Fig. 6.1
Illustration of various types of ruptures. (a) Retroperitoneal rupture. Dorsal or dorsolateral rupture usually leads to a leak into the retroperitoneum, often causing asymmetric displacement and squeezing of the abdominal content. As a consequence, asymmetric bulging of the abdominal wall may be encountered. Due to the restricted retroperitoneal space and the consistency of the retroperitoneal tissues, retroperitoneal leaks often temporarily seal, before definite – sometimes free – rupture. “Contained” rupture is therefore used synonymously to retroperitoneal rupture in the literature. (b) Intraperitoneal rupture. More anterior rupture may immediately communicate with the peritoneal cavity, and due to the low resistance in this space and the good compliance of the abdominal wall, massive amounts of blood may flow into this cavity. “Free” rupture is therefore regularly used as a synonym. Bulging of the abdomen usually is symmetric. (c) Aortocaval fistula. Right lateral rupture into the vena cava causes a communication of a high-pressure to a low-pressure system. This left to right shunt leads to massive increase in cardiac output and eventually to high-output congestive heart failure. The abdomen is usually unremarkable, although an abdominal thrill may be palpated or auscultated. (d) Aorto-left renal vein fistula. Dorsal rupture into a retroaortic left renal vein accounts for 90 % of this type of rupture. In addition to the signs and symptoms of aortocaval fistula, hematuria or varicocele may frequently develop. (e) Aortoenteric fistula. Rupture into the bowel creates a communication between usually the third or fourth part of the duodenum and the aorta. However, all parts of the gastrointestinal systems may be involved. Due to the leak into a low-pressure system, blood may immediately ascend to the stomach and pretend an upper GI bleeding. Less frequently, a lower GI bleeding may reveal as an aortoenteric fistula, e.g., the jejunum. (f) Arterio-ureteral fistula. Rupture into the ureter most often occurs in the region of the iliac bifurcation either between the native aneurysmatic iliac artery or a previously placed graft for aortoiliac replacement. Hematuria and hydronephrosis are the most common signs of AUF. (g) Chronic contained rupture. Retroperitoneal rupture may lead to a slow progressive bleeding that is contained by the resistance of the periaortic tissues and may exert chronic stone mill-like pressure to the adjacent structures such as the vertebral column. Erosion of vertebral bodies has been documented radiologically and surgically. Correspondingly, chronic back pain with or without irradiation to the groin is the most presenting symptom in this type of rupture
Physicians should – independent of their specialties – be aware of the early signs of potential abdominal aortic aneurysm rupture: syncope, transient hypotension, and/or loss of consciousness. Rapid diagnosis due to early suspicion of RAAA may be lifesaving as hemodynamic instability may suddenly ensue due to continuous blood loss, “secondary” rupture, and/or ACS.
Usual Presentation of RAAA
Retroperitoneal Rupture
Rupture of the posterior or lateral aneurysm wall into the retroperitoneal cavity (Fig. 6.1a), generally called retroperitoneal or also “contained” rupture, is the most common site of rupture found in RAAA patients. Due to the posterolateral localization of the tear, the blood will rapidly expand into the retroperitoneal space. However, bleeding will often be temporarily sealed, because of the anatomy and consistency of the retroperitoneal space and tissues that will “contain” bleeding by tamponade due to increased retroperitoneal pressure. Clinically, this manifests as back or flank pain with or without abdominal pain and (temporary) hypotension. The pain is usually severe, constant, and unaffected by position and can radiate to the chest, scrotum, inguinal region, or the thigh. On inspection, patients are pale and sweaty, sometimes restless, and often report feeling cold. Physical examination may show a pulsatile mass in the upper abdomen. The latter is often missing, however, especially in obese patients and/or those with severe hypotension caused by hemorrhagic hypovolemia.
This period of self-tamponade provides the window of opportunity for the treatment of patients with this type of rupture. They remain relatively stable, sometimes even for a few hours, during which patients may rapidly be transferred to an institution familiar with the management of RAAA. Patients are, however, at great risk for “secondary” rupture, especially when reanimation includes aggressive blood pressure and fluid resuscitation as taught for many years. Therefore, these patients should be followed by the principles of hypotensive hemostasis described in the literature: fluid restriction and keeping the systolic blood pressure low [7–9].
If not suspected right away, contained RAAA may develop a variety of misleading symptoms and clinical as well as radiological signs because of the growing intra-abdominal pressure and compression of abdominal organs such as the intestines or the ureters because of the growing hematoma. Even angina-like symptoms may occur, especially when ACS develops leading to low cardiac and coronary filling pressures [6]. Not infrequently, however, true angina pectoris develops due to severe hypotension and hypovolemia caused by the RAAA. The author has experienced situations where patients were kept in the medical emergency department for many hours before RAAA has been detected “incidentally” while performing a (contrast-enhanced) computed tomographic scan for an entire different reason. This kind of diagnostic delay significantly worsens the outcome; the mortality rate increases from 45 to 55 % when diagnosis is delayed for up to 10 h or as high as 100 % when missed even longer [10]. It is strongly suggested, therefore, that in any patient with sudden abdominal and/or back and/or flank pain, RAAA must always be considered in the differential diagnosis. Algorithms and emergency checklists should be updated accordingly. However, retroperitoneal rupture may present in a quite unusual fashion such as painless or painful testicular ecchymosis also called the “blue scrotum sign of Bryant” [11, 12].
Intraperitoneal Rupture
As many as 65 % of patients with ruptured abdominal aortic aneurysms die of sudden cardiovascular collapse before arriving at a hospital. Most of these patients suffer from anterior rupture, also called “free” rupture, with massive bleeding into the peritoneal cavity (Fig. 6.1b). In contrast to the posterior retroperitoneal rupture, there is no resistance that would allow temporary sealing and containment of the rupture. The blood may fill up the intraperitoneal space until the patient’s exsanguination. Clinically, sudden severe abdominal and/or back pain is usually followed by collapse because of uncontrolled bleeding. Patients usually remain hemodynamically unstable and do not temporarily recover like the patients suffering from retroperitoneal contained rupture. The abdomen may appear balloon-like due to rapid expansion of the abdominal wall, while in patients with retroperitoneal rupture, an asymmetric bulging may be detected. Some patients may be found dead minutes after free intraperitoneal rupture and therefore mistakenly be diagnosed as cardiac sudden death patients.
Unusual Presentation of RAAA
Rarely, abdominal aortic aneurysms rupture into abdominal veins, small bowel segments, or even the ureter, producing fistulae of the respective hollow structures. The patient’s presentation varies depending on the localization of the rupture and the organs involved.
Aortocaval Fistula
Rupture into the inferior vena cava (Fig. 6.1c) will produce an aortocaval fistula (ACF) of varying diameter. Depending on the size of the communication between the aorta and vena cava, variable clinical manifestations may be detected. The classic presentation of patients with ACF is a triad of abdominal and/or back pain, a pulsatile abdominal mass, and a continuous bruit on abdominal auscultation (sometimes accompanied by a palpable thrill) [13–15]. However, the prevalence of this classic triad varies significantly between studies and may be as low as 17 % [14, 15]. High-output congestive heart failure may be the leading manifestation with patients showing dyspnea, pulmonary edema, tachycardia, wide pulse pressure, cyanosis, dilated superficial veins on the abdominal wall or the legs, and lower limb edema [13, 14, 16, 17]. A variety of other symptoms may mislead the clinicians in making the correct diagnosis of RAAA in the form of aortocaval fistula: angina pectoris [13], palpitations [18], fever [19], and rectal bleeding [20] due to rupture of distended veins. Oliguria [15, 19] and renal insufficiency [21–24] caused by decreased renal perfusion and hematuria caused by kidney malperfusion and/or superficial renal or bladder vein rupture [25] may trigger the wrong diagnosis of kidney or bladder disease. Acute hepatorenal failure has been described as a first manifestation at presentation [26]. In fact, probably half of all aortocaval fistulae are missed [19], and ACF is frequently incidentally detected during elective AAA surgery [14]. Hypotension, pulsatile peripheral veins [13], and diminished lower limb pulses [13, 19] may eventually lead to the correct diagnosis when detected. Although rupture of AAA is the main cause of ACF, other causes exist such as trauma and surgery of the lumbar spine [13, 14].
It is important that clinicians and emergency staff be trained in detecting ACF. The outcome of accidentally discovered ACF during surgery is significantly worse because of major blood loss or pulmonary embolism from aortic thrombus caused by the inadequate operative strategy due to ignorance [14]. Preoperative detection of ACF is important and nowadays should be accomplished by contrast-enhanced computed tomographic angiography (CTA) [13, 14, 19, 27].
Aorto-left Renal Vein Fistula
Rupture into the left renal vein (Fig. 6.1d) might be regarded as equivalent to aortocaval fistula with special considerations. Pathophysiologically, this type of arteriovenous fistula behaves similarly to the aortocaval fistula with possible high-output congestive heart failure and all the clinical manifestations as described above. However, due to its site of rupture into the left renal vein, signs and symptoms regarding the kidney and bladder are accentuated. This is best represented by the “abdominal pain, hematuria, silent left kidney” syndrome described in the early 1990s by Mansour et al. [28]. Pain is usually felt in the left flank and radiates to the groin. It is accompanied by hematuria in 85 % of patients [29], and ureteral colic is often suspected rather than an AAA that has ruptured into the left renal vein [30]. Despite the fact that this kind of RAAA is very rare, diagnosis should be promptly made when these symptoms are present [29]. The outcome is similarly worsened because of ignorance of the underlying pathology and the discovery of the condition during surgery. It is important to note that in more than 90 % of the cases, the rupture occurs dorsally into a retroaortic left renal vein, a rare anomaly affecting 1–2.4 % of people [28, 29]. Finally, two patients who presented with a large left-sided varicocele, presumably due to left renal vein hypertension and impaired venous return from the left testicle, have been described [29, 31]. Furthermore, recently, a female patient with a retroaortic left renal vein fistula masquerading as pelvic congestion syndrome has been described by Fassiadis et al. [32]. Of the 32 cases described up to 2013, all but two were male [32–34]. Very recently, Wu et al., in a letter to the editor, describe the case of a 30-year-old man who was brought to the hospital following trauma involving an abdominal stab wound [35]. The postoperative CT scan following emergency abdominal surgery revealed an aorto-left renal vein fistula that was secondarily treated by endovascular repair.
Aortoenteric Fistula
Rupture into the bowel (Fig. 6.1e) creates a communication between a non-sterile compartment, the bowel, and a sterile compartment, the aorta. Anatomically, the third or fourth parts of the duodenum are most commonly involved due to their topographic relationship to the anterior aortic wall and their fixation to the retroperitoneum by the ligament of Treitz [36], but other parts may be involved. Two types of aortoenteric fistulas (AEFs) are recognized: primary and secondary [37]. Primary fistulas occur de novo between the aorta and the bowel, the more common secondary fistulas between an aortic graft and a segment of bowel. Accordingly, clinical presentations vary depending on the size and localization of the communication with the bowel, the dynamic of perforation, and the presence or not of previous open vascular or endovascular interventions. Patients with aortoenteric fistula (AEF) may present with few symptoms beyond abdominal discomfort [38] with or without an elevated CRP and white blood cell count, if perforation is impending or temporarily sealed. In fact, symptoms may be attributed to peptic ulceration, and the proton pump inhibitors prescribed may temporarily relieve the pain [38]. On the other end of the spectrum, AEF patients may present as an emergency, either with massive gastrointestinal (GI) bleeding, with frank sepsis, or both. Patients with significant GI bleeding induced by AEF present with hematemesis, melena, and anemia, sometimes accompanied by syncope or shock [39–41]. Massive hemorrhage is commonly preceded by an episode of small brisk bleeding which stops spontaneously. This so-called herald bleed is characteristic of an AEF [36]. Diagnosis of AEF is often delayed for days or even weeks, and patients sometimes receive multiple blood transfusions before the diagnosis of AEF is established [39]. However, patients may just present with abdominal pain and melena or recurrent rectal bleeding [38]. Melena as the first manifestation of AEF may mislead clinicians to look for peptic ulcer disease, gastritis, esophageal varices, Meckel’s diverticulum, or Mallory-Weiss syndrome. Presentation with rectal bleeding and flank pain for 2 weeks before establishing the diagnosis of primary AEF has been described [42]. Unexplained fever may occur in patients with primary [43, 44] or secondary [45] AEF, and missing the diagnosis may end fatally. Some patients present with (recurrent episodes of) sepsis caused by primary [46] or secondary [47] AEF. Diagnosis may be delayed for months, as reported in a 78-year-old female treated for recurrent episodes of Enterobacter cloacae sepsis with antibiotics before finally detecting a secondary AEF [47].
In summary, establishing the diagnosis of primary or secondary AEF is very challenging, and a high index of suspicion is required because of the variability of clinical presentation. The classical clinical triad consisting of upper gastrointestinal bleeding, abdominal pain, and a pulsatile abdominal mass is present in only 10 % of patients suffering from primary AEF [48, 49]. Presentation of secondary AEF is even more complex, and the clinical manifestations are often crucial to the diagnosis of AEF, because no single imaging modality is capable of depicting this condition with high sensitivity and specificity. However, if clinically suspected, upper GI endoscopy (to include the entire duodenum), contrast-enhanced computed tomographic angiography, and, sometimes, plain angiography or ultrasound may be required to confirm the diagnosis. Unfortunately, preoperative diagnosis of AEF is reached in only 50 % of the patients [36], exposing half of the patients to a high risk for intraoperative massive bleeding and complications as with aortocaval and aorto-left renal vein fistulas.
Arterio-ureteral Fistula
Rupture into the ureter (Fig. 6.1f) will create a communication between the aorta and the iliac arteries and anastomotic aneurysms or vascular graft material in the aortoiliac position and the ureter [50, 51]. The left and right ureter seems to be involved almost alike, whereas bilateral involvement is only 1 % [51]. Arterio-ureteral fistula (AUF) is an uncommon diagnosis that is often missed due to its misleading presentation. In a recent systematic review of 139 cases from 1899 to 2008 by van den Bergh et al., all patients presented with hematuria [51]. Some patients required acute intervention for massive hematuria, while in most patients hematuria was less intense, and they presented after having experienced multiple intermittent episodes of bleeding. In 74 % of AUF patients, hematuria was the only manifestation, 17 % had accompanying flank or back pain, 7 % showed signs of infection, and 1 % had urinary retention at first presentation. Three quarters of the patients suffered from urologic symptoms for a longer period before initial presentation such as hydronephrosis, ureteral stenosis, a previously damaged ureter, or signs of chronic urinary tract infection. AUF is a life-threatening condition, and the outcome is strongly inversely associated with the length of diagnostic delay [52, 53]. Therefore, all clinicians, especially urologists, and emergency staff should be trained to have a high level of suspicion for the presence of AUF in patients with a background of pelvic oncologic or vascular pathologic features or surgery, abdominal or pelvic radiotherapy, urinary diversion surgery, and ureteral stenting. Further specific diagnostic investigations should be performed immediately, when an AUF is suspected [54]. Often, repeated studies and provocative testing are required to confirm the diagnosis of AUF [55].
Chronic Presentation of RAAA
Chronic Contained Rupture
Retroperitoneal rupture may lead to slow progressive bleeding, eventually forming a large hematoma that is contained by the resistance of the periaortic tissues (Fig. 6.1g) [56, 57]. Clinical presentation is like a colorful bouquet of flowers: most patients suffering from chronic contained rupture (CCR) present with chronic back pain with or without irradiation to the groin [58–61]; other pain-related manifestations reported are lumbar spondylitis-like symptoms [61–63], left lower extremity weakness or neuropathy [64–66], or even crural neuropathy [56]; and vertebral erosion [67–69], left psoas hematoma [60], or even obstructive jaundice [70] are further clinical manifestations. Not surprisingly, RAAA is mostly missed in these patients, and they may be treated, for example, for back pain or neurological symptoms instead. Chronic back pain of unknown origin should raise the clinicians’ suspicion for CCR, and further diagnostic investigations (contrast-enhanced CT angiography and/or magnetic resonance imaging) should be performed. Although CCR patients are generally hemodynamically stable, missing the diagnosis, and hence rapid treatment, could lead to fatal free rupture and death [61, 65, 69, 71].
Presentation with Abdominal Compartment Syndrome
The presence of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) may further confuse the presentation of patients suffering from RAAA. ACS as a consequence of IAH leads to (multiple) organ dysfunction at the early stage, and patients therefore may be investigated for diseases of almost every organ system [6, 72]. If not treated rapidly and appropriately, eventually full-blown multiple organ failure (MOF) will develop. Although ACS usually occurs perioperatively [73], probably as part of the reperfusion injury to the abdominal organs, patients with an RAAA may present with mild to full-blown ACS already on admission. Clinically, renal dysfunction, respiratory insufficiency due to increased airway pressures and decreased pulmonary compliance, cerebral dysfunction due to increased intracranial pressure, decreased cardiac output, signs of right heart failure, angina pectoris-like symptoms, and loss of bowel function due to poor intestinal perfusion may be encountered [72]. Contrary to popular opinion, clinical examination appears to be inaccurate to diagnose IAH/ACS [74–76]. The only reliable diagnostic tool to detect and discriminate ACS is early and repeated measurement of the intra-abdominal pressure (through measurement of the bladder pressure, e.g., using a Foley manometer) [77, 78]. Therefore, regular (1–2 hourly) or continuous IAP monitoring is recommended in RAAA patients [7, 73]. Given the serious consequences of missed ACS and the fact that ACS can imitate many reasons for organ failure, it is strongly recommended that all emergency staff be trained in the recognition of the potentially fatal diagnosis of abdominal compartment syndrome as a consequence of RAAA.
Presentation of Women with RAAA
Despite the ongoing discussion about the gender differences in the outcome of (ruptured) abdominal aneurysm repair and documented worse outcomes of RAAA repair in women [79], little is known about the differences in presentation of women with RAAA compared to men. It seems that women present, at an older age, with smaller aneurysm diameter at rupture and worse vascular anatomy [80, 81]. In a large randomized controlled trial in the UK, comparing an endovascular versus and open repair strategy for RAAA, women were shown to profit from endovascular aneurysm repair [82]. Therefore, RAAAs should be rapidly diagnosed in women so they can be referred to a specialized center with the skills and facilities necessary to perform EVAR, if their anatomy is suitable.
Presentation of Children with RAAA
Abdominal aortic aneurysms in children are distinctly rare and rupture of them even rarer [83, 84]. Acquired AAA in children is associated with various predisposing factors, including infection (e.g., bacteria, tuberculosis, and fungal infection) [85], congenital connective tissue disease (e.g., Marfan’s syndrome, Ehlers-Danlos syndrome, and tuberous sclerosis) [86, 87], trauma (e.g., umbilical artery catheterization) [88], and vasculitis (e.g., Takayasu arteritis, polyarteritis nodosa, giant cell arteritis, and Kawasaki’s syndrome) [89]. In comparison with acquired abdominal aortic aneurysm, congenital AAA has an unknown etiology [90, 91]. Clinical presentation may vary from a complete lack of symptoms to ruptures [84, 92–94]. Mild abdominal distension is sometimes the only abdominal symptom of rupture in children [93, 94]. A pulsatile abdominal mass may be detected unexpectedly only after laparotomy, and the delay in diagnosis may lead to fatal outcome [93, 94]. Emergency staffs should be aware of the rare and distinct possibility of aortic rupture in children of any age suffering from known or unknown AAA of various etiologies. Immediate further investigation (e.g., contrast-enhanced computed tomographic angiography) is mandatory as soon as signs of major bleeding are present.
Misdiagnosis of RAAA
Hemodynamic stability seems to play a major role when it comes to misdiagnosis of RAAA and as a consequence treatment delay [95]. Among 98 patients undergoing emergency AAA repair, 56 patients were hemodynamically stable at presentation, and misdiagnosis was significantly more common in these patients than in those who were in shock (58.9 % vs 26.2 %, p = 0.002). Median time delay from presentation to diagnosis was significantly increased (144 min vs 12 min, p < 0.0001), and median time from diagnosis to arrival in theater was significantly longer (90 min vs 48 min, p = 0.02) in patients who were hemodynamically stable at presentation. Of the 56 patients who were hemodynamically stable at presentation, 19 underwent hemodynamic decompensation before surgery with a significantly increased mortality compared with those who remained stable (73.7 % vs 37.8 %, p = 0.02). Of these 19 patients, only five were correctly diagnosed at presentation. Gastrointestinal and renal/urinary tract pathologies were the most frequent misdiagnoses, followed by back, thoracic, or cardiac pathologies [95].
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