and 2 patients had fever. The stone of all patients were fragmented by using holmium laser lithotripter. In 5 patients stone residual fragments were removed by grasper while other 10 patients were left to pass fragments spontaneously. No intraoperative and postoperative urological or obstetric complication was seen. Conclusion: Laser lithotripsy is safe and efficacious in pregnant patients who have ureteral stone that does not respond to conservative management.

Stones in special situations

There are several special situations in which urinary lithiasis presents management challenges to the urologist. An in-depth knowledge of the pathophysiology, unique anatomy, and treatment options is crucial in order to maintain good health in these patients. In this review, we summarize the current literature on the management of the following scenarios: bladder stones, stones in bowel disease, during pregnancy, in association with renal anomalies, with skeletal deformities, in urinary diversions, and in children.

Urolithiasis in pregnancy

Clinicians are faced with multiple diagnostic and treatment challenges when managing pregnant women with urolithiasis. Anatomical and physiological changes during pregnancy have to be taken into account whilst simultaneously considering both the expectant mother and the foetus. Ultrasonography remains the first-choice imaging modality, notwithstanding its potentially poor diagnostic accuracy. There is currently no consensus on second-line investigation for suspected urolithiasis. Low-dose non-contrast CT is highly sensitive, but the long-term effects of ionizing radiation on the foetus remain unknown. As far as treatment is concerned, expectant therapy is the primary option for management in the majority of cases. Percutaneous nephrostomy or ureteric stent placements are safe temporizing measures in relieving an acutely obstructed system and should be expedited in the presence of sepsis. Studies have shown ureteroscopy to be safe and effective during pregnancy with no significant risk to the foetus. It is important for the clinician to explain clearly the risks associated with the investigation and management options to the pregnant patient, including an acknowledgement that some of these remain unquantified, or even unknown.

Urolithiasis in pregnancy

Urolithiasis in pregnancy is a major health concern and can potentially affect the well-being of both mother and foetus. Management of this condition often entails simultaneous multidisciplinary involvement of obstetrician, radiologist and urologist. Additionally, adverse effects with usage of anaesthesia, radiation, medications and surgery on mother and foetus, limit utilisation of the full armamentarium of diagnostic and therapeutic modalities that are commonly used in non-pregnant women. This review was conducted using an electronic literature search of peer reviewed journal articles. Clinical studies were identified in the bibliographic database- PubMed (Medline), Ovid and eMedicine(WebMD) using the keywords: hydronephrosis, urolithiasis, kidney stone, urinary tract infection, pregnancy and ultrasound, incidence and epidemiology of renal stones.

Ureteral Stent Insertion in the Management of Renal Colic during Pregnancy

To determine an optimal invasive intervention for renal colic patients during pregnancy after conservative treatments have been found to be unhelpful. Among the available invasive interventions, we investigated the reliability of a ureteral stent insertion, which is considered the least invasive intervention during pregnancy. Between June 2006 and February 2015, a total of 826 pregnant patients came to the emergency room or urology outpatient department, and 39 of these patients had renal colic. The mean patient age was 30.49 years. In this retrospective cohort study, the charts of the patients were reviewed to collect data that included age, symptoms, the lateralities and locations of urolithiasis, trimester, pain following treatment and pregnancy complications. Based on ultrasonography diagnoses, 13 patients had urolithiasis, and 13 patients had hydronephrosis without definite echogenicity of the ureteral calculi. Conservative treatments were successful in 25 patients. Among these treatments, antibiotics were used in 15 patients, and the remaining patients received only hydration and analgesics without antibiotics. Several urological interventions were required in 14 patients. The most common intervention was ureteral stent insertion, which was performed in 13 patients to treat hydronephrosis or urolithiasis. The patients' pain was relieved following these interventions. Only one patient received percutaneous nephrostomy due to pyonephrosis. No pregnancy complications were noted. Ureteral stent insertion is regarded as a reliable and stable first-line urological intervention for pregnant patients with renal colic following conservative treatments. Ureteral stent insertion has been found to be equally effective and safe as percutaneous nephrostomy, which is associated with complications that include bleeding and dislocation, and the inconvenience of using external drainage system.

Is there a relationship between the grade of maternal hydronephrosis and birth weight of the babies?

Mild hydronephrosis may be present in upto 90% of pregnancies. The degree of hydronephrosis was determined by maximal calyceal diameter (MCD). The aim of this study is to investigate whether there is a relationship between grade of maternal hydronephrosis and birth weight of the babies. Subjects were examined in three groups: group 1 MCD of 5-10 mm (grade I), group 2 10-15 mm (grade II) and group 3 patients >15 mm (grade III). There were 45, 30, 13 patients in the groups, respectively. Estimated fetal weight (EFW) at the time that hydronephrosis was diagnosed, birth weight and duration of pregnancy were compared. The average birth weight of the babies was not statistically different in the three groups (p > 0.05), but there was a statistically significant difference in fetal weights at the time of diagnosis (p = 0.02). The grade of maternal hydronephrosis does not affect the duration of pregnancy.

Current status of ureteroscopy for stone disease in pregnancy

Ureteroscopic management of urolithiasis in pregnancy has been on the rise. Technological advancements such as the development of the semi-rigid or flexible ureteroscope, improvements in the design of baskets used for retrieval and the availability of laser have enabled atraumatic fragmentation of stones. We did a systematic review of literature from January 1990 to December 2012. Data were analysed separately for the time period from January 1990 to June 2010 (Period 1) and for last 2.5 years from July 2010 to December 2012 (Period 2). Inclusion criteria were all English language articles with at least three patients reported. Data were extracted on the outcomes and complications reported in the literature. A total of 271 procedures (116 in period 1, 155 in period 2) across 21 studies were reported in the last 22 years. General anaesthesia was used in 38% (44/116) in period 1 and in 64% (99/155) in period 2. The average stone size (7.6 mm) and stone-free rate (SFR) (85%) were similar in both time periods. Fluoroscopy was used in 20% (23/116) and 24% (38/155) in period 1 and 2, respectively. There were fewer complications in period 1 (n = 9) than period 2 (n = 25). These complications were divided into obstetric (n = 5) and non-obstetric complications (n = 29). There were no maternal or foetal deaths during the 22 years. Stone treatment using ureteroscopic techniques in pregnancy can achieve a high success rate. Evidence suggests a rise in the risk of complications with increasing number of these procedures in pregnancy.

Challenges on percutaneous nephrolithotomy in pregnancy: Supine position approach through ultrasound guidance

Urolithiasis in pregnancy represents a major diagnostic and therapeutic challenge to the obstetrician, urologist, radiologist and anesthetist. It is a cause of major concern, considering the potential adverse effects of radiation exposure and of any invasive surgical procedure and anesthesia on the mother and fetus. Fortunately, with conservative management, 70-80% of symptomatic calculi pass spontaneously with no sequel. However, fever, infection, uncontrolled pain and progressive hydronephrosis are indications for surgical intervention when retrograde placements of a ureteral stent or a percutaneous nephrostomy tube are the most traditional options. The recent technological advances in stone fragmentation devices and the administration of safe anesthesia have forced clinicians to embark on more definitive stone management techniques in pregnancy. Ureteroscopy is considered the first definitive treatment of obstructive ureteral calculi during all trimesters of pregnancy, but also has limitations. Although generally avoided during pregnancy, percutaneous nephrolithotomy can be a good treatment choice in selected patients.

Kidney stones and pregnancy

Kidney stones are common and do not spare the pregnant population. Although a simple stone event is usually straightforward in the general population, it is complex during pregnancy. Acute nephrolithiasis is associated with a unique set of complications during pregnancy and, because of imaging limitations, diagnosis is challenging. Multidisciplinary care is the key in proper management decisions. The pathophysiology of kidney stone formation in the pregnant state is also unique. Herein, we discuss the complexity of kidney stones and pregnancy.

Pregnancy-Associated Kidney Injury

A 23-year-old G1P0000 without prior past medical history is 31 weeks pregnant with prenatal care presents with complaints of worsening leg and face swelling for the past 2 days now seeks care because of headache, diarrhea, nausea, and vomiting. On exam she is found to have a blood pressure of 120/86, edema, and brisk deep tendon reflexes. Laboratory testing revealed hemoglobin 11.3 g/dl, platelet count 141,000/μl white blood count 18,000/μl, creatinine 1.1 mg/dl, aspartate aminotransferases (AST) 65 U/l, lactate dehydrogenase (LDH) 400 U/l, total bilirubin 1.1 mg/dl, prothrombin time (PT) 14.7 s, ammonia of 90 mcg/dl, blood glucose 139 mg/dl, calcium 7.3 mg/dl, and uric acid of 6.0 mg/dl. The urinalysis demonstrated WBC’s 3–5/hpf, RBC’s 3–5/hpf—non-dysmorphic, renal tubular epithelial cells were seen and a urine protein to creatinine ratio of 2. One day after hospitalization the patient’s blood pressure was 145/87 with a similar blood pressure 6 h later.

Use of renal resistive index and semi-rigid ureteroscopy for managing symptomatic persistent hydronephrosis during pregnancy

PURPOSE

The aim of this study was to evaluate the use of Doppler ultrasonography (DUS) and semi-rigid ureteroscopy (URS) for managing symptomatic persistent hydronephrosis during pregnancy.

MATERIALS AND METHODS

The study included 19 pregnant patients with unilateral symptomatic persistent hydronephrosis. All pregnant patients were assessed with conventional ultrasonography (US) followed by DUS for both kidneys.

RESULTS

The mean patient age was 26 years (range 19-40), and the gestational period was 24 weeks (range 16-33). There was a significantly higher mean resistive index in the kidneys with ureteral obstruction than in the contralateral normal kidneys. Spinal anesthesia was performed on 18 patients, while general anesthesia was performed on 1 patient. Endoscopically stones were found in 17 patients (89.5%), while no stone was found in 2 patients (10.5%). The stones were fragmented by holmium laser and retracted with forceps. After lithotripsy, a ureteral JJ stent was inserted in 8 of 17 (47%) patients with ureteral stones. Intraoperatively, there were no obstetric complications, while ureteral perforation was seen in one patient. Two patients are still pregnant at the time of this writing, and 17 babies were born normally.

CONCLUSIONS

Both RI and ΔRI increase in unilateral symptomatic persistent hydronephrosis during pregnancy. Semi-rigid URS can be used successfully for diagnosis and treatment in these patients.

Imaging of pregnant and lactating patients: part 2, evidence-based review and recommendations

OBJECTIVE

The objectives of this article are to discuss the current evidence-based recommendations regarding the use of diagnostic imaging in the evaluation of pulmonary embolism, appendicitis, urolithiasis, and cholelithiasis during pregnancy.

CONCLUSION

Diagnostic imaging should be performed during pregnancy only with an understanding of the maternal and fetal risks and benefits, the comparative advantages of different modalities, and the unique anatomic and physiologic issues associated with pregnancy.

The efficacy and safety of ureteroscopy for ureteral calculi in pregnancy: our experience in 32 patients

The aim of this study was to investigate the efficacy and safety of ureteroscopy (URS) in pregnant women. A retrospective analysis was performed on 32 pregnant patients referred to our center between April 2005 and November 2010 with hydronephrosis requiring surgical intervention. A semirigid URS of 9.5 F was used in all patients. The mean age of patients was 27.8 years (range 20-39), and the mean gestation duration was 24 weeks (15-34). The ultrasound findings were diagnostic of obstructive ureteral calculi in 16 (50%) patients and the mean stone diameter was 8 mm. Spinal anaesthesia was performed in 22 (68.8%) patients, while general anaesthesia was performed in 7 (21.8%) patients. Ureteric stones were found in 27 (84.3%) patients during endoscopy, 10 being distal, 9 middle and 8 proximal. There were no stones in five patients. The stones were fragmented with pneumatic lithotripsy in 8 patients and with holmium laser in 17 patients and the fragments were retracted with forceps. Of the 32 patients, 19 (59.4%) required JJ stent insertion peroperatively. There was no serious complication intraoperatively, while urinary tract infection developed in four and renal colic in two patients postoperatively. In one patient, sepsis developed postoperatively, and improved with appropriate treatment. All babies were born normally. Semirigid ureteroscopy for diagnosing and treating ureteral calculi by intracorporeal pneumatic or holmium laser lithotripsy is a safe and reasonable treatment option for pregnant patients.

Urologic emergencies in pregnancy

The management of urological emergencies during pregnancy presents unique clinical challenges for the treating physician. Clinical signs and symptoms are often subtle while diagnostic and therapeutic options are limited in treating patients to avoid fetal morbidity. A high index of suspicion with early diagnosis and treatment are essential for the management of genitourologic emergencies in pregnant women. It is essential for patients to be managed on an individual basis using a multidisciplinary approach.

Urinary Stone Disease during Pregnancy: One Problem, Two Patients

Urolithiasis in pregnant women is a quite uncommon event: about one in 1500 pregnancies is complicated by urinary calculi and it occurs in 80–90% of the patients during the second or third trimester of pregnancy.

Several factors may predispose stone formation in the upper urinary tract during pregnancy: the “physiological” hydronephrosis, the gestational hypercalciuria, and an elevation in both glomerular filtration rate and renal plasma flow, associated with an increase of creatinine clearance and higher renal filtration rate of sodium, calcium, and uric acid. Flank or abdominal pain is the most common symptom associated with evident or microscopic hematuria. Differential diagnosis of pain varies according to its location: it could be of gastrointestinal or gynecologic origin.

Diagnosis is previously based on ultrasound evaluation. The use of radiation must be avoided during pregnancy, even if the risk of fetal injures depends on gestational age and radiation dosage. Most of the symptomatic ureteral stones affecting pregnant women pass spontaneously: therefore therapy could be conservative (hydration, analgesia, antibiotics, antiemetics) in the most of cases, although in the 15–30% of the cases it is necessary to adopt an active treatment, like percutaneous nephrostomy drainage, ureteral stent insertion or ureterorenoscopy.

Management of urinary calculi in pregnancy: a review

Nephrolithiasis during pregnancy can represent a clinical dilemma because of potential risks to both mother and fetus. While the incidence of symptomatic nephrolithiasis during pregnancy varies between 1 in 244 to 1 in 2000 pregnancies, the actual incidence is likely to be higher. A significant proportion of patients with asymptomatic renal calculi are detected incidentally in the nonpregnant population compared with pregnant women. Factors that contribute to the diagnostic challenges include anatomic and physiologic changes to the female urinary tract during pregnancy and the limitations on the use of ionizing radiation. The treatment of such patients requires a multidisciplinary team approach involving the urologist, obstetrician, and radiologist. The potential hazards of intervention (either surgical or medical) and anesthesia need to be considered carefully.

Management of Symptomatic Urolithiasis During Pregnancy

Urinary calculi during pregnancy present not only a diagnostic challenge but also a management dilemma. In this retrospective study, we describe our experience with diagnosis and management of symptomatic urolithiasis in pregnant women. A total of 18 pregnant women were treated for urolithiasis at the Department of Urology, Kaohsiung Municipal Hsiao-Kang Hospital, between 1999 and 2004. The incidence of symptomatic urolithiasis during pregnancy was 0.35%. Of the 20 stones found, nine were on the right side and 11 were on the left, and two patients had bilateral urinary stones. Most urolithiasis cases during pregnancy (55.5%) occurred in the third trimester. Flank pain (94.4%) was the most common clinical presentation. Conservative management was successful in 10 patients until the end of pregnancy and then definite treatment was performed. In four patients, a double-J stent was inserted successfully for persistent pain. In three cases with persistent pain, failure of double-J stent placement was treated with ureteroscopic lithotripsy under epidural anesthesia. One patient received percutaneous nephrostomy for persistent renal colic and pyonephrosis. Ultrasonographic evaluation of pregnant women with suspected renal colic is a reasonable diagnostic procedure. Ureteroscopy is another choice when conservative treatment fails.

Urolithiasis in pregnancy

The presentation of urolithiasis is often dramatic, but rarely is it more anxiety provoking than during pregnancy. The evaluation and the intervention are often approached with trepidation as the health of the mother and the fetus must be taken into account. The typical diagnostic course and surgical management used in the nonpregnant population must be reevaluated in the expectant mother. Failure to promptly diagnose and manage urolithiasis during pregnancy may have adverse consequences for mother and child. The authors present a review of the relevant anatomic and physiologic changes of pregnancy as they affect stone disease and outline options for radiologic evaluation and surgical management.

Urologic Radiology During Pregnancy

The pregnant patient presents a unique diagnostic challenge to the urologist because the well-being of both the mother and fetus must be considered. Radiation exposure to the fetus during gestation presents risks such as cell death and teratogenic effects, carcinogenesis, and genetic effects, which must be considered when selecting diagnostic tests. However, with the exercise of good clinical judgment and the use of the armamentarium of diagnostic imaging modalities available, the pregnant patient can be managed with minimal, if any radiation exposure to the fetus.

Urolithiasis in Pregnancy: Current Diagnosis, Treatment, and Pregnancy Complications

Urolithiasis complicates up to one in every 200 pregnancies; consequently, the practicing obstetrician should be aware of the symptoms of urolithiasis, the diagnostic procedures available for its diagnosis, and their associated risks. These include ultrasound, urography, and magnetic resonance imaging. Diagnosis of urolithiasis during pregnancy can be a challenge as a result of the normal physiological changes of pregnancy. Conservative management is the first-line treatment for noncomplicated urolithiasis in pregnancy. If spontaneous passage of the stone does not occur or if complications develop, urologic consultation should be obtained. Several obstetric complications have been associated with urolithiasis, including preterm labor and preterm premature rupture of membranes, although the reported rates of these complications in association with urolithiasis vary widely and overlap normal background rates. Given that urolithiasis will be encountered by most obstetricians, and that obstetricians are often on the front line of management for this condition, an appreciation of current diagnostic modalities, treatment protocols, and associated potential obstetric complications is warranted.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to recall that urolithiasis is common in pregnancy, state that there are a variety of diagnostic procedures, summarize that conservative treatment is usually successful, and explain that complications of pregnancy usually occur when there is failure of conservative treatment.

Are changes in urinary parameters during pregnancy clinically significant?

We aimed to objectively determine changes in the various urinary parameters along with CaOx saturation level during pregnancy. The study included 15 pregnant women who had no known diseases and were taking no medication except prenatal supplements. Mean age of the patients was 26 years (range 20-30). In all of them, this study was carried out in each trimester and 3 months post partum. All participants were followed up, and blood and urine samples were obtained during the pregnancy and during 3 months post partum. All subjects collected 24-h urine samples. The pregnant women had hypercalciuria in all three trimesters. Except for the first trimester, urine calcium levels in all trimesters were significantly higher when compared with the post-partum period (P<0.01 for second trimester, P<0.05 for third trimester). Urine oxalate level in post-partum period was significantly higher than urine oxalate levels in each trimester (P<0.05). The urine citrate levels were similarly higher than normal levels in three trimesters. Urine citrate level of the post-partum period was in normal reference ranges. This difference was not statistically significant (P>0.05). We believe that hypercalciuria encountered at pregnancy is a reversible physiologic condition. Also, citrate and magnesium as urinary inhibitors increased in urine during gestation preventing stone formation. We think that long time periods are needed for hypercalciuria to be able to lead to the formation of urinary calculi in pregnant women (except women having a positive family history). Therefore, we think that the pregnancy alone does not predispose to a suitable condition for calculi.

Renal ultrasound

Renal US is one of several imaging modalities available to the EP in the evaluation of patients with acute urologic disorders. It offers excellent anatomic detail without exposure to radiation or contrast agents but is limited in its assessment of renal function. It is an important alternative to helical CT scanning for evaluating renal colic, especially in children and pregnant women. It has an important role in excluding bilateral renal obstruction as the cause of acute renal failure. It is likely that Doppler renal US also will take on a prominent role in the evaluation of renal vascular disorders. It already has become the standard of care in the management of renal transplant patients. Bedside emergency renal US performed and interpreted by EPs with limited training and experience is increasing in use and gaining acceptance. At present, the primary role of renal US is to identify hydronephrosis in patients with renal colic or acute renal failure but, in the future, its role likely will expand as technology advances and its use increases. In many patients, bedside renal US may obviate the need for further diagnostic workup and speed the diagnosis and treatment of an emergency patient.

Nephrolithiasis and pregnancy

PURPOSE OF REVIEW

Urolithiasis during pregnancy is not common, however, it is a difficult condition to both diagnose and treat. There are many safety concerns that must be considered for both the mother and fetus. In this review we detail the different options available to the urologist and we highlight a treatment algorithm that we use when faced with a pregnant patient suspect of having a urinary calculus.

RECENT FINDINGS

Changes in ultrasound, limited intravenous urograms and magnetic resonance imaging have improved our ability to diagnose urolithiasis in pregnancy. Additionally ureteroscopy has emerged not only as a diagnostic tool but also as a modality for definitive treatment that can safely be used during the intrapartum period.

SUMMARY

When diagnosing urolithiasis in the gravid patient, the first line study should be ultrasound, using change in resistive index and transvaginal ultrasound. If these are not diagnostic, then a limited intravenous urograms should be performed. Once a diagnosis has been established, initial treatment should be conservative since 70-80% of patients will pass their stones. When intervention is necessary, the placements of an internal stent or percutaneous nephrostomy tube or ureteroscopy with definitive stone treatment are all reasonable options.

Renal vein Doppler ultrasound of maternal kidneys in normal second and third trimester pregnancy

The flow pattern in intrarenal veins depends on renal parenchymal histology and cardiac physiology. The intrarenal venous impedance index obtained by Doppler ultrasound is related to compliance in vein, and can be helpful in the assessment of renal parenchymal compliance. The purpose of this study was to determine whether normal pregnancy has a significant effect on intrarenal venous blood flow, and assess if the physiological pyelocaliectasis causes a measurable reduction in venous impedance indexes in pregnant women. Doppler ultrasound of intrarenal veins was performed in 35 asymptomatic pregnant women in the second and third trimester of gestation, and in 24 non-pregnant healthy women. After grading the degree of hydronephrosis, venous impedance index was obtained from the interlobar veins. The venous waveforms in pregnant women showed diminished phasic oscillations owing to elevated pre-systolic flow. The mean venous impedance indexes in pregnant women were significantly lower than the values in non-pregnant subjects, 0.30+/-0.10 versus 0.44+/-0.06 in the right (p<0.001), and 0.36+/-0.11 versus 0.41+/-0.07 in the left kidney (p=0.03). There was an inverse correlation between the grade of pelvicalyceal dilatation and the venous impedance indexes in both kidneys in pregnant women (r=-0.62, p<0.001 for the right kidney, and r=-0.38, p=0.05 for the left kidney). An abnormally reduced venous impedance index in pregnant women can at least in part be explained by reduced vascular compliance from increased interstitial pressure subsequent to partial obstruction of ureters by the gravid uterus, and caution should be exercised in interpreting it as a sign of pathological ureteral obstruction.

Tips and tricks for the management of retained ureteral stents

BACKGROUND AND PURPOSE

Retained ureteral stents, especially those that are encrusted and associated with a stone burden, can be a difficult management problem. We review our experience and the different options employed for treating this complication.

PATIENTS AND METHODS

From July 1998 to February 2002, 26 retained ureteral stents were managed in our department. The average patient age was 45.9 years (range 8-77 years). The average time the stent had been in place was 10.7 months (range 3-28 months). Prior to planning definitive therapy, a plain radiograph with tomographic views was reviewed.

RESULTS

A guidewire or Glidewire was often placed adjacent to the stent in order to maintain ureteral access and in some cases was able to facilitate removal of the retained stent. The patients required an average of 2.7 endourologic procedures (range 1-4) performed at one or more sessions to remove the stent and all associated stone burden. If the stone burden could not be entirely removed then stent extraction and subsequent sessions were performed until stone-free status was achieved. Cystolitholapaxy was required to treat the distal component of stent encrustation in 20 cases. Percutaneous nephrolithotomy was performed in four patients, antegrade ureteroscopy with or without intracorporeal lithotripsy in four patients, retrograde ureteroscopy with or without laser lithotripsy in five patients, and extracorporeal shockwave lithotripsy in seven patients to treat the proximal component of stent encrustation. The stent could be removed in a single anesthetic session in 23 of 26 cases (88.5%). Analysis revealed that the major component of the encrustations was a combination of calcium oxalate and phosphate.

CONCLUSION

Successful management of retained ureteral stents requires careful planning and may entail a combination of endourologic approaches. It is imperative to avoid using significant force, which can result in severe ureteral injury or breakage of the stent. If encrustations are present along the stent, we believe in treating the distal component prior to managing any proximal or ureteral components.

Ureteroscopy and holmium:YAG laser lithotripsy: an emerging definitive management strategy for symptomatic ureteral calculi in pregnancy

OBJECTIVES

To review the results of holmium laser lithotripsy in a cohort of patients who presented with symptomatic urolithiasis in pregnancy. Symptomatic urolithiasis in pregnancy that does not respond to conservative measures has traditionally been managed with ureteral stent insertion or percutaneous nephrostomy. Holmium:yttrium-aluminum-garnet (YAG) laser lithotripsy using state-of-the-art ureteroscopes represents an emerging strategy for definitive stone management in pregnancy.

METHODS

A retrospective analysis was conducted at two tertiary stone centers from January 1996 to August 2001 to identify pregnant patients who were treated with ureteroscopic holmium laser lithotripsy for symptomatic urolithiasis or encrusted stents. Eight patients with a total of 10 symptomatic ureteral calculi and two encrusted ureteral stents were treated. The mean gestational age at presentation was 22 weeks. The mean stone size was 8.1 mm. The stones were located in the proximal ureter/ureteropelvic junction (n = 3), midureter (n = 1), and distal ureter (n = 6).

RESULTS

Complete stone fragmentation and/or removal of encrusted ureteral stents were achieved in all patients using the holmium:YAG laser. The overall procedural success rate was 91%. The overall stone-free rate was 89%. No obstetric or urologic complications were encountered.

CONCLUSIONS

Ureteroscopy and holmium laser lithotripsy can be performed safely in all stages of pregnancy, providing definitive management of symptomatic ureteral calculi. The procedure can be done with minimal or no fluoroscopy and avoids the undesirable features of stents or nephrostomy tubes.

The current management of urolithiasis during pregnancy

The management of urolithiasis in pregnancy can present complex challenges to the urologist. However, if the principles discussed above are followed, these difficult clinical problems can be approached in a rational manner.

Doppler waveform of the ureteric jet in pregnancy

We have shown that the function of the bladder vesicoureteric junction (VUJ) can be studied by the Doppler waveform of the ureteric jet, and this reflects the active sphincteric mechanism of the VUJ. We wished to investigate if the hormonal changes of pregnancy cause any alteration of VUJ function. A total of 107 pregnant women and 375 nonpregnant women were recruited. Three scans, 20 and 32 weeks of gestational age and 3 months postpartum, were done. The occurrence of a monophasic waveform in the nonpregnant group was 1.9%. In the pregnancy group, this was 18.7%, 41.1% and 1.6% at 20, 32 weeks of gestational age and 3 months postpartum, respectively. The difference in occurrence of the monophasic waveforms was statistically significant (both p = 0.0005 at 20 and 32 weeks). This suggests an adverse hormonal effect on the vesicoureteric junction during pregnancy, and may be a factor in the increased risk of UTI in pregnancy.