5.7

common cause of paediatric end-stage renal failure need- ing transplantation and dialysis.

Non-traumatic catastrophic haemorrhage from the uri- nary tract is uncommon, but can occur secondary to tu- mours and congenital lesions. e.g. aneurysms of the renal artery. Bladder haemorrhage requiring emergency treat- ment is rare.

Spontaneous bladder rupture is uncommon, usually oc- curring in alcoholics or following cystoplasty.

Torsion of the testicle or the appendix of the testicle and priapism may require emergency imaging.

5.7.2 Obstruction of the Upper Urinary Tract

Obstruction of the upper urinary tract is only an emer- gency if it is acute, and even more so when obstruction oc- curs in a single kidney or transplant. The physiology of urine transportation is rapidly disrupted by obstruction.

Under normal circumstances, urine is stored with the col- lecting system at low pressures, 10 cm of water and period- ic rises in pressure (up to 15 cm water) and expels urine into the ureter, which propels urine at pressures between 20 and 60 cm of water into the bladder. In an obstructed state, the upper tract compensates by increasing renal blood flow and increasing both the frequency and pressure of ureteric peristalsis, but such compensation is transient.

Peristalsis becomes inefficient, and the ureter dilates ren- dering peristalsis even more ineffectual. Dilatation of the collecting system initially compensates for increasing pres- sure within it, but eventually it loses the battle and glomerular filtration rate falls secondary to a decreasing blood flow. Vascular resistance increases and progressive nephron damage ensues.

Rupture of the pelvi-calyceal system with extravasation temporarily decreases the intra-pelvi-calyceal pressure [1], but within hours of the onset of obstruction, nephron dam- age occurs which, if left untreated, will be irreversible. To minimise the extent of potential renal impairment, ob- struction must first be confirmed and then treated. The cause of obstruction is largely irrelevant. It does not matter whether it is due to a stone, sloughed papilla or blood clot.

5.7.1 Introduction

Urinary obstruction is the leading cause of damage to the urinary tract and is frequently in need of urgent treatment, especially when complicated by sepsis. Obstruction, its di- agnosis and treatment necessitate all the skills that form the bedrock of uroradiology and no hospital with an emer- gency department can adequately operate without such skills. Any part of the urinary tract can be obstructed from a single calyx to a stone lodged behind a urethral stricture that causes acute urinary retention. The role of imaging and intervention is to define the site and cause of obstruc- tion and then to relieve it until the cause has been dealt with or if it cannot be, to provide long-term relief. Obstruc- tion can occur in utero as well as at any age and is the most

Non-traumatic

Uroradiological Emergencies

D. Rickards

5.7

5.7.1 Introduction . . . . 523

5.7.2 Obstruction of the Upper Urinary Tract . . . . 523

5.7.2.1 Clinical Findings . . . . 524

5.7.2.2 Diagnostic Imaging . . . . 524

5.7.2.3 Plain Films and Excretory Urography . . . . 524

5.7.2.4 Ultrasound . . . . 526

5.7.2.5 Computed Tomography . . . . 527

5.7.2.6 Magnetic Resonance Urography . . . . 529

5.7.3 Treatment of Acute Urinary Obstruction . . . . 530

5.7.3.1 Patient Preparation and Consent . . . . 530

5.7.3.2 Localisation of the Pelvi-calyceal System . . . 531

5.7.3.3 Puncture of the Pelvi-calyceal System, Track Dilatation and Tube Placement . . . . . 531

5.7.3.4 Post-operative Care . . . . 532

5.7.4 Spontaneous Haemorrhage from the Urinary Tract . . . . 533

5.7.4.1 Clinical Findings . . . . 533

5.7.4.2 Radiological Findings . . . . 533

5.7.5 Spontaneous Bladder Rupture . . . . 534

5.7.6 Testicular Torsion . . . . 534

5.7.7 Priapism . . . . 535

References . . . . 535

Contents

They present with the same symptoms and signs, and are investigated and treated the same way.

5.7.2.1 Clinical Findings

Patients experience acute loin pain which can be severe, even intolerable. The pain is not alleviated by any position the patient might adopt. Vomiting and nausea are com- mon. Initially urinary output will not fall, but will eventu- ally fail because of dehydration, especially in children [2].

Renal function will deteriorate if left untreated, but the danger lies in hyperkalaemia, which can rapidly occur en- dangering cardiac function which can prove fatal. In a sin- gle functioning kidney, complete anuria is possible. Ob- struction in a transplant kidney may be silent as the kidney is denervated. Renal output will be noticeably reduced if not non-existent, but transplant patients who know their transplant and renal status well will know there is some- thing amiss.

Haematuria may be macroscopic but is usually not. The great danger other than hyperkalaemia is sepsis. Obstruc- tion occurring in infected upper tract systems or due to infected stones can rapidly lead to septicaemia. In such circumstances, both the septicaemia and the obstruction demand treatment. Treating the septicaemia alone is un- likely to prove successful.

The causes of obstruction are numerous and largely irrelevant in the emergency situation. The commonest cause is calculus disease, where a stone has become lodged in part of the upper tract, usually the ureter, but it can ob- struct a single calyx at its infundibulum or a calyceal diver- ticulum at its neck, where it communicates with the pelvi- calyceal system [3]. Other luminal causes are a sloughed papilla, blood clot or a fungus ball, to name a few. Extralu- minal or luminal abnormalities do not cause acute ob- struction and are therefore not an emergency.

5.7.2.2 Diagnostic Imaging

Where the clinical signs and symptoms all too clearly point to acute obstruction, imaging is needed to (a) confirm ob- struction, (b) guide interventional therapeutic measures and (c) to determine the level and cause of obstruction once it has been relieved, and the sepsis, if present, is treat- ed

Plain films and excretory urography are being sur- passed by non-contrast computed tomography and ultra- sound. The availability of CT is a problem in many centres and might not be available at all, so all techniques need to be considered. Prior to imaging, the patient needs resusci- tation with analgesia and an IV access with our without a saline infusion depending on status. The majority, if not all, patients with acute obstruction will require hospitalisa- tion.

5.7.2.3 Plain Films and Excretory Urography

Stones are radio-opaque in 90% of cases, and a careful search over the renal outlines and along the ureters is re- quired (Figs. 1, 2). Lucent stones will not be seen, nor very small stones (less likely to cause obstruction), and stones will be missed or over-diagnosed because of phleboliths, etc. The size of the stone is important. Up to 90% of stones 5 mm or less can be expected to pass spontaneously within 4 days [4], and it is probable that the osmotic diuresis engendered by excretory urography pre-empt this. The affected kidney may show some modest enlargement.

Following IV contrast, the classic features are as follows:

1. Prolonged and dense nephrogram (Fig. 3) 2. Delayed pyelogram (Fig. 4)

3. Dilatation of the upper urinary tract above the point of obstruction (Fig. 5)

4. Extravasation of contrast (Fig. 6) 5. Nephromegaly

There is no point in prescribing exactly what sequence of films are needed, because each unit has its own protocol and the examination needs to be tailored to the patient’s clinical condition as well as to available resources. The emergency protocol in the present author’s unit is a plain film followed by a 10-min full-length film, which is likely to show a normal pyelogram on one side and a dense pyelogram on the affect- ed side. At this point, no further films are necessary, as the

Fig. 1. A faint left distal ureteric stone (arrow)

clinical diagnosis has been confirmed and all efforts are con- centrated on treatment. Delayed films can be made, which will reveal the level and perhaps the cause of obstruction.

The usual sequence involves doubling times until the anatomical information is clear, i.e. 20, 40, 80 and 160-min full-length films as are needed.

Where extravasation occurs, contrast is seen where con- trast should not be, but the appearances can be very con- fusing. This can be expected in up to 33% of cases [5].

Pyelosinus extravasation is the most common situation, obscuring the normal sharp calyceal pattern, extending Fig 3. At 5 min there is a normal right pyelogram mad a dense left nephrogram with no pyelogram. Classic signs of acute obstruction Fig. 2. A small calculus overlying the transverse process of L4 on the left (arrow)

Fig 4. At 30 min there is a normal right pyelogram, but on the left, there is dilatation of the pelvi-calyceal system and the contrast within the left side is not as dense as that on the right. This is due to dilution of contrast within a urine-distended pelvi-calyceal sys- tem. There is a small stone (not seen) at the left vesico-ureteral junction (VUJ). This is partial obstruction

Fig. 5. Obstruction due to a distal left ureteric stone. Full-length

KUB done 20 min after IV contrast. There is dilatation of the left

pelvi-calyceal system and ureter down to the VUJ where an intra-

luminal filling defect is seen. This represents partial obstruction

around the renal pelvis and outlining the proximal ureter.

Less common is extravasation into the renal capsule. Once extravasation occurs, there is a decrease in renal pelvic pressures and glomerular filtration and urine formation continue despite obstruction. It is at this stage that a pyelo- gram rapidly appears. Although the appearances are alarming, extravasation is always benign and self-limiting.

Where there is obstruction to a part of a kidney, similar, but segmental, abnormalities are seen.

Obstruction occurring in a poorly functioning kidney does not come under the heading of an emergency.

5.7.2.4 Ultrasound

In acute obstruction, pyelocaliectasis is typically absent or there is only slight pelvi-calyceal dilatation. Stones within the collecting system are easily seen (Fig. 7); the latter can be seen in normal and unobstructed patients [6]. Dilata- tion of the collecting system is not synonymous with

obstruction, nor does the absence of dilatation exclude ob- struction; therefore, grey-scale imaging has a limited role.

Where there has been a delay in patient presentation, di- latation will be seen and may be complicated by infection, either an infected hydronephrosis or a pyonephrosis, which is associated with suppuration of renal parenchyma. If debris is seen with the collecting system, a pyonephrosis is more likely [7], but it is irrelevant as both conditions re- quire urgent drainage. Unobstructing stones may be seen, which suggests a dislodged calculus is the cause. An at- tempt should be made to image the ureter, which is slightly easier if it is dilated, and to follow it down to an obstruct- ing calculus (Fig. 8). If the bladder is distended, the distal Fig. 6. The left upper tract is normal. The appearances on the right

are confusing, but there are dilated calyces and there is contrast where contrast should not be. This must represent obstruction and extravasation. In this case, the extravasation is into the perinephric space and contrast is mingling with peri-nephric fat

Fig 7. There is a large calculus in the right renal pelvis. It is causing some obstruction as suggested by dilatation of upper pole calyces

Fig 8. There is an obstructing left ureteric calculus (arrow) caus-

ing allot of proximal dilatation of the pelvi-calyceal system. This

was a single kidney in a young man whose other kidney was re-

moved due to a Wilm’s tumour

The primary advantage of non-contrast CT is the ability to identify calculi, especially those small obstructing cal- culi overlying bone. Finding a calculus is one thing, but determining whether it is the cause of obstruction is an- other. Dilatation of the pelvi-calyceal system and ureter down the side of the calculus is strong evidence of obstruc- tion, as with the excretory urogram. Comparison with the ipsilateral normal side is helpful (Figs. 9, 10). The presence of perinephric stranding both around the kidney and ureter (Figs. 11–13), renal enlargement and a lower attenu- ation value of the affected kidney increase the diagnostic likelihood of obstruction [14]. A decrease of 4 Hounsfield units in the affected kidney suggests obstruction [15]. It is a non-specific finding that can occur in acute pyelonephri- tis, which can mimic colic. Not all obstructing stones have high attenuation on CT. Indivar (a drug used in im- mundeficeincy virus infection) induces symptomatic nephrolithiasis in 4% of cases, and very poorly calcified matrix stones are not seen on CT [16, 17]. The degree of perinephric stranding gives some indication as to the degree of obstruction. When extensive, high-grade ob- struction could be predicted and the opposite when mild [18], and indeed, when extensive, the more likely the spon- taneous passage of a stone [19]. Also predicting sponta- neous passage, stone size is helpful. Those stones <3 mm are likely to pass, whereas those above 8 mm are not.

In 90% of patients presenting with acute flank pain, the absence or presence of an obstructing calculus can easily be made, but there are pitfalls. Phleboliths are not sur- rounded by soft tissue and can be associated with a tail of soft tissue which is the collapsed associated vein (Figs. 14, 15) [19]. Looking at a reconstructions helps enormously in defining the dilated ureter above a possible stone (Fig. 16).

The radiolucent centre that phleboliths have on plain films cannot be seen on CT. Vascular calcification is usually lin- ureters can be seen as well as the vesico-ureteric junction.

Stones must be sought there. Peri-nephric urinomas and subcapsular fluid collections are suggestive of obstruction with extravasation.

Colour Doppler may help. Up to 90% of patients with acute obstruction have asymmetrical ureteric jets [8], and in complete obstruction, no jet is seen from the affected side. Prominent vessels simulating pelvi-calyceal dilatation are easily distinguished. A raised resistive index (RI) im- plies a raised impedance of renal blood flow, which occurs in acute obstruction. It is not always easy to get a good trace as patients will be in pain and not able to cooperate fully. Obesity compounds difficulties as do ectopic kidneys.

The RIs in excess of 0.7 are suggestive of acute obstruction, but with sensitivities between 40 and 100% reported [9], it is not worth measuring.

5.7.2.5 Computed Tomography

Smith et al. in 1995 proposed the use of CT in acute ob- struction [10]. Non-contrast CT findings correlate well with those on excretory urography [11], and for detecting stones is nearly 100% specific and sensitive [12]. The tech- nique continues to evolve with new technology. The 64- slice scanners with 1-mm slices are the present gold stan- dard. Immediate reformatting in the coronal and sagittal plane with manipulation of the image allow for easy defin- ition of the ureter, but there is a trade-off with dose [13].

No preparation, no contrast media and no delayed studies are needed. Patients can be scanned supine or prone. The prone position can identify possible interposition of the splenic or hepatic flexure of the colon between the posteri- or abdominal wall and the kidney. If seen, this would alter placement of nephrostomy tubes.

Fig. 9. The right renal pelvis is dilated as compared

with the left. The perinephric fat is normal

Fig 10. Non-contrast CT. There is a dilated right mid ureter (arrow) which has a slightly thickened wall.

The left ureter is normal

Fig 11. Non-contrast CT. There is marked stranding within the perinephric fat of the left kidney without any obvious pelvi-ca- lyceal dilatation. This is strong evidence of obstruction

Fig. 12. Non-contrast CT. There is marked stranding around the mid-left ureter (arrow), clear evidence of obstruction

Fig. 13. Non-contrast CT. At a level just 1 cm

below the scan in Fig. 12 is the obstructing

calculus (arrow)

ear and often quite symmetrical. Barium in diverticulae, brachytherapy seeds implanted for prostate cancer are but examples of other opacities that can mimic obstructing calculi. Conditions that mimic renal colic can be suspected on unenhanced CT and signs must be sought. Conditions include pancreatitis, appendicitis, hydrosalpinx and aortic aneurysm. Renovascular entities, e.g. renal vein thrombo- sis, are difficult to diagnose on unenhanced CT (Fig. 17).

5.7.2.6 Magnetic Resonance Urography

Using T2-weighted sequences, MRU is a reliable and non- invasive method to demonstrate urinary tract dilatation and level of obstruction. The MRU cannot characterise small intraureteral filling defects and will miss most ca- lyceal stones, but it is as good as CT is demonstrating per- inephric stranding and other causes of acute flank pain [20].

The MRU is best reserved for selected patients, i.e. those pregnant, on indivar therapy and in whom the suspicion of extraurinary disease is high [21].

Fig. 16. Reconstructed non-contrast CT. There is a calculus in the mid-left ureter and the dilated ureter can easily be seen above it.

The amount of perinephric stranding can also be appreciated.

There is very little in the way of pelvi-calyceal dilatation Fig. 14. Non-contrast CT. There is a large opacity in the right infe-

rior hemipelvis (arrow). It is slightly posterior for the normally sit- ed ureter and it is not surrounded by any soft tissue. This makes a phlebolith more likely

Fig. 15. Coronal reconstruction non-contrast CT. An opacity (ar-

row) in the right hemipelvis is a phlebolith. No surrounding soft

tissue and no ureter is seen superiorly

5.7.3 Treatment of Acute Urinary Obstruction

The aim of any treatment is (a) to relieve obstruction to the upper urinary tract, thereby minimising or eradicating the possibility of permanent renal damage, (b) to relieve the pain associated with obstruction and (c) to treat infection caused by obstruction. This can be done antegradely by percutaneous nephrostomy or retrogradely by placing a JJ stent at cystoscopy. Cystoscopy involves a general anaes- thetic, theatre time and it will often not be possible to by- pass an obstructing calculus with any guidewire–catheter combination, so the ideal treatment of obstruction is nephrostomy. This involves the following:

1. Patient preparation and consent 2. Location of the pelvi-calyceal system

3. Puncture of the pc system, tract dilatation and drainage tube placement

4. Post-operative care

5.7.3.1 Patient Preparation and Consent

Informed consent must be obtained and complications ex- plained. Major complications, such as haemorrhage, must be stated, i.e. those that adversely affect the patient or need an- other procedure to correct. These can be expected in 3%

[22]. Haematuria can be expected in all patients. Vascular damage needing surgical intervention is rare (<0.5%) [23].

Haemorrhage due to a pseudoaneurysm, arterio-venous malformation or vessel laceration are amenable to angio- graphic embolisation and can be expected in 2% of cases [24]. Any patient with a bleeding diathesis or on anticoagu- lants require special attention. In all patients, a coagulation profile and full blood and platelet count are mandatory. Ab-

normalities require correction to within acceptable limits, i.e. an INR (international normalized ratio) of <1.3, platelets of 80,000 ¥10

/l and a prothrombin time of <3 s. Clearly, a balance needs to be struck between the time taken to correct a bleeding diathesis and the danger to the patient with an obstructed kidney. This requires experience and an experi- enced operator to insert the nephrostomy for it to be shown that fewer complications can be expected [25].

Complications secondary to infection range from a low- grade fever to septic shock. Fevers and chills can be expect- ed in 21% of cases [26]. Septic complications in patients with a pyonephrosis occur in at least 25% and can be very severe [27, 28]. Other factors that predispose to infection are diabetes, urinary diversions (ileal loop, ileocycocystoplasty, etc.), bladder dysfunction and steroid therapy. These pa- tients should have IV access via a saline drip and appropri- ate antibiotic cover [29]. Anaesthetic support should be sought and access to an ITU bed available should the pa- tient develop septic shock requiring ventilatory support.

Sepsis can be minimised with less manipulation during nephrostomy placement and very little contrast instilled into the pc system, reducing any rise in pelvi-calyceal sys- tem, track dilatation and tube placement pressure reducing bacteraemia [30, 31]. No diagnostic studies should be per- formed until the drained urine is clear of infection. It can- not be stressed enough that infection and sepsis can occur within minutes of nephrostomy placement, and it is the op- erator’s responsibility to put in place all possible prophy- lactic procedures and to anticipate serious complications and have therapeutic measures in place. In our unit, even in the absence of a potential pyonephrosis, prophylactic an- tibiotics are given (e.g. 120 mg gentamicin IV, Hoechst Marion Roussel, West Malling, UK). Other complications are rare; these include puncture of adjacent organs, usually colon, hydrothorax and pneumothorax. Success rates in di- lated kidneys of 98% can be stated [32, 33], but if undilat-

Fig. 17. Non-contrast CT. This patient presented

with acute right renal colic and CT shows that

the stone has passed into the bladder

to confirm its intra-calyceal location, and that urine should be sent for bacteriology. Then, a little contrast and air is in- jected into the pelvi-calyceal system. Air will outline the posterior calyces and contrast the dependent ones [34–36].

Then a sheathed needle (18 G with a 5-F sheath Angiomed, Karlsuhe, Germany) is placed into a targeted calyx under fluoroscopic guidance. This method has the attendant dan- ger of increasing intracalyceal pressure and thereby dissem- inating infection into the vascular space due to intrarenal reflux. In dilated systems, the initial step as outlined above can be omitted. Through the sheath, a 0.035-in. curved tip hydrophilic guidewire (Terumo, Leuven, Belgium) is ad- vanced under fluoroscopy into the collecting system and sheath advanced over the guide wire to safely anchor its tip within the pelvi-calyceal system. By manipulating the curved tip of the wire, it is usually possible to get it down the ureter as long as it is not obstructed at the pelviureteric junction. If it is, then the guide wire needs to be passed into the upper pole calyces. The sheath then needs to be fully ad- vanced over the wire and then the hydrophilic wire ex- changed to a 0.035-in. metal wire (Superstiff Amplatz, Boston Scientific, Watertown, Mass.). Then, a track is dilat- ed using facial dilators and a nephrostomy drain is inserted.

Under all conditions, an 8-F catheter self-retaining (Soft drain, Angiomed) will suffice. To easily insert this, the track ed, success rates can fall to 85% [32], but these have

improved with recent changes in technique.

All nephrostomies should be done under sedation and analgesia, and patients should be monitored with pulse oximetry and given oxygen. Where the patient, despite these measures, cannot cooperate, general anaesthesia must be considered, and is mandatory in children. The pa- tient is then placed prone oblique on a fluoroscopy table, with the obstructed kidney uppermost.

5.7.3.2 Localisation of the Pelvi-calyceal System

Fluoroscopy

Those patients who have had a diagnostic excretory uro- gram may have a delayed pyelogram that allows for accu- rate puncture of the contrast filled collecting system under fluoroscopic control. Where the diagnosis has been made by CT or US, it is not worth giving contrast to opacify the pelvi-calyceal system because of the very considerable de- lay in the pyelogram that obstruction causes, which could be hours.

Ultrasound

If the pelvi-calyceal system is dilated, ultrasound can be used to define a point on the patient’s back above a calyx and then the system is punctured. In systems that are only minimally dilated or non-dilated, continuous US is needed.

For this, the probe is inserted in a sterile cover to allow the operator full use during needle placement.

Computed tomography

Computed tomography is useful where US cannot define the collecting system. In practice, this is rare in normal-sit- ed kidneys, but in ectopic and displaced kidneys, it can be invaluable.

5.7.3.3 Puncture of the Pelvi-calyceal System, Track Dilatation and Tube Placement

Two methods in common practice depend on whether the pelvi-calyceal system is dilated or not. All punctures should ideally be directed towards the papillary tip of a posterior- facing lower pole calyx and approached through the rela- tively avascular line between the anterior and posterior branches of the renal artery (Brodel line 33). The patient’s skin is cleansed, draped and local anaesthetic is infiltrated down to the capsule of the kidney and given sufficient time to take effect. If the pelvi-calyceal system in undilated, un- der guidance a 15-cm 22-g flexible Chiba needle (Becton Dickinson and Company, Franklin Lakes, N.J.) is passed in- to the most dilated part of the collecting system, whether that be the renal pelvis or infundibulum. Urine is aspirated

Fig. 18. Following opacification of the collecting system, a shea-

thed needle has been placed via a lower pole calyx, a guide wire

passed through the sheath into the renal pelvis and down the

ureter. There is extravasation of contrast confusing the picture. A

dilator has been passed over the guide wire to dilate the tract

should be dilated up to 10 F to accommodate the redundan- cy in the catheter by straightening with J shape that the catheter will ultimately assume. The drainage catheter is passed over the guide wire until all of its side holes are with- in the collecting system. In practice, this means that the end of the catheter will be down the ureter. The guide wire is re- moved, and under fluoroscopic guidance, the catheter is gently withdrawn while deploying its self-retaining proper- ties. The catheter needs to be within the renal pelvis. It is wise to suture the catheter in place as well. Any temptation to extend the procedure, such as inserting a JJ stent, must be avoided. In acute obstruction, the aim is to relieve it. Stents can be placed at a later date, if appropriate.

This simplified description is not always borne out in practice. Initial puncture of the collecting system may well be associated with extravasation of any contrast instilled into the collecting system or contrast there following an IV injection of contrast (Figs. 18, 19).

5.7.3.4 Post-operative Care

The patient should be carefully monitored for any signs of sepsis or significant blood loss [37, 38]. The drained urine volumes must be monitored and cultures performed to look for urosepsis. Diagnostic studies can be done within 24 h of nephrostomy insertion if there was no evidence of sepsis and infected urine; if there was, these must be de- layed until the urine is crystal clear, and the patient apyrex-

ial and well. Any further interventions, e.g. JJ stent place- ment, ureteroscopy and percutaneous nephrolithomy must also be delayed until there is no sign of residual infection.

Complicated Cases

Not all kidneys are normally sited and body habitus can cause problems. A few examples are considered:

Transplant Kidneys

Obstructed transplants must be treated as an emergency [39]. They are superficially situated in an iliac fossa, dener- vated and extra-peritoneal in location and ideally suited to ultrasound-guided techniques. The basic technique is the same as for normally sited kidneys, but the puncture site must be kept as lateral as possible to avoid the peritoneum and colour Doppler is useful in avoiding major vessels.

Blood loss can be expected to be more of a problem be- cause Brodel’s line cannot be accessed.

Ectopic Kidneys and Other Congenital Anomalies

Obstructed pelvic kidneys pose a major problem. They are extraperitioneal in location, usually have bowel between them and the anterior abdominal wall, and have pelvic bone posteriorly. No safe approach under any guidance is possible, and if a retrograde approach is for some reason impossible, a puncture through the anterior abdominal wall has to be done. Bowel perforation becomes a real problem and appropriate antibiotics must be given. Low- lying kidneys, malrotated kidneys and fused kidneys do not usually present a problem. Clearly, obstructed upper moieties of duplex kidneys require an upper pole approach often above the twelfth rib.

Horseshoe Kidneys

The lower poles of horseshoe kidneys are medially situated and both ureters and major vessels can be closely related to them. It is therefore wise to puncture through the laterally placed upper pole calyces which may involve a puncture above the twelfth rib.

Children

Essentially, this is the same approach as for adults, but smaller drainage catheters (5–6 F) are needed and tube stabilisation is difficult [40, 41]. General anaesthesia is mandatory.

Pyonephrosis

If pelvi-calyceal systems are full of thick and infected urine, aspiration of urine through either a Chiba or sheathed needle may be difficult or impossible. If the sys- Fig. 19. A drainage catheter has been passed over the guide wire

and is located in the renal pelvis

capsular, perinephric or retroperitoneal. The extent of haematuria, if it occurs, does not indicate the severity of bleeding, as most bleeding occurs outside the luminal space.

Massive bladder haemorrhage can be caused by haem- orrhagic cystitis [45], vascular tumours and arteriovenous malformations.

5.7.4.1 Clinical Findings

Renal haemorrhage communicating with the collecting system presents with haematuria. Blood clots form within the renal pelvis and their passage down the ureter can re- sult in typical renal colic and transient obstruction with hydronephrosis. Profuse bleeding can cause clot retention.

Renal haemorrhage not communicating with the collecting system causes flank pain and a flank mass. Both types of haemorrhage can be associated with hypotension and a fall in the haematocrit requiring transfusion. Haematuria will occur in all patients with bladder haemorrhage and clot retention is common.

5.7.4.2 Radiological Findings

Radiological findings depend on where the bleeding has occurred.

Intraluminal Bleeding

Clots within the collecting system cause filling defects on excretory urography and have a high attenuation on CT, typically 50–70 Hounsfield units [46]. Clot appears echogenic on US, but it is a non-specific finding. The un- derlying cause of bleeding may well be confirmed by all three modalities, but angiography may be needed.

tem is dilated, confirmation of needle tip placement is not too difficult, but if undilated, it is very difficult. There is no easy answer to this. An approach to the undilated pelvi-ca- lyceal system will have to be made with a sheathed needle through which guide wires can be placed and manipulated under both US and fluoroscopic control. Once it is thought that the sheath is well into the collecting system, a little contrast can be injected, but this may show a bizarre appearance in a pyonephrosis, quite unlike the normal col- lecting system and often with no drainage down the ureter.

These cases require great experience.

Displaced Kidneys

Kidneys can be very significantly displaced by other intra- abdominal pathologies. Because they are a posterior struc- ture, they are usually displaced inferiorly or anteriorly.

Computed tomography is then the best method of locating the collecting system and missing other intra-abdominal organs (Fig. 20).

5.7.4 Spontaneous Haemorrhage from the Urinary Tract

Spontaneous haemorrhage from the urinary tract is defined as bleeding with no history of preceding trauma, but due to a renal, systemic or coagulation abnormality.

Common causes are malignant tumours, renal artery aneurysms, arterio-venous malformations [42], benign tu- mours (e.g. angiomyolipomas) [43] and vasculitis (e.g. pol- yarteritis nodosa and anticoagulant therapy), although 40%

of anticoagulant-induced haemorrhage have significant un- derlying urinary tract disease [44]. Bleeding can occur in the collecting system, but it can also be intraparenchymal, sub-

Fig. 20. An obstructed kidney due to a pelvic stone

displaced anteriorly because of massive spleno-

megaly. Under CT, a needle has been advanced

from the posterior abdominal wall into the collecting

system, missing all other organs and with drainage

safely achieved

Subcapsular Haematomas

Subcapsular haematomas occur between the renal par- enchyma and the renal capsule. The capsule is not elastic, so bleeding is usually limited and its cause will be tampon- aded. The collecting system will be attenuated and dis- placed. Computed tomography will show a non-enhancing soft tissue mass around the kidney. Underlying pathology, e.g. tumour, must be carefully sought.

Treatment of Haemorrhage

If surgery is not considered an option, embolisation is an option. Selective renal angiography will possibly pinpoint the bleeding vessel or vessels, and superselective can- nulation can be followed by embolisation with coils (Figs. 21a,b). Bladder haemorrhage that does not respond to cystoscopic means may be controlled by embolising the anterior trunk of the internal iliac artery on both sides because of a rich anastomosis. Embolisation should be per- formed with gelfoam pledglets or the equivalent to mini- mize the risk of bladder wall necrosis [47].

5.7.5 Spontaneous Bladder Rupture

Spontaneous bladder ruptures are rarely reported. They have been reported in alcoholics who overdistend their bladders because of an excessive fluid intake [48]. Other causes are bladder tumours, radiation injury, during labour and chronic bladder inflammation [49]. Patients present with lower abdominal pain and anuria. The perforation is extraperitoneal and diagnosis is made by cystography or CT cystography. Treatment is either by surgery or catheter- isation.

5.7.6 Testicular Torsion

In most units, the diagnosis of testicular torsion is made

clinically. Where doubt exists, the scrotum is usually ex-

plored as an emergency, and if torsion is found, it is cor-

rected. The degree and duration of torsion are crucial in

determining the viability of the testicle. Complete torsion

will result in necrosis of the testicle and its viability will

only be salvaged if surgery is performed within 4 h. De-

Fig. 21. a Renal angiogram shows a large aneurysm arising

from a lower pole vessel. b Renal angiogram shows coils

obliterating the aneurysm

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8. Deyoe LA, Cronan JJ et al. New techniques of ultrasound and color Doppler in the prospective evaluation of acute renal ob- struction: Do they replace the intravenous urogram? Abdom Imaging 20:58–63, 1995

9. Older RA, Stoll HL et al. Clinical value to reno-vascular resis- tive index measurement in the diagnosis of acute obstructive uropathy. J Urol 157:2053–2055, 1997

10. Smith RC, Rosenfield AT, Choe KA et al. Acute flank pain: com- parison on non-contrast CT and excretory urography. Radiol- ogy 194:789–794, 1995

11. Sourtzis S, Thibeau JF et al. Radiographic investigation of re- nal colic: unenhanced CT compared with excretory urography.

AJR 172:1491–1494, 1999

12. Boulay I, Holtz P et al. Ureteral calculi: diagnostic efficiency of helical CT and implications for treatment of patients. AJR 172:1485–1490, 1999

13. Mamarsadeghi D, Heinz-Peerrl G et al. Unenhanced mutlide- tector row CT in patients with suspected of having urinary stone disease: effects of sector width on diagnosis. Radiology 235:530–536, 2005

14. Georgiades CS, Moore CJ, Smith DP. Differences of renal parnechymal attenuation for acutely obstructed and unob- structed kidneys on unenhanced helical CT: A useful sec- ondary sign? Am J Roentgenol 176:965–968, 2001

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layed surgery will result in an infracted testicle [50]. Ultra- sound with colour Doppler will show either an avascular testicle (Fig. 22) or one with a decreased flow when com- pared with the non-torted testicle, but the delay in getting an ultrasound done and its relative limitations in defining the degree of torsion render the investigation a waste of precious time.

5.7.7 Priapism

Priapism is a prolonged and usually painful erection not initiated by sexual stimuli. Two types occur, high and low flow. Low-flow priapism results in stasis within the corpora that causes a decreased oxygen tension and acidosis which, if not corrected, will result in impotence. Emergency surgery to irrigate the corpora or perform shunts between the corpora and the spongiosum are needed. High-flow priapism is usually the result of perineal trauma; colour Doppler ultrasound will differentiate between the two.

Low-flow cases will have a little flow within the corpora and is useful in directing treatment towards emergency surgery [51].

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