VOTW: DVT

This week’s VOTW is brought to you by Drs Kim, Nguyen and Sanghvi!

A patient with a previous history of DVTs no longer on anticoagulation presented with 4 days of right lower extremity pain, shortness of breath and chest pain. A POCUS of the lower extremities showed…

Clip 1 shows a non-compressible R common femoral vein containing echogenic material concerning for a DVT. The clot is seen extending into the saphenous vein as it takes off from the common femoral vein. Clip 2 shows the L common femoral vein also with a DVT extending into the saphenous vein. You can see that there is enough force applied with the probe to compress the artery completely, yet the vein is not fully compressed.

Chronic DVT

The appearance of these DVTs suggest that they are chronic. In general, chronic DVTs are more echogenic and have a more ragged appearing edge. Over time, DVTs tend to recanalize centrally. In image 1 below, you can see there is some areas that are recanalizing outlined in green. Image 2 shows an illustration of acute vs chronic DVTs.

DVT with area of recannalization

Acute vs Chronic DVTs

Acute DVT

An acute DVT generally has smoother edges and is less echogenic than a chronic DVT. Some acute DVTs cannot be seen with ultrasound and their presence can only be identified by the inability to collapse the vessel completely. If you are placing enough pressure to collapse the artery but the vein is not yet collapsed, this is concerning for a DVT.

Tips and tricks for lower extremity DVT studies

1. Use a linear transducer and choose the DVT setting

2. Squirt gel on the entire thigh instead of the probe so you don’t have to repeatedly re-gel the probe

3. Start in the inguinal crease and identify the take-off of the saphenous vein. This is a common site for a DVT and is the proximal starting point for our ED performed limited compression studies. Compress and take a clip here.

4. While the saphenous vein is considered a superficial vein, clots close to the sapheno-femoral junction should be treated with anticoagulation.

5. The common femoral vein bifurcates into the deep femoral vein (DFV) and superficial femoral vein (SFV). The DFV courses deep and is difficult to evaluate. The SFV is a mis-nomer and is actually a deep vein. Follow the SFV as far as you can down the thigh compressing every 2cm

6. Move onto compression of the popliteal region where the popliteal vein is on top of the artery (“pop on top”)

7. Compressing obliquely is a common reason the vein does not compress completely resulting in a false positive interpretation. Use your non-probe hand to assist in compressing the vein perpendicularly to the femur.

Back to the patient
A CTA chest was negative for pulmonary embolism and patient was discharged on oral anticoagulation and outpatient follow up.

Happy Compressing and De-compressing,

Your Sono Team

VOTW: Emphysematous Pyelonephritis

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

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.