Neurogenic Bladder: The Kidneys Used To Be What Killed People

Neurogenic bladder after spinal cord injury: the kidneys used to be what killed people

A 70-year British study published in Spinal Cord in 2017 followed 5,483 people with traumatic spinal cord injury across two spinal centres, tracking deaths from 1943 to the end of 2014. It is one of the longest-running datasets in the field, and buried in it is one of the great unheralded successes of twentieth-century medicine.

Between 1944 and 1969, urogenital causes — urinary tract infections, urosepsis and renal failure — were the leading cause of death after spinal cord injury, accounting for 32.8 per cent of deaths.

By 2005 to 2014, urogenital causes had fallen to 8.7 per cent, and had dropped to fourth place.

Kidneys stopped killing people. Not because spinal cord injury changed, but because bladder management and renal surveillance changed. Intermittent catheterisation replaced permanent indwelling drainage as the default. Pressures in the bladder started being measured rather than assumed. People started having their kidneys imaged every year whether or not anything appeared to be wrong.

But read the second number in that study as well. In 2014, age-standardised urogenital mortality in this population was still around twelve times the rate in the general population of England and Wales. The problem was reduced by roughly three quarters. It was not solved.

And the thing that reduced it is the thing most often quietly dropped. Surveillance is boring. It involves an appointment for a problem the person does not have, about an organ they cannot feel, in a system that struggles to fund anything preventive. Twenty years after an injury, when the spinal unit is far away and the person has a job and a life and nothing hurts, the annual renal review is the easiest thing in the world to let slide.

That is what this guide is about.

We support people with spinal cord injury across New South Wales, including catheter and continence support under clinical plans written by the person’s treating team. We are not a urology service and nothing here is medical advice. Bladder management after spinal cord injury is specialist territory, and the right answer for an individual comes from a spinal unit or a neuro-urologist, not a website.

Two kinds of bladder, and why the difference drives everything

A bladder has two jobs: hold urine at low pressure, and empty completely when you decide to. Both depend on coordination between the detrusor — the bladder’s muscular wall — and the sphincters that hold the outlet closed.

Spinal cord injury breaks the coordination. How it breaks depends on where the injury is.

Reflexic bladder — also called upper motor neuron, spastic, or hyperreflexic. This follows injuries above the sacral segments, which is most injuries. The reflex arc through the sacral cord survives, but the brain can no longer control it. The detrusor contracts involuntarily when the bladder fills, producing urgency and incontinence the person cannot prevent, and often incomplete emptying.

Areflexic bladder — also called lower motor neuron, flaccid, or acontractile. This follows injuries affecting the sacral segments themselves, the conus medullaris or the cauda equina. The reflex arc is destroyed. The bladder does not contract at all. It fills, and fills, and overflows, with large retained volumes.

And the dangerous one: detrusor-sphincter dyssynergia. Here the detrusor contracts and the external sphincter contracts at the same time instead of relaxing. The bladder squeezes hard against a closed outlet. Pressure inside the bladder rises steeply, and there is nowhere for the urine to go except backwards, up the ureters, towards the kidneys.

That is the mechanism that used to cause kidney failure. Not infection primarily — pressure. Sustained high bladder pressure causes reflux of urine towards the kidneys, hydronephrosis, scarring and, eventually, renal failure. It happens slowly, over years, and it produces no symptoms the person can feel, because they have no sensation from the bladder.

This is the whole reason surveillance exists. The damage is silent, cumulative, and detectable only by looking.

It is also why “is the person dry and comfortable?” is the wrong question to judge bladder management by. A bladder can be perfectly continent and quietly destroying the kidneys. Dryness is a quality-of-life goal. Low pressure is a survival goal. They are not the same goal and they occasionally conflict.

What surveillance actually involves

The specifics are set by the treating service and vary with the individual, their management method and their history. Broadly, long-term follow-up after spinal cord injury involves some combination of:

Upper tract imaging — ultrasound of the kidneys and bladder, looking for hydronephrosis, scarring, stones and residual volumes. Typically annual or at an interval set by the service.

Renal function blood tests. With an important caveat: serum creatinine is a poor marker of kidney function in this population, because creatinine is produced by muscle and people with spinal cord injury have reduced muscle mass. A creatinine that looks reassuring can sit alongside meaningfully reduced function. This is a known pitfall and a reason imaging and specialist interpretation matter more than a number on a pathology report.

Urodynamics — direct measurement of pressure inside the bladder as it fills and empties. This is the test that identifies dyssynergia and high storage pressures. It is uncomfortable, inconvenient and the single most informative test in the field. It is usually done at baseline and then repeated when something changes or at intervals the service sets.

Cystoscopy — looking inside the bladder, particularly relevant for people with long-term indwelling catheters, for bladder stones and for cancer surveillance.

Review of the management plan itself — because what suited somebody at 25 may not suit them at 55, and because hand function, carer availability, living arrangements and goals all change.

If you support somebody with a spinal cord injury and nobody can tell you when their last renal ultrasound was, that is the gap to close. Not next year. Now. It is a phone call to the GP or the spinal outreach service, and it is the single highest-value thing in this guide.

The management options, and the logic behind each

What follows is descriptive, not advisory. The choice between these is a specialist decision balancing renal protection, continence, hand function, carer availability, body habitus, lifestyle and the person’s own priorities.

Intermittent catheterisation. A catheter is passed to drain the bladder and removed, typically four to six times a day. This has become the default where it is feasible, because it keeps the bladder cycling at low pressure, empties it completely, and avoids a permanent foreign body in the urinary tract. It requires either adequate hand function to self-catheterise, or a worker or family member available at each time — which is a funding question as much as a clinical one.

Indwelling urethral catheter. A catheter left in place, draining continuously. Simple, reliable, requires no hand function. The trade-offs are significant with long-term use: higher rates of bladder stones, recurrent infection, urethral trauma and erosion, and — with very long-term use — increased bladder cancer risk.

Suprapubic catheter. An indwelling catheter through the abdominal wall directly into the bladder. For many people this is preferable to long-term urethral catheterisation: it avoids urethral damage, is easier to manage independently, is less intrusive sexually, and is generally easier for workers to care for. It requires a surgical procedure to establish.

Reflex voiding, with or without sphincterotomy. Allowing the bladder to empty on reflex into a condom drainage system, sometimes after surgical division of the sphincter to lower outlet resistance. Used mainly in men. It manages pressure but gives up continence.

Botulinum toxin injection into the detrusor. Reduces involuntary contractions and lowers storage pressure, usually combined with intermittent catheterisation. Needs repeating.

Anticholinergic and beta-3 agonist medications. To relax the detrusor and reduce storage pressure. Side effects, particularly from anticholinergics, include dry mouth, constipation — which matters a great deal when bowel management is already difficult — and cognitive effects worth discussing.

Bladder augmentation. Surgery to enlarge the bladder using a segment of bowel, creating a large low-pressure reservoir. Reserved for situations where other approaches have not controlled pressure.

Continent catheterisable stoma, such as a Mitrofanoff. A surgically created channel from the bladder to an abdominal stoma, allowing catheterisation through the abdomen. Can transform independence for somebody with limited hand function or difficulty with urethral access.

Ileal conduit. Urinary diversion to an abdominal stoma with an external bag. Generally a late option, but a genuinely good one for some people and not a failure.

Sacral anterior root stimulation. An implanted stimulator used in selected cases, usually with posterior rhizotomy.

Two things worth saying about this list. First, changing method is normal and not a defeat. Many people move from intermittent catheterisation to a suprapubic catheter in their fifties as shoulders wear out and transfers get harder, and that is a sensible adaptation rather than a decline. Second, the method that preserves the kidneys wins. Where continence and renal protection conflict, the kidneys come first, and a good service will say so plainly.

Urinary tract infection, and the over-treatment problem

This section matters because the most common error in the long-term care of people with spinal cord injury is treating urine rather than treating people.

Almost everybody who uses a catheter has bacteria in their urine. Permanently. This is asymptomatic bacteriuria, and in catheter users it is the normal state, not an infection. It does not require antibiotics, and treating it does active harm: it drives antibiotic resistance, so that when a genuine infection arrives — and in this population a genuine urinary infection can become urosepsis quickly — the available drugs no longer work.

Yet urine gets sent, bacteria are found, and antibiotics are prescribed, over and over, often prompted by a well-meaning carer noticing cloudy or strong-smelling urine.

Cloudy or smelly urine is not, on its own, an infection. It commonly reflects hydration, diet or normal colonisation.

A urinary tract infection in somebody with a spinal cord injury usually presents systemically or through altered function rather than through the symptoms the general population gets, because the person cannot feel their bladder. Things that genuinely suggest infection include:

• Fever
• New or worsened autonomic dysreflexia — in injuries at or above T6 this is frequently the first signal
• Increased spasticity
• New incontinence between catheterisations, or leaking around a catheter
• Malaise, lethargy, feeling generally unwell, loss of appetite
• Visible blood in the urine
• Abdominal or flank pain or discomfort, where sensation allows
• Confusion, in older people
• Cloudy sediment combined with any of the above

What should happen is that a clinician assesses the person, not the specimen. And the right rule for support workers and families is: report the change, describe the person, do not request antibiotics. A dated note saying “spasticity markedly increased since Tuesday, two episodes of dysreflexia, off food, temperature 37.9” is far more useful than a urine sample.

Recurrent genuine infections are a signal to re-examine the bladder management, not to keep prescribing. Repeated infection often means incomplete emptying, high residual volumes, stones, or a method that is no longer working.

The long-term complications worth knowing about

Bladder stones. More common with long-term indwelling catheters. Can cause infection, bleeding and dysreflexia. Found on imaging or cystoscopy.

Kidney stones. Related to immobilisation, calcium metabolism, infection and urinary stasis.

Hydronephrosis and renal scarring. The silent consequence of sustained high bladder pressure. Found by surveillance imaging, by definition, because it produces no symptoms the person can detect.

Urethral trauma, erosion and false passages. From long-term or repeated urethral catheterisation.

Bladder cancer. This is uncomfortable to write about and it belongs here. Long-term indwelling catheterisation is associated with increased risk of bladder cancer, including squamous cell carcinoma, which is an unusual type in the general population. The British 70-year study cited a United States standardised mortality ratio of 6.7 for bladder cancer in this population.

The practical point is not alarm — it is that this is a recognised reason cystoscopic surveillance exists for people with very long-term indwelling catheters, that any visible blood in the urine needs proper investigation rather than being written off as catheter trauma, and that it is a legitimate consideration in the decision between indwelling drainage and other methods over a lifetime.

Autonomic dysreflexia. Bladder distension is the single most common trigger. Any new or increased pattern of dysreflexia is a bladder question first.

Fluid, and the trade-off nobody explains well

Fluid intake sits at the centre of several competing pressures and people are often given contradictory advice.

More fluid dilutes urine, reduces stone risk and may reduce infection risk. More fluid also means more volume, more catheterisations, more risk of overfilling between them, and more inconvenience — which for someone at work or travelling is not a trivial consideration.

The result is that people quietly restrict fluid to manage their day, and nobody discusses it. It is extremely common and it is worth raising openly, because the right answer is an individual plan from the treating service that accounts for the person’s actual life, rather than a generic instruction to drink more that they will not follow.

Independence, and what it is worth

Self-catheterisation is life-changing where it is achievable. It removes dependence on another person’s schedule for something that happens five or six times a day, every day, forever.

Whether it is achievable depends mainly on hand function, which depends mainly on injury level. People with injuries at C7 and below often manage it. At C6 it is sometimes possible with adaptive equipment. Above that it generally is not, and alternatives like a suprapubic catheter or a catheterisable stoma become much more attractive precisely because they can restore independence.

Worth knowing:

• Occupational therapy assessment is the key step, and specialist spinal OTs know adaptations most generalists do not.
• Adaptive equipment matters — catheter guides, mirrors, leg spreaders, pre-lubricated and hydrophilic catheters, grip aids.
• The NDIS funds assistive technology and training towards this. Capacity building for self-management is a legitimate and well-justified plan item, and it reduces core support costs over time, which is an argument worth making explicitly at a planning meeting.
• Consumables are generally supplied through state continence schemes and the Commonwealth Continence Aids Payment Scheme rather than the NDIS, though the boundary is worth checking for an individual.

The funding question nobody wants to have

Intermittent catheterisation four to six times a day, every day, is a support requirement. For someone who cannot self-catheterise, that is four to six worker attendances daily, forever, and they are not evenly spaced across a convenient shift pattern.

If a plan does not fund that properly, what happens in practice is that catheterisation gets bundled into existing visits, intervals stretch, the bladder overfills, pressure rises and dysreflexia and infection follow. The clinical consequence of an inadequate plan is renal damage, and it arrives quietly, years later.

The AlphaBeta report prepared for SpinalCure Australia in 2020 put personal care at $31.4 billion of a total $74.5 billion lifetime cost of spinal cord injury in Australia — 42 per cent — against health care at $3.3 billion. It also found that bladder or bowel control loss affects 80 per cent of people with spinal cord injury and is the leading cause of rehospitalisation due to infection.

Those two facts belong together. The expensive part is the support, and underfunding the support produces the hospitalisations.

If you are preparing for a plan reassessment, the evidence that works is specific: how many catheterisations a day, how long each takes including setup and hygiene, at what times, what happens when they are missed, and a letter from the treating service stating the clinical requirement and the renal risk of not meeting it.