A male patient has a detrusor pressure at maximum flow rate of 70 cm H2O, a maximum detrusor pressure of 80 cm H2O and a maximum flow rate of 8 mL/sec. What is his bladder outflow obstruction index?
Answer A
The bladder outlet obstruction index (BOOI) enables classification of patients’ voiding into obstructed, unobstructed or equivocal once calculated numerically and is commonly plotted on the International Continence Society nomogram. This replaces the Abrams-Griffiths number and nomogram.
The BOOI is calculated using the following formula: pdetQmax – (2*Qmax)
Bladder contractility index can also be calculated from these variables to determine ranges of contractility using the following formula: pdetQmax + (5*Qmax).
A bladder contractility index of <100 is weak, 100–150 is normal and >150 is strong contractility.
A patient has a spinal cord injury at the level of T4. Which complication can develop?
Answer B
Autonomic dysreflexia is a serious and potentially fatal complication of spinal cord injuries above the level of T6. In patients with a cord lesion above the level of T6 and an intact distal autonomous cord, noxious stimuli (such as urinary tract instrumentation, constipation or blocked catheter) lead to disordered sympathetic response. Vasoconstriction of vascular beds (including splanchnic circulation, skin and skeletal muscle) below the level of the lesion leads to hypertension. To counteract the hypertension, bradycardia may be seen; however due to the level of cord injury the normal physiological response by baroreceptors, including vasodilatation, is prohibited. Above the level of the cord lesion there is flushing and sweating. Systemic features include anxiety and nausea. Management includes preliminary preventative measures, identifying those at risk of autonomic dysreflexia and early recognition. Once it has been identified that this is a urological emergency, the patient should be sat up, triggering factors should be removed and hypertension treated with oral nifedipine, glyceryl trinitrate (GTN) spray, sublingual captopril or administration of intravenous labetalol.
Which of the following is an NIDDK criteria for interstitial cystitis?
Answer C
Chronic pelvic pain is a spectrum of conditions including urological, gynaecological, musculoskeletal and gastrointestinal pelvic pain syndromes. Urological syndromes comprising pelvic pain syndromes include prostate pain syndrome, bladder pain syndrome (including interstitial cystitis), genital pain syndrome and urethral pain syndrome. Bladder pain syndrome is the preferred nomenclature for syndromes previously known as interstitial cystitis and painful bladder syndrome and this terminology has been adopted by the European Association of Urology and the International Association for the Study of Pain. Interstitial cystitis, described classically as the pathognomonic Hunner’s ulcer and inflammation, is part of the spectrum of bladder pain syndrome.
A consensus criterion for the diagnosis of interstitial cystitis was developed following a series of workshops over 20 years ago. Interstitial cystitis is a symptom complex diagnosed by excluding known causes of symptoms. This NIDDK criteria was intended for use in scientific studies and is shown in table below.
NIDDK diagnostic criteria for BPS/IC:
Further Reading: Gillenwater JY, Wein AJ. Summary of the national institute of Arthritis, Diabetes, digestive and kidney diseases workshop on interstitial cystitis, national institutes of health, Bethesda, Maryland, August 28–29, 1987. J Urol, 1988; 140: 203–206.
How does Cystistat (hyaluronic acid) work?
Answer D
There are numerous treatment regimens for bladder pain syndrome with different modes of administration and mechanism of action. Oral therapy includes the histamine receptor antagonist hydroxyzine (blocking mast cell activation) and pentosan polysulphate (Elmiron) which acts by repairing defects in the GAG layer. Intravesical treatments include local anaesthetics, heparin, pentosan polysulphate, hyaluronic acid and dimethyl sulphoxide (DMSO). DMSO acts by scavenging free radicals thus decreasing inflammation. Hyaluronic acid acts by repairing defects in the GAG later and it is postulated that heparin has similarities with the GAG layer.
Further Reading:
Vij M, Srikrishna S, Cardozo L. Interstitial cystitis: Diagnosis and management. Eur Obstet Gynecol Reprod Biol, 2012; 161: 1–7.
What is the prevalence of overactive bladder syndrome?
The EPIC study (Irwin et al.) estimated the prevalence of lower urinary tract symptoms, overactive bladder, urinary incontinence and lower urinary tract symptoms suggestive of bladder outflow obstruction. Lower urinary tract symptoms were common, experienced by an estimated 45% of individuals, with a smaller proportion thought to be suggestive of bladder outflow obstruction (21.5%). Approximately 8% were estimated to suffer from urinary incontinence and 11% from overactive bladder symptoms.
Further Reading: Irwin DE, Zopp ZS, Agatep B, Milsom I, Abrams P. Worldwide prevalence estimates of lower urinary tract symptoms, overactive bladder, urinary incontinence and bladder outlet obstruction. BJU Int, 2011; 108(7): 1132–1138.
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