VOTW: Emphysematous Pyelonephritis

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This weeks’s VOTW is brought to you by Dr. Dozois!

A 60 yo female w/ hx of DM presented with 1 week of progressively worsening R flank pain, fever and vomiting. Symptoms and UA was consistent w/ pyelonephritis. A POCUS was performed which showed…

Clip 1 and 2 shows the right kidney with echogenic foci with “dirty shadowing” in the renal parenchyma concerning for air within the kidney. This is concerning for emphysematous pyelonephritis.  A hypoechoic region towards the inferior pole of the kidney is concerning for a perinephric abscess.

Emphysematous pyelonephritis is a rare, severe gas-forming infection of the renal parenchyma with mortality rates ranging from 40-90%. Most (95%) are associated with uncontrolled diabetes. Usual pathogen is E. Coli. Management options include IV antibiotics plus percutaneous nephrostomy, or ureteral stenting, or nephrectomy which is becoming less and less preferred.

POCUS for pyelonephritis?

  • POCUS is insensitive for pyelonephritis alone and kidneys usually appear normal. Abnormalities are identified in only 25% of cases. The most common finding is focal/segmental hypoechoic regions (edema).

  • POCUS is useful for assessing complications of pyelonephritis including hydronephrosis, perinephric abscess, and emphysematous pyelonephritis all of which would prompt CT imaging and urologic evaluation.

  • Considering POCUSing a patient with pyelonephritis if they are worsening despite antibiotics, if there is a concern for associated downstream obstruction or if they are in septic shock.

Back to the patient

The patient was actually a transfer from an outside hospital for emphysematous pyelonephritis seen on CT. Urology was consulted who admitted the patient to the SICU for a planned nephrectomy in the morning 😊

VOTW: Intussusception

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Today’s VOTW is brought to you by Dr. Fagan, Dr. Davitt and Dr. Lat!

A 2 year old male presented with abdominal pain and vomiting x1 day as well as cough and nasal congestion x2 days. On exam, he was clutching his abdomen in discomfort. A POCUS was performed which showed…

Clip 1 shows an abdominal ultrasound in the RUQ showing the classic “target sign” measureing 3.5cm, concerning for intussusception. You can visualize a smaller circular structure within a larger circular structure representing a part of bowel telescoping into the next part of the bowel. In the center, there are small circular hypoechoic lymph nodes surrounded by echogenic mesenteric fat that serves as the leading point of the intussusception.

Image 1. Target or donut sign

Ultrasound is the test of choice for intussusception and several studies have shown high sensitivity (94%) and specificity (99%) when POCUS is performed by PEM physicians (2).

POCUS for Intussusception

  • Most commonly occurs at the ileo-cecal junction and most commonly found in the right lower or right upper quadrant

  • Look for a target sign or donut sign (in transverse view, see above) or sandwich or pseudokidney sign (in longitudinal view, see below)

  • Diameter > 2cm (remember in-✌-ssusception)

    • May see mesenteric fat and lymph nodes in the center

Image 2. Pseudokidney or sandwhich sign

How to perform the study            

  • Use warm gel, have parents help distract, scan on parent's lap!

  • Use the linear probe

  • Picture frame pattern- start in the RLQ w/ probe marker to pts R scan towards the RUQ, then turn the probe w/ marker to pts head and scan towards the LUQ, then turn the probe w/ marker to pts R and scan down to the LLQ

  • Lawnmower pattern- start in the RLQ and lawnmower the entire abdomen scanning up and down from right to left with the probe marker to the pts R

  • Measure the diameter of the intussusseption if found

Image 3. Picture frame pattern

Back to the patient

Surgery was consulted, the patient underwent an air enema with resolution of the intussusseption. The patient was then discharged home.

References:

  1. Lin-Martore. PEM POCUS Series: Intussusception. https://www.aliem.com/pem-pocus-series-intussusception/

  2. Lin-Martore M, Kornblith AE, Kohn MA, Gottlieb M. Diagnostic Accuracy of Point-of-Care Ultrasound for Intussusception in Children Presenting to the Emergency Department: A Systematic Review and Meta-analysis. West J Emerg Med. 2020 Jul 2;21(4):1008-1016. doi: 10.5811/westjem.2020.4.46241. PMID: 32726276; PMCID: PMC7390574.

VOTW: Soft Tissue Foreign Body

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This week’s VOTW is brought to you by Dr. DeStefano and Dr. Wong!

A 3 year old female was brought into the ED a week after a she slid down a wooden pillar and suffered a splinter into her right thigh. A POCUS of the area showed…

Clip 1 is a POCUS of the posterior thigh that shows a small echogenic object with posterior acoustic shadowing. As the they scan through the area, we can tell that the object is linear, about 1cm in length and that its trajectory courses from the dermis to the subcutaneous layer and ends just before entering the muscle. There is no reverbration artifact which is consistent with wood. There is no surrounding signs of abscess of cellulitis.

POCUS for Foreign Bodies

Soft tissue foreign bodies can be imaged by x-ray, CT or ultrasound. Many of us reach for X-rays first but is that really the right move?

X-rays have poor sensitivity for foreign bodies especially for radiolucent objects such as plastic and wood(1). 

Ultrasound on the other hand is highly sensitive for foreign bodies, regardless of what the composition, and has the following advantages over X-rays including:

  1. No radiation

  2. Can map out the shape, trajectory, depth of the object at bedside

  3. Evaluate for involvement of tendons, muscles, joints

  4. Evaluate or complications such as cellulitis or abscess

  5. Guide removal of the object in real time (see videos below)

Characteristics of common foreign bodies on US

Glass: hyperechoic, + shadow, + reverb artifact

Metal: hyperechoic, + shadow, + reverb artifact

Wood: hyperechoic, + shadow, - reverb artifact

Plastic: hyperechoic, + shadow, - reverb artifact

Here is an example of metal which is hyperechoic with reverberation artifact (repeated hyperechoic horizontal lines extending deep to the object)

Metal foreign body with reverberation artifact

Technique

  1. Use a linear probe.

  2. Scan the area of interest in both transverse and sagittal.

  3. Look for a hyperechoic structure with posterior shadowing +/- reverbration artifact.

  4. Identify the shape, length, trajectory and surrounding structures.

  5. For very supericial foregin bodies, try using a water bath to increase the distance between the probe and foreign body (this brings the object closer to the "focal point", the part of image with the best "two-point discrimination" or resolution, which is closer to midway down the screen). Water also provides a great acoustic window.

Foreign body removal using ultrasound-guidance

Check out these great videos on how to use ultrasound to assist w/ foregin body removal

  1. https://www.youtube.com/watch?v=x80NrSUNRrI

  2. https://www.youtube.com/watch?v=OeFDg1hZRDk

  3. https://www.youtube.com/watch?v=h1YQY7guUb0

Back to the patient:

The team identified the splinter in the soft tissue with no evidence of celluitis or abscess. The team approrpiately did not order an x-ray and saved the patient from unecessary radiation! The patient was referred to outpatient general surgery for evaluation for removal of the object.

References:

  1. Pattamapaspong N et al. Accuracy of radiography, computed tomography and magnetic resonance imaging in diagnosing foreign bodies in the foot. Radiol Med. 2013 

  2. https://rebelem.com/pocus-and-soft-tissue-foreign-bodies/

  3. https://sjrhem.ca/detection-of-foreign-bodies-in-soft-tissue-a-pocus-guided-approach/