Urinary retention: causes, complications and management

Internal Medicine · Urology

Urinary retention is characterised by an inability to empty the bladder completely or voluntarily, resulting in the accumulation of urine. It may present as an acute condition, with sudden and often painful inability to pass urine, or as chronic retention, in which incomplete bladder emptying develops gradually and may remain relatively asymptomatic. Although urinary retention is more frequently associated with older men because of benign prostatic enlargement, it can affect individuals of all ages and sexes. Early recognition is important because untreated retention may lead to recurrent urinary tract infections (UTIs), bladder dysfunction and upper urinary tract damage.Causes and clinical presentationUrinary retention may arise from bladder outlet obstruction, impaired detrusor muscle contraction, or a combination of both. The underlying causes may be anatomical, neurological, pharmacological or functional.Obstructive causes: Benign prostatic hyperplasia (BPH) is a leading cause in older men. Prostate cancer, urethral strictures, bladder or urethral stones, blood clots, pelvic organ prolapse and pelvic masses may also obstruct urine flowNeurological causes: Spinal cord injury, multiple sclerosis, Parkinson’s disease, stroke, diabetic neuropathy and cauda equina syndrome may interfere with the neural pathways responsible for bladder sensation and contractionInfectious and inflammatory causes: Urinary tract infections, acute prostatitis, urethritis and severe genital inflammation may precipitate retention through swelling, pain or reflex inhibition of bladder emptyingMedication-related causes: Anticholinergic drugs, antihistamines, decongestants, opioids, tricyclic antidepressants and some anaesthetic agents may impair detrusor contraction or increase outlet resistanceOther causes: Postoperative retention, pelvic or spinal anaesthesia, severe constipation and reduced mobility may contribute, particularly among older adultsAcute retention is typically characterised by sudden inability to void, suprapubic pain, bladder distension and restlessness. In chronic retention, symptoms may include hesitancy, weak urinary stream, straining, incomplete emptying, frequent urination and nocturia. In some cases, painless retention may be detected incidentally or may present as overflow incontinence, in which small amounts of urine leak from an overdistended bladder.Complications of urinary retentionPersistent urine accumulation may increase intravesical pressure and impair bladder function. Recurrent UTIs, bladder calculi, haematuria and overflow incontinence may develop. Chronic overdistension may result in detrusor muscle decompensation, reducing the ability of the bladder to contract effectively even after the obstruction has been relievedIn severe or prolonged cases, elevated bladder pressure may be transmitted to the upper urinary tract, causing hydroureter, hydronephrosis and renal impairment. Recurrent infections may progress to urosepsis, particularly in vulnerable individuals. Chronic retention accompanied by hydronephrosis, stage 3 chronic kidney disease, recurrent culture-proven UTIs or urosepsis is considered high-risk and warrants prompt assessment and interventionDiagnosis and evaluationA detailed clinical history should be obtained, including the onset and duration of symptoms, previous episodes, urinary stream characteristics, bowel habits, neurological symptoms, recent surgery and medication use. A focused examination should include abdominal palpation for bladder distension, genital and pelvic assessment when indicated, digital rectal examination in men with suspected prostatic disease, and a neurological examination where relevantPost-void residual (PVR) urine volume should be measured using bladder ultrasonography or catheterisation. A PVR greater than 300 mL, documented on at least two occasions over six months, is used in the American Urological Association consensus definition of non-neurogenic chronic urinary retention; however, clinical decisions should not rely on this threshold aloneUrinalysis and urine culture may be performed to identify infection or haematuria. Serum creatinine and estimated glomerular filtration rate should be assessed when renal impairment is suspected. Renal and bladder ultrasonography may be indicated in chronic retention, particularly when a large residual volume, palpable bladder or upper urinary tract involvement is suspected. Uroflowmetry, cystoscopy and urodynamic studies may be considered when the diagnosis remains uncertain or when neurological dysfunction, urethral obstruction or impaired detrusor contractility is suspectedManagement strategiesManagement is guided by the severity and duration of retention, underlying cause, bladder function and risk of complications.Immediate bladder decompression: Acute urinary retention is a urological emergency and should be managed with prompt bladder drainageUrethral catheterisation is generally performed to relieve discomfort, reduce bladder distension and prevent further complicationsIf urethral catheterisation is unsuccessful or contraindicated, suprapubic catheterisation may be considered. Complete and prompt bladder decompression is generally preferred, with monitoring for haematuria, hypotension and post-obstructive diuresis, particularly after drainage of large volumesPharmacological treatment: In men with acute retention associated with BPH, an alpha-1 adrenergic blocker, such as Tamsulosin or Alfuzosin, may be initiated before catheter removal to improve the likelihood of successful spontaneous voidingA trial without catheter is subsequently performed when clinically appropriate. Persistent or recurrent retention may require further evaluation and definitive treatmentTreatment of the underlying cause: Reversible precipitating factors should be addressed. Suspected infections should be treated with appropriate antimicrobial therapy, while constipation should be managed and potentially contributory medications reviewed or discontinued when clinically appropriate. BPH-related obstruction may require medical or surgical treatmentDepending on the underlying pathology, procedures such as transurethral resection of the prostate, laser-based prostate surgery or urethral stricture treatment may be consideredLong-term bladder management: For chronic retention, clean intermittent catheterisation is generally preferred when patients or caregivers can perform it safelyIndwelling urethral or suprapubic catheterisation may be required when intermittent catheterisation is unsuitable or adequate bladder emptying cannot otherwise be achievedPatients with low-risk, asymptomatic chronic retention may be monitored through periodic assessment of symptoms, PVR volume and renal function. Those with hydronephrosis or impaired renal function require active intervention and follow-upConclusionUrinary retention may result from obstructive, neurological, infectious or medication-related causes and can progress from a reversible voiding disturbance to significant bladder and renal complications. Prompt recognition, bladder decompression in acute presentations and systematic evaluation of the underlying cause are essential. Individualised treatment, appropriate catheterisation strategies and regular monitoring can help preserve bladder function, prevent recurrent episodes and reduce the risk of long-term complications.[1]Reference(s):1. Serlin DC, Heidelbaugh JJ, Stoffel JT. Urinary Retention in Adults: Evaluation and Initial Management. Am Fam Physician. 2018;98(8):496-503. https://www.aafp.org/afp/2018/1015/p496