There are several normative age-related changes of the genitourinary and gastrointestinal systems that can lead to serious health problems for the elderly. With regard to the genitourinary system, there is a progressive and structural breakdown of the kidneys with age, and problems with urinary continence that results from decreased bladder capacity and compliance, and an increase in involuntary bladder contractions (Aldwin & Gilmer 2004). In males, enlargement of the prostate also contributes to incontinence (Dubeau 1997), and prostate cancer is one of the primary causes of death (McClain & Gray 2000). Although urinary tract infections (UTIs) increase with age, women are at greater risk, with the incidence in males only approaching that of women when they are 60 years or older (Foxman 2002). Unlike the genitourinary system, the gastrointestinal system retains much of its regular function, and it is unclear whether the few normal changes do affect the health of the older population. Some potential issues include slowing in large intestine motility, and diminished gut motility, with an increase in water resorption in the colon, which contributes to hard stool and increased risk of constipation, rectal fissures, hemorrhoids, and diverticular diseases (Wilson et al. 1997).
In persons with SCI, the effects of neurogenic bladder may compound the effects of aging in persons with SCI (Madersbacher & Oberwalder 1987) since bladder management techniques, such as the use of indwelling catheters, may contribute to the occurrence of common complications such as UTIs (Charlifue et al. 1999) and for a higher risk of developing bladder cancer (Groah et al. 2002). Similarly, neurogenic bowel may also compound aging after SCI given that persons with SCI often have higher rates of bowel-related complications compared to the general population (Cosman et al. 1993).
In this section, 9 longitudinal studies and 13 cross-sectional studies (see Table 9) on the genitourinary and gastrointestinal systems after SCI are reviewed.
From the list of identified studies on the genitourinary system (see Table 9), there are four longitudinal studies (Viera et al. 1986; DeWire et al. 1992; MacDiarmid et al. 1995; Sekar et al. 1997) suggesting there are no differences in renal function over time among persons using various bladder management techniques. However, the samples of these studies did incur typical SCI-related complications such as UTIs and bladder stones, and there were some indications of renal decline. For instance, Lamid (1988) found that after 4 YPI, the number of vesicoureteral refluxes increased and progressed to grades II and IV, which caused kidney damage with caliectasis in 27 of 32 patients with SCI followed over 12 YPI. Finally, Sekar and colleagues (1997) reported that renal function (as measured by total and individual kidney effective renal plasma flow; ERPF) decreased over time in their SCI sample (N = 1114) with a slight reversal occurring at 10 YPI. A methodological strength of the study was the assessment of ERPF, which is thought to be a more sensitive measure of kidney function than serum creatinine (Kuhlemeier et al. 1984a). Based on the findings of the identified studies, it may be that significant declines in renal function occur approximately at 5 YPI.
Work regarding age of onset and the genitourinary system is also needed as the findings of a cross-sectional study by Kuhlemeier and colleagues (1984b) suggests that persons with acute SCI (N = 160) who were younger than 20 or older than 50 had comparable levels of individual and global kidney effective plasma flows compared to AB controls (N = 287), whereas persons with between 21-51 had impaired renal function.
Overall, the risk for prostate cancer appears to be lower in persons with SCI due to impaired testosterone levels, but prostate cancer screening should be encouraged given the possibility that males with SCI who do develop prostate cancer may have poorer outcomes than AB males (Scott et al. 2004).
With regard to women with SCI (n = 62), Kalpakjian and colleagues (2010) found that they experience greater symptom bother in certain areas related to menopause compared to AB controls (n = 66). Specifically, women with SCI reported greater bother of somatic symptoms, bladder infections, and diminished sexual arousal. However, the patterns of symptoms, transitioning through menopause, and age at final menstrual period transitions were comparable between groups. Overall, the authors concluded that in important ways, women with SCI appear to experience menopause similarly to their peers.
Although bowel function is clearly impaired in persons with SCI compared to AB controls, one study (Lynch et al. 2000) demonstrated that continence deteriorates with increasing age in an AB population (N = 467) but does not change with increasing age in persons with SCI (N = 467).This supports a Level 4 study that found that gastrointestinal transit times and colonic dimensions neither change during the first decade nor within the second decade post-SCI (Faaborg et al. 2011). However, a 10-year longitudinal study (Faaborg et al. 2008) suggests persons with SCI do incur an increase in constipation-related symptoms over time. One possible reason for this occurrence is due to the evidence that high amplitude propagating contractions (HAPC) are absent in persons with SCI compared to AB controls (Ancha et al. 2010). HAPC are often associated with colonic mass movements and are thought to be a precursor of bowel evacuation. Thus it is an important factor in the occurrence of difficulty with evacuation post-SCI. Conversely, the need fhat bowel dysfunction worsens over time for persons with SCI but three stor assistance from medications or persons does not change, while fecal incontinence decreases. It may be tudies (Menardo et al. 1987; Krogh et al. 2000; Emmanuel et al. 2009) provide evidence that level of injury plays a primary role in the extent of bowel dysfunction. At this time, the SCI evidence on aging and the gastrointestinal system is limited, but attention to bowel symptoms should be incorporated into routine follow-up procedures and education (Charlifue & Lammertse 2002).
There is Level 4 evidence (Viera et al. 1986; DeWire et al. 1992; MacDiarmid et al. 1995; Sekar et al. 1997) that there are no differences in renal functioning up to 4 YPI using various bladder management techniques with some decline occurring beyond that time.
There is Level 4 evidence (Lamid 1988) that repeated episodes of vesicoureteral reflux can cause kidney damage as early as four YPI in some persons with SCI.
There is Level 4 evidence (Sekar et al. 1997) that renal plasma flow declines until 10 YPI after SCI, at which time a slight reversal occurs.
There is Level 5 evidence (Kuhlemeier et al. 1984b) that suggests age of SCI onset may be an important factor related to renal function, with persons with SCI who are under 20 and older than 50 having comparable renal function to AB controls, whereas persons between those ages have impaired functioning compared to the general population.
There is Level 5 evidence (Lynch et al. 2000) demonstrating a deterioration in bowel continence with increasing age in an AB population but no change with age in persons with SCI.
There is Level 4 evidence (Faaborg et al. 2008) suggesting persons with SCI do incur an increase in constipation-related symptoms and decrease in fecal incontincence over time.
There is Level 4 evidence (Faaborg et al. 2011) that gastrointestinal transit times and colonic dimensions do not change over time in persons with SCI.
There is Level 5 evidence from three studies (Menardo et al. 1987; Krogh et al. 2000; Emmanuel et al. 2009) that level of injury, and not necessarily age or YPI, plays a primary role in the extent of bowel dysfunction.
Various bladder management techniques (indwelling catheterization versus intermittent catheterization) may not impact renal functioning in persons with SCI over time.
Repeated episodes of vesicoureteral reflux can cause kidney damage as early as four years post-injury.
After SCI, renal plasma flow declines until 10 years post-injury, at which time, a slight reversal occurs.
Age of onset may play a role in minimizing renal decline, with adults who are under 20 and older than 50 having comparable renal functioning to the able-bodied population, while those between those ages have impaired functioning.
Bowel incontinence increased with age in the able-bodied population but does not change in persons with SCI.
Persons with SCI may experience an increase in constipation-related symptoms and decrease in fecal incontinence over time.
Level of injury, and not age or years post-injury, plays a primary role in the extent of bowel dysfunction.