THE
USE AND RATIONALE OF SELECTIVE ALPHA BLOCKADE IN CHILDREN WITH NON-NEUROGENIC
NEUROGENIC BLADDER DYSFUNCTION
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GUY BOGAERT, GOEDELE
BECKERS, RITA LOMBAERTS
Department
of Urology, Pediatric Urology, Department of Pediatric Nephrology and
Transplantation, UZ Leuven, Belgium, and Department of Pediatric Urology,
Linz, Austria
ABSTRACT
Introduction:
We present here a long-term observation of 2 children with a rare syndrome
with a non-neurogenic neurogenic bladder dysfunction (Hinman’s syndrome),
and we investigated the safety and efficacy of long-term use of terazosine
in association with prophylactic antibiotics, timed voiding and a bowel
regimen.
Materials and Methods: Two children, 7 years-old
(22 kg) and 11 years-old (36 kg) presented in 1997 to our pediatric urology
clinic with symptoms of urgency, frequency, urge incontinence and nocturnal
enuresis. Both children were placed in a regimen of terazosine (starting
with 0.5 mg increasing until 2 mg).
Results: There were no significant side
effects throughout the entire treatment. The first 7-year old boy however
developed some dizziness when the dose of terazosine was increased to
2 mg (after 4 weeks of administrating 1 mg), and this disappeared immediately
when the dosage was reduced back to 1 mg daily. The urgency symptoms improved
in both boys after 3 weeks of 1 mg terazosine. The secondary enuresis
in the 11 year-old boy resolved after 2 months of 2 mg terazosine.
Conclusion: It is possible to say that the
alpha-blocker medication, terazosine can be administered safely to children
with a non-neurogenic bladder dysfunction, also known as the Hinman’s
syndrome. These results have shown that dysfunctional voiding, postvoiding
residual and upper tract involvement can disappear over time when long
term terazosine is given in combination with timed voiding, prophylactic
antibiotic therapy and treatment of the associated constipation. Our observations
also suggest a permanent effect after discontinuing the medication.
Key
words: bladder, neurogenic; voiding dysfunction; children; enuresis;
adrenergic alpha-antagonists
Int Braz J Urol. 2004; 30: 128-134
INTRODUCTION
Frank
Hinman described in 1973 the rare syndrome with a non-neurogenic neurogenic
bladder dysfunction in children (1). Since then, several articles have
been published on this syndrome and its treatment (2-4). The symptoms
are variable, ranging from frequency to severe incontinence. In addition,
the videourodynamic findings may vary from mild detrusor overactivity
and little postmicturition residue to severe bladder dysfunction associated
with end stage renal failure. The most typical finding is of functional
bladder outlet obstruction or detrusor sphincter dyssynergia although
there is no anatomic correlation. Most importantly, there is no neurologic
abnormality. Associated problems such as behavioral and psychosocial problems
and bowel dysfunction, especially constipation are also seen in the Hinman
syndrome. All the components must be included in the diagnostic and treatment
approach.
Stockamp, in 1975, first described the use
of a non-selective α-blocker in non-neurogenic bladder outlet dysfunction
(5). In 1992 the use of the non-selective α-blocker phenoxybenzamine was
reported in combination with urinary diversion in the Hinman syndrome
as a partial success (6). The phenoxybenzamine medication never gained
popularity because of the severe side effects such as hypotension and
dizziness.
More recently, selective α-blocker medication
have been successfully administered in patients with lower urinary tract
symptoms (LUTS) and benign prostatic hypertrophy (BPH) without a significant
incidence of the feared side effects like hypotension and dizziness. However,
the use of these drugs in children is not common because of the limited
indication and the very small number of children with the Hinman syndrome.
In addition, there are no dose-response studies published on selective
alpha-blocking medication in children.
In this long-term observation of 2 children
with the Hinman syndrome, we investigated the safety and efficacy of long-term
use of terazosine in association with prophylactic antibiotics, timed
voiding and a bowel regimen.
MATERIALS
AND METHODS
Two
children, 7 (22 kg) and 11 years (36 kg) old presented in 1997 to our
pediatric urology clinic with symptoms of urgency, frequency, urge incontinence
and nocturnal enuresis.
The first 7-year old boy presented with
a long-standing daytime voiding problem and enuresis. Although he became
dry during daytime at 2.5 years of age, he always had urgency and he was
never dry at night. He had also suffered from chronic constipation since
birth. His physical exam, including a specific neurological evaluation
of the lower extremities, was normal. Urine and blood analysis for renal
function was normal. His maximum flow rate was 5.3 ml/sec with a post
void residual of 130 ml. In his voiding diary, he recorded daytime volumes
between 50 and 270 ml. He was wearing diapers at night and after weighing
the diapers together with the first void in the morning, he produced between
200 and 300 ml urine during the night. Ultrasound showed a left hydro-ureteronephrosis
and marked bladder wall thickening. Intravenous urography (IVU) additionally
showed a “Christmas-tree” shaped bladder (Figure-1). Video-urodynamic
examination showed a poorly compliant bladder, an open bladder neck, no
hyperreflexia, high voiding pressures (the maximum detrusor pressure was
53 mm H2O) and detrusor/sphincter dyssynergia. Magnetic resonance imaging
(MRI) of his spine and brain was normal. A DTPA-scan with furosemide-administration
(0.5 mg/kg body weight) showed delayed excretion at the left kidney, a
total GFR of 73 mL/min/1.73 m2 and a normal differential renal function.
A treatment regimen with oxybutinin 0.1
mg/kg body weight three times a day, nitrofurantoin 2 mg/kg at bedtime,
aggressive treatment of his constipation, timed voiding and physiotherapy
was initiated. However, after 8 weeks, his treatment seemed unsuccessful,
as the voiding symptoms including persistent postvoid residual volumes
between 140 - 200 mL and the hydroureteronephrosis did not improve. The
option of clean intermittent catheterization (CIC), was refused by the
boy and his family. The option of treatment with an uroselective alpha
blocker terazosine was discussed including possible side effects and the
fact that there were no dose response studies known in children. A dosage
of 0.5 mg terazosine at bedtime was started, the oxybutyine medication
was stopped and the constipation treatment and physiotherapy was continued.
Because the medication was well tolerated without any side effects, the
dosage was increased to 1 mg terazosine at bedtime after 2 weeks. Another
4 weeks later, the dose was further increased to 2 mg but because of dizziness
it was immediately discontinued and 1 mg continued. The urological symptoms
resolved and imaging appearances returned to normal. Terazosine was stopped
after 32 months of treatment. The boy is now 12 years old and is still
followed every 6 months. He takes currently no medication and is symptom
free.
The second boy was 11-year old when he came
to our clinic and he presented with a secondary nocturnal enuresis for
4 months. He was born with a tetralogy of Fallot for which he underwent
cardiac surgery at 2 years of age. He was dry day and night at 2 years
of age, but he always had some urgency and frequency and a tendency to
constipation. His physical exam, including a clinical neurological evaluation,
was normal. His urine was clear, microscopic evaluation of the urine was
normal and the urine culture negative. The maximal flow rate at presentation
was 8 ml/sec with a postvoiding residual volume of 240 ml (Figure-2).
Blood analysis showed an elevated urea of 70 mg/dl and a creatinine of
1.91 mg/dl. His creatinine clearance was 32 ml/min/1.73 m2. A proteinuria
of 188 mg/24 hours was noted. His voiding diary he recorded daytime voided
volumes between 100 and 300 mL. On ultrasound he was noted to have bilateral
hydro-ureteronephrosis, bilateral renal parenchymal atrophy and increased
bladder wall thickness (Figures-3 and 4). Unfortunately, due to technical
problems he did not undergo a videourodynamic evaluation. However, he
did have a voiding cystourethrogram (VCUG) where a spindle-shaped dilation
of the proximal urethra was seen.
Nitrofurantoin 2 mg/kg at bedtime, aggressive
treatment of his constipation, timed voiding and physiotherapy failed
to produce any improvement in 8 weeks. CIC was refused by the boy and
his family. After similar counseling terazosine, 0.5 mg at bedtime was
added to the other treatment regimen. For 2 weeks of medication, there
were no problems or side effects of therefore the dosage was increased
to 1 mg terazosine. After another month of treatment with 1 mg terazosine
and no side effects, the dose was increased to 2 mg. The patient remained
on this dosage for 25 months. Prophylaxis and physiotherapy were stopped
after 12 months.
Both children have now discontinued the
medication for more then 18 months and remain symptom free.
RESULTS
During
the entire treatment with terazosine, special attention regarding potential
side effects of α-blocker medication was addressed to the children and
their parents: postural hypotension, dizziness, headache and rhinitis.
However, there were no significant side effects throughout the entire
treatment. The first 7-year old boy however developed some dizziness when
the dose of terazosine was increased to 2 mg (after 4 weeks of administrating
1 mg), and this disappeared immediately when the dosage was reduced back
to 1 mg daily.
The urgency symptoms improved in both boys
after 3 weeks of 1 mg terazosine. The secondary enuresis in the 11-yr
old boy resolved after 2 months of 2 mg terazosine.
Dilation of the upper urinary tract improved
in both boys after 4 months of terazosine 1 and 2 mg treatment respectively.
Post voiding residual volume was the last
symptom to improve. Volumes diminished after 6 months of terazosine 1
mg treatment in the 7-year old boy and in the 11-year old boy, it improved
after 9 months of treatment (2 mg). At the same time, distinct improvement
of the urinary flow was observed and this amelioration persisted during
treatment and after discontinuing the medication (Figure-5).
The creatinine clearance remained stable
at 73 ml/min/1.73 m2 in the 7 years old boy whereas in the 11 years old
one it improved from 32 ml/min/1.73 m2.
After discontinuing the terazosine medication,
both boys had further stable renal function without residual hydronephrosis.
They have almost normal appearing bell shape urinary flows and the residual
post-voiding volumes remain below 30 ml.
DISCUSSION
This
long-term observation in two children has shown that α-blocker-medication
terazosine 1 - 2 mg daily can be an important adjunct in treating voiding
dysfunction in children with non-neurogenic neurogenic bladder dysfunction
and that the medication can be given safely over a longer period.
Until today, there has been no confined
etiology for the Hinman syndrome found. However, there is a trend that
nowadays we are confronted with earlier stages of the syndrome. This might
be due to the fact that back in 1973 children with bladder function problems
consulted their physician very late compared to today. In the situation
of end stage renal disease, only urinary diversion, bladder augmentation
and renal transplantation were possible options. As these children are
nowadays seen in an earlier stage without end stage renal disease but
with severe bladder and bowel function problems, attempts with medication,
clean intermittent catheterization and other non surgical methods are
used to avoid renal deterioration.
The rationale for giving α-blocker-therapy
in case of voiding dysfunction was given by Krane et al. in 1973 (7,8)
showing that bladder emptying significantly improved after phenoxybenzamine
was administered to children with neuropathic bladder dysfunction. In
children without neurological abnormalities, Stockamp was the first in
1975 to report the successful use of phenoxybenzamin in the situation
of upper tract complications due to functional infravesical obstruction
(5). Upper urinary tract dilatation improved in 3 out of 5 children. De
Vooght in 1976 (9) found that the best results of α-blocker-therapy were
seen in children with neuropathic bladder dysfunction with increased urethral
outflow resistance associated with absent or slight detrusor activity.
Side effects of non-selective α-blocker
medication such as hypotension, dizziness and headache has limited the
general clinical use. The introduction of selective α-blocker medication
such as terazosine has opened a new treatment option regimen in patients
with functional bladder outlet obstruction. The first group of patients
that would benefit from such a treatment was patients with lower urinary
tract symptoms (LUTS) due to benign prostatic hypertrophy (BPH) and this
has been clinically confirmed. However, the experience of selective α-blockers
in children is limited. Austin et al. has reported in 1999 a short term
follow up study with the use of 1 mg of doxazosine in children with the
Hinman syndrome, with good results in 1 patient out of 4 (4).
Terazosine 1 – 2 mg was chosen in
our treatment alternative for the treatment of functional bladder outlet
obstruction in our pediatric patients because terazosine is a selective
α1-blocker for which no cell-apoptosis has been described. It is known
that the average dose of terazosine in adults is 5 mg for an adult of
70 – 80 kg, therefore the dosage for our patients was calculated
as 1 mg terazosine per 20 kg body weight. This calculation appeared to
be correct as in the first 7 yr old boy whose weight was 22 kg and he
received 1 mg terazosine whereas he experience some dizziness when he
took 2 mg. The second 11 yr old boy weighted 36 kg and had good results
without side effects with the dosage of 2 mg terazosine.
The fact that terazosine has such a long
term beneficial effect on the bladder function in these both children
remains somewhat hypothetical. One might argue that if these children
did not have Hinman syndrome. The difference between functional bladder
outlet obstruction and detrusor sphincter dyssynergia is not always a
clear cut. However, in our patients, the classical presentation and imaging
appearances makes the diagnosis most probable. In addition, these patients
might have developed more severe symptoms but for our early diagnosis,
they might be cured now.
The exact etiology of the Hinman-Syndrome
is not known and therefore it is unknown if the α1-adrenoreceptors would
play a role in this matter. De Groat described the modulation of voiding
and storage reflexes by activation of α1-adrenoreceptors in animals (10).
This study described the predominance of α1-presynaptic bladder modulation
in the bladder body of young rats, and a α1-postsynaptic predominance
in the bladder base of older rats. In addition, in humans urethral α-adrenoreceptors
have been described and they are supposed to mediate contraction and assist
in the maintenance of urinary continence (11). It is also known that excitatory
neuromuscular transmission in the urinary bladder arises predominantly
through activation of the parasympathetic pathways. Cholinergic transmission
plays a role in regulating the residual urinary volume at the end of a
voiding cycle, and inhibitory sympathetic transmission in the detrusor
is important during the filling phase. Sympathetic nerves may act on parasympathetic
nerve terminals and inhibit cholinergic and non-cholinergic excitation
(12).
The possible associated problems of the
Hinman syndrome such as behavioral and psychosocial problems may also
have an influence on bladder and bowel function problems. Behavioral problems
might cause a “stress-induced” elevated sympathetic tonus
inducing sphincter dyssynergia, an elevated bladder tonus and an elevation
of the post-micturition residual urine.
This supports the hypothesis of the benefit
of the α-blocker-therapy that could help in regaining a normal micturition
pattern. Secondary to the improved bladder function, the bladder wall
thickness might decrease and will secondarily improve the upper tract
drainage.
This is exactly what happened in our patients.
The observation that it took more than 3
weeks to improve the urgency voiding symptoms, 4 months to improve renal
drainage and even 9 months to see effect on postvoid residual and urinary
flow explain the long standing and complex etiology of the syndrome. Although
all these symptoms occurred in the identical time frame further observations
in larger patient groups will demonstrate if these effects will be consistent.
After discontinuing the medication for more
then 18 months, the patients did not relapse to their previous bladder
function problem. There is no exact explanation for this permanent action.
It is also unknown if the medication could have been stopped earlier and
still have had beneficial effect. In addition, the functional bowel problems
have been resolved with the treatment regimen. Because of the other factors
such as the physiotherapy, the attention and motivation, these children
received during the treatment it is not certain how important each of
the treatment factors are.
In conclusion it is possible to say that
the alpha-blocker medication, terazosine can be administered safely to
children with a non-neurogenic bladder dysfunction, also known as the
Hinman syndrome. These results have shown that dysfunctional voiding,
postvoiding residual and upper tract involvement can disappear over time
when long term terazosine is given in combination with timed voiding,
prophylactic antibiotic therapy and treatment of the associated constipation.
Our observations also suggest a permanent effect after discontinuing the
medication.
REFERENCES
- Hinman F, Baumann FW: Vesical and ureteral damage from voiding dysfunction
in boys without neurologic or obstructive disease. J Urol. 1973; 109:
727-32.
- Rapariz Gonzalez, MA: Sphincter reeducation in non-coordinated urination
syndrome. Arch Esp Urol. 1997; 50: 625-32.
- Maizels M, King LR, Firlit CF: Urodynamic biofeedback: A new approach
to treat vesical sphincter dyssynergia. J Urol. 1979; 122: 205-9.
- Austin PF, Homsy YL, Masel JL, Cain MP, Casale AJ, Rink RC: Alpha-adrenergic
blockade in children with neuropathic and non-neuropathic voiding dysfunction.
J Urol. 1999; 162: 1064-7.
- Stockamp K: Treatment with phenoxybenzamine of upper urinary tract
complications caused by intravesical obstruction. J Urol. 1975; 113:
128-31.
- Breuer J, Foll J, Renz-Polster H, Rebmann H, Rosendahl W, Wilbert
D: Hinman syndrome. Pronounced renal failure as a sequel of pseudo-neurogenic
disorder of bladder emptying. Monatsschr Kinderheilkd. 1992; 140: 162-5.
- Krane RJ, Olsson CA: Phenoxybenzamine in neurogenic bladder dysfunction.
I. A theory of micturition. J Urol. 1973; 110: 650-2.
- Krane RJ, Olsson CA: Phenoxybenzamine in neurogenic bladder dysfunction.
II. Clinical considerations. J Urol. 1973; 110: 653-6.
- de Voogt HJ, Van der Sluis C: Preliminary evaluation of alpha-adrenergic
blocking agents in children with neurogenic bladder due to myelomeningocele.
Dev Med Child Neurol Suppl. 1976; 37: 82-8.
- de Groat WC, Yoshiyama M, Ramage AG, Yamamoto T, Somogyi GT: Modulation
of voiding and storage reflexes by activation of alpha1-adrenoceptors.
Eur Urol. 1999; 36: 68-73.
- Koyanagi T: Studies on the sphincteric system located distally in
the urethra: The externa urethral sphincter revisited. J Urol. 1980;
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- Rushton DN: Handbook of Neuro-Urology. London, Marcel Dekker Inc.,
England. 1994; p. 404.
_________________________
Received:
November 12, 2003
Accepted after revision: December 20, 2003
_______________________
Correspondence address:
Dr. Guy Bogaert
Dept Urology, Pediatric Urology
Herestraat 49, B-3000
Leuven, Belgium
Fax: + 32 1634-6931
E-mail: guy.bogaert@uzleuven.br |