Tag Archives: radiology

The Utility of MRI in the Emergency Department

Author: Adrianna Long, MD (Emergency Medicine Staff at Winn Army Community Hospital, Fort Belvoir, GA) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital) and Brit Long, MD (@long_brit)

It is important that providers make the correct choice for imaging when dealing with emergent conditions. MRI is a costly choice, but sometimes the most appropriate to evaluate for specific pathology. It is imperative to weigh the risk and benefits of MRI as compared to other imaging modalities. Also, in many facilities, MRI is only available during business hours, which makes obtaining emergent MRIs very difficult. So, when is ordering an MRI in the Emergency Department indicated?

MRI of the Brain

MRI has a significantly greater detection rate for acute ischemic infarction than CT, particularly in an early setting.  CT has been reported to have a sensitivity ranging from 73-88% for acute stroke within the first 12 hours. In comparison, MRI has a sensitivity of 93-100% and may be able to detect acute ischemic injury within a few minutes of onset.1,2 However, not all patients that have acute strokes are candidates for interventions including tPA or endovascular therapy, so it is important to choose the appropriate imaging modality as an MRI may not be indicated emergently.

There is no standard imaging protocol for the evaluation of acute stroke or TIA beyond head CT noncontrast. The goal of neuroimaging is to provide rapid information and increase providers’ decision-making with regards to reperfusion therapy without causing harm from delays.3

A study recently published reviewed the imaging of 8,247 patients who were evaluated with TIA or minor stroke in 2011, revealing that approximately 50% of patients underwent MRI imaging within 2 days of presentation. The use of MRI to evaluate TIA or stroke is limited in many facilities with lack of availability, and MRIs are often ordered by inpatient services rather than emergently.4

The American College of Neuroradiology, the American College of Radiology, and Society of NeuroInterventional Surgery have made a joint statement with regards to the imaging of acute stroke and TIA. When determining whether endovascular therapy should be considered, they have found that noncontrast CT with digital subtraction angiography, noncontrast CT with CTA, and MRI with MRA are equivalent options for clinicians.5 Of those imaging modalities, noncontrast CT with CTA is the preferred strategy currently when selecting intraarterial thrombectomy candidates, as CT is widely available and faster.6

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While a cavernous venous thrombosis (CVT) is a rare diagnosis, the use of MRV offers an alternative diagnostic modality. The MRV is more sensitive at diagnosis of a CVT than an unenhanced CT.7 Therefore, when considering CVT as a diagnosis, MRV may be considered for imaging, but CT venography is rapid, readily available, and an accurate technique to detect CVT.7

MRI of the Spine

The early diagnosis of an epidural abscess is essential to minimize patient morbidity and mortality. A study of 63 patients with spinal epidural abscess indicated that a delay in diagnosis greater than 24 hours occurred in 75% of cases, and persistent motor weakness resulted in 45% with diagnostic delays.8 The ACR ranks MRI of the spine with and without contrast as the most appropriate study to evaluate for infectious processes of the spine. When there is clinical suspicion for an epidural abscess, the emergency physician should insist on early MRI to prevent poor neurologic outcomes.9

The sudden onset of neurologic deficit due to neoplasm is another emergency that requires immediate imaging, neurosurgical consult, and treatment with high dose steroids.10

Epidural hematoma is a rare cause of back pain that may be associated with myelopathy and usually the result of recent spinal procedures or trauma. The symptoms may present similarly to an acute disc herniation. Patients who may be of particular risk are those on anticoagulant therapy.10

Cauda equina syndrome (CES) is suspected when there is severe lower back pain and radicular symptoms, especially at L5/S1, with saddle anesthesia and bowel/bladder/sexual dysfunction. The diagnosis of CES requires an emergent MRI followed by rapid surgical decompression.11

Basically, if serious underlying pathology is plausible or there is evidence of neurologic involvement in patients with back pain, MRI is the study of choice.9

MRI to evaluate for appendicitis

 Pediatric patients:

Efforts are being made to decrease ionizing radiation exposure in pediatric patients, and MRI has been shown to be useful for the diagnosis of acute appendicitis.12 MRI protocols have been created with combined use of ultrasound to diagnose appendicitis in many hospitals for adult and pediatric patients. In one institution over 30 months, MRI has been shown to have a sensitivity of 96.8%, specificity of 97.4%, negative predictive value of 98.9%, and positive predictive value of 92.4%.13

A retrospective study at another institution with utilization of MRI for 49 pediatric patients with suspected appendicitis after having indeterminate ultrasound found a sensitivity of 94% and a specificity of 100% for diagnosis of acute appendicitis. There were a total of 16 patients diagnosed with appendicitis. The use of MRI aided clinicians in obtaining final diagnoses as well, including other diagnoses such as pyelonephritis, constipation, pelvic inflammatory disease, ruptured ovarian cyst, hemorrhagic cyst, and epiploic appendagitis.14

A study of 662 pediatric patients imaged with CT versus MRI found  no significant difference in time to antibiotic administration, time to appendectomy, perforation rate, or hospital length of stay for patients imaged with either modality.15

Pregnant patients:

In 2011, the American College of Radiology (ACR) designated ultrasound as the initial imaging study choice to evaluate for acute appendicitis in pregnant patients.16 However, there have been multiple studies published indicating that ultrasound may not be the most appropriate imaging study to evaluate for appendicitis in pregnant patients since nonvisualization of the appendix has been reported to range as high as 68-97%.17-19 The efficiency of ultrasound may be limited due to bowel gas, body habitus, and anatomic displacement of the appendix, as well as patient tolerance in the setting of an acute abdomen.18

A meta-analysis of 6 articles analyzing the diagnostic strength of MRI in 359 pregnant women with suspected appendicitis found a specificity of 98% and 99% negative predictive value when a normal appendix is visualized.20

The ACR endorses the use of MRI when ultrasound cannot provide diagnostic information in pregnant patients. MRI has been shown to be useful for multiple diagnoses in pregnant patients with acute abdominal/pelvic pain.21 A retrospective study including 171 patients undergoing MRI with a pregnant appendicitis protocol had an appendix visualization rate of 69%. Furthermore, the overall diagnostic rate was 43.3% finding ovarian masses, ovarian torsion, uterine fibroid tumors, ectopic pregnancies, hernias, renal abscess, as well as appendicitis.22

MRI of the Hip

The use of MRI in the Emergency Department to evaluate for suspected hip fracture can be useful when the clinician has a high suspicion and there is a negative Xray or CT. Despite the use of CT to evaluate for hip fractures, there are still 2-4% with missed hip fractures.23,24 While there is a general consensus that a delay to surgery >48 hours is associated with a higher mortality, and a retrospective study of 6,638 patients with hip fractures indicated that surgery before 12 hours improved survival.25 The results of this study suggest that rapid diagnosis of a hip fracture is essential so patients can receive the appropriate treatment as soon as possible to avoid complications.

There is 100% sensitivity and 99% specificity in detecting hip fractures with abbreviated MRI. This hip protocol MRI may also be used to detect avascular necrosis (AVN) with a sensitivity of 97% and 100% specificity.26

Hazards in MRI scanning

Patients should be adequately screened prior to obtaining MRI, and alternative imaging should be considered in patients with:

  1. Renal disease (especially a GFR lower than 30mL/min)
  2. Allergy to gadolinium
  3. History of injury involving projectiles
  4. History of surgery with retained metallic items, e.g. surgical clips, pacemaker, stents
  5. Claustrophobia27

Nephrogenic systemic fibrosis (NSF) is a potentially fatal condition that has been associated with the use of gadolinium.28 A study of 8997 patients who received gadolinium showed a total of 15 patients (0.17%) who subsequently developed NSF, with a GFR of less than 30mL/min in all of the affected patients.29

Of note, there is inherent risk in sending patients who may become unstable during transport and time to obtain the MRI. Most MRIs require time away from the ED, utilizing emergency staff and equipment outside of the ED, for a prolonged period, or there may be a need to transport to a facility where MRIs are available.

Bottom line:

An MRI should only be ordered in the ED when the patient’s treatment and/or management will be affected.

The misuse of MRIs in the ED generates unnecessary costs to patients and increased time in the department.  It is essential to weigh the risk(s) of ordering an MRI for your patient in the ED.

The indications for emergency MRI Brain include clinical concern for acute ischemic stroke, particularly wherein the management may differ with possible intervention versus less aggressive treatment plans.

If there is clinical concern for new spinal cord compression from disease or injury, an emergency MRI evaluation is necessary. 

The indications for emergency spinal MRI include suspicion for:

  • Spinal cord compression (herniated disc, burst fracture, tumors, etc)
  • Spinal infection (i.e. abscess)
  • Spinal trauma (epidural hemorrhage, etc)
  • Demyelination with acute neurologic changes

Additionally, emergency MRIs may be considered if there is concern for:

  • Appendicitis in the pregnant or pediatric patient
  • Hip fracture not detected on plain film or CT

 

References/Further Reading:

  1. Krieger DA, Dehkharghani S. Magnetic Resonance Imaging in Ischemic Stroke and Cerebral Venous Thrombosis. Top Magn Reson Imaging. 2015;24(6):331-352.
  2. Lev MH. CT versus MR for acute stroke imaging: is the “obvious” choice necessarily the correct one? AJNR Am J Neuroradiol. 2003;24(10):1930-1931.
  3. Lin MP, Liebeskind DS. Imaging of Ischemic Stroke. Continuum (Minneap Minn). 2016;22(5, Neuroimaging):1399-1423.
  4. Chaturvedi S, Ofner S, Baye F, et al. Have clinicians adopted the use of brain MRI for patients with TIA and minor stroke? Neurology. 2017;88(3):237-244.
  5. Wintermark M, Sanelli PC, Albers GW, et al. Imaging recommendations for acute stroke and transient ischemic attack patients: a joint statement by the American Society of Neuroradiology, the American College of Radiology and the Society of NeuroInterventional Surgery. J Am Coll Radiol. 2013;10(11):828-832.
  6. Goyal M, Hill MD, Saver JL, Fisher M. Challenges and Opportunities of Endovascular Stroke Therapy. Ann Neurol. 2016;79(1):11-17.
  7. Leach JL, Fortuna RB, Jones BV, Gaskill-Shipley MF. Imaging of cerebral venous thrombosis: current techniques, spectrum of findings, and diagnostic pitfalls. Radiographics. 2006;26 Suppl 1:S19-41; discussion S42-13.
  8. Davis DP, Wold RM, Patel RJ, et al. The clinical presentation and impact of diagnostic delays on emergency department patients with spinal epidural abscess. J Emerg Med. 2004;26(3):285-291.
  9. Seidenwurm DJ, Wippold FJ, 2nd, Cornelius RS, et al. ACR Appropriateness Criteria((R)) myelopathy. J Am Coll Radiol. 2012;9(5):315-324.
  10. Arce D, Sass P, Abul-Khoudoud H. Recognizing spinal cord emergencies. Am Fam Physician. 2001;64(4):631-638.
  11. Mukherjee S, Thakur B, Crocker M. Cauda equina syndrome: a clinical review for the frontline clinician. Br J Hosp Med (Lond). 2013;74(8):460-464.
  12. Moore MM, Brian JM, Methratta ST, et al. MRI for clinically suspected pediatric appendicitis: case interpretation. Pediatr Radiol. 2014;44(5):605-612.
  13. Kulaylat AN, Moore MM, Engbrecht BW, et al. An implemented MRI program to eliminate radiation from the evaluation of pediatric appendicitis. J Pediatr Surg. 2015;50(8):1359-1363.
  14. Rosines LA, Chow DS, Lampl BS, et al. Value of gadolinium-enhanced MRI in detection of acute appendicitis in children and adolescents. AJR Am J Roentgenol. 2014;203(5):W543-548.
  15. Aspelund G, Fingeret A, Gross E, et al. Ultrasonography/MRI versus CT for diagnosing appendicitis. Pediatrics. 2014;133(4):586-593.
  16. Rosen MP, Ding A, Blake MA, et al. ACR Appropriateness Criteria(R) right lower quadrant pain–suspected appendicitis. J Am Coll Radiol. 2011;8(11):749-755.
  17. Israel GM, Malguria N, McCarthy S, Copel J, Weinreb J. MRI vs. ultrasound for suspected appendicitis during pregnancy. J Magn Reson Imaging. 2008;28(2):428-433.
  18. Lehnert BE, Gross JA, Linnau KF, Moshiri M. Utility of ultrasound for evaluating the appendix during the second and third trimester of pregnancy. Emerg Radiol. 2012;19(4):293-299.
  19. Vu L, Ambrose D, Vos P, Tiwari P, Rosengarten M, Wiseman S. Evaluation of MRI for the diagnosis of appendicitis during pregnancy when ultrasound is inconclusive. J Surg Res. 2009;156(1):145-149.
  20. Long SS, Long C, Lai H, Macura KJ. Imaging strategies for right lower quadrant pain in pregnancy. AJR Am J Roentgenol. 2011;196(1):4-12.
  21. Furey EA, Bailey AA, Pedrosa I. Magnetic resonance imaging of acute abdominal and pelvic pain in pregnancy. Top Magn Reson Imaging. 2014;23(4):225-242.
  22. Theilen LH, Mellnick VM, Longman RE, et al. Utility of magnetic resonance imaging for suspected appendicitis in pregnant women. Am J Obstet Gynecol. 2015;212(3):345 e341-346.
  23. Hakkarinen DK, Banh KV, Hendey GW. Magnetic resonance imaging identifies occult hip fractures missed by 64-slice computed tomography. J Emerg Med. 2012;43(2):303-307.
  24. Iwata T, Nozawa S, Dohjima T, et al. The value of T1-weighted coronal MRI scans in diagnosing occult fracture of the hip. J Bone Joint Surg Br. 2012;94(7):969-973.
  25. Bretherton CP, Parker MJ. Early surgery for patients with a fracture of the hip decreases 30-day mortality. Bone Joint J. 2015;97-B(1):104-108.
  26. Khurana B, Okanobo H, Ossiani M, Ledbetter S, Al Dulaimy K, Sodickson A. Abbreviated MRI for patients presenting to the emergency department with hip pain. AJR Am J Roentgenol. 2012;198(6):W581-588.
  27. Institute for Magnetic Resonance Safety E, and Research (IMRSER). Magnetic Resonance (MR) Procedure Screening Form For Patients and Magnetic Resonance (MR) Environment Screening Form for Individuals. 2017.
  28. Grobner T. Gadolinium–a specific trigger for the development of nephrogenic fibrosing dermopathy and nephrogenic systemic fibrosis? Nephrol Dial Transplant. 2006;21(4):1104-1108.
  29. Prince MR, Zhang H, Morris M, et al. Incidence of nephrogenic systemic fibrosis at two large medical centers. Radiology. 2008;248(3):807-816.

 

Commonly Missed Findings on CT Abdomen/Pelvis

Author: Emily Thompson, MD (EM Resident Physician, North Shore University Hospital) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital) and Brit Long, MD (@long_brit)

Computed Tomography.  The donut of truth.  If you are like me (even if you aren’t an intern), you probably dread the patient with non-specific abdominal pain.  I certainly breathe a little easier sending a patient home with a negative CT abdomen/pelvis.  However, the power of x-ray vision doesn’t allow us to turn off our brains.  Certain pathologies may have only subtle findings on CT, and others may lend themselves better to other imaging modalities, such as ultrasound.  By being aware of these pathologies and how to identify them, we can better recognize patients at risk of a missed diagnosis.

Case 1

A 45-year-old male is a restrained driver in a single car, head-on collision with a telephone pole.  He presents to a level-one trauma center by BLS ambulance in a c-collar.  His heart rate is 120, blood pressure is 100/60, respiratory rate is 24, and O2 saturation is 96% on 100% non-rebreather.  His eyes are closed, and he is moaning and making gurgling sounds.  He withdraws from pain, and he smells of alcohol.  He has shortening of his left leg and a seatbelt sign. The patient is put on the monitor, 2 large-bore IVs are placed running normal saline, and the patient is intubated.  The patient has bilateral breath sounds, a soft, obese abdomen, and intact distal pulses.  FAST exam is negative and the patient’s blood pressure responds to 2L normal saline, so the pelvis is stabilized and the patient is transported to CT.  The images are reviewed by the on-call radiology resident, as well as the ED resident and trauma surgeon, who found a left hip dislocation, an acetabular fracture, and two right lower rib fractures, with no other obvious injuries.  On day 2 in the surgical ICU he develops a fever and peritonitis.  Repeat CT shows free air and fluid.

 

Missed Injuries in Trauma

Bowel Rupture

Trauma is the most common cause of small bowel perforations.  These are the third most common traumatic perforations after liver and spleen and are usually associated with other injuries.  The most common CT finding is free air, but the leaks are less dramatic than with gastroduodenal perforation.  Other findings include a visible bowel wall lesion, “misty” mesentery, intestinal pneumatosis, free fluid, and extraluminal fecal matter.  CT is more sensitive than plain x-rays and extremely specific (95.4%).  However, free air may be as little as 50% sensitive for detecting bowel perforation.11

The best way to manage these patients is to be aware of the possibility of bowel injury, re-examine them frequently, and re-image them or even send them for ex-lap if their condition changes. One study reviewed trauma victims who underwent exploratory laparotomy after repeat CT.  While the initial CT was only 30% sensitive for bowel perforations, the second was 82% sensitive.13  These patients likely developed new symptoms that led to their repeat scans, which introduces some bias into the study.  However, it is important to remember that a single CT is only a “snapshot,” and patients with serious blunt trauma may have occult injuries that destabilize later.

 Bladder Trauma

Bladder injuries in trauma are relatively rare.  They are most commonly caused by blunt trauma to the pelvis.  They can be due to a direct blow to a full bladder, causing a dome rupture, or they can be associated with pelvic fractures, particularly disruption to the pelvic ring.  Bladder rupture is usually not immediately life-threatening, and the more common extraperitoneal ruptures are managed expectantly with catheter drainage.  Intraperitoneal ruptures, on the other hand, require surgical repair.  Extravasation of urine into the peritoneal space can result in chemical peritonitis and sepsis.

While a CT may be able to directly visualize breaks in the bladder wall, findings are usually more non-specific: free fluid, ascites, or bladder wall enhancement.  Suspicion should be high for GU injuries in pelvic trauma.  Every patient with gross hematuria or inability to void requires evaluation for GU tract damage.  Retrograde cystography is nearly 100% sensitive for bladder injury.  CT cystography is being used more often as part of the standard trauma series and is 85-100% sensitive for bladder rupture.9

Diaphragmatic Injury

The diaphragm is in the shadowy borderlands between the thoracic and abdominal cavity and is caught at the top of the CT abdomen/pelvis.  It can be damaged by penetrating trauma anywhere between the fourth rib or tip of the scapula and the inferior rib margin.  It can also be ruptured by blunt trauma that increases intra-abdominal pressure.   Injuries occur most commonly on the left side, as the liver shields the right.  The diaphragm heals poorly and delay in diagnosis may result in expansion of the injury or herniation of abdominal organs into the chest cavity.  These complications may present months to years after the injury and are very difficult to repair.1

CT diagnosis of a diaphragmatic injury is usually made by direct visualization of the irregularity or discontinuity in the diaphragm.  Unfortunately, the diaphragm is thin, mobile, and difficult to image.  CT has fairly poor sensitivity for diaphragmatic injuries.  One study found CT was only 82% sensitive and 88% specific for a diaphragm injury.15  For those watching at home, that means that nearly a fifth of stable patients with no diaphragm injury identified by CT went on to have one diagnosed by laparoscopy at 48 hours.  Another study, a retrospective review of blunt diaphragm injuries identified by laparotomy, found that only 57% of pre-op CT scans had signs of diaphragmatic damage.12

So how do we identify these small, slippery, and potentially serious lesions?  Clinically correlate, of course.  Be aware of injuries that have the potential to cross between the thoracic and abdominal cavities (for example, penetrating trauma as high as the fourth rib).  Know that CT will be negative for a significant percentage of patients with diaphragmatic injury.  If your suspicion is high enough, discuss laparoscopy with your friendly local trauma surgeon.1

 

Case 2

A 76-year-old woman with a past medical history of hypertension, diabetes, hyperlipidemia, hypothyroidism, dementia, and atrial fibrillation presents to the emergency department with abdominal pain.  She is mildly tachycardic, tachypneic, and normotensive, with an irregular heartbeat.  She is moaning in pain and holding her abdomen, but is unable to characterize or localize the pain.  Her abdomen is non-distended, soft, and diffusely tender with voluntary guarding.  Her home health aid has her medication list, which includes an 81 mg aspirin, but is unsure who her primary doctor is.  She has never had a colonoscopy.  CT abdomen/pelvis shows a small amount of pelvic free fluid and thickening of the small bowel wall.

 

Non-traumatic Abdominal Pathology

Mesenteric Ischemia

The classic presentation of mesenteric ischemia is abdominal pain out-of-proportion to exam.  Patients may lose blood supply to their bowels by a variety of mechanisms: generally embolic, thrombotic, or hypovolemic (dissection and vasculitis are less common causes).5  Each of these patients will have a different history, for example, atrial fibrillation in the patient with embolic ischemia.

While CT is generally the best imaging modality for mesenteric ischemia, CT findings are relatively non-specific.  The most common finding is bowel wall thickening.  This may be associated with the target sign, or an alternating high and low attenuation pattern due to submucosal hemorrhage or edema.  Other findings include free fluid and bowel dilation.  More specific signs include bowel pneumatosis and ischemia to other abdominal organs such as the liver and spleen (indicating that clots have been showered from a source like the heart).  Finally, CT angiography may offer visualization of the clot itself, filling defects, or gas in the intestinal vessels.5,7

For further discussion, go here: http://www.emdocs.net/mesenteric-ischemia-power-review/

Torsion

Torsion is the twisting of an organ around its blood supply.  While virtually any organ can torse, the ones that will be missed by CT are ovaries and testicles.  Ovarian torsion presents with sharp lower abdominal pain/tenderness and adnexal tenderness on bimanual exam.  There may be a palpable mass either from the torsed ovary itself, the twisted vascular pedicle, or a mass that caused the torsion in the first place.  CT may show displacement of the ovary toward the midline, enlargement, surrounding inflammatory changes, and uterine deviation toward the affected side.

Ultrasound is the imaging modality of choice.  The most common finding is an enlarged ovary with heterogeneous echotexture.  The follicles may also move peripherally giving the “string of pearls” sign.  Unlike testicular ultrasound, Doppler plays virtually no role.  The ovary has a dual blood supply, so a torsed ovary may have flow.  A normal ovary can also have no flow, and flow asymmetry is common based on menstrual cycle phase.  The whirlpool sign may be present, which is color Doppler of the actual blood vessels in the pedicle twisted around each other.  See further discussion here: http://www.emdocs.net/ovarian-torsion-pearls-and-pitfalls/

Testicular torsion occurs when the testicle spins on its spermatic cord causing acute scrotal pain, pain with palpation, and a high-riding testicle in transverse lie.  Unlike ovarian torsion, Doppler is key.  The money is in the “buddy shot” of the testicles side-by-side showing asymmetric or absent flow to one.  Grey scale abnormalities usually don’t appear until it is too late.  Remember, a testicle is 100% salvageable at 6 hours, 20% at 12 hours, and approaches 0% at 24 hours, so don’t forget to check below the waist in a male patient with abdominal pain.2  See further discussion here: http://www.emdocs.net/testicular-torsion-pearls-and-pitfalls/

Cholelithiasis

CT scan is only about 75% sensitive for gallstones.  Gallstones often have the same density as bile, which makes them invisible on CT.  Ultrasound is the best imaging modality for gallstones, with 96% accuracy, and should be used first to assess right upper quadrant pain.3

Contrary to popular belief, CT does fairly well identifying acute cholecystitis: 91.7% sensitive and 99.1% specific in one paper.8  Research directly comparing CT and ultrasound is limited, and most studies are small and showed their effectiveness to be similar.  In 1981, a combination of major and minor criteria was found to be 100% sensitive and 96% specific for cholecystitis.14  However, in a 2012 study of over 5,000 patients, ultrasound is only 81% sensitive and 83% specific for cholecystitis.4

Ultrasound is still the preferred modality for diagnosing cholecystitis due to easy access, speed, and lack of radiation.  The findings are the same for CT and ultrasound: hydrops, wall thickening or edema, and pericholecystic fluid.  CT will likely not pick up a stone in the neck of the gall bladder.  CT may be helpful for atypical presentations of acute cholecystitis, acalculous cholecystitis, and to identify complications such as gallbladder perforation.  However most stable patients who are highly suspicious for biliary disease should undergo ultrasound and follow up with MRCP.  For a fantastic review of pathologies and imaging modalities check out “Evaluating Patients with Right Upper Quadrant Pain” by Genevieve Bennett in the resources section.3

 

Resources/Further Reading:

  1. Arora, Sanjay; Menchine, Mike. “Cracking the Chest: Paper Chase 2 – CT for Diaphragm Injury.”  EM:RAP. 2016 Jan.  Accessed 4 April 2016.
  2. Ayoob, Andres R; Lee, James T. “Imaging of Common Solid Organ and Bowel Torsion in the Emergency Department.” AJR.  2014 Nov;203:W470-81.
  3. Bennett, Genevieve L. “Evaluating Patients with Right Upper Quadrant Pain.” Radiol Clin N Am. 2015;53:1093-30.
  4. Cartwright, Sarah L; Knudson, Mark P. “Diagnostic Imaging of Acute Abdominal Pain in Adults.” American Family Physician. 2015 April 1;91(7): 452-60.
  5. Gray-Eurom, Kelly; Deitte, Lori. “Imaging the Adult Patient with Nontraumatic Abdominal Pain.”  EB Medicine.  Published: February 2007.  Accessed: 2 April 2016. http://www.ebmedicine.net/topics.php?paction=showTopicSeg&topic_id=12&seg_id=84
  6. Fagenholz, Peter J, et al. “Computed Tomography is more sensitive than Ultrasound for the Diagnosis of Cholecystitis.” Surgical Infections. 2015, Oct 5;16(5): 509-12.
  7. Firetto, Maria Cristina; Lemos, Alessandro A. et al. “Acute bowel ischemia: analysis of diagnostic findings at MDCT angiography.”  Emerg Radiol. 2013;20:139-147.  DOI 10.1007/s10140-012-1078-4.
  8. Harvey, Robert T.; Miller, Wallace T. “Acute Biliary Disease: Initial CT and Follow up US versus Initial US and follow-up CT” Radiology.  1999 Dec;213(3).
  9. Hass, Christopher, et al. “Limitations of Routine Spiral Computerized Tomography in the evaluation of bladder trauma.” The Journal of Urology.  1999 July;162: 51-2
  10. Hefny, et al. “Usefulness of free intraperitoneal air detected by CT scan in diagnosing bowel perforation in blunt trauma: experience from a community-based hospital.” Injury. 2005 Jan;46(1):100-4
  11. Lo Re, Guiseppe; et al. “Small Bowel Perforations: What the Radiologist Needs to Know.” Semin Ultrasound CT MRI.  2006;37:23-30.
  12. Sprunt, Julie M, et al. “Computed Tomography to Diagnosed Blunt Diaphragm Injuries: Not Ready for Prime Time.”  The American Surgeon. 2014 Nov 11;80(11): 1124-7.
  13. Walker, Mark L.; et al. “The Role of Repeat Computed Tomography in the Evaluation of Blunt Bowel Injury.”  The American Surgeon. 2012 September;78(9): 979-85.
  14. Worthen, Nancy J, et al. “Cholecystitis: Prospective Evaluation of Sonography and 99mTc-HIDA Cholescintigraphy.” AJR. 1981;137:973-78.
  15. Yucel, Metin. “Evaluation of the diaphragm in penetrating left thoracoabdominal stab injuries: The role of multislice computed tomography.”    2015 Sep;46(9): 1734-7. doi:10.1016/j.injury.2015.06.022

Bounceback: An Unrelenting Headache

Author: Rachel Wightman, MD (Senior EM Resident, NYU) // Editors: Adaira Landry, MD, & Justin Bright, MD

CC: Headache

First visit

HPI: 29 year old female with a prior history of headaches, presented with two days of gradual onset, atraumatic, right sided headache that is throbbing in nature. The patient reported heaviness about the eye but no visual changes or disturbances. No neck pain, fevers, chills. She described feeling slightly light-headed but no balance loss. She had a mechanical trip and fall yesterday without head trauma, and her headache had been present for a day prior to the fall.
ROS: otherwise normal.
PMH/PSH: headaches, depression, anxiety, asthma
SH: no smoking, no etoh, no drugs
Allergies: Penicillin (rash)

Pertinent Exam
Vitals: 98.6F, BP: 156/85 P: 101, RR: 16, O2: 98%RA
Gen: A&Ox3, well-developed, well-nourished
HEENT: normocephalic, atraumatic, conjunctiva wnl, EOM wnl, PERRL, normal fundoscopic exam, crisp optic discs, normal ROM neck/supple
Chest: wnl
Abd: wnl
Musculoskeletal: wnl
Neuro: CN2-12 intact, normal reflexes, normal muscle tone, normal coordination

Labs: Serum HCG negative

Imaging: None ordered

ED Course: The patient was believed to be experiencing a migraine headache. She had no evidence of head trauma, no signs of infectious etiology, and had no clinical findings or hx for SAH. She was administered Toradol, IVF and Reglan, and discharged with instructions to follow up with neurology and possibly have an outpatient MRI.

Discharge Dx: Headache

Bounce Back Visit
The patient re-presented to the Emergency Department 14 hours later with worsening headache and nausea. Minimal additional history was obtained. The physical exam was documented as unchanged from the prior exam, and the patient was again diagnosed with a likely migraine. Her pain was uncontrolled with Toradol, Reglan, and IVF. The patient subsequently received dexamethasone and magnesium with improvement in pain. The new discharge plan was a steroid taper and outpatient neurology follow-up. At time of discharge patient reported worsening pain and requested a neurology consult. A head CT was also ordered at that time.

Neurology Consult Note:
29 year old obese female on OCPs with R frontal headache radiating to left, stabbing, unremitting. Headache associated with worsening on valsalva maneuvers, dizziness, pain on eye movement, but no vomiting. History tension-type headache in the past, but this headache is different, failing ibuprofen 400mg therapy which usually relieves her headache. FH: Maternal Grandmother with venous clots resulting in stroke, mother with PFO and stroke at age 40 unknown if hypercoagulability workup performed.

ED COURSE:
In addition to the medication given above, a head CT was performed. CT images demonstrated a right transverse and straight sinus thrombosis.

CVST1

CVST2

DIAGNOSIS: Cerebral Venous Sinus Thrombosis

Background:

Cerebral venous sinus thrombosis (CVST) is a rare but serious cause of neurologic symptoms. CVST results from venous outflow obstruction causing increased intracranial pressure, increased retrograde venous pressure, a decrease in cerebral blood flow, decreased cerebral perfusion pressure and eventually venous infarction. CVST is estimated to account for fewer than 1-2% of all strokes. It affects mostly younger adults and children with the mean age of presentation at 39 years. Women are affected more often than men with a 3:1 female predominance. This gender imbalance is thought to be due to the increased risk for CVST associated with pregnancy, puerperium, and with use of oral contraceptives. More than 85% of pts with CVST have at least one identifiable risk factor and multiple risk factors may be found in about half of patients with CVST. The most frequently cited risk factors include pro-thrombotic conditions including genetic and acquired conditions. Other less common risk factors include CNS/sinus infection, head injury, inflammatory bowel disease and cirrhosis.

Clinical Presentation:

The clinical presentation for CVST is highly variable and non-specific. Signs and symptoms are divided into three categories: 1) isolated intracranial hypertension 2) a focal syndrome including focal deficits, seizures or both 3) encephalopathy causing multifocal signs, mental status changes, stupor, or coma. Patients can present acutely, sub-acutely, or with chronic symptoms. Other variables affecting presentation include site and number of occluded vessels, presence of parenchymal brain lesions, patient age and gender. CVST cannot be diagnosed on clinical grounds alone and neuroimaging is required for diagnosis.
Diagnostic Imaging:

Non-contrast head CT is typically the first study performed in patients with suspected CVST in the ED because it is readily available and the most useful test to evaluate for conditions that can mimic CVST clinically. Common findings of CVST on head CT are generalized swelling or localized areas of hyper-density indicating cerebral infarction (seen in up to 40% cases). Direct signs of CVST can sometimes be seen on CT scan and include the dense triangle sign, as seen on CT scan in our patient, which indicates fresh thrombus in the posterior aspect of the superior sagittal sinus. Non-contrast head CT can be normal in 25-30% of patients with CVST. In hospitals without MRI capability, CT venogram is the confirmatory test for CVST. However, MRI/MRV is the most sensitive and specific imagining modality for CVST and can best determine the location and age of a thrombus.

Management:

Anticoagulation with heparin is the standard therapy for CVST. At this time no clinical guideline exists to recommend un-fractionated heparin (UFH) versus enoxaparin (LMWH) for therapy and there are no prospective, randomized trials of systemic anticoagulation use in treatment CVST. Hemorrhagic infarction is associated with 40% of CVST, however, most experts recommend use of anticoagulation in patients with CVST even in the setting of known hemorrhagic infarction on imaging. Systemic TPA and direct endovascular thrombolysis are considered experimental therapy at this time and cannot be routinely recommended. Patients with CVST will require anticoagulation beyond hospital discharge. The duration of anticoagulation is dependent on the etiology of thrombosis.

Hospital Course:

The patient was admitted to the stroke unit for anticoagulation of right transverse and straight venous sinus thrombosis. She was started on a heparin drip, transitioned to enoxaparin, and then bridged to warfarin. Thrombophilia studies demonstrated a low anti-thrombin level and an elevated anti-2 beta glycoprotein antibody, suggesting a hypercoagguable genetic disorder. The patient was discharged home on hospital day seven with no residual deficits on warfarin with plans to repeat coagulation studies in six weeks.

Errors in Evaluation

Lack of full history: Patient risk factors for CVST were not elicited on first visit. Additionally, changes in headache symptoms from previous headaches were not adequately explored. Any alteration in patient headache symptoms should trigger further evaluation and consideration of possible secondary cause of headache.

Anchoring bias: Anchoring to the diagnosis of possible migraine headache from the initial visit likely led to delayed diagnosis and near-miss on second visit to the ED. It is important to ask all patients with reported history of migraines how the diagnosis was made because many patients with headache sometimes attribute any and all headaches to “migraine.” Making a new diagnosis of migraine headache in the Emergency Department should cause providers to pause and consider other possible etiologies of headache.

Failure to broaden differential: CVST is rare diagnosis with variable presentation and can often be missed on initial presentation. Physicians need to expand their differential and think about CVST in order to make the diagnosis. Not all headaches are migraines so we should be sure to document our thought process well when seeing these patients.

References

Ferro JM, Canhao P. Treatment and prognosis of cerebral venous sinus thrombosis. Uptodate.com. Accessed 8/14.
Ferro JM, Canhao P. Etiology, clinical features and diagnosis of cerebral venous sinus thrombosis. Uptodate.com. Accessed 8/14.
Fischer C, Goldstein J, Edlow J. Cerebral venous sinus thrombosis in the emergency department: retrospective analysis of 17 cases and review of the literature. J Emerg Med. 2010.38(2):140-7.
Matharu et al. Thunderclap headache: an approach to a neurologic emergency. Current Neurology and Neuroscience Reports. 2007. 7(2):101-9.
Singh A, Soares WE. Management Strategies for Acute Headache in the Emergency Department. Emergency Medicine Practice. June 2012. 14(6):1-42. EB Medicine.net.