Bladder emptying

Two types of urinary tract symptoms are commonly seen in MS incomplete bladder emptying and incontinence. Incomplete bladder emptying is due to dyscoordination of the external urethral sphincter and detrusor activity.14 Most patients who develop this condition require intermittent or permanent uri-I nary catheterization.14 Incontinence in most MS patients is... 

Lower abdominal fullness, hesitancy, straining to void, decreased force of stream, interrupted stream, sense of incomplete bladder emptying. May have urinary frequency and urgency, too. Abdominal pain if acute urinary retention is also present. 

Postvoid residual urine volume Amount of urine left in the urinary bladder after the patient has been asked to empty the bladder. Assessed by urethral catheterization or ultrasonography. Normal postvoid residual urine volume should be less than 50 mL. An increased postvoid residual urine volume is consistent with incomplete bladder emptying. 

Diagnosis of BPH requires a careful medical history, physical examination, objective measures of bladder emptying (e.g., peak and average urinary... 

The urethral sphincter, a combination of smooth and striated muscles within and external to the urethra, maintains adequate resistance to the flow of urine from the bladder until voluntary voiding is initiated. Normal bladder emptying occurs with opening of the urethra concomitant with a volitional bladder contraction. 

Mechanism of Action A cholinergic that acts directly at cholinergic receptors in the smooth muscle of the urinary bladder and GI tract. Increases detrusor muscle tone. Therapeutic Effect May initiate micturition and bladder emptying. Improves gastric and intestinal motility. 

The projection from the locus coeruleus to limbic cortex may regulate emotions, as well as energy, fatigue, and psychomotor agitation or psychomotor retardation (Fig. 5—26). A projection to the cerebellum may regulate motor movements, especially tremor (Fig. 5—27). Brainstem norepinephrine in cardiovascular centers controls blood pressure (Fig. 5—28). Norepinephrine from sympathetic neurons leaving the spinal cord to innervate peripheral tissues control heart rate (Fig. 5—29) and bladder emptying (Fig. 5—30). 

FIGURE 5—30. Noradrenergic innervation of the urinary tract via sympathetic neurons leaving the spinal cord regulates bladder emptying via alpha 1 receptors. 

Hussaini SH, Pereira SP, Veysey MJ, Kennedy C, Jenkins P, Murphy GM, Wass JA, Dowling RH. Roles of gall bladder emptying and intestinal transit in the pathogenesis of... 

As BPH progresses, the excess tissue results in prostatic enlargement and causes urethral obstruction. This obstruction is typically associated with characteristic symptoms such as hesitancy in starting urination, diminished urine stream size and force, involuntary interruptions in stream, and a sensation of incomplete bladder emptying (Claridge, 1966). In men with BPH, the mean decrease in maximum urinary flow rate is about 0.2 ml/s/year (Ball et al, 1981). 

The peripheral effects concern the motility and tonus of gastrointestinal smooth muscle segmentation is enhanced but propulsive peristalsis is inhibited. The tonus of sphincter muscles is markedly raised (spastic constipation). The antidiarrhetic effect is used therapeutically (loperamide, p.180). Gastric emptying is delayed (pyloric spasm) and drainage of bile and pancreatic juice is impeded because the sphincter of Oddi contracts. Likewise, bladder function is affected specifically bladder emptying is impaired owing to an increased tone of the vesicular sphincter. 

Isoxazolecarboxamide derivatives, (ni), effective as a1L-adrenoreceptor agonists were prepared by Leonardi (3) and were effective in treating incontinence as well as voiding problems such as weak stream and incomplete bladder emptying. 

The ANS is also affected and postural hypotension may occur since sympathetic control of blood vessels is lost. Other areas affected by neuropathy include the gut, urinary bladder and sexual function, leading to diarrhoea, incomplete bladder emptying and impotence respectively. 

Stimulation of bicarbonate secretion, gall-bladder emptying and inhibition of gut motility... 

Objective measures of bladder emptying (e.g., uroflowmeter and postvoid residual urine volumes) are also useM after 6 to 12 months of 5a-reductase inhibitor therapy or 3 to 4 weeks of a-adrenergic antagonist therapy. Laboratory tests (e.g., blood urea nitrogen, creatinine, PSA) and urinalysis should be monitored regularly. In addition, patients should have an annual digital rectal examination. 

The use of a adrenoceptor blockers (e.g. phenoxy-benzamine 0.7mg/kg orally four times a day, ace-promazine 0.02-0.04 mg/kg i.m. or orally four times a day) in combination with bethanechol decreases urethral sphincter tone in horses with bladder paresis (Schott 1998). In theory, partial relaxation of the urethral sphincter could improve bladder emptying at lower intravesicular... 

Acts directly at cholinergic receptor of smooth muscle of urinary bladder and GI tract. Increases tone of detrusor muscle, may initiate micturation (urination), bladder emptying. Stimulates gastric intestinal motility. 

A variety of exogenous (radioisotopic and nonradioisotopic) and endogenous markers have been used to estimate clearance (Table 24-2). Measurement of clearance may require accurate measurements of both plasma and urinary concentrations of the marker used plus a reliable urine collection. For a reliable plasma measurement, the substance must have reached a steady-state concentration and not be rapidly changing. For a reliable urine collection, the urine flow must be adequate (several mL/min), the collection period of long enough duration, and complete bladder emptying achieved these requirements are problematic. 

Obstructive symptoms, also known as prostatism or bladder outlet obstruction, result when dynamic and/or static factors reduce bladder emptying. The force of the urinary stream becomes diminished, urinary flow rate decreases, and bladder emptying is incomplete or takes a longer time. Patients report urinary hesitancy and straining and a weak urine stream. Urine dribbles out of their penis, and their bladder always feels full, even after they have voided. Some patients state that they need to press on their bladder to force urine out. In severe cases, patients may go into urinary retention when bladder... 

Objective measures of bladder emptying include peak and average urinary flow rate (normal is at least 10 to 15 mL/s). This is determined using a uroflowmeter, which literally checks the rate of urine flow out of the bladder. This is a quick noninvasive outpatient procedure in which the patient s urinary flow is clocked during voiding. A low urinary flow rate implies failure of bladder emptying, but the degree of bladder outlet obstruction correlates poorly with peak urinary flow rate. 

In patients being treated with pharmacotherapy, objective measures of bladder emptying are also useful at an appropriate time after drug therapy begins (6 to 12 months for 5a-reductase inhibitors, 3 to 4 weeks after the start of i-adrenergic antagonists). These include the uroflowmeter and PVR urine volume, as described in the section on diagnostic evaluation section in this chapter. 

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