What are the next steps for a patient with a post-void residual (PVR) volume of 111 ml and no enlarged prostate?

From the Guidelines

For a patient with a post-void residual (PVR) volume of 111 ml and no enlarged prostate, the next steps should include continued monitoring and further evaluation of potential causes, as recommended by the most recent guideline 1. This PVR value falls in a borderline range - while not severely elevated (typically concerning when >200 ml), it is higher than the normal range of less than 50 ml. The patient should be scheduled for a follow-up urinalysis and PVR measurement in 4-6 weeks to determine if this is a persistent finding, as suggested by the principle of monitoring for changes in bladder emptying ability 1. In the meantime, the patient should be advised to practice double voiding (urinating, waiting a few minutes, then attempting to urinate again) and timed voiding every 3-4 hours while awake. A bladder diary recording fluid intake, voiding times and volumes for 3 days would provide valuable information, helping to identify patterns or issues related to bladder function. If symptoms like hesitancy, weak stream, or incomplete emptying are present, a urodynamic study might be warranted to assess bladder function, considering the potential for detrusor underactivity, neurological conditions affecting bladder function, or bladder outlet obstruction from other causes. Medications that may affect bladder function (such as anticholinergics, alpha-agonists, or certain antidepressants) should be reviewed and potentially adjusted, taking into account the patient's overall health and medication regimen. No specific medication is indicated at this time based solely on this PVR finding without accompanying symptoms or a clear diagnosis, emphasizing the need for a comprehensive evaluation before initiating treatment. Key considerations in managing this patient include:

• Monitoring PVR to assess for persistent elevation or changes in bladder emptying ability 1
• Evaluating for symptoms of lower urinary tract dysfunction
• Reviewing medications for potential impact on bladder function
• Considering further diagnostic testing, such as urodynamic studies, if symptoms or PVR findings suggest underlying bladder dysfunction.

From the FDA Drug Label

CLINICAL PHARMACOLOGY Bethanechol chloride acts principally by producing the effects of stimulation of the parasympathetic nervous system. It increases the tone of the detrusor urinae muscle, usually producing a contraction sufficiently strong to initiate micturition and empty the bladder. The patient has a post-void residual (PVR) volume of 111 ml, which indicates that the bladder is not being fully emptied.

• Next steps for this patient may include:
  • Medication with bethanechol chloride to increase the tone of the detrusor urinae muscle and initiate micturition.
  • Monitoring of the patient's PVR volume to assess the effectiveness of treatment.
  • Further evaluation to determine the underlying cause of the patient's urinary retention, if not already done. 2

From the Research

Post-Void Residual Volume of 111 ml and No Enlarged Prostate

• A post-void residual (PVR) volume of 111 ml is considered elevated, but it does not meet the criteria for nonneurogenic chronic urinary retention, which is defined as a PVR of greater than 300 mL that persists for at least 6 months and is documented on 2 or more separate occasions 3.
• The patient's condition may be related to detrusor underactivity (DU), a poorly understood dysfunction of the lower urinary tract that can arise from multiple etiologies, including neurogenic and non-neurogenic causes 4.
• The absence of an enlarged prostate suggests that the patient's condition may not be related to benign prostatic hyperplasia (BPH), but other factors such as detrusor overactivity or bladder outlet obstruction (BOO) may still be contributing to the elevated PVR.

Next Steps

• Further evaluation, including a pressure-flow urodynamic study, may be necessary to differentiate between detrusor underactivity and other conditions such as overactive bladder (OAB) or BOO 4.
• The patient's symptoms and medical history should be carefully assessed to determine the underlying cause of the elevated PVR and to guide treatment decisions.
• Treatment options may include behavioral modifications, pharmacotherapy, or intermittent catheterization, depending on the underlying cause of the patient's condition and the presence of any associated symptoms or complications 3, 5.

Predicting Acute Urinary Retention

• A study found that prostate volume and prostate-specific antigen (PSA) levels were significant predictors of acute urinary retention (AUR) in men with elevated PVRs 6.
• However, in this case, the patient does not have an enlarged prostate, so these factors may not be relevant.
• Other factors, such as the patient's age, medical history, and presence of any underlying neurological or muscular conditions, may need to be considered when assessing the risk of AUR.