VOTW: Subchorionic Hemorrhage

Case: A 26 yoF who was 5 weeks pregnant presented to the ED after being pushed out of a parked car by her partner. She complained of wrist pain but requested an US to check on her pregnancy. She denied vaginal bleeding or pelvic pain. She had an IUP that was confirmed via US before the assault.

A transvaginal US was performed (video 1) that showed a subchorionic hemorrhage (SCH) > 50% of the gestational sac. Note: be careful not to confuse a large SCH with another gestational sac (image 1). 

Image 1

A SCH typically occurs within the first 20 weeks of gestation and is when blood accumulates between the uterine wall and the chorionic membrane (image 2). While many are found incidentally, some patient's may present with vaginal bleeding.

(What is the chorion? It is a membrane that surrounds the developing fetus along with the amnion. It eventually forms the fetal placenta and provides nourishment and protection for the developing embryo.)

On ultrasound, a SCH will typically appear as a crescentic collection with an elevation of the chorion. The echotexture can vary from hyperechoic (acute) to hypoechoic (chronic) based on the duration of the SCH. A SCH is considered large if it is > 50% of the size of the gestational sac. While many resolve during pregnancy, a large SCH can increase the risk of placental abruption, preterm labor, and miscarriage. These patients therefore require close OB follow-up for serial ultrasounds.

Case conclusion: the patient’s workup was negative, she was educated about the found SCH, and given OB follow-up later that week. 

Happy scanning!

Ariella Cohen, M.D.

References:

https://radiopaedia.org/articles/subchorionic-haemorrhage-2?lang=us

https://my.clevelandclinic.org/health/symptoms/23511-subchorionic-hematoma

VOTW: Big Flex

77 yoF presented to the ED with left middle finger pain, swelling, and discoloration of ~1 week proximally (image 1). 

Image 1: digit swelling and abscess

She was tachycardic and febrile on arrival. Physical exam revealed ¾ Kanavel signs (flexion at rest, pain with passive extension, fusiform swelling of the digit). Ultrasound was performed using a water bath (image 2).

Image 2: water bath technique

POCUS findings concerning for flexor tenosynovitis include a hypoechoic peritendunous effusion and a thickened synovial sheath that may be hyperemic.

Video 1/Image 3: shows fluid surrounding the flexor tendon in short axis.

Image 3: Short axis of flexor tendon with surrounding fluid

Video 2/Image 4: shows a long axis view of the finger with fluid in the pre-tendon area and surrounding edema.

Image 4: Long axis of flexor tendon with abscess/edema

Case conclusion: orthopedics was called and performed a bedside I&D. They were able to express “copious amounts of purulent fluid” but did not appreciate pus along the tendon sheath itself. The patient was admitted for IV abx and is getting daily wound checks by orthopedics.

Note: While the Kanavel signs and ultrasound are useful diagnostic aids, they are non-specific and should not be used as a rule-out test. Remember that many inflammatory processes will often create edema that appears hypoechoic on ultrasound.

Happy scanning!

- Ariella Cohen

References:

https://www.emdocs.net/ultrasound-probe-pocus-for-flexor-tenosynovitis/

https://www.researchgate.net/figure/Ultrasound-appearance-of-normal-flexor-tendon-sheath-and-tenosynovitis-a-Normal_fig1_51104450

VOTW: I'd Tap That

Case 1: A 69 yoF with a PMHx of osteoarthritis presented to the ED with 1 day of worsening knee pain. The workup revealed a moderate-sized effusion and elevated CRP. These factors, combined with her discomfort, prompted the providers to perform an arthrocentesis.

Approach: While there are many approaches you can take to tap a knee effusion, the one I have seen most often is the suprapatellar approach (note: it is best to identify the area with the biggest pocket). Next, gather your equipment for a regular arthrocentesis plus a probe cover. Once you identify your pocket, turn your probe so it is in-plane with your needle. Advance your needle until you see it enter your fluid pocket and aspirate. Remember to put color flow over the expected trajectory of your needle to avoid vasculature.

Image 1: Knee arthrocentesis set-up

• Video 1 shows the moderate-sized effusion in the suprapatellar region. (note: you can also see a separate, rounded, fluid-filled area, which is the pre-patellar bursae).

• Video 2 shows the needle in-plane during active aspiration.

• Video 3 shows the needle in the decompressed joint space.

Case 2: A 102 yoF came to the ED with difficulty ambulating due to ankle pain. On exam, she had swelling, tenderness, and pain with passive/active range of motion. Bedside US showed a joint effusion and inflammatory markers were elevated. In conjunction with the family, the decision was made to tap the ankle joint.

Image 2: normal tibiotalar joint space

Image 3: tibiotalar joint space with effusion

Video 4 shows a fluid collection at the tibiotalar joint. 

Video 5 shows Dr. Tran performing a dynamic aspiration of the ankle effusion.

Results: Results from the arthrocentesis in case 1 showed inflammatory arthritis and case 2 was gout. While neither case turned out to be septic arthritis, both patients felt much better after the tap and were able to ambulate. 

Why use ultrasound? Using ultrasound guidance to perform an arthrocentesis allows you to see the exact location of the joint effusion, improving your first-pass success rate. In addition, using color-doppler before the tap decreases the risk of neurovascular injury.

References:

https://coreultrasound.com/knee-aspiration-and-injection/

https://cdn.mdedge.com/files/s3fs-public/Document/June-2017/em049070329.PDF

https://www.tamingthesru.com/blog/mastering-minor-care/ankle-arthrocentesis

Happy scanning! 

Ariella Cohen M.D.