UAB may exist without any of the symptoms described above. In this instance, the patient may have lost the sensory perception of bladder distention. Therefore, the health-care providers should be alert for signs that may suggest UAB such as a huge suprapubic mass that turns out to be a distended bladder. The chronically distended bladder with or without bilateral hydronephrosis may be discovered during a routine physical examination being performed for another unrelated complaint or as an incidental finding in abdominal ultrasound, CT scan of the abdomen, or MRI. In all these cases, UAB needs to be included in the differential diagnosis.

Once a patient is suspected of having underactive bladder, it will be up to the health-care provider to confirm that symptoms and/or signs that the patient is manifesting are due to an underactive bladder. The evaluation for confirming the UAB must be thorough and in a phased approach in order to arrive at an accurate diagnosis.

The history must detail the voiding symptoms and document the presence of hesitancy, weak stream, urine flow intermittency, post-void dribbling, straining to void, and feeling of incomplete voiding. For those who present with acute urinary retention, attempts should be made to obtain potential precipitating factors that led to urinary retention. In elderly men, one may suspect a long-standing obstructive uropathy on the basis of benign prostatic hypertrophy (BPH) or urethral stricture. Was it an associated surgery that led to postoperative retention? Was it the use of pharmacologic agents that can induce urinary retention such as the use of an alpha agonist to reduce upper respiratory tract congestion or the use of anticholinergic agents or sedatives that can inhibit bladder contractility? Is patient on chronic antidepressant medications that can cause depression of the detrusor function?

For those who present with an indwelling catheter or already on intermittent catheterization to drain the urinary bladder or just having significant voiding symptoms with high post-void residual urine, it is imperative that attempt should be made to determine any predisposing factors such as neurologic disorders including spinal cord injury, cerebrovascular accidents, Parkinson’s disease, multiple sclerosis, spina bifida, and diabetic neuropathy (Miyazato et al. 2013).

There are also other non-neurologic conditions that can lead to UAB that one needs to explore. This includes habit and behavior towards fluid intake and toileting frequencies. A combination of excessive fluid intake of over the required daily requirements associated with infrequent voiding has been postulated to lead to chronic overdistention and detrusor underactivity. The infrequent voiding syndrome that is also referred to as the “lazy bladder” had been associated with the busy housewives, teachers, nurses, and people who are afraid to use public rest rooms (Purohit et al. 2008). Delay in voiding when the bladder is already full leads to overdistention of the bladder that could lead to detrusor muscle overstretching, and this overstretched detrusor could potentially lead to underactivity (Finkbeiner and Lapides 1974). This is the rationale for catheterizing women in prolonged labor so as not to encounter prolonged overdistention of the urinary bladder.

Another important history that should be obtained is previous surgical intervention related to the lower urinary tract. For women, history of radical hysterectomy could lead to detrusor underactivity due to disturbance of the motor nerves to the bladder (Seski and Diokno 1977). On the other hand, the various anti-incontinence surgeries for stress urinary incontinence could lead to increased urethral resistance that may produce obstructive phenomena to the outlet that may cause obstruction (Lemack 2006). If unattended, over time, the detrusor could fail and lead to urinary retention.

In men, because of high incidence of obstruction secondary to benign prostatic enlargement, transurethral resection of the prostate is a very common procedure performed in these men with significant voiding symptoms especially those with high post-void residual urine. Unfortunately, there are a few men where the urinary retention is not going to respond successfully to the TURP procedure because the basic pathology is underactive bladder, either as a primary condition or secondary to chronic obstructive uropathy (Ignjatovic 2001). Lastly, the use of drugs that can lead to detrusor weakness should be uncovered. Foremost, among these medications are the antidepressants, anticholinergic, alpha agonists, and narcotics.

A focused physical examination is essential in a comprehensive evaluation of a patient suspected of having an UAB. This should include an overall general assessment of the physical and cognitive ability as this could impact the ability to control bladder function. Is the patient ambulatory or mobility impaired, and if so, is the patient needing support to ambulate? This is important because voiding may be inhibited by poor ambulation or lack of help to be able to micturate at appropriate places. Likewise, assessing the level of cognition is important to determine the ability of the person to pick up the queue to void on time and in appropriate place.

Physical examination should include assessment of neurologic signs that may point to the various neurologic conditions including Parkinson’s disease, cerebrovascular accident, multiple sclerosis, spinal cord lesions, and spina bifida. Abdominal examination should include inspection and palpation of the suprapubic area to identify any signs of distended bladder especially for patients having frequent voiding with or without constant urinary dribbling that may suggest urine overflow. The lumbar area should also be palpated for any evidence of any masses or tenderness that may indicate hydronephrosis.

Genital and perineal examination is mandatory for suspected cases of UAB. The skin of the genitalia and the perineum may indicate significant irritation manifested by erythema or even excoriation and ulceration from chronic urinary leakage and wearing of undergarments/diapers. For men, the penis and scrotum and its content should be evaluated. Digital rectal examination should elicit the anal sphincter tone and the voluntary ability to contract the sphincter. The prostate is palpated to assess the size and evidence of any tenderness or masses or nodules. One should remember that the size of the prostate on digital rectal examination does not necessarily correlate to the voiding symptoms. A small size prostate may present with a more intense lower urinary tract symptoms than one with a large prostate palpated on digital examination.

For women, a vaginal inspection, speculum examination, and bimanual examination need to be performed. Inspection should identify the health of the vaginal mucosa to identify signs of atrophy and signs of skin irritation suggestive of atrophic vaginitis. Pelvic organ prolapse is identified visually for any organ protruding outside of the vaginal introitus and provoked by asking the patient to strain and cough to determine the extent of the prolapse. One should also look for evidence of urine leakage during coughing and straining. The lack of leakage does not eliminate urinary incontinence; however, the presence of urine leakage during straining or coughing is a positive sign for stress urinary incontinence. The vaginal speculum is used to inspect the cervix and the vaginal mucosa and to assess the level of the individual pelvic organ prolapse if one is present. The prolapsing organ should be identified such as cystocele (anterior), rectocele (posterior), uterus, or intestine/enterocele (central/vaginal vault). The severity of prolapse should be established using the pelvic organ quantification (POPQ) method (Diokno and Borodulin 2005). This is important because in severe vaginal prolapse, chronic obstruction from the prolapsing pelvic organ could lead to chronic urinary retention. Digital examination of the anal canal should also be performed to assess the anal tone and voluntary strength as well as assess the status of the rectovaginal wall.

In both men and women, the perineal sensation should be tested for sensory deficiency by testing the ability to perceive a gentle pinprick applied to the saddle and the perianal area. Without performing this maneuver, one may miss saddle perineal anesthesia that may be the only neurologic sign that may suggest sacral cord lesions that may be contributing to an underactive bladder.

Urinalysis should look for signs of pyuria and bacteriuria, and if infection is suspected, urine culture and sensitivity should be ordered. Urinalysis should also seek to check the presence of glucose as this may correlate to diabetes and its potential consequence, diabetic neuropathy, and for albumin for possible kidney disease. Specific gravity should also be tested to provide a hint of the ability of the kidney to concentrate the urine. Nephrogenic diabetes insipidus causing excessive diuresis can lead to chronic bladder overdistention and underactive bladder (Lemack 2006). Blood tests that may contribute to the overall assessment of UAB include the renal panel (BUN, creatinine, GFR rate), serum protein, electrolytes, and glucose/Hgb A1c levels.