1.2 Gravitational-wave Data Analysis
1.2.1 Response to Interferometer
48 the baseline results.
In up to 75% of these patients this author was personally involved in obtaining the information and in the management of the patients. In the remaining, it was done by either casualty officers or urology residents whom the author had trained on the data collection.
Some patients had obtained definitive treatment of the cause of the UR as at the time of analysis of this data while others were still awaiting treatment. This information was also entered in the questionnaire.
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CHAPTER FIVE 5.0 RESULTS
One hundred and eighteen (118) adult male patients were seen and treated for UR during the study period; however, eight (8) patients were lost to follow up during subsequent review. The analysis presented here is for the one hundred and ten (110) patients seen till the end of the study. The patients seen in this study were adults male of the ages ranged from 17 to 100 years with a mean age of 56 ±19.3SD years. The age distribution is shown in Figure 1 below:
Figure 3- Age Distribution among the 110 Patients with Urinary Retention
Urinary retention was commonest in the age range 60 - 79 years accounting for almost half of the patients in the study (27.3% +21.8% = 49.1%). Patients within the ages of 20 - 29 years accounted for 12.7%. The much older age group (≥ 90 years) and the younger (≤ 20 years) had the lowest rate of developing UR.
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Following the initial management of the patients, causes of UR found are shown in the table below:
TABLE 1: Causes of Urinary Retention in the 110 Patients
Cause No of patients Percent
BPH
Urethral stricture
57 22
51.8 20.0 Cancer of the prostate
Urethral injury
8 8
7.3 7.3 Bladder Tumour
BPH and Urethral stricture
7 4
6.4 3.6
Bladder/Urethral Stone 2 1.8
Bladder neck stenosis 1 0.9
Cancer of the prostate and urethral stricture 1 0.9
Total 110 100.0
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The patients were then grouped based on the cause of UR, the mean age and standard deviation of each group was calculated and shown in Table 2:
TABLE 2 – Age Distribution of 110 Patients Based On Causes of Urinary Retention
Causes of UR Age range (years) Mean age (years) Standard Deviation(SD) BPH
Urethral stricture Cancer of the prostate Urethral trauma Bladder tumour
51 – 100 18 – 56 54 – 96 17 – 30 32 - 65
66.5 40.9 68.5 24.6 50.9
10.8 13.2 6.5 5.0 13.5
There were only two patients with UR from bladder/urethral stone and they were 32 and 38 years.
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From this study, majority of the patients (53.4%) were found to have AUR, 30.5% had CUR while 16.1% developed acute-on-chronic UR as shown below:
Figure 4- Types of Urinary Retention in 110 Patients
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The causes in each of the type of UR were also analysed and presented as follows:
TABLE 3: Causes / Types of Urinary Retention in the 110 Patients
Types of UR
Causes of UR Acute UR
No (%)
Chronic UR No (%)
Acute-on-chronic UR No (%)
Total No (%) BPH
Urethral stricture Urethral injury Cancer of the prostate Bladder tumour
BPH and urethral stricture Bladder/urethral stone Cancer of the prostate and urethral stricture
Bladder neck stenosis Total
31 (52.5) 11 (18.6) 8 (13.6) 3 (5.1) 4 (6.8) - 2 (3.4) - -
59 (100)
18 (53) 7 (20.6) -
3 (8.8) 3 (8.8) 2 (5.9) - 1 (2.9) -
34 (100)
8 (47.0) 4 (23.5) -
2 (11.8) -
2 (11.8) -
- 1 (5.9) 17 (100)
57(51.8) 22(20.0) 8 (7.3) 8 (7.3) 7 (6.4) 4 (3.6) 2 (1.8) 1 (0.9) 1 (0.9) 110(100)
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Similarly, patients were evaluated at presentation for complications associated with the UR.
The following complications were found (Table 4):
TABLE 4: Complications of Urinary Retention in 110 Patients
Complications
No of patients Percent None
Urinary tract infection
66 19
60.0 17.3 Renal Impairment
Anaemia
Renal impairment and UTI
7 6 5
6.4 5.5 4.5
Anaemia And Renal Impairment 4 3.6
Anaemia And UTI 3 2.7
Total 110 100.0
Of the 27 (24.5%) patients who had documented UTI at presentation, E.coli was cultured in 17 (63%) patients, Klebsiella specie in 6 (22.2%) patients, and Pseudomonas aeroginosa in the remaining 4 (14.8%) patients. The patients found to have anaemia (11.8%) had haemoglobin that ranged from 6g/dl to 8g/dl with a mean of 7.2 ±1 SD g/dl. In the patients with renal impairment (14.5%) various degree of derangement in U/E/Cr was recorded. However, 4 of the patients had haemodialysis based on biochemical indication.
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Table 5 shows the deranged U/E/Cr in the 4 patients who had the haemodialysis. The other 12 patients who had not met clinical or biochemical indication for haemodialysis were managed on continuous bladder drainage with a catheter and other modalities for management of renal impairment.
TABLE 5: Biochemical Parameters of the 4 Patients who had Haemodialysis
Biochemical parameters
Serum urea mmol/ L
Serum sodium mmol/L
Serum potassium mmol/L
Serum bicarbonate mmol/L
Serum chloride mmol/L
Serum creatinine mmol/ L Patient 1
Patient 2 Patient 3 Patient 4 Normal range
33 30 28 29 2.1-6.9
130 140 143 140 130-143
3.3 5 4.8 5 3.0-5.6
10 15 22 15 20-28
95 99 107 104 94-108
950 1002 670 720 30-111
All the complications discussed above were seen in the patients with CUR and acute-on-chronic UR.
In 61.0% of the patients, the retention was successfully relieved by urethral catheterization, while in the remaining 39.0% the retention was relieved by SPC.
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Following catheterization, the quantity of urine drained was measured and recorded. The patients were grouped based on the quantity of urine drained, into those with less than 1000mls and those with 1000mls or more. Also the mean urine volume drained was calculated in the patients with the three different types of the UR.
TABLE 6: Volume of Urine Drained Following Catheterization in the 110 patients
Volume No of patients Percent
< 1000mls 80 72.7
≥1000mls 30 27.3
Total 110 100.0
The mean volumes of urine drained in the patients with AUR, CUR and acute-on-chronic UR were 753.7 ±164.8 SD mls, 1259± 214.8 SD mls and 1937.2 ±276 SD mls respectively.
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Majority of the patients were catheterized with no complication. However, some patients had complications as shown in Table 7 below:
TABLE 7: Complications of Relieving Urinary Retention with Catheterization (n=110)
Complications No of patients Percent
None UTI
82 19
74.5 17.3 Haematuria
Urethral injury
6 3
5.5 2.7
Post obstructive diuresis 0 0
Total 110 100.0
The most common complication following catheterization noted in this study was UTI which was seen in 19 patients (17.3%) followed by haematuria in 6 patients (5.5%) and urethral injury in 3 patients (2.7%). None had post obstructive diuresis. The most common bacteria cultured in the patients who developed UTI after catheterization was E. coli in 12 (63.1%) patients, Klebsiella specie in 4 (21.1%) patients while in the remaining 3 (15.8%) patients both Klebsiella specie and Pseudomonas aeroginosa were cultured.
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Out of the fifty seven (57) patients diagnosed with BPH, forty-two (42) had TWOC. Four (4) patients had SPC following failed urethral catheterization and hence were not enrolled for TWOC while out of the remaining eleven (11) patients, 6 had surgery on the ground of significantly deranged renal function and 5 patients based on their choice. The following result was obtained:
Table 8: Outcome of TWOC in 42 patients with Urinary Retention from BPH
Outcome of TWOC No of patients Percent
Successful TWOC (IPSS 0-8) Persisting LUTS (IPSS >8)
Failed TWOC ( Recurrence of AUR) Total
30 9 3 42
71.4 21.4 7.2 100
Both the 11 patients who opted for surgery from the beginning and the 4 patients who had SPC following failed urethral catheterization had prostatectomy as they could not pass urine without the catheter.
Of the patients who were started on TWOC, whose had persisting LUTS (IPSS >8) or went back into retention following removing catheter (failed TWOC) were also counselled for prostatectomy for which some had the surgery as at the time of this analysis while others were awaiting.
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CHAPTER SIX 6.0 DISCUSSION
Urinary retention is one of the common urologic emergencies in our environment. It is commonly caused by BPH, urethral strictures, prostatic cancer, urethral trauma, bladder tumour and stones 1. Only few studies have been done in our environment to assess the causes, and outcome of the treatment of this condition.
Urinary retention was found in this study to be commoner among middle aged and the elderly.
Those in the age group 60-79 years constitute the largest group (27.3% +21.8%= 49.1%). The patients within the age group of 20-29 years accounted for 12.7%. The much older age group (≥ 90 years) and the younger (≤ 20 years) had the lowest rate of developing UR of 2.7% each.
The largest age group in this study was similar with the findings by John MF, et al. in
“Management of Acute Urinary Retention: a Worldwide Survey of 6074 Men with Benign Prostatic Hyperplasia” 3. In their study 39.3% of the patients who presented with AUR were between the ages of 65- 74years. Others were 33.3% those above the age of 75years and 27.4%
were less than 65years. The difference in the second most prevalent age group could be because this study was on all causes of UR. The causes have different peak age of presentation as against the one quoted which was on AUR in patients with BPH only. Urethral stricture and bladder tumour were shown to occur at younger age when compared to BPH and cancer of the prostate (Table 2); hence, it may explain the younger age seen in the second most prevalent age group of the patients in this study. The high prevalence of UR in patients above the age of 60 years is expected as UR is generally known as a disease of the middle aged and the elderly because a significant percentage of the causes of UR such as BPH and cancer of the prostate are commoner in the said age group.
Some of the causes of UR particularly, urethral trauma and urinary stones were seen in younger patients as shown in chapter 5. This is also expected as younger men were more
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commonly involved in RTA which is now the most common cause of urethral trauma 56. Similarly, urinary stones were shown in other studies in Nigeria to be commoner among the younger age groups (<40 years) 75.
The mean age of patients who presented with UR from BPH in this study (66.5 ± 10.8 SD years) was similar to the finding in a previous study on benign prostatic hyperplasia and prostate carcinoma in native Africans done at Zaria, Nigeria, which found a mean age of 66.1 years among 545 patients with BPH 47. Studies from other parts of the world also show similar findings as reported in “Management of Acute Urinary Retention: a Worldwide Survey of 6074 men with Benign Prostatic Hyperplasia” 3. In their study mean age of 65 years, 68 years and 70 years respectively were reported for patients from Middle East, Latin America and Asia respectively. However, the mean age of the patients from France was 72 years. The patients who presented with UR from urethral stricture were younger than those with BPH, the mean age being 40.9 ± 13.2 SD years. This is similar to findings in other studies such as the one by Ahmed A, et al. in Zaria, Nigeria who found the mean age of 40 ± 12.9SD years among 556 male patients with urethral stricture 48. Similarly, Ahmed GI, et al. in their study on ‘‘One-Stage Urethroplasty for Strictures in Maiduguri, North-Eastern Nigeria’’ found a mean age of 45.6 ±19.7 SD years among 91 patients studied 49. The finding was consistent with the known age of presentation of both BPH and urethral stricture 1. The mean age of patients with UR from prostate cancer was higher than that of BPH; this is also expected as cancer of the prostate has been known to be disease of the older aged patients 1.
From this study the mean age of patients with UR from Bladder Tumour was 50.9%; this was also similar to the findings of Ochicha O, et al. in a previous study on bladder cancer in Kano 53 in which they found a mean age of 48.8 years. However, it significantly differs from findings in other parts of the world which put the peak incidence of bladder cancer at the seventh decade in England and Wales 76. This is probably because most bladder cancers in
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Kano were predisposed by previous schistosomiasis 53 which has been shown to present earlier than the one arising from other risk factors.
The most common cause of UR from this study was BPH in 51.8% of the patients. This was followed by urethral stricture in 20%, cancer of the prostate and urethral trauma which were each responsible for UR in 7.3% of the cases, and bladder tumour which accounted for 6.4%
and bladder /urethral stone for 1.8%. Some patients were found to have more than one cause;
3.6% of the patients had both BPH and urethral stricture. These were similar to findings in other studies done across the West African sub region such as the one conducted by Edwin MTY, et al. 31 at Komfo Anokye Teaching Hospital, Kumasi, Ghana who found the causes of UR among 198 men to be BPH (58.1%), urethral stricture (14.7%), cancer of the prostate (13.1%), urethral injury (13.1%), and bladder calculi (0.5%).
Yeboah, et al. at Korle Bu Teaching Hospital, Accra, Ghana also conducted a study on causes of UR from 1982 to 1989 on 1124 patients 1. They found BPH to be the most common cause (46.7%), followed by urethral stricture (31.4%). Others were prostatic cancer 13.8%, urethral rupture 3.6%, and bladder tumour 0.5%, while both BPH and urethral stricture were found in 1.2% of cases. The differences in the percentages of patients may be explained by the differences in the sample size and the duration of the study. However, the percentage of the patients with bladder tumour is much higher in this study. This could be explained by the high prevalence of bladder tumours in our environment as shown by Ochicha O, et al. in an earlier study 53.
Bassey Tom Etuknwa in his study on the management of urinary retention in rural areas at Uyo, Akwa Ibom State, Nigeria found BPH to account for up to 92% of causes of UR, cancer of the prostate in 6%, and urethral stricture in 4% 32. The high percentage of BPH and low percentage for urethral stricture may be due to the fact that, in addition to patients who presented in retention, he recruited others who were relieved of the retention elsewhere and
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presented with urethral catheter in-situ. The patients who presented with urethral catheter-in-situ were more likely to have BPH as cause of their UR, hence the high percentage of the BPH.
The causes in different types of UR were also similar to the findings in general causes. In AUR, CUR and acute-on-chronic UR, BPH was the leading cause followed by urethral stricture.
Most patients who presented with UR were found to have AUR (53.4%). Others were found to have CUR (30.5%) and acute-on-chronic UR (16.1%). Though there is paucity of reports comparing the incidence of the different types of UR, many studies have shown that AUR is the most common urologic emergency 6 , 7, 8. The finding in this study differs from the one found by Van Vuuren SPJ et al. in their study on comparison of men with acute versus chronic urinary retention: aetiology, clinical features and complication 77. They found up to 90.7% of the 558 patients to have AUR, and 9.3% with CUR and acute-on-chronic UR. The differences could be due to the fact that their study was retrospective; some patients with CUR or acute-on CUR may have been missed accounting for their low percentage.
Complications of UR such as UTI, renal impairment, urinary stones, and anaemia are known to be more commonly associated with chronic or acute-on-chronic UR 43. From this study, 60%
of the patients at presentation had no associated complications. Of the complications recorded among the remaining patients, UTI was the most common (24.5%), followed by renal impairment (14.5%) and anaemia (11.8%). These complications occurred singly or in combinations, and were all seen in patients with chronic or acute-on-chronic UR. The finding is consistent with the established pathophysiology of urinary obstruction where most of these complications are seen in patients with chronic stasis of urine as discussed in Chapter 3. They were also similar to those of Van Vuuren SPJ, et al. 77 who found the most common complications among the patients with UR to be UTI in 31.1%, anaemia in 18% and renal failure in 12.7% 77.
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Similarly, all the organisms responsible for UTI in this study were gram negative bacteria, which are the commonest pathogens of the urinary tract 70, 78. The findings were also similar to the ones in the above quoted study by Van Vuuren SPJ, et al.77 who also found E. coli (8%), Klebsiella (6.7%), Entrobacter specie (3.7%) and Proteus (2.5%) as the commonest organisms among the patients with UTI. Other studies were done to find predominant organisms in catheter related UTI. These include the study by Abaeze S, et al. at federal medical centre, Abeokuta, Nigeria 79 in which E.Coli was the commonest pathogen isolated, followed by Klebsiella specie. Others were Staphylococcus aureus and Pseudomonas species. However, Taiwo SS, et al. in Osogbo, Nigeria 80 found Klebsiella specie to be the commonest bacteria cultured followed by E.coli, Staphylococcus aureus and proteus mirabilis. In all the studies, the organisms cultured were predominantly gram negative enterobacteriacae which conform to earlier reports on pathogenic organisms affecting the urinary tract 70, 78.
The immediate management of UR is to decompress the bladder by catheterization. Urethral catheterization is the first modality of decompressing the bladder by most urologists globally 3, 38, 63. In this study urethral catheterization was successfully used to relieve the retention in 61.0% of the patients, failure of which suprapubic catheterization was done in 39.0%. Catheterization apart from relieving the UR, gave a clue to the cause of the retention.
Urethral stricture and urethral stones are known to be the commonest causes of failed urethral catheterization. However, in some instances such as in large median lobe of the prostate and severe bladder neck stenosis urethral catheterization may fail. Van Vuuren et al.77 reported in their study that urethral catheterization was successful in 81% of the patients, 18% had SPC while the remaining 1% had both urethral and suprapubic catheterization. The high percentage of patients who had SPC in this study (31%) as compared to 18% in the quoted study could be due the higher percentage of patients who presented with UR from urethral stricture as compared to the one quoted.
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The volume of urine drained after catheterization (both urethral and SPC) was recorded in all cases in this study. In 80 patients (72.0%) less than 1000mls of urine was drained at catheterization while in the remaining 30 patients (28.0%) up to 1000mls or more of urine was drained. This is similar to the finding in the worldwide survey of patients with AUR from BPH 3 in which less than 1000mls of urine was drained in 72.7% of the patients while more than 1000mls was drained in 27.3% 3. It has been shown in other studies that patients with CUR may have larger quantity of urine owing to gradual distension of the bladder and its painless nature 45.
The successful initial management of a patient with UR is by safe catheterization. This largely depends on the availability of trained personnel who should adopt appropriate techniques and take necessary precautions to prevent complications. However, some complications are known to be associated with catheterization as discussed in chapter 3. Up to 74.5% of the patients in this study did not develop any of the complications. The most common complication was introduction of UTI in 17.3%. This was followed by haematuria in 5.5% of the patients. Three patients (2.7%) had their urethra injured and none had post obstructive diuresis. The prevalence of UTI in this study was similar to the findings of Hans-Joerg Z, et al. who found 13% of their patients had UTI at presentation 66. Only 20.5% of the patients developed UTI in subsequent urine microscopy, culture and sensitivity.
The rate of urethral injury is low in this study. This is expected as the study was done in a teaching hospital setting where catheterization is done generally under supervision of a urologist. Continued education among doctors in teaching hospital setting tends to update their knowledge on the standard technique to adopt during catheterization in order to reduce complication rate. None of the patients in this study developed post obstructive diuresis (polyuria of ≥ 3litres/day or persistent urinary output of ≥200mls/hr). This could be due to the low residual urine volume recorded in most of the patients at presentation (753.7 ±164.8 SD
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mls, 1259± 214.8 SD mls and 1937.2 ±276 SD mls for patients with AUR, CUR and acute-on-chronic UR respectively) which in turn may imply a moderate rise in intravesical pressure. The gradual decompression done in all the patients with CUR and acute-on-chronic UR could also explain the finding.
For those who were started on TWOC in this study, success was recorded in 30 (71.4%) patients, while 9 (21.4%) patients reported persisting LUTS and 3(7.2%) of them had recurrent UR (as shown in table 8). The success rate was similar to findings by Kwangsu P, et al. in their study 15 ‘‘Analysis of the Treatment of Two Types of Acute Urinary Retention’’. They found a success rate of 70% irrespective of the type of AUR (spontaneous or precipitated).
Commencement of appropriate drug therapy at the time of initial catheterization and
subsequent trial without catheter has now been adopted in many centres as the first treatment option for AUR from BPH, with varied success rate 3, 24, 38, 60, 63. This approach has been shown to decrease significantly the load of prostatectomies following UR and in turn decrease
complications associated with the procedure 38, 60. Prolonged catheterization which predisposes to UTI and stone formation is also avoided. Various factors have been identified for improving success rate of TWOC. These include age less than 65 years, small sized prostate,
non-malignant prostate, residual urine less than 750mls and presence of precipitating factors for UR
64. The success rate varied from one centre to the other, but generally the use of - adrenergic blockers such as Alfuzocin and Tamsulosin has been shown to increase the success rate 3, 38. Other patients who had indication for surgery had prostatectomy as presented in chapter 5.
Patients who had SPC on account of urethral stricture or urethral trauma were followed up for a period of 6 to 12 weeks to allow inflammation to subside. They were then investigated to ascertain the characteristics of the stricture before a definitive management was offered.
Patients with bladder tumour were maintained on catheter with periodic change pending when cystoscopy and biopsy would be done and a definitive diagnosis made.