**6.4 Total PSA**

Total PSA should be offered to patients with more than 10 years of life expectancy and in whom the PSA measurement may change the management of the symptoms (AUA 2010). In conjunction with digital rectal examination (DRE), total PSA measurement is the cornerstone of prostatic basic screening. PSA and prostatic volume can be used to evaluate the risks of either needing surgery or developing acute urinary retention.

### **6.5 Uroflowmetry / Peak urinary flow rate**

Uroflowmetry is a simple and noninvasive urodynamic test that allows an objective evaluation of the patient micturition. Even though uroflowmetry is an unspecific evaluation, the micturition graphic may show some recognizable patterns (e.g. meatal stenosis, urethral stricture, BPH) and represent a reproducible way to quantify the strength of the urinary stream. It is a useful preoperative test. Peak urinary flow rate (PFR), or Qmax, appears to predict surgical outcome – patients with a preoperative Qmax > 15 mL/s have poorer outcomes than patients with preoperative Qmax < 15 mL/s do. PFR is an independent predictor for CKD rather than reported LUTS by standardized questionnaires (Hong, Lee et al. 2010). A study conducted by Rule *et* al. in community-dwelling men showed that men with CKD were more likely to have a slow urinary stream (Qmax < 15 mL/s) considering CKD as serum creatinine > 133 μmol/L or as eGFR < 60 mL/min/1,73 m2. (Rule, Jacobson et al. 2005).

Fig. 1. Uroflowmetry. A) Normal patient; B) BPH patient.

Benign Prostate Hyperplasia and Chronic Kidney Disease 363

Manieri *et* al. concluded that bladder wall thickness appeared to be a useful predictor of bladder outlet obstruction, with a value exceeding that of uroflowmetry (Manieri, Carter et al. 1998). However, measurement of bladder wall thickness is currently not part of the recommended diagnostic work-up of patients with LUTS because reliable data on inter- and

Post-void residual urine volume can be measured with sufficient accuracy noninvasively by transabdominal ultrasonography. The measurement variation caused by the method is less than the biologic range of PVR variation (McConnell, Barry et al. 1994). It may also be

It has been well described that large residual urine volumes (>300 mL) affect renal function in advanced BPH (Neal, Styles et al. 1987; Rule, Jacobson et al. 2005). A PVR of more than 100 mL is defined as chronic urinary retention which is significantly associated with CKD in community-dwelling men (Rule, Jacobson et al. 2005). Nevertheless, small residual urine volumes (<100 mL) may also affect renal function as the presence of PVR relates with renal function regardless of the quantity of PVR (Yamasaki, Naganuma et al. 2011). Thus ultrasonographic evaluation of post-void residual is a useful test in the prevention of CKD secondary to BPH. Chronic urinary retention is related with CKD (Rule, Jacobson et al. 2005).

Prostate transrectal ultrasonography (TRUS) is performed to assess prostate size and shape, tissue characterization and occult carcinoma. There is no relationship between prostatic

Fig. 4. Prostate Ultrassound. Prostate transrectal ultrasonography (sagital view).

renal function (Rule, Lieber et al. 2005; Yamasaki, Naganuma et al. 2011).

It is not a routine exam for BPH evaluation. However, cystometry can help to identify high bladder pressure, low bladder compliance and detrusor instability that considerably affects

intra-observer variability, as well as reproducibility, are still lacking.

**6.8 Post-void residual urine evaluation** 

**6.9 Prostate TRUS** 

**6.10 Cystometry** 

measured by invasive methods (catheterization).

enlargement measures and CKD (Rule, Jacobson et al. 2005).

#### **6.6 Renal ultrasonography**

Koch *et* al., performed renal ultrasound scans in a consecutive series of 556 elderly men with LUTS. 14 (2.5%) had hydronephrosis and serum creatinine levels appeared to be correlated with dilatation of the renal pelvis. The authors concluded that renal ultrasound is only indicated in patients with an elevated serum creatinine level and/or post-void residual urine volume (Koch, Ezz el Din et al. 1996). Renal ultrasonography has many advantages over intravenous urography (IVU) for upper urinary tract imaging: simultaneous evaluation of the bladder, post-void residual urine volume and prostate, better characterization of eventual renal masses, no radiation, no side-effects and lower cost.

Fig. 2. Renal Ultrassound. Two ultrasound scans in BPH patient showing bilateral (right and left kidney respectively) ureterohydronephrosis.

#### **6.7 Bladder ultrasonography**

Chronic urinary retention leads to bladder wall thickening with trabeculations via smooth muscle hypertrophy and connective tissue infiltrates (Jones, Gilpin et al. 1991). This can lead in to a decline in bladder compliance with consequent functional or mechanical obstruction at the ureterovesical junction (Sutaria and Staskin 2000). More recently, the measurement of bladder wall thickness by transabdominal ultrasound has gained considerable interest as a noninvasive tool to assess bladder outflow obstruction (Kojima, Inui et al. 1997). Ultrasonic measurement of detrusor wall thickness at the anterior wall of bladders filled with ≥ 250 mL can securely detect bladder outlet obstruction if the value is ≥ 2 mm (Gabuev and Oelke 2011).

Fig. 3. Bladder Ultrassound. Two ultrasound scans in BPH patient. It is possible to observe the trabecullation, bladder wall thickening and diverticulum.

Manieri *et* al. concluded that bladder wall thickness appeared to be a useful predictor of bladder outlet obstruction, with a value exceeding that of uroflowmetry (Manieri, Carter et al. 1998). However, measurement of bladder wall thickness is currently not part of the recommended diagnostic work-up of patients with LUTS because reliable data on inter- and intra-observer variability, as well as reproducibility, are still lacking.
