Clinical Presentation
A 54-year-old African American male with a history of chronic pancreatitis s/p cyst-gastrostomy via midline incision, cholecystitis s/p cholecystectomy, CAD s/p 5 vessel CABG, and poorly controlled IDDM presented to the ED complaining of 3 days of diffuse abdominal pain, obstipation, and intermittent nbnb emesis.
The patient was tachycardic on arrival with dry mucosal membranes and severe diffuse abdominal tenderness and distention with peritoneal signs. The remainder of the patient’s exam and vitals were unremarkable.
Differential Diagnosis
· Mesenteric ischemia
· Bowel obstruction
· Bowel perforation
· AAA / AoD
· Pancreatitis
· Diverticulitis
· Colitis
POCUS: What ‘s the diagnosis?
Diagnosis
The POCUS images demonstrate dilated loops of small bowel with near absent peristalsis, thickened bowel wall and plica circularis, as well as significant pneumatosis intestinalis (hyperechoic artifact within the bowel wall with dirty shadowing), severe intra-hepatic pneumobilia and portal venous air.
A subsequent CT A/P w/ IV contrast showed a high-grade pSBO, but failed to identify the pneumatosis intestinalis and portal venous air, only noting minimal pneumobilia.
Disposition
The patient was admitted to the SICU for a high-grade pSBO, which failed to resolve with non-surgical management. The patient underwent an explorative laparotomy with LOA and partial small bowel resection, which had a focal perforation in the jejunum. The patient had a prolonged hospital stay complicated by septic shock and hypoxic respiratory failure requiring a tracheostomy. Eventually, the patient was discharged to SNF in stable condition.
Discussion
Presentation (Signs & symptoms)
o Sudden onset abdominal pain
o Nausea
o Constipation & Obstipation
o Non-bilious to bilious emesis
o Abdominal distention
Epidemiology
o 2% of all abdominal pain cases presenting to the ED
o 15% of all admissions for abdominal pain
o 65% of cases resolve with non-surgical management
Ø Utilize serial POCUS & abdominal exams to avoid CT use
Etiology
o Adhesions - most common (75%)
o IBD
o Malignancy
o Hernia
Diagnosis
CT A/P
o Traditional diagnostic imaging modality
o IV contrast (or angio)
Ø PO contrast: not routinely indicated; only indicated if concerned for an anastomotic leak
o Sensitivity: 63-100% (better with smaller slices)
o Specificity: 57-100%
o Benefits: able to identify causes of obstruction
o Limitations: cost, radiation, contrast, delay to diagnosis, hemodynamically
unstable patients
2. Ultrasound (12 prospective, observational studies with 1395 patients)
o Should be diagnostic imaging modality of choice
Ø Curvilinear (linear for children or thin patients)
Ø Lawn mower technique (see Figure 1)
Figure 1. Lawn mover technique.
o Sensitivity 92–100%
o Specificity of 94–100%
o +LR 14 – 27
o Benefits: rapid, accurate, no contrast/radiation
o Limitations
Ø Unable to identify cause in 50% of cases
Ø Body habitus
Ø Operator experience
o Findings (see Table 1)
Ø Dilated loops of bowel >2.5cm (outside wall to outside wall)
Ø Abnormal to & fro peristalsis or hyperkinetic
o High risk findings (that may predict high grade SBO and need for surgical intervention)
Ø Bowel wall edema >3-4mm
Ø Edematous plica circulares (keyboard sign)
Ø Aperistalsis
Ø Pneumatosis intestinalis
Ø Free fluid (tanga sign)
Ø Free air
*From Tamburrini et al.
Treatment
o Fluid resuscitation
o Surgical consultation
o Anti-emetics
o NPO
o NGT: only for active emesis
o Abx for perforation
Complications (Risk factors: delayed diagnosis >24hrs, age, co-morbidities)
o Ischemia (30% of cases)
o Necrosis (15% of cases)
o Perforation
o Sepsis
References
Taylor MR, Lalani N. Adult Small Bowel Obstruction. Acad Emerg Med. 2013;20:528- 544.
Gottlieb M, Peksa GD, Pandurangadu AV, et al. Utilization of ultrasound for the evaluation of small bowel obstruction: A systematic review and meta-analysis. Am J Emerg Med. 2018;36(2):234-242.
Becker BA, Lahham S, Gonzales MA, et al. A Prospective, Multicenter Evaluation of Point of care Ultrasound for Small bowel Obstruction in the Emergency Department. Acad Emerg Med. 2019;26(8):921-930.
Tamburrini S, Lugarà M, Iaselli F, et al. Diagnostic Accuracy of Ultrasound in the Diagnosis of Small Bowel Obstruction. Diagnostics (Basel). 2019;9(3):88.