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Khasanov Mardon Mukhammadikulovich, Republican Specialized center of Urology Tashkent. Uzbekistan E-mail: [email protected]
SUPRAVESICAL OBSTRUCTION IN PREGNANCY: LITERATURE REVIEW
Abstract: Supravesical obstruction in pregnant women is considering as physiological condition. However, complicated supravesical obstruction in pregnant women is one of the most common urological disorders. Despite the progress in diagnosis and treatment in modern urology of pregnant women, there are still a number of questions in the management of these patients. Keywords: supravesical obstruction, pregnancy, hydronephrosis.
Introduction results in dilatation, vascular congestion and stasis, all of
The supravesical obstruction during pregnancy con- which increase the risk of ascending infection.
sidered as physiological phenomenon. The clinical significance lies in the possible association with the high incidence of symptomatic bacteriuria and ascending urinary tract infection, urolithiasis, ureteropelvic junction (UPJ) obstruction during pregnancy. In addition, this condition may be related to renal parenchymal involvement and hypertension and, further, be a possible cause of pain observed during pregnancy. However, the condition is frequently overlooked which happens more often now due to the increased use of ultrasonography, also performed subsequent further examinations (urinalyses, blood test, plain radiography, intravenous urography, MRI or CT scans, radioisotope renal scan) and treatments.
For these reasons, we have found it of interest to pay attention to the problem and survey the literature regarding complicated supravesical obstruction during pregnancy.
The occurrence of dilatation of the upper urinary tract in pregnancy has been recognized for over 200 years. Investigators described as, based on post-mortem examination of pregnant women, that the growing uterus by compressing the ureters produced retention of urine in the kidneys, dilatation of the ureters, pelvis and calyces and inflammation of these structures [1]. They also stated that it is obvious that the attacks of pain that occur during pregnancy sometimes result from renal infection, which would be diagnosed more frequently if its existence were recognized [2]. Pyelonephritis occurs more frequently in the second half of pregnancy than in the first, and that this probably results from the growing uterus compressing the ureters at the level of linea terminalis. The compression
Incidence
Dilatation of the upper urinary tract was unusual and slight up until the 20th week of pregnancy. Shortly thereafter dilatation developed abruptly and remained, on the whole, unchanged with respect to grade and incidence, until term. During the latter half of pregnancy the right ureter and the pelvis were found to be dilated in 76, and the left ureter and pelvis in 36% [3]. Severe dilatation was rare, particularly on the left side. The dilatation ceases in all cases at the level of linea terminalis [4]. Other authors have made similar observations [5].
Employing isotope renography Fayad [6] et al and Nieminen et al [7] founds that renographic findings were normal during the first trimester, but that a progressive dilatation and delay in urinary excretion occurs during the following period. At term, abnormalities are seen in 70% on the right side and in 50% on the left side. Spencer et al in 2000, founds that MR excretory urography was a promising technique which affords equivalent functional and additional anatomical information to isotope renography and its more accurate then ultrasound assessment of supravesical obstruction [8].
Peak et al studied 204 patients, comprising 159 pregnant and 45 control subjects. Overall incidence ofhydro-nephrosis found in 90% on the right side and 67% on the left side. Calyceal diameters for both kidneys were found to increase gradually throughout pregnancy, the right more rapidly than the left [4].
Grosjean et al has analyses the MRI of 100 asymptomatic pregnant women. He determined the number and locations of the uretero-hydronephroses and researched
whether there is any relationship between the uretero-hydronephrosis and certain abdominal structures. He focused on the psoas muscle, measured its depth, width and calculated its surface by a reproducible method. The analysis revealed that the uretero-hydronephrosis was predominantly at the right side (63%) and in the majority of the cases limited to the kidney (42%) and/or the proximal third of the ureter (42%) [9].
The study of supravesic obstruction in pregnant women showed that various diagnostic methods such as intravenous urography, MR excretory urography and ultrasound examination revealed ureteregronephrosis, with a higher frequency of occurrence on the right side, even in the absence of pain symptomatology.
Anatomical factors
Comprehensive anatomical and histological investigations of the ureters during pregnancy have been carried out and generally a varying grade of hyperplasia of the periureteral connective tissue, hypertrophy of the ureteral smooth muscle, oedema and increased vascularity were found; the same picture was shown by the genital tract during pregnancy. The most prominent aspect was the hypertrophy of the external longitudinal muscle layer surrounding the distal part of the ureter. It was suggested that this hypestrophy could result in stricture, which would then explain the dilatation [10-12]. The dilatation would have to begin just above the urinary bladder and not first at a level with the linea terminalis, and should also be equally pronounced on both sides.
Hormonal factors
Due to the common embryological origin of the urinary and genital tract, many investigators have thought that they could demonstrate that the hormonal effect which during pregnancy results in a physiological relaxation of the genitals would also result in pathological dilatation of the urinary tract [13-16].
Marchant found that medroxyprogesterone hormone did not result in changes in ureteral activity nor dilation _ENREF_17 [17].
Obstruction
Many similar observation reported supravesical obstruction more marked on the right side. They concluded that dilatation was caused by the pressure of the uterus on the ureters, where these crossed the iliac vessels at the level of linea terminalis, and that the difference in sides
resulted from the different courses of the iliac vessels in relation to the ureters on the two sides [18-20].
Harrow et al. considered that dilatation resulted entirely from compression, and based this on data from intravenous urographies. Using urography on non-pregnant women, hydronephrosis occurs after a few minutes of external compression, and disappears immediately following decompression. In the pregnant woman the dilatation rapidly reduced following decompression by means of a change in position to lying on the side or knee-elbow position; similarly the pain brought about by the dilatation is relieved. The difference in side with respect to the extent of dilatation results from the protective effect of the sigmoid lying above the left ureter. In post-partum patients, the hydronephrosis decreased rapidly. Complete restitution could be seen by 24 h after delivery [21].
Shokeir et al. in his study investigate renal resistive index (RI) in the identification of acute renal obstruction in pregnant women. The study included 22 pregnant women with acute unilateral ureteral obstruction due to a stone disease, 71 normotensive pregnant patients without any pain, and 20 nonpregnant women with normal both kidneys. All patients performed dopler ultrasound examination to calculate RI on kidney with supravesical obstruction and DeltaRI on contralateral kidney. The RI was sensitivity was 45%, specificity 91%, and accuracy was 87%. The corresponding values for DeltaRI were 95%, 100%, and 99%. In acute unilateral ureteral obstruction in pregnant women, the DeltaRI is more sensitive and specific than RI exam, and DeltaRI can used instead of intravenous urography [22].
Reynolds et al. based on an investigation of 130 pregnant women, that the difference in side in combination with the dilatation of left ovarian vein, which occurs in connection with pregnancy, was the cause of the high incidence of right-sided hydronephrosis and pyelonephritis during pregnancy [23].
Kalaitzis et al. determined on his study treatment modalities of symptomatic ovarian vein syndrome in pregnancy. Twelve pregnant women with right ureter and kidney dilatation caused by ureteric obstruction were included to study. For 11 patients performed insertion of Double J stent and for one patient was performed percutaneous nephrostomy. After insertion of Double J stents, respective percutaneous nephrostomy colic attacks went back immediately. Ovarian vein syndrome in
pregnancy can lead supravesical obstruction with colic pain and can become complicated by pyelonephritis. In these cases insertion of a Double J stent or percutaneous nephrostomy is safe and leads to an improvement of complaints immediately [24].
Compression by the uterus can result in acute attacks of pain triggered by acute ureteral obstruction and the obstruction with it the pain can be relieved by a change in position to knee-elbow position [25; 26].
Renal colic is the most frequent non-obstetric cause for abdominal pain and subsequent hospitalization during pregnancy. Ultrasound examination is widely used as the first-line diagnostic test in pregnant women with nephrolithiasis, but and it may be unable to differentiate between ureteral obstruction secondary to calculi and physiologic hydronephrosis [27]. Magnetic resonance imaging (MRI) should be considered as a second-line test, when US fails to establish a diagnosis [28]. Moreover, MRI is able to differentiate physiologic from pathologic dilatation. In the cases of obstruction caused by calculi, there is renal enlargement and perinephric edema, not seen in physiological dilatation. MRI is also helpful to determine complications such as acute complicated pyelonephritis [29, 30]. In unclear situation, Computed tomography is a reliable technique for determining obstruction of urinary tract calculi in pregnant women, and it performed only by indications, because of involves ionizing radiation [31].
Clinical significance
The physiologically asymptomatic supravesical obstruction during pregnancy is, in itself, of no clinical importance, if infection does not occur and that the ureters do not fully blocked.
Pregnant women have an increased morbidity and mortality for UTI owing to the physiologic and immunologic changes in pregnancy. Urinary tract infections are common during pregnancy. The incidence of asymptomatic bacteriuria is on the whole the same in pregnant as in non-pregnant women, 2-10%, whereas the incidence of symptomatic bacteriuria is 3-fold higher in pregnant women, 15% against 5% in non-pregnant women, and the incidence of infection with symptoms in pregnant women with bacteriuria is 30% against 1% in pregnant women without bacteriuria. Infection producing symptoms has, in addition, a considerably greater risk of causing ascending infection during pregnancy [32]. Acute pyelonephritis
occurs in 20% in cases of non-treated bacteriuria, against 2% in those without bacteriuria, and the course is often more serious in pregnant than in non-pregnant women. Ten percent of patients with pyelonephritis develop septicaemia, and 3% septic shock [33].
Easter on her study, hypothesize that urinary tract infection increasing risk of preeclampsia. Study included 129 women with UTI and 235 patients with preeclampsia. Patients with UTI in pregnancy had higher rates of preeclampsia (31.1% vs 7.8%, P < 0.001) compared to those without UTI. UTI in pregnancy is strongly associated with preeclampsia. Prophylaxis against UTI represents to slow or halt the development of preeclampsia [34].
As we have observed hydronephrosis and hydroure-ters, with partial or intermittent obstruction, can be the cause of a number of cases of uncertain abdominal, flank or low back pain, as seen during pregnancy, and which is often of a transient nature provided changes in position occur, which is often the case following hospitalization.
During pregnancy, urolithiasis is a challenge for physician. It requires management of renal colic, infection and renal failure [35]. In cases not effectiveness of conservative treatment requires insertion of a double-J or pigtail catheter [35; 36], performing percutaneous nephrostomy [24; 37] and possibly retention of the catheter until labor has been effective in those cases where it has been attempted. Early intervention in order to derivation of supravesical obstruction must carried out before chronic renal damage occurs [37]. Normal renal function shortly before labor or shortly after achieved in all the reported cases.
Conclusion
Dilatation of the upper urinary tract must seen as a physiological condition during pregnancy. This condition found in almost all pregnant women, most frequently and most pronounced in women pregnant for the first time. It develops quite abruptly around the 20th week of gestation, and is more prominent on the right side where the ureter, due to its course in relation to the iliac vessels, most exposed to compression and it progresses slowly until labor. The dilatation disappears rapidly after birth and has disappeared in 75% a month post-partum. The dilatation includes the renal pelvis and ureters down to a level with the linea terminalis. Dilatation not seen in pregnant women with pelvic kidney.
Peristaltic activity in the ureter is normal during pregnancy and not affected by hormones in physiological
doses. Intraureteral pressure increased above the linea terminalis, and pressure rapidly returns to normal after delivery, indicating obstruction as the most important factor.
The pregnant uterus compresses the ureters, and thus is the only cause of physiological hydronephrosis during pregnancy. Acute hydronephrosis due to complete or intermittent ureteral occlusion not diagnosed fully in all, probably due to lack of attention. Ultrasonography, CT and MRI of the upper urinary tract should performed in cases of uncertain abdominal or flank pain during pregnancy. The treatment will primarily be improvement in drainage by means of positioning of the
pregnant woman on the least-affected side or intermittent knee-elbow position. In cases of persistent severe pain or affected renal function, ureteral stones, alleviation must attempted by the insertion of a DJ stent or perform percutaneous nephrostomy.
UTIs should be adequate and aggressively treated during pregnancy with providing adequate drainage.
Consideration should give to the question whether women with a single kidney obstruction prior to pregnancy, should be subject to monitoring more frequently during pregnancy, performing ultrasonography, CT or MRI, renal function tests and urine cultures.
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