LECTION 2. Topic: “ UROLOGICAL EMERGENCIES AND TRAUMA ”.
Foreign Students’ Medical Faculty
Duration of the leсtion –90min.
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LECTION 2. UROLOGICAL EMERGENCIES AND TRAUMA Urinary retention
Urinary retention is, simply, the inability to empty the bladder. There are several types of retention, and each requires different management. Urinary retention is very uncommon in women.
Complete and painful inability to empty the bladder where the bladder is catheterized and less than 800 ml of urine is drained is called acute urinary retention. Complete and painful inability to empty the bladder where the bladder is catheterized and >800ml of urine is drained is called acute onhronic urinary retention. There is a situation where the patient is still able to void, but because they unable to completely empty their bladder and after each void they consistently leave >500ml of urine behind, they are said to be in chronic retention. This is a somewhat empirical definition of chronic retention, and others define chronic retention as a post-void residual urine volume of >300ml, but the point is that patients with chronic retention of urine retain a substantial volume of urine in their bladders after each void.
The various forms of chronic retention of urine (be they acute-on-chronic or simply chronic) may be associated with such large volumes of retained urine and such high bladder pressures that patients develop back-pressure on their kidneys, leading to the appearances on ultrasound scanning of hydronephrosis and the presence of a raised serum creaitinine (which falls, over the course of several days, after catheterization). Such forms of chronic retention are called high pressure acute-on-chronic retention and high pressure chronic retention. Patients with chronic retention, but no hydronephrosys are said to have low pressure chronic retention.
Why all the fuss about retention volume? Are these definitions necessary?
Firstly, without recording the volume of urine drained from the bladder you cannot make a diagnosis of urinary retention. Some patients present with a history of lower abdominal pain and failing to pass urine (or passing only very small quantities), and have suprapubic tenderness or a tender lower abdominal mass, all of which is suggestive of acute urinary retention. However, when they are catheterized, their bladder is empty or contains only a low volume of urine (well below 800 ml).They are clearly not in urinary retention and there is some other cause for their pain and tenderness such as perforated or ischaemic bowel. They are fluid depleted, hence the history of not passing any urine. So, recording urine volume in a case of suspected urinary retention allows you to confirm the diagnosis. You should record this in the notes so other clinicians looking after the patient know that you made the correct diagnosis.
Secondly, retention volume is useful for determining subsequent management and it also has prognostic value. A patient with high-ppressure chronic retention is likely to have a diuresis once the obstruction has been relieved by passage of a catheter. Recording retention volume allows you to anticipate this diuresis and allows you to be aware of the potential risk of postural hypotension. The diuresis can be profound, many litres of urine being produced in the first few days. The diuresis is due to:
(a) off-loading of retained salt and water (retained in the weeks prior to the episode of retention);
(b) dissipation of the corticomedullary concentration gradient caused by reduced urinary flow through the loop of Henle with maintenance of blood flow through the chronically obstructed kidney;
(c) an osmotic diuresis caused by the high urea level that occurs in such patients.
The diuresis does not usually cause any problems and it usually resolves spontaneously within a matter of days. It is said to be physiological (rather than pathological) because it represents a normal diuretic response to fluid overload. Rarely the patient may develop symptomatic postural hypotension (a preceding postural drop in blood pressure can provide some warning of this) and in such cases intravenous fluid replacement may be necessary.
Retention volume can also be used to indicate the need for subsequent prostate surgery (transurethral resection of the prostate - TURP). Patients with large retention volumes (>1000ml) are less likely than those with smaller volumes to void spontaneously after a trial of catheter removal, and although it is always nice to give them the benefit of the doubt, it is useful to be able to predict that subsequent TURP is likely. A substantial proportion of patients who undergo TURP for urinary retention will not void when their catheter is removed a few days post-operatively. Those with acute retention have a 10% risk of failure to void and those with chronic and acute-on-chronic retention have a 38% and 44% chance of failure to void after surgery. A total of 99% eventually void successfully on subsequent catheter removal several weeks later (Reynard and Shearer, 1999). Thus, retention volume predicts the likelihood of failure to void in these cases. This allows the patient to be counselled pre-operatively about their likelihood of voiding after the operation. It is also reassuring for the surgeon to know that failure to void after TURP is not a complication, but a normal event in the post-operative recovery of many patients.
Most patients with urinary retention will initially be managed by insertion of a urethral catheter. However, in some cases it may not be possible to pass a urethral catheter and a suprapubic catheter should then be placed. This may be undertaken using a percutaneous trocar introducer under local anaesthetic. This should be a reasonably large catheter (a 12 or 14 Ch catheter). Smaller catheters will block within a matter of weeks and cannot easily be replaced, whereas a larger bore catheter is less likely to block and much easier to replace, once the suprapubic catheter track has matured.
There are certain golden rules and contraindications to consider. These are designed to establish that the tender suprapubic mass you can feel is the bladder and not bowel or an abdominal aortic aneurysm (AAA). It is generally taken that the presence of a lower midline abdominal incision is a contraindication to suprapubic catheter placement because adhesions may cause a segment of bowel to be closely applied to the internal surface of the incision. The golden rules are: first, palpate and percuss the bladder, making sure it is not pulsatile;| second, aspirate urine with a fine needle. If you cannot aspirate urine, abandon the procedure. When it has not been possible to aspirate urine suprapubically, or when there is a lower midline abdominal incision there may be loops of adherent bowel, ultrasound-guided placement of a suprapubic catheter or open suprapubic catheter placement under direct vision in an operating theatre should be carried out.
This type of retention can occur as a result of bleeding from a renal or bladder tumor or, commonly, following TURP. It is rare for the patient, even with seemingly very heavy haematuria, to have lost so much blood that they become haemodynamically unstable or require blood transfusion, but as with blood loss from any site it is a wise precaution to insert a wide bore intravenous line and to at least group and save the patient's serum, as well as measuring baseline haemoglobin, platelets and blood clotting. Anticoagulant and antiplatelet drugs should be stopped, if feasible.
The acute management of a patient who tells you that they have been passing blood in their urine and was then unable to void involves insertion of a 3-way 'haematuria' catheter. These come in various sizes, but a 22 or 24 Ch catheter will allow you to evacuate clot and irrigate the bladder .Haematuria catheters have a large distal eye hole, which allows relatively large clots to beaspirated from the bladder. Usually, following aspiration of clot and bladder irrigation, the haematuria settles down and the patient may then undergo upper tract imaging (an IVU or ultrasound) and later a flexible cystoscopy. It is customary to perform cystoscopy after the bleeding has settled down and the catheter has been removed, firstly because visualization of the bladder will not be obscured by the presence of blood, and secondly because the mucosal oedema caused by the catheter will have resolved. However, if the bleeding does not resolve with simple bladder irrigation, and assuming the source is thought to be from the bladder or prostate (i.e. upper tract imaging is normal) then the patient may require cystoscopy under anaesthesia to identify and treat the cause.
Ureteric colic is caused by the passage of a stone, but occasionally by a clot and rarely a necrosed renal papilla, from the kidney through the ureter. The combination of local inflammation and a stretched collecting system and ureter contracting and trying to eject the stone classically causes sudden onset of loin pain, which is very severe and colicky in nature. It may not entirely disappear between exacerbations. Macroscopic or microscopic haematuria may occur, though in a small proportion of cases it may be absent. Though most patients with ureteric colic are young or middle-aged, it can occur in children and elderly individuals. While one should consider other potential diagnoses in a patient of any age, this is particularly important in the elderly where the list of differentials is wider.
A total of 50% of cases of suspected ureteric colic have normal imaging studies or demonstrate another cause for the pain. The list of differential diagnoses includes leaking AAA, perforated peptic ulcer, inflammatory bowel conditions, testicular torsion, ruptured ectopic pregnancy in women, acute appendicitis and myocardial infarction. While a careful history and examination may help in identifying the exact cause of the pain, a high index of suspicion for these alternative diagnoses must be maintained, particularly in elderly patients who are more likely to have other bowel and vascular disease.
IVU is the mainstay of imaging in cases of suspected renal colic in most hospitals. However, some centres prefer to use CTU (CT urography) This allows more rapid urinary tract imaging without the need for contrast injection and has a high sensitivity for ureteric stones. In cases where no ureteric stone is identified, CTU has the advantage over IVU of demonstrating other intra-abdominal pathology. There is a trend towards CTU replacing IVU in the diagnosis of loin pain.
Analgesia: the non-steroidal anti-inflammatory drug diclofenac can provide very effective relief of pain, though opiates (usually pethidine) may also be required. In most cases of ureteric stones the pain will usually resolve spontaneously, either as a result of passage of the stone out of the ureter or once it has come to a halt somewhere in the ureter. Persistent pain (for more than a few days) is an indication for relief of obstruction, either by insertion of a percutaneous nephrostomy into the kidney or by the retrograde passage of a double J stent from bladder to ureter. An alternative, available in some hospitals, is ureteroscopic stone extraction.
There are instances where a patient presents with a ureteric stone and certain features lead you to suspect that there is associated urinary infection. The scenario of ureteric obstruction combined with infection can rapidly (within hours) lead to damage to the affected kidney with long term scarring and loss of functioning renal tissue. Furthermore, infection in an obstructed kidney can lead on to the development of pyonephrosis (pus in the kidney) or a renal or perirenal abscess. Again, this will result in serious damage to the kidney.
The diagnosis of infection in an obstructed kidney is essentially a clinical one, based on the presence of a fever in a patient with radiologic evidence of obstruction. An IVU (or CT) will confirm the presence of a ureteric stone. Alternatively the presence of an obstructed, infected ureteric stone may be suspected in a patient with ultrasonographic evidence of hydronephrosis and a fever. Bacteria are not necessarily seen in the urine nor grown on culture if the obstructing stone prevents passage of bacteria into the bladder.
Resuscitation with intravenous fluids, analgesia, intravenous broad-spectrum antibiotics (e.g. gentamicin combined with ampicillin) and most importantly drainage of the pus with relief of obstruction by percutaneous nephrostomy or retrograde ureteric stent insertion.
Septic shock is a combination of sepsicaemia with hypotension. Sepsicaemia is the syndrome of clinical evidence of infection by which we mean tachycardia (pulse >90 min"1), tachypnoea (>20 respirations min-1), hyperthermia (core temperature >38.3°C; though occasionally hypothermia - core temperature <35.6°C may occur), and evidence of inadequate tissue perfusion such as hypoxia, oliguria and elevated plasma lactic acid levels. Hypotension is defined as a systolic blood pressure <90 mmHg.
Septic shock is traditionally thought of as being due to Gram-negative organisms, but it may also be due to Gram-positive bacteria and fungi. However in the context of urologic surgery and manipulation of the urinary tract, Gram-negative organisms (e.g. E. coli, Klebsiella, Enterobacter serratia, ProteusPseudomonas) are the commonest bacteria to be isolated.
Several factors are involved in the pathophysiology of septic shock. The lipopolysaccharide layer of Gram-negative bacterial cell walls (known as endotoxin) activates humoral pathways (e.g. complement, bradykinin, the coagulation system), macrophages and other cells involved in mediating inflammation. The lipid A part of the lipopolysaccharide is thought to be responsible for most of the toxicity of the endotoxin molecule. Exotoxins (e.g. exotoxin A produced by Ps. aeruginosa) can also initiate septic shock.
Common urological procedures which may be followed by septic shock include TURP, and ureteroscopic and percutaneous stone removal, but even simple catheterization, particularly in the presence of infected urine, can be responsible. Septic shock may occur even when pre-operative urine cultures show no significant growth of bacteria and this forms the basis for the use of prophylactic antibiotics in all patients undergoing TURP and stone surgery irrespective of whether they have an MSU positive for bacteria or not.
Subsequent management of suspected septic shock includes culture of urine, blood and any drain fluid, appropriate antibiotics, volume expansion with normal saline or a plasma expander and oxygen. Monitoring of vital functions should be performed and this should also include measurement of urine output (catheterization allows this to be measured accurately) and blood gases.
Anuria and bilateral ureteric obstruction
Patients who present with anuria (passing no urine at all very small volumes) and who have bilateral hydronephrosis on ultrasound scanning usually have bilateral ureteric obstruction, due either to bladder outlet obstruction, locally invasive prostate cancer, invasive bladder tumours involving both ureteric orifices within the bladder or some retroperitoneal obstructing condition such as malignant retroperitoneal lymphadenopathy (of which there are many causes) or retroperitoneal fibrosis. If the bladder is empty on ultrasound or catheterization and the kidneys are hydronephrotic, then the obstruction is above the level of the bladder outlet. This will be the case, for example, when a prostate cancer invades the lower ureters.
Hystory and, in particular, examination are often enough to make the diagnosis, which may then be confirmed by further investigations. Thus, a patient with a history of recurrent haematuria preceding their anuria by some months may well have a bladder cancer. Back pain suggests retroperitoneal lymphadenopathy. Digital rectal examination of the prostate in males and pelvic examination in females is crucial and may suggest the presence of a locally invasive prostate or cervical cancer. Supraclavicular, cervical or axillary lymphadenopathy may provide an easy target for histological confirmation by biopsy of whatever malignant process is causing the retroperitoneal lymphadenopathy .
Measurement of serum potassium, urea and creatinine are important. If prostate cancer is suspected serum PSA should be measured. A chest X-ray may show evidence of metastatic or primary malignant disease in the lungs. Abdominal and pelvic CT will confirmrm the presence of retroperitoneal or pelvic lymhadenopathy. Transrectal ultrasound and prostatic biopsy are used to provide histological evidence of prostate cancer and cystoscopy will diagnose a bladder cancer.
As for unilateral renal obstruction the mainstay of acute treatment is relief of the obstruction, by percutaneous nephrostomies or retrograde ureteric stents. If the obstruction is distal in the ureter, it is often impossible to pass a stent across the obstruction from below.
This is a necrotizing fasciitis of the male genitalia. It has an abrupt onset and is a rapidly fulminating gangrene which results in destruction of the genitalia. Multiple organisms may be cultured from the infected tissue, both aerobic (e.g. E. coli, Klebsiella, enterococci) and anaerobic (Bacteroides, Clostridium, Fusobacterium, microaerophilic streptococci). It is believed that there is aerobic-anaerobic synergy between the aerobic and anaerobic organisms (i.e. the organisms promote growth and division of each other). Several conditions are thought to predispose to Fournier's gangrene, including diabetes, local trauma (which may be minor), paraphimosis, extravasation of urine from the urethra (e.g. due to traumatic catheterization), circumcision and perianal surgery or sepsis.
The necrotizing fasciitis usually starts as an area of cellulitis adjacent to an entry wound on the penis, scrotum or perineum. This rapidly progresses to a painful, erythematous area which is tender to touch and as the infection progresses subcutaneous gas may be palpated (a characteristic sensation of crepitus is felt when the skin is depressed). The lower abdominal wall may be involved. Rapid onset of gangrene of the skin and subcutaneous tissues of the perineum, shaft of the penis and scrotum follows. The patient is systemically very unwell and if treatment is not instituted immediately death may ensue.
The mainstays of treatment are high-dose intravenous antibiotics with a spectrum of activity against aerobes, anaerobes, Gram-positive and Gram-negative organisms. An initial regime of ampicillin, gentamicin and metronidazole is appropriate until sensitivities from blood or tissue culture are available. Surgical treatment should accompany this regime of antibiotics and this should be done without delay. Obviously necrotic tissue (skin and fascia) together with a margin of apparently healthy surrounding tissue should be removed. This may involve the removal of large areas of tissue and later skin grafting may be required (if the patient survives). Hyperbaric oxygen treatment has been used and is thought to reduce mortality (though not surprisingly there are no randomized, controlled studies comparing one treatment against another) (Dahm et al., 2000). Insertion of a suprapubic catheter may be required to divert urine from the urethra if extravasation of urine from the urethra has occurred. Mortality is in the range of 10-50%.
Torsion of the testis
During fetal development the entire testis may become enveloped by the visceral layer of peritoneum in its descent into the scrotum, and this results in a so-called bell-clapper testis, which can easily rotate on its pedicle and so occlude its blood supply. A urological emergency, the testis is rotated about its intravaginal cord, rendering it ischaemic, swollen and painful. Undescended testes are particularly prone to torsion in the inguinal canal. Although it can occur at any age, the commonest age for torsion is 10-16years and is uncommon over 30years.
Severe scrotal pain of acute onset, radiating to the groin and sometimes to the iliac fossa and to the renal area, reflecting the origin of the developing testis from the region of the kidney. Very occasionally the pain in the loin may be more severe than
the scrotal pain, and a mistaken diagnosis of ureteric colic is made, for the want of not examining the testicle (which will be very tender on palpation). There may be associated vomiting. Fever can occur if the presentation is delayed. Urinary symptoms are absent. Some patients have a history of similar pain that resolved spontaneously, suggesting intermittent torsion. On examination, the patient is usually in considerable distress with pain. Pyrexia is uncommon unless presentation is late and the testis is necrotic. The groins look normal, though there may be tenderness (without peritonism) in the iliac fossa and groin on the affected side. The scrotum is usually swollen and discoloured red/blue. The testis may be seen to lie high and transversely in the scrotum, compared with the normal testis. It is swollen and very tender to touch, often too tender to examine properly. Urinalysis is negative.
The differential diagnoses are principally epididymitis, and torsion of an appendix testis or appendix epididymis. Careful clinical examination which elicits tenderness and swelling in the epididymis, and a completely non-tender testis suggests a diagnosis of epididymitis. However, if there is any testicular tenderness it is safest to explore the scrotum to exclude or confirm the presence of torsion . It must be remembered that when the testis twists, not only is the blood supply to the testis occluded, but so too is that to the epididymis, and the tenderness in the epididymis may therefore be due to torsion.
Adequate analgesia, for example intramuscular pethidine, is essential. Once the diagnosis is made, or if there is any possibility of testicular torsion scrotal exploration must be undertaken as soon as possible. Irreversible ischaemic changes occur after 6 hoursof torsion. The testis is de-torted and bilateral orchidopexy performed using non-absorbable material to prevent future torsion on either side. If the testis is black and fails to recover after several minutes, orchidectomy is necessary (the patient should be warned and consented pre-operatively). There is evidence to suggest that the dead testis may elicit an immune reaction against the contralateral normal testis (as the blood-testis barrier whichnormally isolates the immunogenic spermatozoa from the rest of the body breaks down), and this may subsequently affect the hormonal and spermatogenic function of the opposite testis.
Sometimes it is possible to 'de-tort' the testis percutaneousry, but this can be painful and orchidopexies are still required.
If there is a history of intermittent episodes of sadden-onset of scrotal pain in a young male, the diagnosis of intermittent torsion should be considered and prophylactic bilateral orchidopexies offered.
Torsion of the appendix testis and appendix epididymis
The appendix of the testis is the cranial remnant of the paramesonephric (Mullerian) duct. The appendix of the epididymis is the cranial remnant of the mesonephric (Wolffian) duct. Both tiny vestigial structures are located at the upper pole of the testis or epididymis, respectively and are pedunculated of short stalks.
These appendages can tort, mostly in childhood, producing symptoms and signs similar to those of testicular torsion. The patient is usually less distressed than one with testicular torsion. Other differences include the normal position of the testis, though the swelling and tenderness often obscure this, and the absence of iliac fossa tenderness. Sometimes, in cases presenting early, a ‘blue dot' is visible through the scrotal wall at the upper pole of the testis. If the tenderness is localized to this, the diagnosis is made.
Treatment can be conservative if the diagnosis is certain, since the pain will often last only a few days and the testis is not affected. However, the majority require exploration because of diagnostic uncertainty. A torted appendage is excised and orchidopexies need not be performed.
Priapism is a prolonged painful erection, not associated with sexual desire. After 3 hours the erection becomes increasingly painful, probably because of ischaemia and toxic metabolites. Priapism is classified into the common ischaemic acidotic Tow-flow' and the rare non-ischaemic 'high-flow' types. The high-flow priapism is not painful, and is caused by the traumatic development of arterio-cavernous fistulae.
Diagnosis and investigations
There is little to cause diagnostic confusion in this urological emergency. The cause of the priapism is usually evident from the history, presence of pain, the presence of coexistent disease (haematological, neurological, malignancy), drug history and history of perineal trauma. In young boys priapism is most often due to sickle cell disease or malignancy (e.g. leukaemia). In the older age group it may be idiopathic, but most commonly it is iatrogenic, caused by intracavernosal self-injection therapy used for ED . Other drugs (e.g. antidepressants such as trazodone and fluoxetine; clozapine;chlorpromazine; alpha-adrenergic blockers), sickle-cell disease, malignancy (leukaemia, metastatic prostate cancer, renal cancer and melanoma) and neurologic disorders (spinal cord injury, cauda equina compression, intervertebral disc prolapse). It has also been reported to occur in association with total parenteral nutrition, particularly with the use of intravenous fat emulsions. This is a low-flow type priapism, thought to be due to increased coagulability of the blood or to fat emboli. Perineal or penile trauma can lead to priapism, which may be low-flow (where the venous outflow of the penis is occluded by thrombosis or severe penile oedema) or high-flow (where the cavernosal artery ruptures leading to uncontrolled flow of arterial blood into the corpora). Perineal trauma can occur as a result of bicycle cross bar injuries - where a cyclist comes to a sudden halt and in doing so is thrown onto the cross-bar of his bicycle.
Examination will reveal a dusky erection involving only the corpora cavernosa, with flaccidity of the glans and corpus spongiosum.
Blood gas measurement on blood aspirated from the rigid corpora and duplex ultrasound scanning can be very helpful in determining what type of priapism is present.
Low-flow type: Emergency treatment is required, because of the risk of irreversible ischaemic damage, resulting in corporal fibrosis if >6 hours has elapsed. Aspirating one of the corpora will decompress the priapism and relieve pain. This is accomplished using a wide-bore butterfly inserted perpendicularly to its full depth, aspirating until flaccidity is achieved, then waiting. Some priapisms require no further treatment. Others will re-develop, requiring further aspiration. It two aspirations fail, a tourniquet is applied to the penile base, further aspiration is carried out and a vasoconstrictor (e.g. 0.05-0.1 mg of adrenaline diluted in 5ml saline) is injected and the tourniquet released after 5 minutes. The patient's blood pressure should be monitored after administration of these agents. Usually, this is successful. If the priapism returns, a shunt procedure is undertaken under anaesthetic. This involves creating a fistula from the corpora cavernosa to either the glans using a Tru-cut needle or to the corpus spongiosum or the saphenous vein.
Where a coexistent medical condition is likely to be the cause of the priapism then this should be treated in its on right, together with aspiration and irrigation of the corpora (as described above) if the priapism is of the low-flow variety. For example, in sickle cell disease with priapism (which is most usually of the low-flow type) the patient should receive analgesia, rehydration with intravenous fluids combined with alkalinization of plasma, oxygen should be administered and haemoglobin S levels should be measured. Exchange transfusion may be required to lower the concentration of stickling red cells which by occluding venous outflow from the penis contribute to the development of the priapism in sickle cell disease. Cases of malignant priapism should receive treatment specific to the condition.
High-flow type: less of an emergency and rare, a selective internal pudendal arteriogram is indicated to identify the fistula. Radiological embolization is usually successful in reducing flow through the fistula.
The kidneys are retroperitoneal structures. Their posterior abdominal location, combined with a thick surrounding layer of perirenal fat, the posterior abdominal wall muscles and the lower ribs posteriorly, protects them against injury. As a consequence renal injury usually requires considerable force and it is therefore not surprising that it is often associated with injuries to other intra-abdominal organs.
Renal injuries are most often due to blunt trauma (road traffic accidents, falls, contact sports and assaults) and are less commonly caused by stabbing or gunshot wounds, so-called penetrating injuries. Penetrating injuries are proportionately more common in urban environments. From a management point of view, this classification system - blunt versus penetrating - is useful, because we know from large series of renal injuries that only 2% of blunt injuries will require surgical exploration for repair of the renal injury, whereas approximately 50% of penetrating injuries will do so. Furthermore, we also know that the great majority of patients with gun-shot wounds and approximately 60% of those with renal stab wounds will have injuries of other intra-abdominal organs which, quite independent of any renal injury, will require surgical exploration and repair.
In terms of blunt injuries, there are two categories of patient in whom a significant renal injury is more likely - those patients who have undergone rapid deceleration and children. Rapid deceleration injuries classically occur in high-speed road traffic accident and in falls from a height. The kidney in children is said to be more vulnerable to injury because it is proportionately larger, relative to body size, than that of the adult, there is less surrounding perirenal fat and because children have less protective muscle bulk than adults. Indeed, the kidney is the most commonly injured organ in children with blunt abdominal trauma and the most common mechanisms of injury are bicycle and road traffic accidents.
Thus, with this knowledge in mind it is obvious that history-taking plays a crucial role in the assessment of the patient with a renal injury - it indicates the likelihood of a serious renal injury. Examination also provides important clues as to the likelihood of a significantrenal injury and therefore of the need for imaging and subsequent exploration.
The key points in history-taking are as follows: is the patient an adult or child, was the injury blunt or penetrating, did it involve a rapid deceleration (any high-speed road traffic accident will obviously have involved sudden deceleration as will a fall from a height), has the patient seen blood in their urine?
In terms of examination the following points must be specifically noted: was any recorded blood pressure <90mmHg (recorded at any time, either at the scene of the accident or in hospital), is there evidence of a penetrating injury to the flank, lower chest or abdomen? It is worth emphasizing that though blood pressure may be normal when the patient is in the resuscitation room, if at any time prior to this the recorded blood pressure was <90 mmHg, then renal imaging is indicated.
As stated above, patients with renal injuries often have injuries to other organ systems and the general principles of managing the acute trauma victim should therefore be applied while a history and examination are carried out. This will include establishing and maintaining an adequate airway, and gaining intravenous access to allow rapid infusion of fluids and blood as determined by the patient's haemodynamic status.
Criteria for radiologic imaging in suspected renal injury. The criteria for radiologic imaging are based on the large trauma experience of McAninch from San-Francisco . Many patients with blunt abdominal injuries have microscopic or dipstick haematuria, but do not have significant renal injuries. These criteria for renal imaging are designed to avoid the need for renal imaging in every patient with abdominal trauma. Renal imaging should be performed in:
(a) penetrating trauma to the flank or abdomen regardless of the extent of haematuria (i.e. whether microscopic or macroscopic);
(b) blunt trauma in adults with gross haematuria;
(c) blunt trauma in adults with microscopic or dipstick haematuria (the presence of bleeding, not the amount, determines the need) and a systolic blood pressure <90 mmHg;
(d) deceleration injury (irrespective of the presence or absence of haematuria);
(e) major intra-abdominal injury with microscopic or dipstick haematuria;
(f) any child with flank or abdominal injury with any degree of haematuria (i.e. whether microscopic or macroscopic).
Thus, adults who sustain blunt trauma, have microscopic haematuria and are normotensive (and have not been hypotensive at any stage) do not need renal imaging, unless the injury was a deceleration one or there is an associated major intra-abdominal injury.
To avoid missing significant renal injuries it is important to appreciate that significant renal injuries may be present in the absence of haematuria. This applies to both penetrating abdominal injuries or blunt trauma. This is particularly so with deceleration injuries, which are often associated with renal pedicle (i.e. arterial) injuries which lead to a devascularized kidney - and hence the absence of the source for urinary tract bleeding. Thus, there is no correlation between the degree of haematuria and the extent of renal injury. Clearly haematuria does suggest a possible renal injury, but the key point in abdominal trauma is to consider the possibility of a renal injury based upon the nature of the injury (blunt, penetrating, deceleration etc.).
Any patient with a flank or abdominal penetrating injury who remains haemodynamically unstable despite resuscitation should undergo immediate laparotomy. Surgical exploration should not be delayed to obtain imaging. In such cases on-table single shot intravenous urography can be performed if necessary.
The San Francisco criteria are based on intravenous urography (IVU) (and more latterly CT) as the renal imaging investigation. CT should be used when other abdominal injuries are suspected or when the results of IVU are equivocal. CT has several advantages over IVU. It more accurately stages renal injuries and identifies other intra-abdominal injuries, both factors allowing conservative management to be adopted with greater confidence. While several small series have shown that ultrasound can accurately stage renal injuries and identify those to other intra-abdominal organs, experience in managing renal trauma based on CT or IVU imaging is far greater. It is the extensive experience from the San Francisco General Hospital, based on accurate staging with CT that has allowed a conservative approach to be adopted in most cases of blunt renal injury and many cases of penetrating injury. It is possible that ultrasound may also be able to produce similarly accurate staging - but this has simply not been confirmed in large trauma series.
Imaging allows renal injuries to be identified and staged. Staging is important because it determines subsequent management. Renal injuries are classified according to the American Association for the Surgery of Trauma system .
Criteria for renal imaging in children. The San-Francisco recommendations are that all children (aged < 16 years) who sustain blunt abdominal trauma and have dipstick haematuria or more than 5 red blood cells per high-power field on microscopy should undergo radiologic imaging either IVU or CT.
The great majority of blunt renal injuries can be managed conservatively, with bed rest and analgesia, and depending on the extent of the initial injury serial CT scans to determine whether there is evidence of an expanding haematoma.
A proportion of penetrating renal injuries can also be managed conservatively. In San Francisco approximately 40% of stab wounds and 75% of gunshot wounds require renal exploration. Improved staging, specifically using CT, has allowed a conservative approach to be adopted in many cases.
Absolute indications for renal exploration are persistent hypotension despite resuscitation, an expanding retroperitoneal haematoma (this will usually be identified by serial CT scans) and a pulsatile haematoma (indicating a false aneurysm of a major renal artery). Relative indications for surgical exploration include extensive urinary extravasation (which indicates a collecting system injury) and arterial thrombosis. Minor degrees of urinary extravasation may be managed expectantly (anticipating spontaneous resolution) or by a ureteric stent which acts to improve urinary drainage.
Because of its retroperitoneal location the ureter is well protected from external trauma. Penetrating trauma is the commonest mechanism of injury. In the UK where gunshot wounds are rare, most cases of ‘penetrating' ureteric injury are related either to pelvie surgery (colorectal or gynaecological) or occur during ureteroscopy. The ureter is vulnerable to injury during pelvic surgery because of its intimate relationship with the broad ligament and uterine artery in women (hence it may be injured during hysterectomy) and the rectosigmoid colon and mesocolon in both sexes.
Blunt ureteric trauma is rare. Deceleration injuries can disrupt the pelviureteric junction, effectively disconnecting the ureter from the kidney.
The diagnosis of a ureteric injury will to some extent depend on the clinical context in which the injury occurs. A transected ureter may be obvious at the time of surgery, but if doubt exists about the possibility of a ureteric injury then the ureter can be directly inspected or a retrograde ureterogram can be obtained. Postoperative ureteric injury should be suspected in a patient who develops flank pain, ileus, unexplained pyrexia or drainage of clear fluid from a drain (or healing drain site or abdominal wound) or per vagina (post-hysterectomy). When one suspects drain fluid to be urine a small quantity can be sent for estimation of creatinine level. A creatinine level at or near that of a serum sample confirms that the fluid is lymph; urine will have a much higher creatinine level.
Where a ureteric injury is suspected, IVU should be the first line investigation. This will often demon strate hydronephrosis of the affected kidney, delayed excretion of contrast and absence of contrast in the ureter below the level of the injury. Of course, the entire length of the ureter is not always visualized, even in a normal ureter, and the kidney may not be hydronephrotic if there is free drainage of urine into the abdomen or retroperitoneum from a ureteric transection. Thus, if there is a strong suspicion of a ureteric injury, cystoscopy and retrograde ureterography should be performed. This technique has the advantage that a partial ureteric transection can be stented with a double J ureteric stent at the same time as the procedure, and in some cases this may be all that is necessary to allow the ureteric injury to heal.
Primary anastomosis of ureteric injuries that are identified peroperatively is suitable for virtually all injuries other than those involving the distal ureter where a potentially tenuous blood supply can compromise healing. If such an anastomosis is under any degree of tension then it will not heal and a persistent leak of urine will occur. In such cases to bridge a ureteric defect and so avoid tension in the anastomosis, a flap of bladder can be fashioned, swung upwards to bridge the ureteric defect, and then fashioned into a tube into which the ureter is tunnelled. This is called a Boari flap. Alternatively, a transverse incision in the wall of the bladder will allow reimplantation of the transected ureter into the bladder, any discrepancy in ureteric length being overcome by closing the bladder incision longitudinally, so effectively lengthening the bladder in a vertical direction . The bladder is held in its new location by several 'hitch' sutures, which hold the bladder onto the psoas minor tendon, hence the technique is called the 'psoas hitch'. If the length of injured ureter is very large, and reimplantation into the bladder is not feasible, then the affected ureter may be swung across to the opposite ureter (behind the mesentery of the bowel) and anastomosed to this ureter. This is called a transureteroureterostomy (or TUU).
Where the diagnosis of a ureteric injury is made post-operatively an attempt at insertion of a ureteric 'double J' stent at the time of retrograde ureterography can be made. If a guidewire can be passed across the area of injury, so allowing access to the non-injured ureter above, then it is usually possible to pass a stent. If there is a demonstrable collection of urine around the site of ureteric injury, a percutaneous drain can be placed with radiological screening. If a double J stent cannot be passed then open surgical repair by one of the techniques described above should be the next step.
The mechanisms of bladder injury are specific. As with renal injures, a carefully taken history should alert you to the possibility that a bladder injury might have occurred.
The bladder may be injured at the time of endoscopic bladder surgery (transurethral resection of bladder tumor is the classic culprit) or pelvic surgery, particularly Caesarian section. Such injuries are usually obvious at the time of the procedure. Traumatic bladder injuries occur as a result of either a blow to the lower abdomen, particularly when the bladder is full, or in association withpelvic fracture, where a sharp bone edge from the fractured pelvis can directly damage the bladder. Penetrating (externally penetrating) bladder injuries are unusual in the UK, but obviously a penetrating wound in the lower abdomen should alert you to the possibility that the bladder may have been injured. Spontaneous rupture of the bladder can occur in patients who have undergone previous bladder augmentation (where a segment of detubularized bowel is stitched onto the dome of the bladder in order to increase its capacity).
The patient with a bladder injury will usually in complain of lower abdominal or suprapubic pain (though patients with neurological disorders such as spina bifida or spinal cord injuries - some of whom may have had a bladder augmentation –may not do so and this can lead to a delay in diagnosis). The other symptoms of a bladder injury include difficulty or inability to void (a bladder which is emptying into the peritoneal cavity obviously may not empty per urethra) and haematuria. Examination may reveal lower abdominal tenderness and an ileus with abdominal distension and absent bowel sounds.
Retrograde cystography is the most accurate method of diagnosing a bladder injury. This involves the passage of a urethral catheter, instillation of contrast into the bladder and X-ray screening into identify a leak. Generally speaking at least 400 ml of contrast should be instilled into the bladder. A small perforation can be plugged by small-bowe1 or omentum, and this may not be apparent if lower volumes of contrast, resulting in inadequate bladder distension, are used. Once this has been done all of the contrast should be drained from the bladder and a post-drainage film taken. Sometimes a small leak of contrast may be obscured by the presence of dense contrast in a full bladder and may only be apparent when the contrast has been drained from the bladder.
Retrograde cystography allows classification of bladder injuries into those that are extraperitoneal and those that are intraperitoneal; the former obviously being contained within the pelvis with no leak of urine into the peritoneal cavity. This is a useful classification system because it determines subsequent treatment. Extraperitoneal perforations can, generally speaking, be managed by a period of catheter drainage (with antibiotic cover throughout this period) and the majority will heal within 10 to 14 days (some take a little longer). Confirmation of healing can be obtained by a repeat cystogram. Intraperitoneal bladder perforations, on the other hand, should be managed by open surgical repair, again with post-operative bladder catheter drainage.
One word of warning: bladder injuries may coexist with urethral injuries, particularly when there is a pelvic fracture. When blood is present at the meatus, or if it is absent but a catheter will not pass into the bladder, a retrograde urethrogram should be performed to exclude a urethral injury. Though the presence of visible blood at the urethral meatus is often due to a urethral injury in isolation, it must be remembered that it could also be coming from either a bladder or renal injury. As stated above (Renal trauma) any trauma patient with macroscopic haematuria should undergo renal imaging and in the context of urethral bleeding, bladder imaging should also be done. Of course, if a urethral catheter cannot be passed into the bladder because of a urethral disruption, then a retrograde cystogram cannot be done. In such a situation how can one adequately visualize the bladder? A suprapubic catheter should be placed either percutaneously, or (more commonly) by formal open cystostomy, through a short transverse lower abdominal incision with direct visualization and catheterization of the bladder. If a percutaneous suprapubic catheter has been placed then a cystogram can be obtained via this catheter. If an open cystostomy is done then the inside of the bladder can be directly inspected at the time of the procedure.
Urethral injuries may involve the anterior urethra or posterior urethra. The anterior urethra extends from the external urethral meatus to the distal end of the membranous urethra (wherein lies the external urethral sphincter). The posterior urethra includes the membranous urethra (and therefore the external sphincter) and the prostatic urethra.
The mechanism of injury to the anterior urethra is very different from that in injuries of the posterior urethra. The former are caused by instrumentation (cystoscopy, catheterization, including inflating a catheter balloon in the urethra or removal of a catheter with the balloon inflated) or fall astride injuries (little boys - or men - forcefully hitting the cross bar of their bicycles or receiving a blow to the perineum). This crushes the bulbar urethra against the inferior pubis. More rarely the anterior urethra may be torn when the erect penis is forcibly bent, which literally fractures the corpora cavernosa and sometimes the corpus spongiosum, within which the anterior urethra runs. Posterior urethral injuries on the other hand are usually due to pelvic fractures, which usually require massive force. Posterior urethral injuries are therefore often associated with damage to major pelvic blood vessels, resulting in life-threatening blood loss. The management of anterior and posterior urethral injuries is therefore very different.
Presentation of anterior urethral injuries
Once again, history-taking is very important in reaching a correct diagnosis. A history of a fall astride injury or other blow to the perineum should arouse your suspicion that there may be an anterior urethral injury. The patient may be unable to void. Examination may reveal blood at the external meatus or bruising of the penis, perineum or lower abdomen, the exact distribution being determined by which layer of penile fascia has been disrupted. Buck's fascia is a tube of connective tissue surrounding the corpora cavernosa and corpus spongiosum. Proximally it fuses with the tunica albuginea of the corpora (the tunica albuginea is the thick, cylindrical tube of connective tissue that encases each corpus) and this fusion of Buck's fascia with the corpora prevents further spread of any extravasated blood. Thus, an anterior urethral injury which does not rupture Buck's fascia will result in penile bruising that is confined to the shaft of the penis. If Buck's fascia is ruptured, the bruising is then confined by the next (more superficial) layer of connective tissue, Colles fascia. Colles fascia fuses posteriorly with the perineal body and extends a little way down each thigh. Bleeding beneath this layer of fascia will thus create bruising of a characteristic pattern in the perineum, the so-called butterfly bruising of anterior urethral rupture . Colles fascia is renamed Scarpa's fascia as it sweeps upwards into the abdomen. Superiorly it is attached to the clavicles, so if Buck's fascia is ruptured allowing blood to extravasate beneath Colles fascia and if the bleeding from an anterior urethral injury is extensive enough, bruising may extend all the way to the clavicles.
Retrograde urethrography is used to identify the presence of a urethral injury . A small (e.g.) catheter is inserted with its tip just inside the urethral meatus and the balloon inflated to prevent it from falling out (alternatively a penile clamp can be applied to the end of the penis to stop contrast from flowing out of the penis on injection). Water soluble contrast is injected and screening performed during the injection. Extravasation of contrast confirms a urethral injury. A patient who has sustained a fall astride injury, and who has blood at the external meatus, but no extravasation is said to have an anterior urethral contusion.
Anterior urethral contusions can be managed by advancing a small-bore silicone catheter (12 Ch) into the bladder and this is left on free drainage for 10 to 14 days. Broad-spectrum antibiotics are prescribed. Patients with extravasation (indicating incomplete or complete anterior urethral disruption) should be managed by suprapubic catheterization - so diverting urine away from the site of injury while the urethra heals. Urethral catheterization can convert an incomplete disruption to a complete one, and may introduce infection into the haematoma. The segment of intact urethral mucosa will allow re-epithelialization of the urethra and while some patients may subsequently develop a stricture, many of these are mild and of no functional significance. Voiding urethrography (introduction of contrast into the bladder, clamping of the suprapubic tube, followed by the patient passing urine) 3 to 4 weeks later will determine whether the urethra has healed, at which time the suprapubic catheter can be removed.
In cases of penetrating anterior urethral injury or those associated with penile fracture, primary repair of the urethra should be performed over a urethral catheter.
Presentation and investigation of posterior urethral injuries
As stated above, posterior urethral injuries usually occur as a consequence of pelvic fracture , and are thus often associated with life-threatening pelvic bleeding (from torn pelvic veins) and other injuries, both abdominal and chest as well as head injuries and other fractures. Bladder and renal injuries may coexist with the posterior urethral disruption. Catheterization is important to allow monitoring of urine output in patients who are likely to be haemodynamically unstable, and also to establish urinary drainage, so preventing leakage of urine into the pelvis.
The haemodynamically unstable patient. Whether a retrograde urethrogram is obtained in the emergency room will depend on the need for urgent surgery for treatment of associated injuries. The patient may have coexistent intra-abdominal bleeding necessitating urgent laparotomy - obviously there may not be time to obtain a retrograde urethrogram in such a case. In this instance a gentle attempt should be made to catheterize the bladder in the operating theatre, and any resistance to catheterization will indicate the need for placement of a suprapubic catheter at the time of laparotomy.
Treatment of posterior urethral injuries
Placement of a suprapubic catheter under direct vision at the time of laparotomy is usually safer than percutaneous catheterization (see below), as long as the pelvic haematoma is not disturbed, and it affords the possibility of inspecting the inside of the bladder for injuries, which should be repaired at that time.
The haemodynamically stable patient. In the stable patient with a pelvic fracture in whom urgent laparotomy is not required and where there is no blood at the external meatus, a gentle attempt at catheterization should be made. If the catheter passes easily into the bladder and clear urine with no haematuria is obtained then a bladder injury is unlikely and a formal cystogram is not necessary, though it can certainly be comforting if a cystogram is obtained and it is normal. Any resistance to passage of the catheter indicates the need for retrograde urethrography. If this demonstrates a posterior urethral rupture, whether partial or complete, then a suprapubic catheter should be placed. Again, formal open cystostomy (direct exposure of the bladder via a suprapubic incision) is better than percutaneous suprapubic catheterization because (1) it allows accurate placement of the catheter in the bladder - in the presence of a pelvic fracture it is all too easy to catheterize the pelvis haematoma or the peritoneal cavity, with the potential for bowel perforation. Perforating bowel is a serious complication in any situation, but contamination of a pelvic haematoma with bowel organisms could lead to life-threatening sepsis; (2) it allows associated bladder injuries to be identified and repaired. A catheter may not necessarily provide adequate urinary diversion if there is an associated bladder injury. Failure to repair such injuries may lead to extravasation of urine, which again may lead to the potentially disastrous consequence of infection of the pelvic haematoma.
Blood at the external urethral meatus is an indication for retrograde urethrography. No attempt at urethral catheterization should be made. If the urethra is normal, the catheter may be advanced into the bladder and a cystogram should be done to determine whether a bladder injury is present. If the posterior urethra is disrupted, a suprapubic catheter is inserted and a delayed anastomotic urethroplasty performed to restore continuity 3 months later. Most patients with a pelvic fracture will undergo an abdominal as well as pelvic CT scan, so it is unlikely that significant renal injuries will be missed, but it is worth repeating that any trauma patient with macroscopic haematuria (even if this is a small amount at the external urethra meatus) should have imaging of the kidneys (IVU or better still a CT scan).
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