From the Guidelines
Acute urinary retention is most commonly caused by benign prostatic hyperplasia (BPH), urethral stricture, neurological disorders, medications (especially anticholinergics, decongestants, and opioids), or urinary tract infections. The causes of acute urinary retention can be multifactorial, and it is essential to evaluate patients for underlying conditions that may be contributing to the development of urinary retention.
Common Causes of Acute Urinary Retention
- Benign prostatic hyperplasia (BPH) is a common cause of acute urinary retention in men, as it can increase urethral resistance and overcome bladder contractility, leading to painful bladder distension 1.
- Urethral stricture is another potential cause of acute urinary retention, as it can narrow the urethra and impede urine flow.
- Neurological disorders, such as spinal cord injury or stroke, can also cause acute urinary retention by disrupting the normal functioning of the bladder and urethra 1.
- Certain medications, including anticholinergics, decongestants, and opioids, can increase the risk of acute urinary retention by relaxing the bladder muscle or tightening the urethral sphincter.
- Urinary tract infections can also cause acute urinary retention, particularly in patients with underlying urological conditions.
Evaluation and Management
Patients with acute urinary retention should be evaluated for underlying causes, including BPH, urethral stricture, neurological disorders, medications, or urinary tract infections. Treatment begins with bladder decompression via urethral catheterization, typically using a 14-16 French Foley catheter. If urethral catheterization fails, suprapubic catheterization may be necessary. The catheter should drain no more than 1 liter initially to prevent post-obstructive diuresis and hypotension. For men with BPH, alpha-blockers like tamsulosin (0.4 mg daily) or alfuzosin (10 mg daily) should be started immediately, as they can help relax the urethral sphincter and improve urine flow 1. 5-alpha reductase inhibitors like finasteride (5 mg daily) may be added for long-term management of enlarged prostates. Patients should increase fluid intake after catheterization to prevent infection and blood clots, and follow up with a urologist for definitive management of the underlying cause.
From the FDA Drug Label
In A Long-Term Efficacy and Safety Study, efficacy was also assessed by evaluating treatment failures Treatment failure was prospectively defined as BPH-related urological events or clinical deterioration, lack of improvement and/or the need for alternative therapy. BPH-related urological events were defined as urological surgical intervention and acute urinary retention requiring catheterization.
The causes of acute urinary retention are not directly stated in the provided drug labels. However, it can be inferred that Benign Prostatic Hyperplasia (BPH) is a contributing factor, as the studies discussed in the labels evaluate the efficacy of finasteride in reducing the risk of acute urinary retention in patients with BPH.
- BPH-related urological events are mentioned as a cause of treatment failure, which includes acute urinary retention requiring catheterization 2.
- The MTOPS Trial also discusses the reduction of risk of acute urinary retention in patients treated with finasteride tablets compared to patients treated with placebo 2. However, the exact causes of acute urinary retention are not explicitly stated in the provided text.
From the Research
Causes of Acute Urinary Retention
- Obstructive causes, with benign prostatic hyperplasia (BPH) being the most common cause, accounting for 53% of cases 3
- Infectious, inflammatory, iatrogenic, and neurologic causes can also affect urinary retention 3
- Spontaneous acute urinary retention (AUR) is often caused by the progression of BPH, leading to a mechanical obstruction of the bladder outlet 4
- Precipitated AUR can be caused by various factors, including medications, surgery, and other medical conditions 4
- Neurological causes, such as nerve damage or neurological disorders, can also lead to AUR 4, 3
- Myogenic causes, such as muscle weakness or dysfunction, can also contribute to AUR 4