Tag: nephrolithiasis

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Case 72: A Ureteral Jet in the Setting of Nonobstructing Nephrolithiasis

Liam DiZio, Elaine Yu

A 43-year-old female with a history of hepatic adenoma status post embolization and microwave ablation presented to the emergency department with one week of constant right flank and right lower chest wall pain. She denied fever, nausea, vomiting, dysuria, hematuria, chest pain, dyspnea, or recent trauma. An outpatient ultrasound performed two days prior demonstrated an 8 mm nonobstructing right renal calculus. Given her history, recurrent hepatobiliary pathology, nephrolithiasis, and musculoskeletal pain were at the top of her differential.

Vital Signs: BP 121/89 | HR 81 | RR 16 | Temp 98.0°F | SPO2 99% on FA

On examination, the patient was well appearing and in no acute distress. The abdomen was soft, non-distended, and non-tender without guarding or rebound. There was no costovertebral angle tenderness.

Creatinine was 0.74 mg/dL, lipase 32 U/L, and urinalysis was negative for blood, leukocyte esterase, nitrites, and WBCs.

Given the patient's persistent flank pain and concern for nephrolithiasis or urinary obstruction, a focused point-of-care renal and bladder ultrasound was performed.

Figure 1. Longitudinal grayscale image demonstrating a 6.5 mm nonobstructing right renal calculus.
Video 1. Color Doppler demonstrating a right ureteral jet entering the bladder.

Given reassuring ultrasound findings, a CT abdomen/pelvis with contrast was ordered to evaluate for hepatobiliary and renal pathologies. The CT confirmed a nonobstructive right nephrolithiasis. It also showed a stable hepatic adenoma with postprocedural changes and no evidence of active hemorrhage.

Hospital Course:

Given the reassuring laboratory evaluation and lack of obstructive findings/concerning hepatobiliary findings on imaging, the patient's symptoms were ultimately felt to be musculoskeletal rather than secondary to nephrolithiasis or a recurrent hepatobiliary pathology. She was discharged with conservative management and outpatient follow-up.

Discussion

Ureteral jets are intermittent bursts of urine entering the bladder from the ureterovesical junction during ureteral peristalsis and can be visualized on bladder ultrasound using color doppler. To view them, the bladder should be visualized in the transverse view with focus on the trigone [1]. Color doppler should then show intermittent jets of fluid entering the bladder within 5-10 minutes [1]. Absence of jets after five minutes of observation has an 87-95% sensitivity for complete ureteral obstruction [2]. However, because ureteral jets are intermittent and influenced by hydration status and bladder volume, they should always be interpreted in the context of the clinical presentation and other sonographic findings [3].

In this case, for example, despite the presence of a right renal calculus, this patient had no hydronephrosis and a robust ipsilateral ureteral jet on color doppler, supporting preserved ureteral patency. These findings were subsequently confirmed by CT, which demonstrated nonobstructive right nephrolithiasis.

Although ureteral jet assessment is not routinely incorporated into point-of-care ultrasound protocols for renal colic, it is a rapid, noninvasive addition to the exam that may improve diagnostic confidence when combined with grayscale findings [3]. This case highlights how evaluation of ureteral jets complemented the absence of hydronephrosis and supported the diagnosis of a nonobstructing renal calculus.

References:

  1. Deschamps J, Dinh V, Ahn J, Genobaga S, Lang A, Lee V, Krause R, Tooma D, White S. Bladder ultrasound made easy: Step-by-step guide. POCUS 101. Published 2023. Accessed July 28, 2026. Available from: https://www.pocus101.com/bladder-ultrasound-made-easy-step-by-step-guide/
  2. Gibbons RC, Chiem AT. Renal and genitourinary ultrasound evaluation in emergency and critical care: an overview. Diagnostics (Basel). 2024;14(12):1250.
  3. Wong A, O'Connor M, et al. Bedside assessment of the kidneys and bladder using point-of-care ultrasound. POCUS J. 2023;8(1):22-32.
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Case 42: Nephrolithiasis

Alex Liang, Rachna Subramony

A 48 year old male with past medical history of Crohn’s Disease, cryptogenic cirrhosis, pancytopenia, portal vein thrombosis, Factor V Leiden, and prior history of kidney stones presenting with right sided flank pain, dysuria, and hematuria worsening over the past 4 days. He reports similar symptoms in the past associated with his previous findings of kidney stones. He denies fever, nausea, vomit, diarrhea, chest pain, shortness of breath, or anuria.

Vitals: BP 123/80 mmHg | Pulse: 101 | Temp: 98.5 °F (36.9 °C) | Resp: 20 | Wt: 65.8 kg (145 lb) | SpO2: 97%

On physical examination, the patient is alert and uncomfortable but not in acute distress. Abdominal examination reveals a soft, non-distended abdomen with right flank and right costovertebral angle (CVA) tenderness. The remainder of the physical exam, including cardiac, pulmonary, and neurologic exams, was unremarkable.

A bedside ultrasound was performed on the right kidney.

Figure 1: Several renal calculi in the medullary pyramids of the right kidney. The largest measures approximately 6.8mm in diameter.

Discussion

Nephrolithiasis, commonly referred to as kidney stones, is a prevalent condition with an estimated annual incidence rate of approximately 0.5% to 1% in the general population and a lifetime risk of 10%-15% with higher prevalence among men. Risk factors for nephrolithiasis include dehydration, dietary factors (high sodium or oxalate intake), obesity, metabolic syndrome, and recurrent urinary tract infections1,2.

The differential diagnosis for nephrolithiasis includes conditions that present with acute flank pain, hematuria, and urinary symptoms. Such conditions include pyelonephritis, renal infarction, or ureteropelvic junction obstruction. In this patient, the presentation of acute right flank pain with costovertebral angle tenderness accompanied by dysuria and gross hematuria is strongly indicative of nephrolithiasis.

On physical examination, patients with nephrolithiasis typically present with costovertebral angle tenderness on the affected side with otherwise minimal abdominal findings. The clinician should be attentive of systemic signs such as fever and tachycardia, as they may suggest a concurrent urinary tract infection or obstructive pyelonephritis and require further work up. In this case, the patient presented without fever or systemic signs of infection, supporting a diagnosis of uncomplicated nephrolithiasis.

While non-contrast computed tomography (CT) of the abdomen and pelvis is the gold standard for diagnosing nephrolithiasis, ultrasound remains an asset in the detection of stones with a sensitivity of 54% and specificity of 71%. In some cases, such as in pregnant patients, ultrasound is the preferred modality due to its lack of ionizing radiation. In this case, a renal ultrasound revealed several stones in the medullary pyramids of the right kidney, with the largest measuring 6.8mm in diameter. It is important to note that CT does have higher sensitivity (88%) and lower specificity (58%) compared to ultrasound. Despite this, no evidence has shown that increased CT use is associated with improved patient outcomes when compared to ultrasonography 3.

When performing a point-of-care ultrasound (POCUS) exam for nephrolithiasis, the curvilinear or phased-array transducer should be placed in the flank region along the midaxillary line to obtain longitudinal and transverse views of the kidney. The exam focuses on the identification of hydronephrosis, which appears as anechoic dilation of the renal collecting system, and the detection of renal calculi, which appear as echogenic foci with posterior acoustic shadowing.

Management of nephrolithiasis depends on the size and location. Stones that are less than or equal to 5mm are typically managed conservatively with hydration and analgesia. Medication such as tamsulosin can be given to aid in the expulsion of the stones. Stones that are 10mm or greater, causing significant obstruction, or with concurrent infection or renal impairment often require more invasive measures such as extracorporeal shock wave lithotripsy (ESWL), ureteroscopy with laser lithotripsy, or percutaneous nephrolithotomy 4.

Recurrence of nephrolithiasis is common, with a rate of approximately 50% within 10 years. Patients can decrease this risk with preventative strategies such as dietary modifications (increased fluid uptake, reduced sodium and oxalate consumption) and addressing underlying metabolic abnormalities 4.

References

  1. Pearle MS, Calhoun EA, Curhan GC. Urologic Diseases in America Project: Urolithiasis. J Urol. 2005;173(3):848–857. doi:10.1097/01.ju.0000152082.14384.d7.
  2. Scales CD, Smith AC, Hanley JM, Saigal CS. Prevalence of Kidney Stones in the United States. Eur Urol. 2012;62(1):160–165. doi:10.1016/j.eururo.2012.03.052.
  3. Smith-Bindman R, Aubin C, Bailitz J, et al. Ultrasonography versus Computed Tomography for Suspected Nephrolithiasis. N Engl J Med. 2014;371(12):1100-1110. doi:10.1056/NEJMoa1404446.
  4. Curhan GC. Epidemiology of Stone Disease. Urol Clin North Am. 2007;34(3):287–293. doi:10.1016/j.ucl.2007.05.003.
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