April 2020 - UCSD Ultrasound

April 28, 2020December 23, 2020

Case # 20: Right Lower Quadrant Pain

A 40 year old male presented with a 4 day history of right lower quadrant pain. He reported that the pain was at its worse when it started but gradually improved. When in the ED he noted only minimal discomfort without the help of analgesics. He denied ever having anorexia, fever, chills, nausea, vomiting, GU complaints. During examination, he had moderate tenderness to palpation in the right lower quadrant without rebound or guarding.

Vitals: T 97.7F BP 130/77 HR 66 RR 16 SP02 100%

An abdominal ultrasound of the RLQ was performed and the following images were seen. What do you see and what is your most likely diagnosis?

Answer and Learning Points

Answer

In both the longitudinal and transverse views, you see a tubular structure in the right lower quadrant that is non- compressible, greater than 6mm (measures 15.6 mm), and lacks peristalsis. You can also appreciate some dependent free fluid around the appendix. These findings are consistent with the diagnosis of acute appendicitis.

CT abdomen/pelvis showed a retrocecal appendix with finding of acute uncomplicated appendicitis. No bowel obstruction or intra-abdominal/pelvic abscesses. Labs showed a slight leukocytosis to 14, otherwise were reassuring. Patient was given a dose of Zosyn in the emergency department and take to the OR for appendectomy by general surgery.

Learning Points

- Appendicitis is the most common abdominal surgical emergency that presents to the ED in western countries [1].
- The sensitivity and specificity of ultrasound for the diagnosis of appendicitis appears to be around 86% and 81%, respectively, based on results from older studies [2].
- Ultrasound can be used to diagnosis acute appendicitis and may be the imaging modality of choice in certain patient populations such as pregnant women and children [3].
- To obtain images you can use either the linear or curvilinear probe. Ask the patient to point where exactly they hurt and place the probe there. If you don’t see it you can use the landmark of the iliac crest (most lateral), psoas muscle (posterior), and iliac artery (most medial). Move superior and inferior along the iliac artery and the appendix should be just anterior to iliac artery. If you still haven’t found it, “lawnmower” along the right lower quadrant. Look for a tubular, blind ended pouch that has no peristalsis. It should be compressible and measure <6mm in AP diameter [4].

References

1. Caterino, S., et al. Acute abdominal pain in emergency surgery. Clinical epidemiologic study study of 450 patients. Ann Ital Chir. 1997; 68: 807-817.
2. Lim H, Bae S, Seo G: Diagnosis of acute appendicitis in pregnant women: value of sonography. AJR Am J Roentgenol 1992;159(3): 539–542.
3. Excerpt From: Mike Mallin & Matthew Dawson. “Introduction to Bedside Ultrasound: Volume 2.” Emergency Ultrasound Solutions, 2013. Apple Books. https://books.apple.com/us/book/introduction-to-bedside-ultrasound-volume-2/id647356692Mallin, M, Dawson, M. Introduction to Bedside Ultrasound: Volume 2. Emergency Ultrasound Solutions, 2013. Apple Books. https://books.apple.com/us/book/introduction-to-bedside-ultrasound-volume-2/id647356692. Accessed April 18^th, 2020.
4. www.5minsono.com

The following authors contributed to this post:

Amir Aminlari, MD; Danika Brodak, MD; Michael Macias, MD

April 28, 2020July 21, 2020

Case # 19: Under Pressure

A 27 year-old female presented to the emergency department with a two week history of headache, posterior eye pain, visual changes. She denied trauma, fever, focal neurological changes, or visual field deficits. She was seen by the optometrist earlier in the day and was sent to the ED for further evaluation. Her neurological examination was normal.

Eye exam: PERRL, EOMI, no injection/discharge, visual acuity 20/15 OS, 20/20 OD, IOP L19, R19

An ocular ultrasound is performed and the images below are seen. What do you see and what is your most likely diagnosis? What is your management?

Left eye

Right eye

Answer and Learning Points

Answer

On both images of the right and left eye you see papilledema which is demonstrated as a bulging optic disc protruding into the posterior chamber.

CT Head non-contrast was obtained which showed " a partially empty pituitary sella which can be seen with intracranial hypertension, otherwise no acute findings." Ophthalmology was consulted. Their exam was unremarkable except for bilateral papilledema. An LP was performed which showed an elevated OP at 36. After large volume CSF removal the patient reported improvement in symptoms. Closing pressure was 22. The CSF studies were unremarkable. Patient was discharged with an MRI/MRV performed as outpatient and neuro-ophthalmology follow up. MRI brain showed mild flattening of the optic nerve heads which is nonspecific but could correlate with intracranial hypertension in the right clinical setting.

Learning Points

- Papilledema may be directly visualized with ultrasound as a bulging optic disc elevated more than 0.6mm from the retina. There are also studies that show a correlation between increased intracranial pressure and optic sheath nerve diameter greater than 5mm when measured 3mm posterior to the retina. (1-4)
- A width of > 5mm has a pooled sensitivity of 90% and specificity of 85% for detecting an ICP > 20mmHg in trauma patients with head injuries (5-6)
- It is important to note that the optic nerve sheath diameter should be measured when the sides are parallel, as it can be artificially increased otherwise. (7)
- When obtaining an ocular ultrasound use the high frequency linear probe on the ocular setting. If there is not an ocular setting, it is best to err on the high side with regard to gain.
- Although controversial, some sources advise to avoid ocular ultrasound when concerned about globe rupture as any pressure on the eye could worsening the rupture.

References

1. Marchese, R.F., et al. Identification of optic nerve swelling using point-of-care ocular ultrasound in children. Pediatric Emergency Care. 2018; 34(8):531-536.
2. Kimberly, H.H., Shah, S., Marill, K., & Noble, V. Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Academic Emergency Medicine. 2008; 15(2):201-4.
3. Amini, A., et al. Use of the sonographic diameter of optic nerve sheath to estimate intracranial pressure. The American Journal of Emergency Medicine. 2013; 31(1):236-9.
4. Xu, W., Gerety, P., Aleman, T., Swanson, J., & Taylor, J. Noninvasive methods of detecting increased intracranial pressure. Child’s Nervous System. 2016; 32(8):1371-86.
5. Dubourg, J., et al. Ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure: a systematic review and meta-analysis. Intensive Care Medicine. 2011;37(7):1059–1068.
6. Rajajee, V., Vanaman, M., Fletcher, J.J., & Jacobs, T.L. Optic nerve ultrasound for the detection of raised intracranial pressure. Neurocritical Care. 2011;15(3):506–515.
7. Mallin, M, Dawson, M. Introduction to Bedside Ultrasound: Volume 2. Emergency Ultrasound Solutions, 2013. Apple Books. https://books.apple.com/us/book/introduction-to-bedside-ultrasound-volume-2/id647356692. Accessed April 17^th, 2020.

The following authors contributed to this post:

Amir Aminlari, MD; Danika Brodak, MD; Michael Macias, MD; Rachna Subramony, MD

April 24, 2020July 21, 2020

Case # 18: Respiratory Distress: It’s not all COVID.

During the COVID-19 pandemic, a 67 year old woman is brought to the ER by family for respiratory distress and altered mental status. She was alert but not oriented and unable to answer questions on arrival with moderate respiratory distress. Family stated that she had a history of asthma and takes "other" medications, but where otherwise unaware of her past medical history. She had been using her inhaler without relief and has not had any sick contacts, cough or fever.

Vitals: T: 98.7, HR: 112, BP: 190/110, RR: 40, SpO2 80 on RA

She was in moderate respiratory distress, crackles on exam, no pitting edema. She was placed on a non-breather (avoiding NIPPV) and a thoracic plus cardiac ECHO was preformed.

After reviewing the images, what would you do next?

Answer and Learning Points

Answer

The images would suggest that this patient is most likely suffering from heart failure with an acute exacerbation. There are diffuse B-lines, obvious decrease contractility and a dilated IVC. These images are not typical of COVID-19 infections, which have pleural thickening and scattered b-lines (see COVID section). This patient was put on a nitro drip and given diuretics, with a significant improvement in her respiratory status in the ER. She ultimately tested COVID negative and was discharged from the hospital after aggressive diuresis.

During the same shift, numerous COVID-19 positive patients were seen. Below are images of COVID-19 cases for comparison and more can be found at The POCUS Atlas.

While the sensitivity and specificity of ultrasound to diagnosis COVID-19 has yet to be determined, this case illustrates how alternative findings can still impact clinical care and potentially avoid intubation.

COVID +

On the same shift, numerous COVID-19 patients were also seen, with variable pre-test probability. ECHO for these patients would not reveal an alternative diagnosis (such as our CHF case). There were however some classic findings on ultrasound. Note below two patients with thoracic scans. There are scattered B-lines (unlike our CHF patient, who had diffuse B-lines). There is also pleural thickening and at times an irregular pleural border.

Author

Sukhdeep Singh, MD. Clinical Faculty, UCSD Department of Emergency Medicine. Director of POCUS, El Centro Regional Medical Center.

References

DeRose et al, How to Perform Pediatric Lung Ultrasound Examinations in the Time of COVID‐19. Journal of Ultrasound in Medicine. 22 April 2020.
The POCUS Atlas. http://www.thepocusatlas.com/covid19