Clip showing dilated loops of bowel measuring 4-5cm. The plicae circulares are prominent and visualized ("keyboard sign"). There is also evidence of slowed, to and from peristalsis ("Swirl sign").
Ideen Zeinali, MD and Matthew Edwards
Department of Emergency Medicine, Baylor College of Medicine & Case Western Reserve University School of Medicine
A 45-year-old African female presented with her family to Komfo Anoyke Teaching Hospital in Kumsai, Ghana for evaluation of three days of worsening abdominal pain. Her family reported a fever and vomiting beginning that day, and noted that her last bowel movement was the day before. Her family was prompted to bring her to the hospital due to her worsening confusion and mental status.
The patient's past medical history was significant for the repair of an inguinal hernia approximately three years prior to her presentation to our hospital. Her family denied any history of abdominal trauma. We were unable to obtain any further medical history due to the patient's limited mental status upon arrival.
| Blood pressure | Pulse | Respiratory Rate | Pulse Oximetry | Temperature(oral) |
|---|---|---|---|---|
| 90/70 | 130 | 30 | 95% | 102°F |
General:
The patient was a diaphoretic and uncomfortable appearing woman who appears confused.
Cardiovascular:
Tachycardia, with normal S1 and S2 and no murmurs, gallops, or rubs noted.
Respiratory:
Tachypneic, with diminished breath sounds at the bilateral lung bases. Her lungs were otherwise clear to auscultation.
Abdomen:
Abdomen was distended, tympanic to percussion, and was diffusely tender to light palpation.
Extremity:
Distal pulses were palpable in all limbs and there was no edema noted to her bilateral lower extremities.
Neuro:
Glasgow Coma Scale of 13.
Clinical Differential Diagnosis
Ultrasound Imaging Findings
Clip showing dilated loops of bowel measuring 4-5cm. The plicae circulares are prominent and visualized ("keyboard sign"). There is also evidence of slowed, to and from peristalsis ("Swirl sign").
Still image shows free fluid between loops of bowel ("Tanga sign").
Differential Diagnosis Based on Imaging
Small Bowel Obstruction vs bowel perforation
Clinical Course and/or Management
On initial evaluation of the patient to the emergency department (ED), she was noted to be septic, borderline septic shock. The patient was started on fluids and IV antibiotics. Point of Care Ultrasound (POCUS) performed showing a negative FAST, but distended loops of bowel with decreased peristalsis concerning for a small bowel obstruction (SBO). A nasogastric tube was placed and large volume of output was produced. Differential diagnoses for the cause of the patient's sepsis and bowel obstruction could have been due to bowel perforation, infectious source (i.e. typhoid), biliary tract infection (i.e. ascending cholangitis), etc. She remained in the ED for two days and was eventually taken to the ICU. The patient did not receive surgery and her final status was unknown.
Diagnosis
Small Bowel Obstruction & Sepsis
Discussion
Small bowel obstruction (SBO) is a disease of diverse etiologies, most commonly due to adhesions from previous surgeries, hernia, malignancy and Crohn's disease. This makes it difficult to identify the cause solely based on a patient's medical history. It often presents with nondescript symptoms, such as diffuse abdominal pain, vomiting, abdominal distension, and constipation, further posing a challenge in differentiating it from other acute abdominal diseases. Physical examination may be similarly uninformative, as abdominal auscultation has low sensitivity and specificity for bowel obstruction. Abdominal radiographs and computed tomography (CT) are commonly employed as initial imaging of SBO due to the relatively low expense of the former and the ability of the latter to identify complications such as ischemia as well as a possible transition point. These imaging modalities, however, are frequently unavailable in resource poor settings. They are also costly, more time consuming, cannot be done bedside, which is not ideal in unstable patients.
Small bowel obstruction is associated with a high risk of bowel necrosis, strangulation, and perforation, and delay in care is associated with a higher risk of bowel resection. Bedside ultrasound is an alternative imaging modality that can allow rapid diagnosis and treatment. A study done by Jang et al evaluating a sample of symptomatic ED patients showed 81% to 97% specificity of ultrasound in detecting obstruction (depending upon the ultrasound finding employed) compared to abdominal X-ray at 66%. Although there are no ultrasound criteria for the diagnosis of SBO, there is some consensus within the literature on its typical features. These include a fluid-filled small bowel lumen of greater than 2.5cm and thickened bowel walls greater than 3mm. Other findings on ultrasound concerning for SBO include the Tanga sign and Swirl sign. Tanga sign is a triangular shaped pocket of free fluid between loops of bowel, and this indicates either perforation or edema. It is also associated with higher grade obstruction. Swirl sign is where slow peristalsis is visible as hyperechoic material moves back and forth within thickened bowel loops. Jang's study reported that dilated loops of bowel on ultrasound had a sensitivity of 91% and a specificity of 84%, while decreased peristalsis had a specificity of 98% but low sensitivity.
In a meta-analysis completed, multiple studies have agreed that EM physicians produce highly accurate exams diagnosing SBO after only short term training, and their exams have been noted to show high specificity in diagnosis, which could lead to earlier surgical management and better patient outcomes. Secondary to the low sensitivity, negative diagnoses should warrant further investigation, and furthermore, US has been shown to be limited when diagnosing a partial SBO as well as identifying a transition point or etiology of the obstruction. It's important to consider that in low income countries, infectious etiologies should be considered as a possible source of SBO and warrant further tests be done for investigation. Ascaris lumbridcoides is a worldwide distributed infection with high prevalence in East Asia, Latin America and Africa, and its most common complication is creating an SBO via the physical presence of paralyzed worms causing local inflammation or muscle spasm. Strongyloides stercolaris has been shown to cause an ileus and intestinal obstruction, and Aeromonas infection has been known to cause SBO from an intramural hemorrhage edema.
References