Fowler’s Syndrome affects young women after the
menarche, who develop painless retention at high bladder volumes, often
following apparently unconnected precipitating events, such as minor surgery. Often, history of prior LUTS is minimal and most of the women will not report
any prior urinary tract problems. It is estimated that around 40% of women
affected have Polycystic Ovary Syndrome. It is important to exclude occult or
undiagnosed neurological problems as a cause. The scientific explanation for
the underlying sphincter problem in Fowler’s syndrome is not understood. It has
been hypothesized that changes in the ion channels of the skeletal muscles of
the urinary sphincter may be affected by the hormonal environment of the
menarche (“hormonal channelopathy”) leading to abnormal communication directly
between muscle cells (ephaptic transmission). As a consequence, the sphincter
becomes overactive and hypertrophic, and reacts excessively to direct
stimulation.
Diagnostic criteria include:
UR of at least 1 liter on at least one occasion; exclusion of other causative
factors; raised maximum urethral closure pressure on urethral pressure
profilometry; increased sphincter volume on ultrasound or MRI assessment; and;
a characteristic urethral sphincter EMG. Difficulties with IC can be
profound—insertion of the catheter can be straightforward but then discomfort
may develop, as if the sphincter were gripping the catheter, leading to
consequent difficulty on catheter withdrawal. Flow rate patterns tend to be
interrupted. Small volumes often are passed by micturition, leaving substantial
PVR.
The most specific diagnostic
test for Fowler’s Syndrome is a urethral sphincter EMG (USEMG), which differs
from the pelvic floor EMG generally used for neurourological patients. In
USEMG, the EMG needle is placed to one side of midline in the anterior vaginal
wall, at the mid-urethral point, and advanced on to the dorsal aspect of the
urethra. The neurophysiologist undertaking the test has to pay special
attention to the audio signal being generated by the EMG, which confirms
successful entry into the sphincter zone. The diagnostic parameter for Fowler’s
Syndrome is an audio signal likened to the sound of whale noises in the ocean.
Pelvic floor EMG often is non-diagnostic in this patient group.
Management of Fowler’s
syndrome is specialized, and a sympathetic approach and consideration of
psychological elements are essential. Strong efforts should be made to reduce
the polypharmacy that many of these patients have, particularly attempting to
discourage use of opiate drugs. For those patients manifesting the
characteristic EMG signal who are unable to tolerate IC, the treatment of
choice is sacral nerve stimulation (SNS), which
can achieve normal voiding in a significant proportion of women affected.
Management is difficult in patients without the characteristic EMG signal, or
those patients where the SNS percutaneous needle electrode test fails to elicit
a significant improvement in symptoms. Suprapubic catheter placement is
generally unsatisfactory in younger women. No drug treatment has yet been established
as deriving any substantive benefit. Botulinum injection into the urethral
sphincter has not been tested on a systematic randomized basis. Ultimately,
reconstructive surgery using a continent diversion (Mitrofanoff procedure) may
be necessary.
