Bladder Ultrasound

Tanping Wong

1. A 68-year-old man with a history of benign prostatic hypertrophy, who underwent transurethral resection of the prostate (TURP) 7 years prior, presents with 6 weeks of dyspepsia, anorexia, and weight loss. He is noted to have a creatinine of 10 mg/dL (normal when checked 2 years prior). Transverse (Figure 65.1A,

Video 65.1A) and sagittal (Figure 65.1B,

Video 65.1B) ultrasound views are obtained at the level of the umbilicus.

Figure 65.1

What is the most appropriate next step in his management?

A. Computed tomography (CT) scan for further evaluation of abdominal mass

B. Emergent surgery/urology consult for bladder rupture

C. Nephrology consult to initiate emergent hemodialysis

D. Place a Foley catheter for obstructive uropathy

View Answer

1. Correct Answer: D. Place a Foley catheter for obstructive uropathy

Rationale: Detection of a distended bladder at the level of the umbilicus is highly suggestive of urinary retention. This patient had bilateral hydronephrosis and a Foley catheter was placed with 1000 mL of urine output. His creatinine eventually decreased to normal in the subsequent week. The etiology of his urinary retention is likely secondary to the recurrence of benign prostatic hypertrophy.

Point-of-care ultrasound is indicated to rapidly evaluate bladder volume with suspected obstruction. Bladder volume can be calculated using the formula (0.75 × width × length × height). CT scan may be indicated for further evaluation if an obstructing mass is suspected (unlikely in this scenario), but emergent bladder decompression is the most appropriate next step. There is no evidence of bladder rupture and free intraperitoneal fluid would not have the “rounded” appearance of the bladder, as seen here. Relief of the obstruction is the first step in the treatment of this patient’s renal failure even if emergent dialysis is indicated.

Selected References

1. Boniface KS, Calabrese KY. Intensive care ultrasound: IV. Abdominal ultrasound in critical care. Ann Am Thorac Soc. 2013;10(6):713-724.

2. Chan H. Noninvasive bladder volume measurement. J Neurosci Nurs. 1993;25:309-312.

3. Kelly CE. Evaluation of voiding dysfunction and measurement of bladder volume. Rev Urol. 2004;6(suppl 1):S32-S37.

2. A 68-year-old man with a history of benign prostatic hypertrophy presents with 4 weeks of abdominal pain, anorexia, weight loss, and decreased urine output. On physical examination, the bladder is palpable at the level of the umbilicus, and point-of-care ultrasound shows a distended bladder with bilateral hydronephrosis. A Foley catheter is placed and 400 mL of urine output is noted. Repeat ultrasound of the bladder is shown in Figure 65.2 and

Video 65.2.

Figure 65.2

What is the most appropriate next step in the management of this patient’s renal failure?

A. Initiate intravenous (IV) hydration.

B. Measure urine sodium and urine creatinine.

C. Reposition or replace the Foley catheter.

D. Perform a CT to evaluate for obstructing malignancy.

View Answer

2. Correct Answer: C. Reposition or replace the Foley catheter

Rationale: An adequately positioned Foley catheter should completely drain the bladder.

Video 65.2 shows a distended bladder with the Foley catheter in place, suggesting that it is likely obstructed. Flushing, replacing, or repositioning the catheter would be the most appropriate action. Placement within the prostatic urethra is another common cause of catheter malfunction, which should prompt repositioning or replacement as well. Relief of the bladder obstruction should be performed prior to any further evaluation or treatment for additional causes of renal failure.

Selected References

1. Boniface KS, Calabrese KY. Intensive care ultrasound: IV. Abdominal ultrasound in critical care. Ann Am Thorac Soc. 2013;10(6):713-724.

2. Subramanian V. The risk of intra-urethral Foley catheter balloon inflation in spinal cord-injured patients: lessons learned from a retrospective case series. Patient Saf Surg. 2016:10(14):14.

3. An 80-year-old man with a history of emphysema was admitted to the medical intensive care unit (ICU) for the treatment of a chronic obstructive pulmonary disease (COPD) exacerbation. On hospital day 6, he was noted to be delirious. His vitals are normal, his neurologic examination is nonfocal, and he has abdominal tenderness. Point-of-care ultrasound is shown in Figure 65.3A (

Video 65.3A) and Figure 65.3B (

Video 65.3).

Figure 65.3

What is the most appropriate next step in the management of this patient’s delirium?

A. Nonpharmacologic management including circadian rhythm reorientation

B. Start broad-spectrum antibiotics

C. Place a Foley catheter

D. Perform an emergent CT scan of his head

View Answer

3. Correct Answer: C. Place a Foley catheter

Rationale: Figure 65.3A, B shows a distended bladder, suggesting that acute urinary retention is the most likely cause of the patient’s delirium. Risk factors for acute urinary retention are older age, history of benign prostatic hyperplasia, neurologic impairment, anticholinergic and sympathomimetic drugs, infection, bed-bound state, and constipation. Although being in the ICU is a risk factor for delirium, this is less likely as the patient has been improving, and specific treatments are limited. Infection is another common cause of delirium, but does not appear to be the most likely cause in this case. CT scan of the head is warranted in delirious patients with focal neurologic deficits, which are not present in this case, but may be considered for further evaluation if relief of the urinary obstruction is not therapeutic.

Video 65.3A and B shows distended enlarged bladder in transverse and sagittal views.

Selected References

1. Chan H. Noninvasive bladder volume measurement. J Neurosci Nurs. 1993;25:309-312.

2. Waardenberg IE. Delirium caused by urinary retention in elderly people: a case report and literature review on the “cystocerebral syndrome”. J Am Geriatr Soc. 2008;56(12):2371-2372. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1532-5415.2008.02035.x.

4. A 68-year-old man with a history of cirrhosis is admitted to the medical ICU with decompensated cirrhosis. He improves over the course of 5 days and his Foley catheter is removed. Six hours later, you are told by his nurse that the patient’s bladder scan volume is 1500 mL. You perform an ultrasound of the bladder (Figure 65.4 and

Video 65.4).

Figure 65.4

What is the most appropriate next course of action?

A. A Foley catheter should be reinserted

B. Perform a CT to evaluate for bladder obstruction

C. Perform a paracentesis to drain the ascites

D. Reassure the nurse, as the bladder volume is estimated to be approximately 300 mL

View Answer

4. Correct Answer: D. Reassure the nurse, as the bladder volume is estimated to be approximately 300 mL

Rationale:

Video 65.4 shows a bladder with estimated volume of 300 mL (volume = 0.75 × width × length × height).

Video 65.4 also shows ascites inferior to the nondistended bladder. The patient should void and have his bladder volume monitored.

Early removal of catheters reduces the risk of catheter-associated urinary tract infection. Accuracy of postvoid bladder volume assessment avoids unnecessary bladder reinsertion, but bladder scans are often inaccurate in patients with obesity, anasarca, and ascites. Point-of-care ultrasound is more accurate in the assessment of bladder volume and can distinguish between bladder volume and ascites. CT imaging is not necessary to evaluate for bladder obstruction. Paracentesis is not indicated for the ultrasound findings in the absence of other concerns.

Selected References

1. Chan H. Noninvasive bladder volume measurement. J Neurosci Nurs. 1993;25:309-312.

2. Park YH, Ku JH, Oh S-J. Accuracy of post-void residual volume measurement using a portable ultrasound bladder scanner with real-time pre-scan imaging. Neurourol Urodyn. 2011;30:335-338. doi:10.1002/nau.20977.

3. Prentice DM, Sona C, Wessman BT, et al. Discrepancies in measuring bladder volumes with bedside ultrasound and bladder scanning in the intensive care unit: a pilot study. J Intensive Care Soc. 2018;19(2):122-126. https://www.ncbi.nlm.nih.gov/pubmed/29796068.

5. An 82-year-old man presents with 3 days of fever and dysuria. On presentation, he has a temperature of 38.5°C, HR 110 bpm, BP 90/60 mm Hg, RR 22/min, and SpO₂ 95% on room air. His physical examination is normal but laboratory evaluation is notable for white blood cells (WBC) 14 × 10⁹/L, creatinine 2.0 mg/dL (baseline 1.0), and hemoglobin 9 g/dL. His urinalysis shows 100 red blood cells (RBC) and 50 WBC/high-power field (HPF). Point-of-care ultrasound is performed and shown in Figure 65.5A (

Video 65.5A) and Figure 65.5B (

Video 65.5B).

Figure 65.5

In addition to antibiotics and admission, what is the most appropriate management of this patient?

A. Send urine for cytology and order CT of the abdomen and pelvis

B. Start treatment for benign prostatic hyperplasia and refer the patient to Urology

C. Start antifungal treatment for a fungal urinary tract infection

D. Place a Foley catheter for acute urinary retention

View Answer

5. Correct Answer: A. Send urine for cytology and order CT of the abdomen and pelvis

Rationale: The ultrasound (Figure 65.5) shows a bladder mass that is highly suggestive of bladder cancer. Patients with bladder cancer present with hematuria, urinary symptoms, and constitutional symptoms. Further workup for carcinoma with urine cytology and CT scan is warranted. Ultrasound plays an important role in the detection of bladder lesions and the early diagnosis of bladder carcinoma. There is no evidence to suggest urinary retention or benign prostatic hyperplasia in this case, and fungal bladder infection is unlikely to cause a mass like this.

Selected References

1. Gharibvand MM. The role of ultrasound in diagnosis and evaluation of bladder tumors. J Fam Med Prim Care. 2017;6(4):840-843. doi:10.4103/jfmpc.jfmpc_186_17.

2. Smereczynski A. Sonography of tumors and tumor-like lesions that mimic carcinoma of the urinary bladder. J Ultrason. 2014;14(56):36-48. doi:10.15557%2FJoU.2014.0004.

6. A 56-year-old man was recently diagnosed with a liver abscess. He was treated with percutaneous drainage and antibiotics. He was discharged home but presents to the Emergency Department (ED) with difficulty urinating, pelvic pain, and fevers. His physical examination is notable only for a temperature of 38.6°C and suprapubic tenderness. Laboratory evaluation shows serum creatinine 0.9 mg/dL, WBC 20 × 10⁹/L, and urinalysis shows three WBC/HPF. A point-of-care ultrasound is shown in Figure 65.6A (