CASE REPORT aneurysm, abdominal, aortic

Chronic Contained Rupture of an Abdominal Aortic Aneurysm Presenting as a Lower Extremity Neuropathy

Rupture of an abdominal aortic aneurysm often presents with a pulsatile abdominal mass, abdominal pain, and hypotension. Recent clinical reports describe patients with less apparent clinical signs and symptoms who were found later in their evaluation to have a contained rupture of an abdominal aortic aneurysm. Even more unusual is a chronic contained rupture of an abdominal aortic aneurysm. Our patient had a chronic contained rupture of an abdominal aortic aneurysm that presented with erosion into the lumbar vertebral bodies and subsequent lumbar neuropathy. CT scan confirmed the contained rupture of the aortic aneurysm and the patient underwent suc- cessfal repair of his aortic aneurysm. Our report discusses the significance of atypical presentations of abdominal aortic aneurysm rupture and the im- portance of prompt diagnosis and definitive repair. [Higgins R, Peitzman AB, Reidy M, Stapczynski S, Steed DL, Webster MW: Chronic contained rupture of an abdominal aortic aneurysm presenting as a lower extremity neuropa- thy. Ann Emerg Med March 1988;17:284-287.]

I N T R O D U C T I O N Patients with rupture of an abdominal aortic aneurysm typically present

with a pulsatile abdominal mass, abdominal or back pain, and hypotension. If the rupture is initially contained within the retroperitoneum, the patient may be normotensive. A high degree of clinical suspicion for rupture of an abdominal aortic aneurysm should lead to emergency laparotomy with lim- ited studies and is associated with perioperative mortality of 30% to 60%. 1

Recent clinical reports z-4 describe patients with less apparent clinical signs and symptoms who have been found later in their evaluation to have a con- tained rupture of an abdominal aortic aneurysm. Varying symptomatology, including chronic back pain or neurologic complaints, had led to further evaluation. Erosion into the anterior spinal ligament or lumbar body by an abdominal aortic aneurysm may produce back pain.Z, 4 A leaking abdominal aortic aneurysm may present as an acute femoral neuropathy with retroperi- toneal compression of the femoral nerve. 5-8 In these settings, computerized tomography (CT) scan of the abdomen has been useful in confirming the diagnosis.9-11

Even more unusual is a chronic contained rupture of an abdominal aortic aneurysm, rod6 We report a patient with abdominal aortic aneurysm who presented with left leg weakness.

CASE REPORT A 75-year-old man presented complaining of lower left extremity weakness

that had progressively worsened during the previous three weeks. He had increased difficulty in walking and also noted "numbness" of the shin and toes of the left leg. He denied lower back pain, abdominal pain, inguinal or femoral pain, or antecedent history of trauma to his back or leg. The pa- tient's medical history was significant for mild hypertension. He was taking no medication at the time.

On physical examination, the patient appeared older than his stated age. He was in no acute distress. His blood pressure was 110/70 m m Hg (non- orthostatic) with a sinus tachycardia at 110 beats per minute. The patient was afebrile with a temperature of 37.1 C. Chest and cardiac examinations were unremarkable. The abdomen was soft and flat with a midepigastric

Robert Higgins, MD* Andrew B Peitzman, MD* Margaret Reidy, MDt Stephen Stapczynski, MD:t- David L Steed, MD* Marshall W Webster, MD* Pittsburgh, Pennsylvania

From the Departments of Surgery,* Neurology, t and Medicinie,¢ University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.

Received for publication August 25, 1987. Accepted for publication December 1, I987.

Address for reprints: Andrew B Peitzman, MD, 1087 Scaife Hall, Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261.

17:3 March 1988 Annals of Emergency Medicine 284/159

ABDOMINAL AORTIC ANEURYSM Higgins et al

F I G U R E 1. A b d o m i n a l C T scan shows a 5-cm aortic aneurysm. The aorta has been displaced anteriorly by a large retroperitoneal hematoma. The le f t k i d n e y has been p u s h e d laterally.

FIGURE 2. A b d o m i n a l CT at the level of the iliac crest. There is exten- sive contained hematoma primarily to the left of midline. Extravasation of IV c o n t r a s t is s een w i t h i n th i s hematoma.

fullness. There were act ive bowel sounds and no hepatosplenomegaly. Neurologic examinat ion showed the patient to be alert and oriented. How- ever, he was unable to stand or walk due to the weakness of his left leg. Crania l ne rves II-XII were in tac t . Motor strength was 4/5 in both arms and the right leg, and 3/5 in the left leg. Deep tendon reflexes were 1 + for biceps and triceps; and were absent bi- laterally in the knee and ankle. Senso- ry e x a m i n a t i o n revealed decreased pinprick sensation over the entire left leg. Position sense was intact. The pa- t ient had down-going Babinski 's re- flexes bilaterally. Peripheral vascular examina t i on demons t r a t ed no rma l femoral and dorsalis pedis pulses bilat- erally.

Laboratory data on admiss ion in- cluded WBC, 20,400 with 69% poly- morphonuclear neutrophils and 17% bands; hematocrit, 39%; normal elec- trolytes; BUN, 30 mg%; and creati- nine 1.2 mg%.

Impression on admission was a left L2-4 neuropraxic lesion. Lumbosacral spine films showed normal alignment. There was diffuse osteopenia as well as compress ion of the superior end plate of L-1 with anterior osteophyte format ion suggesting tha t the com- pression fracture was not acute. There was no other significant abnormality of the lumbosacral spine.

The pat ient was admit ted to the N e u r o l o g y Service. E l ec t romye lo - graphic studies were consistent with a lumbar plexopathy, demonstrating se- vere denervation with no motor units present in the left vastus lateralis, vastus medialis, adductor longus, or iliopsoas muscles. Mild denervation was present in the anterior tibialis and medial gastrocnemius muscles. Left external obl ique and lumbar para- spinous muscles were normal. Twen- ty-four hours after admission, it was noted that the patient had a pulsatile, nontender 5-cm supraumbilical mass.

The Vascular Surgery Service was con- sulted. The patient adamantly denied history of abdominal, flank, or back pain.

A C T scan with IV contrast demon- strated a 5-cm infrarenal abdominal

aort ic a n e u r y s m wi th a large left retroperitoneal hematoma (Figure l). On several cuts, obvious extravasation of dye was seen within this retroperi- toneal h e m a t o m a (Figure 2). Noted also was a 20% anterior vertebral body

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FIGURE 3. Disruption of the left pos- terolateral wall of the abdominal aor- ta is noted on this CT scan. There is 20% to 30% loss of the lumbar ver- tebral body on this ~scan.

erosion at the level of the aneurysm and hematoma (Figure 3).

The patient was transferred directly from radiology to the operating room, w h e r e he u n d e r w e n t e x p l o r a t o r y laparotomy. He had a 6-cm infrarenal abdomina l aort ic aneurysm wi th the l e f t side of the re t roper i toneum com- prising the pulsati le mass. There was no evidence of acute intraperi toneal or re t roper i toneal hemorrhage. The ret- r o p e r i t o n e u m on the le f t a lso was e d e m a t o u s to the level of the pan- creas. Proximal and distal control of the aorta was obtained and the aneu- rysm was incised. The left and pos- terior walls of the aneurysm were ab- sent. Posteriorly, there was extensive de s t ruc t i on of the l u m b a r ver tebra l bodies at three levels w i t h 25% to 30% loss of the bodies.

Laterally, a well-organized hemato- ma was evacuated from the left side of t he r e t r o p e r i t o n e u m . T h i s cavi ty , w h i c h was wel t encapsu la ted , mea- sured 12 x 15 cm. A straight Dacron ® graft was placed, and the pat ient toler- ated the procedure well. Cul tures of the r e t rope r i t onea l h e m a t o m a were sterile.

The pat ient ' s postoperat ive course was complicated by atrial fibrillation, urosepsis, diarrhea, poor oral intake, and m e n t a l s ta tus changes. He im- proved slowly and was discharged to a

chronic care facility two months after admission.

DISCUSSION Sealed rupture of an abdominal aor-

tic aneurysm has become a commonly repor ted problem.12 16 C o n t a i n e d or sea led r u p t u r e s m a y p r e s e n t diag- nos t i c puzz les w i t h no ev idence of b l o o d l o s s or h e m o d y n a m i c in - stability.

Szi lagyi et al f i rs t i n t roduced the concept of contained or sealed rupture of the abdominal aorta in 1965. 57 In describing seven patients who present- ed wi th a septic clinical picture, they defined a sealed rupture as one that " m a y r e p r e s e n t a t ea r of l i m i t e d length on the posterior aneurysm wall and be effectively walled off before ex- t e n s i v e e x t r a v a s a t i o n t a k e s p lace . " Ruptured aneurysm was not suspected at presentation. Each pat ient present- ed wi th abdominal or back pain but normal blood pressure. At the t ime of autopsy or operation, the aneurysms were < 5 cm in transverse diameter, and the site of perforat ion was always posterola tera l and adjacent to t issue that would contain the leak.

R e t r o p e r i t o n e a l h e m a t o m a s have been known to cause peripheral neu- r o p a t h i e s , u s u a l l y i n v o l v i n g t h e femoral nerve. However, this is gener- ally a complicat ion of anticoagulat ion

therapy or hemophi l ia . 18 Much less frequently, localized neurologic defi- ci ts have preceded the d iagnos i s of r u p t u r e d a b d o m i n a l a o r t i c a n e u - rysm. s-8

The femora l nerve compr i s e s the pos te r io r po r t i ons of nerve roo t s of L-2, L-3, and L-4 and then originates at the cephalad border of L-5. Its fibers course through psoas muscle, emerge at the level of S-I, and run under the i n g u i n a l l i g a m e n t . T h e o b t u r a t o r nerve similarly arises from the lumbar plexus, courses behind the psoas mus- cle, and then courses posterolateral ly to the i l iac artery. Both the femoral and obturator nerves are protected an- t e r i o r l y by the psoas m u s c l e . The combinat ion of a femoral or obturator neuropa thy and an abdominal aort ic aneurysm indicates rupture of the an- eurysm.

Vertebral body erosion has been re- ported infrequently as a complicat ion of a b d o m i n a l aor t ic aneurysm.2-4,19 Isolated cases of lower back pain, neu- ropathy, or l u m b a r v e r t e b r a l body changes have been reported.2-8,19

Our pat ient presented with chronic lumbar neuropathy and a chronic con- tained rupture of his abdominal aortic aneurysm. This presentat ion alone is infrequent, 12-16 but the lack of a his- tory of back or abdominal pain in this se t t ing has not been p r ev ious ly re- por ted . The pa t i en t ' s l u m b a r spine f i l m s were i n t e r p r e t e d as n o r m a l . However, the CT scan findings (Figure 3) and opera t ive f ind ings con f i rmed bony destruction.

Jones et al recently provided a defi- n i t ion for chronic contained rupture of abdominal aortic aneurysm32 The c r i t e r i a i n c l u d e : k n o w n a b d o m i n a l aortic aneurysm, previous pain symp- toms that may have resolved, a pa- t ient who is hemodynamica l ly stable and whose hematocr i t is normal, CT scan showing retroperitoneal hemato- ma, and pathologic confirmat ion of a well-organized hematoma. Immedia te operation is mandatory in these cases, as previously reported cases, wi th one exception, 2o have indicated that these chronic contained ruptures of abdomi- nal aort ic aneurysm u l t i m a t e l y wil l rupture freely.

17:3 March 1'988 Annals of Emergency Medicine 286/161

ABDOMINAL AORTIC ANEURYSM Higgins et al

SUMMARY The clinical presentat ion of abdomi-

nal aortic aneurysm rupture includes abdominal or back pain, hypotension, and a pulsat i le abdominal mass. How- ever, the ini t ia l symptoms of a leaking abdomina l aor t ic a n e u r y s m m a y be mis t aken for sepsis, neuropathy, in- guinal hernia, or other etiologies that can lead to lethal errors in diagnosis and treatment. The presence of lum- bar neuropathy and a pulsati le abdom- inal mass, regardless of the presence of abdominal or back pain, should be presumed to indicate a sealed rupture of an abdominal aortic aneurysm. As in our case, p rompt operat ive inter- vention can result in survival.

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3. Choplin RH, Karstaedt N, Wolfman NJ: Rup

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I7. Szilagy DE, Elliott JP, Smith RF: Ruptured abdominal aneurysm simulating sepsis. Arch Surg 1965;91:263-275.

18. Brower TD, Wilde AH: Femoral neuropathy in hemophilia. J Bone Joint Surg 1966;48A: 487-492.

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