VOTW: Twinkle Artifact

This week's VOTW is brought to you by Dr. Sanghvi and the UST!

An 80 year old male w/ hx of CVA, non-verbal, PEG dependence, hx urosepsis presented from a nursing home w/ hypotension and “rule out sepsis”. Given the broad differential, the UST performed multiple scans including aorta, echo, chest, FAST, renal and bladder. The left kidney showed hydronephrosis and a POCUS of the bladder was performed which showed...

Clip 1 shows a transverse view of the bladder w/ color doppler placed over the L ureterovesicular (UVJ) junction demonstrating “twinkle artifact” 🌟. This indicates the presence of a stone!

The stone can also be seen without color doppler in clip 2 as a hyperechoic structure with posterior acoustic shadowing. It is associated with upstream hydroureter which can be seen as the clip fans thru. The rectum posteriorly is also distended and filled w/ stool.

Twinkle Artifact

Twinkle artifact

While we often only find indirect signs for ureteral stones on POCUS (hydronephrosis/hydroureter), you might sometimes be able to find the culprit stone on your bladder views. They are easy to miss since the bladder wall is also echogenic, especially if the stone is small. This is where twinkle artifact can be useful!!

When color doppler is used over a rough, hyperechoic, irregular object like a stone, the ultrasound waves get reflected internally within the stone, tricking the machine into thinking that there is movement, resulting in the stone being highlighted by a rainbow doppler signal. Sometimes it will have a rainbow tail extending away from the probe.

The presence of twinkle artifact has a high positive predictive value for the presence of kidney stone (1) and is more sensitive for detection of small stones than is acoustic shadowing (2).

Back to the patient

A CTAP showed three obstructing L ureteral stones, largest being 9mm. Urology was consulted and patient underwent L ureteral stent placement with findings of “pus behind left ureteral stone”. The patient was admitted to the MICU for septic shock.

References

1. Dillman J, Kappil M, Weadock W et al. Sonographic Twinkling Artifact for Renal Calculus Detection: Correlation with CT. Radiology. 2011;259(3):911-6. doi:10.1148/radiol.11102128 

2. Hosn S, Rutten C, Murphy A, et al. Twinkling artifact. Reference article, Radiopaedia.org (Accessed on 20 Feb 2024) https://doi.org/10.53347/rID-21828

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 😊

POTD: Testicular Dislocation

Today’s Trauma Tuesday POTD is about a rare but dangerous type of straddle injury in males: testicular dislocation.

Most commonly found in young males involved in a decelerating motorcycle accident, testicular dislocation presents with severe unilateral or bilateral scrotal and/or inguinal pain. Because there may be multiple other distracting injuries incurred as a result of the accident, a genitourinary exam will be vital in identifying this injury.

On exam, you will find that the testicle has been dislocated from its normal home in the scrotum to another location due to blunt force tearing the fascia of the spermatic cord. Half of the time, that location is the inguinal pouch, and you may find a palpable mass representing the testis at the inguinal crease. The corresponding hemiscrotum will be empty. Interestingly, unilateral and bilateral testicular dislocation appears to occur at the same rate, so don’t forget to check the other side as well. Other locations the dislocated testis may end up are the penis, the perineum, and the abdomen.

Manual reduction may be attempted but is often limited by intractable pain and therefore infrequently successful. There also may be concomitant torsion. Emergent urology consult for operative intervention is usually indicated.

Prolonged dislocation may affect fertility and increases the risk of testicular malignancy in the future

Sources:

Zavras N, Siatelis A, Misiakos E, Bagias G, Papachristos V, Machairas A. Testicular Dislocation After Scrotal Trauma: A Case Report and Brief Literature Review. (2014) Urology case reports. 2 (3): 101-4.

S. L. Schwartz, G. Faerber. Dislocation of the testis as a delayed presentation of scrotal trauma. (1994) Urology.