Ultrasound

Ultrasound Case of the Month

Video by Victoria Fox; Text by Nichole Michaeli

The Case

51 year old male who presents post-op day 4 after an abdominal surgery with vomiting and abdominal pain and distention. Patient does not endorse fevers or chills, and denies bowel movements or flatus in past day.

Vital signs: BP 144/81 HR 83 Temp 98.2 RR 16 O2 95%

Pertinent physical exam findings:

Alert and oriented x3. Comfortable, no pallor.

Abdomen is distended, tympanic, tender to palpation. Surgical wounds in the LLQ and superior to the umbilicus are intact. Wound to the R abdomen is open with clear drainage.

Catheter in place with clear urine.

A bedside abdominal ultrasound is performed.


What is the diagnosis?

Small bowel obstruction

In the United States, post-operative adhesions from prior abdominal surgery are the most common risk factor for mechanical bowel obstruction. One systematic review found a 9% incidence of small bowel obstruction by any cause after abdominal surgery. Other risk factors include pelvic surgery, abdominal wall or groin hernia, intestinal inflammation, history of neoplasm, prior irradiation and history of foreign body ingestion.

Small bowel obstruction leads to bowel dilation proximal to the obstruction. As dilation increases, there is a decrease in perfusion with can cause bowel edema, necrosis or even perforation.

Small bowel obstruction will often present with nausea, vomiting, intermittent cramping abdominal pain, and an inability to pass flatus or stool. Initial diagnosis can be made by abdominal ultrasound, but it is less useful for determine the location or cause of the obstruction. Abdominal CT can aid with identifying the specific site and severity of the obstruction, the cause, and potential complications.

Ultrasound Findings

Using a curvilinear transducer, scan the patient’s abdomen with the marker towards the patient’s right. Move your probe up and down interrogating all 4 quadrants of the abdomen. SBO can be identified by looking for the following signs:

  • “Keyboard Sign”: Identify the pilcae circulares, which span the entire width of the bowel wall. These will appear like black and white piano keys- the keyboard sign  

  • Dilated Fluid Filled Loops: Measure the width of the bowel. Dilation >2.5cm is suggestive of obstruction  

  • To-and-Fro: In the fluid filled bowel, you may be able to see the liquid moving backwards and forwards again and again as the bowel peristalsis, but there is a distal obstruction. 

  • Tanga Sign: Look for free fluid outside the bowel wall


Case Conclusion

The patient had a CT abdomen/pelvis which showed high-grade small bowel obstruction with transition in the distal ileum. A nasogastric tube was placed and the patient was admitted to surgery for management of the small bowel obstruction.   

Image 1: Keyboard Sign

Image 1: Keyboard Sign

Dilated Bowel Loops >2.5cm

Dilated Bowel Loops >2.5cm

Tanga Sign

Tanga Sign

Another example of small bowel obstruction

Faculty Reviewer: Dr. Kristin Dwyer

References

  1. Bordeianou L, Dante D. UpToDate: Epidemiology, clinical features, and diagnosis of mechanical small bowel obstruction in adults.

  2. ten Broek RP, Issa Y, van Santbrink EJ, et al. Burden of adhesions in abdominal and pelvic surgery: systematic review and met-analysis. BMJ. 2013 Oct; 347:f5588.

  3. Frasure SE, Hildreth AF, Seethala R, Kimberly HH. Accuracy of abdominal ultrasound for the diagnosis of small bowel obstruction in the emergency department. World J Emerg Med. 2018;9(4):267-271.

  4. Unlüer EE, Yavaşi O, Eroğlu O, et al. Ultrasonography by emergency medicine and radiology residents for the diagnosis of small bowel obstruction. Eur J Emerg Med. 2010 Oct;17(5):260-4.

AEM Early Access 22: Test Characteristics of Point of Care Ultrasound for the Diagnosis of Retinal Detachment in the Emergency Department

Welcome to the twenty-second episode of AEM Early Access, a FOAMed podcast collaboration between the Academic Emergency Medicine Journal and Brown Emergency Medicine. Each month, we'll give you digital open access to an recent AEM Article or Article in Press, with an author interview podcast and suggested supportive educational materials for EM learners.

Find this podcast series on iTunes here.

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DISCUSSING (CLICK ON LINK FOR FULL TEXT, OPEN ACCESS THROUGH January 31):

Test Characteristics of Point of Care Ultrasound for the Diagnosis of Retinal Detachment in the Emergency Department. Daniel J. Kim, MD,  Mario Francispragasam, MEd, MD, Gavin Docherty, MD, Byron Silver, MSc, MD, Ross Prager, BSc, Donna Lee, MD, RDMS, and David Maberley, MSc, MD. 

LISTEN NOW: FIRST AUTHOR INTERVIEW WITH Daniel J. Kim, MD

Profile Shot [Daniel Kim].jpg

Daniel J. Kim, MD

Department of Emergency Medicine

Vancouver General Hospital

Director, Ultrasound Fellowship Program

University of British Columbia

@dan___kim

ABSTRACT

Previous studies of point of care ultrasound (POCUS) have reported high sensitivities and specificities for retinal detachment (RD). Our primary objective was to assess the test characteristics of POCUS performed by a large heterogeneous group of emergency physicians (EPs) for the diagnosis of RD.

Methods: This was a prospective diagnostic test assessment of POCUS performed by EPs with varying ultrasound experience on a convenience sample of emergency department (ED) patients presenting with flashes or floaters in one or both eyes. After standard ED assessment, EPs performed an ocular POCUS scan targeted to detect the presence or absence of RD. After completing their ED visit, all patients were assessed by a retina specialist who was blinded to the results of the POCUS scan. We calculated sensitivity and specificity with associated exact binomial confidence intervals (CI) using the retina specialist's final diagnosis as the reference standard.

Results: A total of 30 EPs enrolled 115 patients, with median age of 60 years and 64% female. The retina specialist diagnosed RD in 16 (14%) cases. The sensitivity and specificity of POCUS for detecting RD was 75% (95% CI 48%-93%) and 94% (95% CI 87%-98%), respectively. The positive likelihood ratio was 12.4 (95% CI 5.4-28.3), and negative likelihood ratio was 0.27 (95% CI 0.11-0.62).

Conclusions: A large heterogeneous group of EPs can perform POCUS with high specificity but only intermediate sensitivity for RD. A negative POCUS scan in the ED performed by a heterogeneous group of providers after a one-hour POCUS didactic is not sufficiently sensitive to rule out RD in a patient with new onset flashes or floaters. This article is protected by copyright. All rights reserved.

ADDITIONAL RELATED READING

Vrablik et al, 2015. The diagnostic accuracy of bedside ocular ultrasonography for the diagnosis of retinal detachment: a systematic review and meta-analysis. https://www.ncbi.nlm.nih.gov/pubmed/24680547

Jacobsen et al, 2016. Retrospective Review of Ocular Point-of-Care Ultrasound for Detection of Retinal Detachment: https://www.ncbi.nlm.nih.gov/pubmed/26973752

Baker et al, 2017. Can emergency physicians accurately distinguish retinal detachment from posterior vitreous detachment with point-of-care ocular ultrasound?: https://www.ncbi.nlm.nih.gov/pubmed/29042095

AEM Commentary on this paper: https://www.ncbi.nlm.nih.gov/pubmed/30112843

Other commentaries on this paper:

NEJM Journal Watch: https://www.jwatch.org/na46896/2018/06/11/dont-try-rule-out-retinal-detachment-with-poc-ultrasound

UC San Diego Ultrasound Division: http://emultrasound.sdsc.edu/index.php/2018/07/25/retinal-detachment/

A Tale of Two Bleeders

The following are two cases of vaginal bleeding seen in the a community Emergency Department during the same shift.

CASE 1:

HPI: 30 year old G3P1 female at 5 weeks pregnancy by LMP who presents to the ED with vaginal spotting. She states it started this morning while urinating. She reports about “a spoonful” of dark red blood with no clots. Associated symptoms include transient, lower abdominal cramping. Her pregnancy has had no complications so far, and she just established pre-natal care. Her second pregnancy was complicated by preterm delivery, for which she underwent C-section.

PE: Hemodynamically stable. No abdominal tenderness, guarding, rebound, or distention. On speculum exam, there is a mild amount of dark red blood and clot in the vaginal vault. No fetal tissue. The cervical os is closed. No CMT. No uterine or adnexal tenderness.

Bedside TVUS: No IUP

What now?

In any case of vaginal bleeding, the first step is determining if the patient is pregnant or not! In this case, we know our patient is pregnant. At this point, we develop our differential:

  1. Ectopic Pregnancy

  2. Abortion

  3. Gestational trophoblastic disease

  4. Implantation bleeding

Unlike our Miranda Rights, your patient is guilty of ectopic pregnancy until proven innocent! This is one of the “can’t-miss” diagnoses that we should all feel comfortable working up and managing.

Ectopic Pregnancy:

  • This occurs when there is conception outside of the uterine cavity. Risk factors include a history of STIs (especially PID), assisted reproductive techniques, history of pelvic surgery, advanced maternal age, previous ectopic pregnancy, and cigarette smoking.

  • The vast majority of ectopics take place in the fallopian tubes (ampullary portion), with about 1% taking place in the abdominal cavity, and <1% are cervical.

  • Most patient’s report a history of missed menses, although up to 15% of patients will report normal menses.

  • Abdominal pain is present in up to 90% of patients with ectopic pregnancies (secondary to tubal distention or rupture), although the absence of pain does not rule out ectopic pregnancy!

  • The physical examination in ectopic pregnancy is variable. In cases of ruptured ectopic pregnancy, the patients may be peritoneal with adnexal tenderness and possibly present in shock. Most patients, however, present with stable vital signs. An adnexal mass or tenderness could be an ectopic, although can also be a corpus luteum cyst in the setting of normal pregnancy and/or recent ovulation. Blood may be appreciated in the vaginal vault, although pelvic examination may be normal as well.

  • Definitive diagnosis of ectopic pregnancy is by ultrasound or direct visualization during laparoscopy or surgery.

  • But what about the beta-HCG level? Although absolute levels and “doubling times” are typically longer in ectopic pregnancy, it turns out that no level can reliably distinguish between a normal and pathological pregnancy.

  • The literature describes a discriminatory zone, or beta-HCG level at which you would expect to see an IUP at 1,500 mIU/mL for transvaginal scanning and 6,000 mIU/mL for transabdominal scanning. That being said, if ectopic is suspected, ultrasound should still be performed even with low beta-HCG levels.

  • The goal of ultrasound is to locate a viable IUP and exclude ectopic pregnancy. Visualizing an IUP is reassuring, although does not definitively exclude ectopic pregnancy if the patient is at high risk for a heterotopic pregnancy. Heterotopic pregnancy (both IUP and ectopic) has increased in the general population, largely in the setting of assisted reproduction technology (currently about 1:3,000 pregnancies).

  • An empty uterus with an embryo visualized outside the uterus is diagnostic, however this is only seen in up to 10% of transabdominal scans, and up to 25% of transvaginal scans. A pelvic mass (especially adnexal) in the setting of free fluid (evaluated in the cul de sac, posterior to the uterus) is highly suggestive of ectopic pregnancy.

  • If an ultrasound is indeterminate and the patient is hemodynamically stable, the patient should have close OB/GYN follow up in two days for a repeat beta-HCG level and be given strict return precautions. However, if the patient’s beta-HCG was above the discriminatory zone, it is advisable to seek consultation in the ED prior to disposition.

  • For ruptured ectopic pregnancies, surgical treatment is the preferred treatment modality.

  • For unruptured ectopic pregnancies, in the absence of contraindications, patients who are hemodynamically stable with minimal symptoms and who have appropriate OB follow up, medical treatment with methotrexate can be considered. This is typically given as a single IM dose, although the success rate of a multiple dose regimen was shown to be higher (92.7% vs 88.1%, p<0.05).

  • Treatment failure overall occurs in about 1/3 of cases. There is about a 5% chance of ectopic rupture and patients should avoid sexual intercourse for 2-3 weeks given the risk for this.

  • Abdominal pain 3-7 days after treatment with methotrexate is a common side effect, often attributed to tubal abortion/distention, although is difficult to differentiate from treatment failure and ectopic rupture. It is suggested that these patients undergo repeat laboratory testing (CBC) and pelvic ultrasound.

Figure 1: Ectopic pregnancy within the left adnexae. Source: Radiopaedia.org

Figure 1: Ectopic pregnancy within the left adnexae. Source: Radiopaedia.org

Figure 2: Fluid appreciated in the cul-de-sac posterior to the uterus. Source: Radiopaedia.org

Figure 2: Fluid appreciated in the cul-de-sac posterior to the uterus. Source: Radiopaedia.org

CASE 2:

History: 36 year old female G3P2 s/p D&C for a missed abortion at 7 weeks who presents to the ED with three days of worsening vaginal bleeding. Today, she reports “a large amount” of dark, red blood with clots. She reports using a pad every 10-15 minutes. Associated symptoms include intermittent, lower abdominal cramping and fatigue. No other associated symptoms. No pregnancy complications in the past.

Pertinent PE: No abdominal tenderness, guarding, rebound, or distention. On speculum examination, there is a moderate amount of blood in the vaginal vault with clots. No fetal tissue. The cervical os is closed. No CMT. No adnexal or uterine tenderness.

Bedside TVUS: No IUP. Heterogenous material appreciated within the uterine cavity.

What now?

This is a case of a patient with retained products of conception (RPOC) following an abortion.

  • Patient’s will often present with vaginal bleeding and pelvic pain, which are expected symptoms typically associated with low morbidity.

  • In patients with heavy vaginal bleeding, prolonged bleeding greater than three weeks, fever, uterine tenderness, and/or pain not controlled by over the counter medications, further evaluation is indicated to rule out other potential etiologies (or rule in RPOC).

  • Ultrasound is the best imaging modality to assess for RPOC

  • In patients with RPOC and bleeding greater than three weeks, hemodynamic instability, or sepsis, surgical treatment is preferred.

  • Patients can otherwise opt for expectant management or medical management, which typically consists of a dose of misoprostol (intravaginally or oral), especially given its low cost, low side effect profile, and easy availability. Notably, after consultation with the patient’s OB/GYN, our patient went home on methergine (an ergot alkaloid and uterotonic medication).

And for both cases, don’t forget the rhogam for your Rh negative patients! The dose is generally 300 micrograms given IM.

Faculty Reviewer: Dr. Kristy McAteer

REFERENCES:

  1. Carusi, Daniella et al. Retained Products of Conception. UptoDate. <www.uptodate.com>. 2018.

  2. Ibrahim, Dalia, Gaillard, Frank, et al. Ectopic Pregnancy. Radiopaedia. <https://radiopaedia.org/articles/ectopic-pregnancy>. 2018.

  3. Tintinalli, et. al. Ectopic Pregnancies and Emergencies in the First 20 Weeks of Pregnancy. Emergency Medicine. 8th Edition. 2016. 628-633.HHHf

FURTHER READING:

  1. 1st Trimester Pregnancy Ultrasound Podcast Part I: http://www.ultrasoundpodcast.com/2014/10/pregnancy-ultrasound-part-1-foamed-back-back-basics-cabo-update/

  2. 1st Trimester Pregnancy  Ultrasound Podcast Part II: http://www.ultrasoundpodcast.com/2014/10/1st-trimester-pregnancy-ultrasound-part-2-ectopic-topics-foamed/

  3. EM in 5: First Trimester Bleeding https://emin5.com/2015/11/09/vaginal-bleeding-in-1st-tm-pregnancy/

  4. EM Updates: Ruling out Ectopic Pregnancy http://emupdates.com/2013/06/03/rule-out-ectopic-in-the-emergency-department/